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IABSD.fr/src/usr.bin/ssh/sshkey.c

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  • Author : markus
    Date : 2020-06-24 15:07:33
    Hash : 727cc923
    Message : only call sshkey_xmss_init() once for KEY_XMSS_CERT; ok djm

  • usr.bin/ssh/sshkey.c
  • /* $OpenBSD: sshkey.c,v 1.110 2020/06/24 15:07:33 markus Exp $ */
    /*
     * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
     * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
     * Copyright (c) 2010,2011 Damien Miller.  All rights reserved.
     *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     */
    
    #include <sys/types.h>
    #include <netinet/in.h>
    
    #ifdef WITH_OPENSSL
    #include <openssl/evp.h>
    #include <openssl/err.h>
    #include <openssl/pem.h>
    #endif
    
    #include "crypto_api.h"
    
    #include <errno.h>
    #include <stdio.h>
    #include <string.h>
    #include <util.h>
    #include <limits.h>
    #include <resolv.h>
    
    #include "ssh2.h"
    #include "ssherr.h"
    #include "misc.h"
    #include "sshbuf.h"
    #include "cipher.h"
    #include "digest.h"
    #define SSHKEY_INTERNAL
    #include "sshkey.h"
    #include "match.h"
    #include "ssh-sk.h"
    
    #ifdef WITH_XMSS
    #include "sshkey-xmss.h"
    #include "xmss_fast.h"
    #endif
    
    /* openssh private key file format */
    #define MARK_BEGIN		"-----BEGIN OPENSSH PRIVATE KEY-----\n"
    #define MARK_END		"-----END OPENSSH PRIVATE KEY-----\n"
    #define MARK_BEGIN_LEN		(sizeof(MARK_BEGIN) - 1)
    #define MARK_END_LEN		(sizeof(MARK_END) - 1)
    #define KDFNAME			"bcrypt"
    #define AUTH_MAGIC		"openssh-key-v1"
    #define SALT_LEN		16
    #define DEFAULT_CIPHERNAME	"aes256-ctr"
    #define	DEFAULT_ROUNDS		16
    
    /* Version identification string for SSH v1 identity files. */
    #define LEGACY_BEGIN		"SSH PRIVATE KEY FILE FORMAT 1.1\n"
    
    /*
     * Constants relating to "shielding" support; protection of keys expected
     * to remain in memory for long durations
     */
    #define SSHKEY_SHIELD_PREKEY_LEN	(16 * 1024)
    #define SSHKEY_SHIELD_CIPHER		"aes256-ctr" /* XXX want AES-EME* */
    #define SSHKEY_SHIELD_PREKEY_HASH	SSH_DIGEST_SHA512
    
    int	sshkey_private_serialize_opt(struct sshkey *key,
        struct sshbuf *buf, enum sshkey_serialize_rep);
    static int sshkey_from_blob_internal(struct sshbuf *buf,
        struct sshkey **keyp, int allow_cert);
    
    /* Supported key types */
    struct keytype {
    	const char *name;
    	const char *shortname;
    	const char *sigalg;
    	int type;
    	int nid;
    	int cert;
    	int sigonly;
    };
    static const struct keytype keytypes[] = {
    	{ "ssh-ed25519", "ED25519", NULL, KEY_ED25519, 0, 0, 0 },
    	{ "ssh-ed25519-cert-v01@openssh.com", "ED25519-CERT", NULL,
    	    KEY_ED25519_CERT, 0, 1, 0 },
    	{ "sk-ssh-ed25519@openssh.com", "ED25519-SK", NULL,
    	    KEY_ED25519_SK, 0, 0, 0 },
    	{ "sk-ssh-ed25519-cert-v01@openssh.com", "ED25519-SK-CERT", NULL,
    	    KEY_ED25519_SK_CERT, 0, 1, 0 },
    #ifdef WITH_XMSS
    	{ "ssh-xmss@openssh.com", "XMSS", NULL, KEY_XMSS, 0, 0, 0 },
    	{ "ssh-xmss-cert-v01@openssh.com", "XMSS-CERT", NULL,
    	    KEY_XMSS_CERT, 0, 1, 0 },
    #endif /* WITH_XMSS */
    #ifdef WITH_OPENSSL
    	{ "ssh-rsa", "RSA", NULL, KEY_RSA, 0, 0, 0 },
    	{ "rsa-sha2-256", "RSA", NULL, KEY_RSA, 0, 0, 1 },
    	{ "rsa-sha2-512", "RSA", NULL, KEY_RSA, 0, 0, 1 },
    	{ "ssh-dss", "DSA", NULL, KEY_DSA, 0, 0, 0 },
    	{ "ecdsa-sha2-nistp256", "ECDSA", NULL,
    	    KEY_ECDSA, NID_X9_62_prime256v1, 0, 0 },
    	{ "ecdsa-sha2-nistp384", "ECDSA", NULL,
    	    KEY_ECDSA, NID_secp384r1, 0, 0 },
    	{ "ecdsa-sha2-nistp521", "ECDSA", NULL,
    	    KEY_ECDSA, NID_secp521r1, 0, 0 },
    	{ "sk-ecdsa-sha2-nistp256@openssh.com", "ECDSA-SK", NULL,
    	    KEY_ECDSA_SK, NID_X9_62_prime256v1, 0, 0 },
    	{ "webauthn-sk-ecdsa-sha2-nistp256@openssh.com", "ECDSA-SK", NULL,
    	    KEY_ECDSA_SK, NID_X9_62_prime256v1, 0, 1 },
    	{ "ssh-rsa-cert-v01@openssh.com", "RSA-CERT", NULL,
    	    KEY_RSA_CERT, 0, 1, 0 },
    	{ "rsa-sha2-256-cert-v01@openssh.com", "RSA-CERT",
    	    "rsa-sha2-256", KEY_RSA_CERT, 0, 1, 1 },
    	{ "rsa-sha2-512-cert-v01@openssh.com", "RSA-CERT",
    	    "rsa-sha2-512", KEY_RSA_CERT, 0, 1, 1 },
    	{ "ssh-dss-cert-v01@openssh.com", "DSA-CERT", NULL,
    	    KEY_DSA_CERT, 0, 1, 0 },
    	{ "ecdsa-sha2-nistp256-cert-v01@openssh.com", "ECDSA-CERT", NULL,
    	    KEY_ECDSA_CERT, NID_X9_62_prime256v1, 1, 0 },
    	{ "ecdsa-sha2-nistp384-cert-v01@openssh.com", "ECDSA-CERT", NULL,
    	    KEY_ECDSA_CERT, NID_secp384r1, 1, 0 },
    	{ "ecdsa-sha2-nistp521-cert-v01@openssh.com", "ECDSA-CERT", NULL,
    	   KEY_ECDSA_CERT, NID_secp521r1, 1, 0 },
    	{ "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com", "ECDSA-SK-CERT", NULL,
    	    KEY_ECDSA_SK_CERT, NID_X9_62_prime256v1, 1, 0 },
    #endif /* WITH_OPENSSL */
    	{ NULL, NULL, NULL, -1, -1, 0, 0 }
    };
    
    const char *
    sshkey_type(const struct sshkey *k)
    {
    	const struct keytype *kt;
    
    	for (kt = keytypes; kt->type != -1; kt++) {
    		if (kt->type == k->type)
    			return kt->shortname;
    	}
    	return "unknown";
    }
    
    static const char *
    sshkey_ssh_name_from_type_nid(int type, int nid)
    {
    	const struct keytype *kt;
    
    	for (kt = keytypes; kt->type != -1; kt++) {
    		if (kt->type == type && (kt->nid == 0 || kt->nid == nid))
    			return kt->name;
    	}
    	return "ssh-unknown";
    }
    
    int
    sshkey_type_is_cert(int type)
    {
    	const struct keytype *kt;
    
    	for (kt = keytypes; kt->type != -1; kt++) {
    		if (kt->type == type)
    			return kt->cert;
    	}
    	return 0;
    }
    
    const char *
    sshkey_ssh_name(const struct sshkey *k)
    {
    	return sshkey_ssh_name_from_type_nid(k->type, k->ecdsa_nid);
    }
    
    const char *
    sshkey_ssh_name_plain(const struct sshkey *k)
    {
    	return sshkey_ssh_name_from_type_nid(sshkey_type_plain(k->type),
    	    k->ecdsa_nid);
    }
    
    int
    sshkey_type_from_name(const char *name)
    {
    	const struct keytype *kt;
    
    	for (kt = keytypes; kt->type != -1; kt++) {
    		/* Only allow shortname matches for plain key types */
    		if ((kt->name != NULL && strcmp(name, kt->name) == 0) ||
    		    (!kt->cert && strcasecmp(kt->shortname, name) == 0))
    			return kt->type;
    	}
    	return KEY_UNSPEC;
    }
    
    static int
    key_type_is_ecdsa_variant(int type)
    {
    	switch (type) {
    	case KEY_ECDSA:
    	case KEY_ECDSA_CERT:
    	case KEY_ECDSA_SK:
    	case KEY_ECDSA_SK_CERT:
    		return 1;
    	}
    	return 0;
    }
    
    int
    sshkey_ecdsa_nid_from_name(const char *name)
    {
    	const struct keytype *kt;
    
    	for (kt = keytypes; kt->type != -1; kt++) {
    		if (!key_type_is_ecdsa_variant(kt->type))
    			continue;
    		if (kt->name != NULL && strcmp(name, kt->name) == 0)
    			return kt->nid;
    	}
    	return -1;
    }
    
    char *
    sshkey_alg_list(int certs_only, int plain_only, int include_sigonly, char sep)
    {
    	char *tmp, *ret = NULL;
    	size_t nlen, rlen = 0;
    	const struct keytype *kt;
    
    	for (kt = keytypes; kt->type != -1; kt++) {
    		if (kt->name == NULL)
    			continue;
    		if (!include_sigonly && kt->sigonly)
    			continue;
    		if ((certs_only && !kt->cert) || (plain_only && kt->cert))
    			continue;
    		if (ret != NULL)
    			ret[rlen++] = sep;
    		nlen = strlen(kt->name);
    		if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) {
    			free(ret);
    			return NULL;
    		}
    		ret = tmp;
    		memcpy(ret + rlen, kt->name, nlen + 1);
    		rlen += nlen;
    	}
    	return ret;
    }
    
    int
    sshkey_names_valid2(const char *names, int allow_wildcard)
    {
    	char *s, *cp, *p;
    	const struct keytype *kt;
    	int type;
    
    	if (names == NULL || strcmp(names, "") == 0)
    		return 0;
    	if ((s = cp = strdup(names)) == NULL)
    		return 0;
    	for ((p = strsep(&cp, ",")); p && *p != '\0';
    	    (p = strsep(&cp, ","))) {
    		type = sshkey_type_from_name(p);
    		if (type == KEY_UNSPEC) {
    			if (allow_wildcard) {
    				/*
    				 * Try matching key types against the string.
    				 * If any has a positive or negative match then
    				 * the component is accepted.
    				 */
    				for (kt = keytypes; kt->type != -1; kt++) {
    					if (match_pattern_list(kt->name,
    					    p, 0) != 0)
    						break;
    				}
    				if (kt->type != -1)
    					continue;
    			}
    			free(s);
    			return 0;
    		}
    	}
    	free(s);
    	return 1;
    }
    
    u_int
    sshkey_size(const struct sshkey *k)
    {
    #ifdef WITH_OPENSSL
    	const BIGNUM *rsa_n, *dsa_p;
    #endif /* WITH_OPENSSL */
    
    	switch (k->type) {
    #ifdef WITH_OPENSSL
    	case KEY_RSA:
    	case KEY_RSA_CERT:
    		if (k->rsa == NULL)
    			return 0;
    		RSA_get0_key(k->rsa, &rsa_n, NULL, NULL);
    		return BN_num_bits(rsa_n);
    	case KEY_DSA:
    	case KEY_DSA_CERT:
    		if (k->dsa == NULL)
    			return 0;
    		DSA_get0_pqg(k->dsa, &dsa_p, NULL, NULL);
    		return BN_num_bits(dsa_p);
    	case KEY_ECDSA:
    	case KEY_ECDSA_CERT:
    	case KEY_ECDSA_SK:
    	case KEY_ECDSA_SK_CERT:
    		return sshkey_curve_nid_to_bits(k->ecdsa_nid);
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519:
    	case KEY_ED25519_CERT:
    	case KEY_ED25519_SK:
    	case KEY_ED25519_SK_CERT:
    	case KEY_XMSS:
    	case KEY_XMSS_CERT:
    		return 256;	/* XXX */
    	}
    	return 0;
    }
    
    static int
    sshkey_type_is_valid_ca(int type)
    {
    	switch (type) {
    	case KEY_RSA:
    	case KEY_DSA:
    	case KEY_ECDSA:
    	case KEY_ECDSA_SK:
    	case KEY_ED25519:
    	case KEY_ED25519_SK:
    	case KEY_XMSS:
    		return 1;
    	default:
    		return 0;
    	}
    }
    
    int
    sshkey_is_cert(const struct sshkey *k)
    {
    	if (k == NULL)
    		return 0;
    	return sshkey_type_is_cert(k->type);
    }
    
    int
    sshkey_is_sk(const struct sshkey *k)
    {
    	if (k == NULL)
    		return 0;
    	switch (sshkey_type_plain(k->type)) {
    	case KEY_ECDSA_SK:
    	case KEY_ED25519_SK:
    		return 1;
    	default:
    		return 0;
    	}
    }
    
    /* Return the cert-less equivalent to a certified key type */
    int
    sshkey_type_plain(int type)
    {
    	switch (type) {
    	case KEY_RSA_CERT:
    		return KEY_RSA;
    	case KEY_DSA_CERT:
    		return KEY_DSA;
    	case KEY_ECDSA_CERT:
    		return KEY_ECDSA;
    	case KEY_ECDSA_SK_CERT:
    		return KEY_ECDSA_SK;
    	case KEY_ED25519_CERT:
    		return KEY_ED25519;
    	case KEY_ED25519_SK_CERT:
    		return KEY_ED25519_SK;
    	case KEY_XMSS_CERT:
    		return KEY_XMSS;
    	default:
    		return type;
    	}
    }
    
    #ifdef WITH_OPENSSL
    /* XXX: these are really begging for a table-driven approach */
    int
    sshkey_curve_name_to_nid(const char *name)
    {
    	if (strcmp(name, "nistp256") == 0)
    		return NID_X9_62_prime256v1;
    	else if (strcmp(name, "nistp384") == 0)
    		return NID_secp384r1;
    	else if (strcmp(name, "nistp521") == 0)
    		return NID_secp521r1;
    	else
    		return -1;
    }
    
    u_int
    sshkey_curve_nid_to_bits(int nid)
    {
    	switch (nid) {
    	case NID_X9_62_prime256v1:
    		return 256;
    	case NID_secp384r1:
    		return 384;
    	case NID_secp521r1:
    		return 521;
    	default:
    		return 0;
    	}
    }
    
    int
    sshkey_ecdsa_bits_to_nid(int bits)
    {
    	switch (bits) {
    	case 256:
    		return NID_X9_62_prime256v1;
    	case 384:
    		return NID_secp384r1;
    	case 521:
    		return NID_secp521r1;
    	default:
    		return -1;
    	}
    }
    
    const char *
    sshkey_curve_nid_to_name(int nid)
    {
    	switch (nid) {
    	case NID_X9_62_prime256v1:
    		return "nistp256";
    	case NID_secp384r1:
    		return "nistp384";
    	case NID_secp521r1:
    		return "nistp521";
    	default:
    		return NULL;
    	}
    }
    
    int
    sshkey_ec_nid_to_hash_alg(int nid)
    {
    	int kbits = sshkey_curve_nid_to_bits(nid);
    
    	if (kbits <= 0)
    		return -1;
    
    	/* RFC5656 section 6.2.1 */
    	if (kbits <= 256)
    		return SSH_DIGEST_SHA256;
    	else if (kbits <= 384)
    		return SSH_DIGEST_SHA384;
    	else
    		return SSH_DIGEST_SHA512;
    }
    #endif /* WITH_OPENSSL */
    
    static void
    cert_free(struct sshkey_cert *cert)
    {
    	u_int i;
    
    	if (cert == NULL)
    		return;
    	sshbuf_free(cert->certblob);
    	sshbuf_free(cert->critical);
    	sshbuf_free(cert->extensions);
    	free(cert->key_id);
    	for (i = 0; i < cert->nprincipals; i++)
    		free(cert->principals[i]);
    	free(cert->principals);
    	sshkey_free(cert->signature_key);
    	free(cert->signature_type);
    	freezero(cert, sizeof(*cert));
    }
    
    static struct sshkey_cert *
    cert_new(void)
    {
    	struct sshkey_cert *cert;
    
    	if ((cert = calloc(1, sizeof(*cert))) == NULL)
    		return NULL;
    	if ((cert->certblob = sshbuf_new()) == NULL ||
    	    (cert->critical = sshbuf_new()) == NULL ||
    	    (cert->extensions = sshbuf_new()) == NULL) {
    		cert_free(cert);
    		return NULL;
    	}
    	cert->key_id = NULL;
    	cert->principals = NULL;
    	cert->signature_key = NULL;
    	cert->signature_type = NULL;
    	return cert;
    }
    
    struct sshkey *
    sshkey_new(int type)
    {
    	struct sshkey *k;
    #ifdef WITH_OPENSSL
    	RSA *rsa;
    	DSA *dsa;
    #endif /* WITH_OPENSSL */
    
    	if ((k = calloc(1, sizeof(*k))) == NULL)
    		return NULL;
    	k->type = type;
    	k->ecdsa = NULL;
    	k->ecdsa_nid = -1;
    	k->dsa = NULL;
    	k->rsa = NULL;
    	k->cert = NULL;
    	k->ed25519_sk = NULL;
    	k->ed25519_pk = NULL;
    	k->xmss_sk = NULL;
    	k->xmss_pk = NULL;
    	switch (k->type) {
    #ifdef WITH_OPENSSL
    	case KEY_RSA:
    	case KEY_RSA_CERT:
    		if ((rsa = RSA_new()) == NULL) {
    			free(k);
    			return NULL;
    		}
    		k->rsa = rsa;
    		break;
    	case KEY_DSA:
    	case KEY_DSA_CERT:
    		if ((dsa = DSA_new()) == NULL) {
    			free(k);
    			return NULL;
    		}
    		k->dsa = dsa;
    		break;
    	case KEY_ECDSA:
    	case KEY_ECDSA_CERT:
    	case KEY_ECDSA_SK:
    	case KEY_ECDSA_SK_CERT:
    		/* Cannot do anything until we know the group */
    		break;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519:
    	case KEY_ED25519_CERT:
    	case KEY_ED25519_SK:
    	case KEY_ED25519_SK_CERT:
    	case KEY_XMSS:
    	case KEY_XMSS_CERT:
    		/* no need to prealloc */
    		break;
    	case KEY_UNSPEC:
    		break;
    	default:
    		free(k);
    		return NULL;
    	}
    
    	if (sshkey_is_cert(k)) {
    		if ((k->cert = cert_new()) == NULL) {
    			sshkey_free(k);
    			return NULL;
    		}
    	}
    
    	return k;
    }
    
    void
    sshkey_free(struct sshkey *k)
    {
    	if (k == NULL)
    		return;
    	switch (k->type) {
    #ifdef WITH_OPENSSL
    	case KEY_RSA:
    	case KEY_RSA_CERT:
    		RSA_free(k->rsa);
    		k->rsa = NULL;
    		break;
    	case KEY_DSA:
    	case KEY_DSA_CERT:
    		DSA_free(k->dsa);
    		k->dsa = NULL;
    		break;
    	case KEY_ECDSA_SK:
    	case KEY_ECDSA_SK_CERT:
    		free(k->sk_application);
    		sshbuf_free(k->sk_key_handle);
    		sshbuf_free(k->sk_reserved);
    		/* FALLTHROUGH */
    	case KEY_ECDSA:
    	case KEY_ECDSA_CERT:
    		EC_KEY_free(k->ecdsa);
    		k->ecdsa = NULL;
    		break;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519_SK:
    	case KEY_ED25519_SK_CERT:
    		free(k->sk_application);
    		sshbuf_free(k->sk_key_handle);
    		sshbuf_free(k->sk_reserved);
    		/* FALLTHROUGH */
    	case KEY_ED25519:
    	case KEY_ED25519_CERT:
    		freezero(k->ed25519_pk, ED25519_PK_SZ);
    		k->ed25519_pk = NULL;
    		freezero(k->ed25519_sk, ED25519_SK_SZ);
    		k->ed25519_sk = NULL;
    		break;
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    	case KEY_XMSS_CERT:
    		freezero(k->xmss_pk, sshkey_xmss_pklen(k));
    		k->xmss_pk = NULL;
    		freezero(k->xmss_sk, sshkey_xmss_sklen(k));
    		k->xmss_sk = NULL;
    		sshkey_xmss_free_state(k);
    		free(k->xmss_name);
    		k->xmss_name = NULL;
    		free(k->xmss_filename);
    		k->xmss_filename = NULL;
    		break;
    #endif /* WITH_XMSS */
    	case KEY_UNSPEC:
    		break;
    	default:
    		break;
    	}
    	if (sshkey_is_cert(k))
    		cert_free(k->cert);
    	freezero(k->shielded_private, k->shielded_len);
    	freezero(k->shield_prekey, k->shield_prekey_len);
    	freezero(k, sizeof(*k));
    }
    
    static int
    cert_compare(struct sshkey_cert *a, struct sshkey_cert *b)
    {
    	if (a == NULL && b == NULL)
    		return 1;
    	if (a == NULL || b == NULL)
    		return 0;
    	if (sshbuf_len(a->certblob) != sshbuf_len(b->certblob))
    		return 0;
    	if (timingsafe_bcmp(sshbuf_ptr(a->certblob), sshbuf_ptr(b->certblob),
    	    sshbuf_len(a->certblob)) != 0)
    		return 0;
    	return 1;
    }
    
    /*
     * Compare public portions of key only, allowing comparisons between
     * certificates and plain keys too.
     */
    int
    sshkey_equal_public(const struct sshkey *a, const struct sshkey *b)
    {
    #ifdef WITH_OPENSSL
    	const BIGNUM *rsa_e_a, *rsa_n_a;
    	const BIGNUM *rsa_e_b, *rsa_n_b;
    	const BIGNUM *dsa_p_a, *dsa_q_a, *dsa_g_a, *dsa_pub_key_a;
    	const BIGNUM *dsa_p_b, *dsa_q_b, *dsa_g_b, *dsa_pub_key_b;
    #endif /* WITH_OPENSSL */
    
    	if (a == NULL || b == NULL ||
    	    sshkey_type_plain(a->type) != sshkey_type_plain(b->type))
    		return 0;
    
    	switch (a->type) {
    #ifdef WITH_OPENSSL
    	case KEY_RSA_CERT:
    	case KEY_RSA:
    		if (a->rsa == NULL || b->rsa == NULL)
    			return 0;
    		RSA_get0_key(a->rsa, &rsa_n_a, &rsa_e_a, NULL);
    		RSA_get0_key(b->rsa, &rsa_n_b, &rsa_e_b, NULL);
    		return BN_cmp(rsa_e_a, rsa_e_b) == 0 &&
    		    BN_cmp(rsa_n_a, rsa_n_b) == 0;
    	case KEY_DSA_CERT:
    	case KEY_DSA:
    		if (a->dsa == NULL || b->dsa == NULL)
    			return 0;
    		DSA_get0_pqg(a->dsa, &dsa_p_a, &dsa_q_a, &dsa_g_a);
    		DSA_get0_pqg(b->dsa, &dsa_p_b, &dsa_q_b, &dsa_g_b);
    		DSA_get0_key(a->dsa, &dsa_pub_key_a, NULL);
    		DSA_get0_key(b->dsa, &dsa_pub_key_b, NULL);
    		return BN_cmp(dsa_p_a, dsa_p_b) == 0 &&
    		    BN_cmp(dsa_q_a, dsa_q_b) == 0 &&
    		    BN_cmp(dsa_g_a, dsa_g_b) == 0 &&
    		    BN_cmp(dsa_pub_key_a, dsa_pub_key_b) == 0;
    	case KEY_ECDSA_SK:
    	case KEY_ECDSA_SK_CERT:
    		if (a->sk_application == NULL || b->sk_application == NULL)
    			return 0;
    		if (strcmp(a->sk_application, b->sk_application) != 0)
    			return 0;
    		/* FALLTHROUGH */
    	case KEY_ECDSA_CERT:
    	case KEY_ECDSA:
    		if (a->ecdsa == NULL || b->ecdsa == NULL ||
    		    EC_KEY_get0_public_key(a->ecdsa) == NULL ||
    		    EC_KEY_get0_public_key(b->ecdsa) == NULL)
    			return 0;
    		if (EC_GROUP_cmp(EC_KEY_get0_group(a->ecdsa),
    		    EC_KEY_get0_group(b->ecdsa), NULL) != 0 ||
    		    EC_POINT_cmp(EC_KEY_get0_group(a->ecdsa),
    		    EC_KEY_get0_public_key(a->ecdsa),
    		    EC_KEY_get0_public_key(b->ecdsa), NULL) != 0)
    			return 0;
    		return 1;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519_SK:
    	case KEY_ED25519_SK_CERT:
    		if (a->sk_application == NULL || b->sk_application == NULL)
    			return 0;
    		if (strcmp(a->sk_application, b->sk_application) != 0)
    			return 0;
    		/* FALLTHROUGH */
    	case KEY_ED25519:
    	case KEY_ED25519_CERT:
    		return a->ed25519_pk != NULL && b->ed25519_pk != NULL &&
    		    memcmp(a->ed25519_pk, b->ed25519_pk, ED25519_PK_SZ) == 0;
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    	case KEY_XMSS_CERT:
    		return a->xmss_pk != NULL && b->xmss_pk != NULL &&
    		    sshkey_xmss_pklen(a) == sshkey_xmss_pklen(b) &&
    		    memcmp(a->xmss_pk, b->xmss_pk, sshkey_xmss_pklen(a)) == 0;
    #endif /* WITH_XMSS */
    	default:
    		return 0;
    	}
    	/* NOTREACHED */
    }
    
    int
    sshkey_equal(const struct sshkey *a, const struct sshkey *b)
    {
    	if (a == NULL || b == NULL || a->type != b->type)
    		return 0;
    	if (sshkey_is_cert(a)) {
    		if (!cert_compare(a->cert, b->cert))
    			return 0;
    	}
    	return sshkey_equal_public(a, b);
    }
    
    static int
    to_blob_buf(const struct sshkey *key, struct sshbuf *b, int force_plain,
      enum sshkey_serialize_rep opts)
    {
    	int type, ret = SSH_ERR_INTERNAL_ERROR;
    	const char *typename;
    #ifdef WITH_OPENSSL
    	const BIGNUM *rsa_n, *rsa_e, *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
    #endif /* WITH_OPENSSL */
    
    	if (key == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    
    	if (sshkey_is_cert(key)) {
    		if (key->cert == NULL)
    			return SSH_ERR_EXPECTED_CERT;
    		if (sshbuf_len(key->cert->certblob) == 0)
    			return SSH_ERR_KEY_LACKS_CERTBLOB;
    	}
    	type = force_plain ? sshkey_type_plain(key->type) : key->type;
    	typename = sshkey_ssh_name_from_type_nid(type, key->ecdsa_nid);
    
    	switch (type) {
    #ifdef WITH_OPENSSL
    	case KEY_DSA_CERT:
    	case KEY_ECDSA_CERT:
    	case KEY_ECDSA_SK_CERT:
    	case KEY_RSA_CERT:
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519_CERT:
    	case KEY_ED25519_SK_CERT:
    #ifdef WITH_XMSS
    	case KEY_XMSS_CERT:
    #endif /* WITH_XMSS */
    		/* Use the existing blob */
    		/* XXX modified flag? */
    		if ((ret = sshbuf_putb(b, key->cert->certblob)) != 0)
    			return ret;
    		break;
    #ifdef WITH_OPENSSL
    	case KEY_DSA:
    		if (key->dsa == NULL)
    			return SSH_ERR_INVALID_ARGUMENT;
    		DSA_get0_pqg(key->dsa, &dsa_p, &dsa_q, &dsa_g);
    		DSA_get0_key(key->dsa, &dsa_pub_key, NULL);
    		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
    		    (ret = sshbuf_put_bignum2(b, dsa_p)) != 0 ||
    		    (ret = sshbuf_put_bignum2(b, dsa_q)) != 0 ||
    		    (ret = sshbuf_put_bignum2(b, dsa_g)) != 0 ||
    		    (ret = sshbuf_put_bignum2(b, dsa_pub_key)) != 0)
    			return ret;
    		break;
    	case KEY_ECDSA:
    	case KEY_ECDSA_SK:
    		if (key->ecdsa == NULL)
    			return SSH_ERR_INVALID_ARGUMENT;
    		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
    		    (ret = sshbuf_put_cstring(b,
    		    sshkey_curve_nid_to_name(key->ecdsa_nid))) != 0 ||
    		    (ret = sshbuf_put_eckey(b, key->ecdsa)) != 0)
    			return ret;
    		if (type == KEY_ECDSA_SK) {
    			if ((ret = sshbuf_put_cstring(b,
    			    key->sk_application)) != 0)
    				return ret;
    		}
    		break;
    	case KEY_RSA:
    		if (key->rsa == NULL)
    			return SSH_ERR_INVALID_ARGUMENT;
    		RSA_get0_key(key->rsa, &rsa_n, &rsa_e, NULL);
    		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
    		    (ret = sshbuf_put_bignum2(b, rsa_e)) != 0 ||
    		    (ret = sshbuf_put_bignum2(b, rsa_n)) != 0)
    			return ret;
    		break;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519:
    	case KEY_ED25519_SK:
    		if (key->ed25519_pk == NULL)
    			return SSH_ERR_INVALID_ARGUMENT;
    		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
    		    (ret = sshbuf_put_string(b,
    		    key->ed25519_pk, ED25519_PK_SZ)) != 0)
    			return ret;
    		if (type == KEY_ED25519_SK) {
    			if ((ret = sshbuf_put_cstring(b,
    			    key->sk_application)) != 0)
    				return ret;
    		}
    		break;
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    		if (key->xmss_name == NULL || key->xmss_pk == NULL ||
    		    sshkey_xmss_pklen(key) == 0)
    			return SSH_ERR_INVALID_ARGUMENT;
    		if ((ret = sshbuf_put_cstring(b, typename)) != 0 ||
    		    (ret = sshbuf_put_cstring(b, key->xmss_name)) != 0 ||
    		    (ret = sshbuf_put_string(b,
    		    key->xmss_pk, sshkey_xmss_pklen(key))) != 0 ||
    		    (ret = sshkey_xmss_serialize_pk_info(key, b, opts)) != 0)
    			return ret;
    		break;
    #endif /* WITH_XMSS */
    	default:
    		return SSH_ERR_KEY_TYPE_UNKNOWN;
    	}
    	return 0;
    }
    
    int
    sshkey_putb(const struct sshkey *key, struct sshbuf *b)
    {
    	return to_blob_buf(key, b, 0, SSHKEY_SERIALIZE_DEFAULT);
    }
    
    int
    sshkey_puts_opts(const struct sshkey *key, struct sshbuf *b,
        enum sshkey_serialize_rep opts)
    {
    	struct sshbuf *tmp;
    	int r;
    
    	if ((tmp = sshbuf_new()) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    	r = to_blob_buf(key, tmp, 0, opts);
    	if (r == 0)
    		r = sshbuf_put_stringb(b, tmp);
    	sshbuf_free(tmp);
    	return r;
    }
    
    int
    sshkey_puts(const struct sshkey *key, struct sshbuf *b)
    {
    	return sshkey_puts_opts(key, b, SSHKEY_SERIALIZE_DEFAULT);
    }
    
    int
    sshkey_putb_plain(const struct sshkey *key, struct sshbuf *b)
    {
    	return to_blob_buf(key, b, 1, SSHKEY_SERIALIZE_DEFAULT);
    }
    
    static int
    to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp, int force_plain,
        enum sshkey_serialize_rep opts)
    {
    	int ret = SSH_ERR_INTERNAL_ERROR;
    	size_t len;
    	struct sshbuf *b = NULL;
    
    	if (lenp != NULL)
    		*lenp = 0;
    	if (blobp != NULL)
    		*blobp = NULL;
    	if ((b = sshbuf_new()) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    	if ((ret = to_blob_buf(key, b, force_plain, opts)) != 0)
    		goto out;
    	len = sshbuf_len(b);
    	if (lenp != NULL)
    		*lenp = len;
    	if (blobp != NULL) {
    		if ((*blobp = malloc(len)) == NULL) {
    			ret = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		memcpy(*blobp, sshbuf_ptr(b), len);
    	}
    	ret = 0;
     out:
    	sshbuf_free(b);
    	return ret;
    }
    
    int
    sshkey_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp)
    {
    	return to_blob(key, blobp, lenp, 0, SSHKEY_SERIALIZE_DEFAULT);
    }
    
    int
    sshkey_plain_to_blob(const struct sshkey *key, u_char **blobp, size_t *lenp)
    {
    	return to_blob(key, blobp, lenp, 1, SSHKEY_SERIALIZE_DEFAULT);
    }
    
    int
    sshkey_fingerprint_raw(const struct sshkey *k, int dgst_alg,
        u_char **retp, size_t *lenp)
    {
    	u_char *blob = NULL, *ret = NULL;
    	size_t blob_len = 0;
    	int r = SSH_ERR_INTERNAL_ERROR;
    
    	if (retp != NULL)
    		*retp = NULL;
    	if (lenp != NULL)
    		*lenp = 0;
    	if (ssh_digest_bytes(dgst_alg) == 0) {
    		r = SSH_ERR_INVALID_ARGUMENT;
    		goto out;
    	}
    	if ((r = to_blob(k, &blob, &blob_len, 1, SSHKEY_SERIALIZE_DEFAULT))
    	    != 0)
    		goto out;
    	if ((ret = calloc(1, SSH_DIGEST_MAX_LENGTH)) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if ((r = ssh_digest_memory(dgst_alg, blob, blob_len,
    	    ret, SSH_DIGEST_MAX_LENGTH)) != 0)
    		goto out;
    	/* success */
    	if (retp != NULL) {
    		*retp = ret;
    		ret = NULL;
    	}
    	if (lenp != NULL)
    		*lenp = ssh_digest_bytes(dgst_alg);
    	r = 0;
     out:
    	free(ret);
    	if (blob != NULL)
    		freezero(blob, blob_len);
    	return r;
    }
    
    static char *
    fingerprint_b64(const char *alg, u_char *dgst_raw, size_t dgst_raw_len)
    {
    	char *ret;
    	size_t plen = strlen(alg) + 1;
    	size_t rlen = ((dgst_raw_len + 2) / 3) * 4 + plen + 1;
    
    	if (dgst_raw_len > 65536 || (ret = calloc(1, rlen)) == NULL)
    		return NULL;
    	strlcpy(ret, alg, rlen);
    	strlcat(ret, ":", rlen);
    	if (dgst_raw_len == 0)
    		return ret;
    	if (b64_ntop(dgst_raw, dgst_raw_len, ret + plen, rlen - plen) == -1) {
    		freezero(ret, rlen);
    		return NULL;
    	}
    	/* Trim padding characters from end */
    	ret[strcspn(ret, "=")] = '\0';
    	return ret;
    }
    
    static char *
    fingerprint_hex(const char *alg, u_char *dgst_raw, size_t dgst_raw_len)
    {
    	char *retval, hex[5];
    	size_t i, rlen = dgst_raw_len * 3 + strlen(alg) + 2;
    
    	if (dgst_raw_len > 65536 || (retval = calloc(1, rlen)) == NULL)
    		return NULL;
    	strlcpy(retval, alg, rlen);
    	strlcat(retval, ":", rlen);
    	for (i = 0; i < dgst_raw_len; i++) {
    		snprintf(hex, sizeof(hex), "%s%02x",
    		    i > 0 ? ":" : "", dgst_raw[i]);
    		strlcat(retval, hex, rlen);
    	}
    	return retval;
    }
    
    static char *
    fingerprint_bubblebabble(u_char *dgst_raw, size_t dgst_raw_len)
    {
    	char vowels[] = { 'a', 'e', 'i', 'o', 'u', 'y' };
    	char consonants[] = { 'b', 'c', 'd', 'f', 'g', 'h', 'k', 'l', 'm',
    	    'n', 'p', 'r', 's', 't', 'v', 'z', 'x' };
    	u_int i, j = 0, rounds, seed = 1;
    	char *retval;
    
    	rounds = (dgst_raw_len / 2) + 1;
    	if ((retval = calloc(rounds, 6)) == NULL)
    		return NULL;
    	retval[j++] = 'x';
    	for (i = 0; i < rounds; i++) {
    		u_int idx0, idx1, idx2, idx3, idx4;
    		if ((i + 1 < rounds) || (dgst_raw_len % 2 != 0)) {
    			idx0 = (((((u_int)(dgst_raw[2 * i])) >> 6) & 3) +
    			    seed) % 6;
    			idx1 = (((u_int)(dgst_raw[2 * i])) >> 2) & 15;
    			idx2 = ((((u_int)(dgst_raw[2 * i])) & 3) +
    			    (seed / 6)) % 6;
    			retval[j++] = vowels[idx0];
    			retval[j++] = consonants[idx1];
    			retval[j++] = vowels[idx2];
    			if ((i + 1) < rounds) {
    				idx3 = (((u_int)(dgst_raw[(2 * i) + 1])) >> 4) & 15;
    				idx4 = (((u_int)(dgst_raw[(2 * i) + 1]))) & 15;
    				retval[j++] = consonants[idx3];
    				retval[j++] = '-';
    				retval[j++] = consonants[idx4];
    				seed = ((seed * 5) +
    				    ((((u_int)(dgst_raw[2 * i])) * 7) +
    				    ((u_int)(dgst_raw[(2 * i) + 1])))) % 36;
    			}
    		} else {
    			idx0 = seed % 6;
    			idx1 = 16;
    			idx2 = seed / 6;
    			retval[j++] = vowels[idx0];
    			retval[j++] = consonants[idx1];
    			retval[j++] = vowels[idx2];
    		}
    	}
    	retval[j++] = 'x';
    	retval[j++] = '\0';
    	return retval;
    }
    
    /*
     * Draw an ASCII-Art representing the fingerprint so human brain can
     * profit from its built-in pattern recognition ability.
     * This technique is called "random art" and can be found in some
     * scientific publications like this original paper:
     *
     * "Hash Visualization: a New Technique to improve Real-World Security",
     * Perrig A. and Song D., 1999, International Workshop on Cryptographic
     * Techniques and E-Commerce (CrypTEC '99)
     * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf
     *
     * The subject came up in a talk by Dan Kaminsky, too.
     *
     * If you see the picture is different, the key is different.
     * If the picture looks the same, you still know nothing.
     *
     * The algorithm used here is a worm crawling over a discrete plane,
     * leaving a trace (augmenting the field) everywhere it goes.
     * Movement is taken from dgst_raw 2bit-wise.  Bumping into walls
     * makes the respective movement vector be ignored for this turn.
     * Graphs are not unambiguous, because circles in graphs can be
     * walked in either direction.
     */
    
    /*
     * Field sizes for the random art.  Have to be odd, so the starting point
     * can be in the exact middle of the picture, and FLDBASE should be >=8 .
     * Else pictures would be too dense, and drawing the frame would
     * fail, too, because the key type would not fit in anymore.
     */
    #define	FLDBASE		8
    #define	FLDSIZE_Y	(FLDBASE + 1)
    #define	FLDSIZE_X	(FLDBASE * 2 + 1)
    static char *
    fingerprint_randomart(const char *alg, u_char *dgst_raw, size_t dgst_raw_len,
        const struct sshkey *k)
    {
    	/*
    	 * Chars to be used after each other every time the worm
    	 * intersects with itself.  Matter of taste.
    	 */
    	char	*augmentation_string = " .o+=*BOX@%&#/^SE";
    	char	*retval, *p, title[FLDSIZE_X], hash[FLDSIZE_X];
    	u_char	 field[FLDSIZE_X][FLDSIZE_Y];
    	size_t	 i, tlen, hlen;
    	u_int	 b;
    	int	 x, y, r;
    	size_t	 len = strlen(augmentation_string) - 1;
    
    	if ((retval = calloc((FLDSIZE_X + 3), (FLDSIZE_Y + 2))) == NULL)
    		return NULL;
    
    	/* initialize field */
    	memset(field, 0, FLDSIZE_X * FLDSIZE_Y * sizeof(char));
    	x = FLDSIZE_X / 2;
    	y = FLDSIZE_Y / 2;
    
    	/* process raw key */
    	for (i = 0; i < dgst_raw_len; i++) {
    		int input;
    		/* each byte conveys four 2-bit move commands */
    		input = dgst_raw[i];
    		for (b = 0; b < 4; b++) {
    			/* evaluate 2 bit, rest is shifted later */
    			x += (input & 0x1) ? 1 : -1;
    			y += (input & 0x2) ? 1 : -1;
    
    			/* assure we are still in bounds */
    			x = MAXIMUM(x, 0);
    			y = MAXIMUM(y, 0);
    			x = MINIMUM(x, FLDSIZE_X - 1);
    			y = MINIMUM(y, FLDSIZE_Y - 1);
    
    			/* augment the field */
    			if (field[x][y] < len - 2)
    				field[x][y]++;
    			input = input >> 2;
    		}
    	}
    
    	/* mark starting point and end point*/
    	field[FLDSIZE_X / 2][FLDSIZE_Y / 2] = len - 1;
    	field[x][y] = len;
    
    	/* assemble title */
    	r = snprintf(title, sizeof(title), "[%s %u]",
    		sshkey_type(k), sshkey_size(k));
    	/* If [type size] won't fit, then try [type]; fits "[ED25519-CERT]" */
    	if (r < 0 || r > (int)sizeof(title))
    		r = snprintf(title, sizeof(title), "[%s]", sshkey_type(k));
    	tlen = (r <= 0) ? 0 : strlen(title);
    
    	/* assemble hash ID. */
    	r = snprintf(hash, sizeof(hash), "[%s]", alg);
    	hlen = (r <= 0) ? 0 : strlen(hash);
    
    	/* output upper border */
    	p = retval;
    	*p++ = '+';
    	for (i = 0; i < (FLDSIZE_X - tlen) / 2; i++)
    		*p++ = '-';
    	memcpy(p, title, tlen);
    	p += tlen;
    	for (i += tlen; i < FLDSIZE_X; i++)
    		*p++ = '-';
    	*p++ = '+';
    	*p++ = '\n';
    
    	/* output content */
    	for (y = 0; y < FLDSIZE_Y; y++) {
    		*p++ = '|';
    		for (x = 0; x < FLDSIZE_X; x++)
    			*p++ = augmentation_string[MINIMUM(field[x][y], len)];
    		*p++ = '|';
    		*p++ = '\n';
    	}
    
    	/* output lower border */
    	*p++ = '+';
    	for (i = 0; i < (FLDSIZE_X - hlen) / 2; i++)
    		*p++ = '-';
    	memcpy(p, hash, hlen);
    	p += hlen;
    	for (i += hlen; i < FLDSIZE_X; i++)
    		*p++ = '-';
    	*p++ = '+';
    
    	return retval;
    }
    
    char *
    sshkey_fingerprint(const struct sshkey *k, int dgst_alg,
        enum sshkey_fp_rep dgst_rep)
    {
    	char *retval = NULL;
    	u_char *dgst_raw;
    	size_t dgst_raw_len;
    
    	if (sshkey_fingerprint_raw(k, dgst_alg, &dgst_raw, &dgst_raw_len) != 0)
    		return NULL;
    	switch (dgst_rep) {
    	case SSH_FP_DEFAULT:
    		if (dgst_alg == SSH_DIGEST_MD5) {
    			retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg),
    			    dgst_raw, dgst_raw_len);
    		} else {
    			retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg),
    			    dgst_raw, dgst_raw_len);
    		}
    		break;
    	case SSH_FP_HEX:
    		retval = fingerprint_hex(ssh_digest_alg_name(dgst_alg),
    		    dgst_raw, dgst_raw_len);
    		break;
    	case SSH_FP_BASE64:
    		retval = fingerprint_b64(ssh_digest_alg_name(dgst_alg),
    		    dgst_raw, dgst_raw_len);
    		break;
    	case SSH_FP_BUBBLEBABBLE:
    		retval = fingerprint_bubblebabble(dgst_raw, dgst_raw_len);
    		break;
    	case SSH_FP_RANDOMART:
    		retval = fingerprint_randomart(ssh_digest_alg_name(dgst_alg),
    		    dgst_raw, dgst_raw_len, k);
    		break;
    	default:
    		freezero(dgst_raw, dgst_raw_len);
    		return NULL;
    	}
    	freezero(dgst_raw, dgst_raw_len);
    	return retval;
    }
    
    static int
    peek_type_nid(const char *s, size_t l, int *nid)
    {
    	const struct keytype *kt;
    
    	for (kt = keytypes; kt->type != -1; kt++) {
    		if (kt->name == NULL || strlen(kt->name) != l)
    			continue;
    		if (memcmp(s, kt->name, l) == 0) {
    			*nid = -1;
    			if (key_type_is_ecdsa_variant(kt->type))
    				*nid = kt->nid;
    			return kt->type;
    		}
    	}
    	return KEY_UNSPEC;
    }
    
    
    /* XXX this can now be made const char * */
    int
    sshkey_read(struct sshkey *ret, char **cpp)
    {
    	struct sshkey *k;
    	char *cp, *blobcopy;
    	size_t space;
    	int r, type, curve_nid = -1;
    	struct sshbuf *blob;
    
    	if (ret == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    
    	switch (ret->type) {
    	case KEY_UNSPEC:
    	case KEY_RSA:
    	case KEY_DSA:
    	case KEY_ECDSA:
    	case KEY_ECDSA_SK:
    	case KEY_ED25519:
    	case KEY_ED25519_SK:
    	case KEY_DSA_CERT:
    	case KEY_ECDSA_CERT:
    	case KEY_ECDSA_SK_CERT:
    	case KEY_RSA_CERT:
    	case KEY_ED25519_CERT:
    	case KEY_ED25519_SK_CERT:
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    	case KEY_XMSS_CERT:
    #endif /* WITH_XMSS */
    		break; /* ok */
    	default:
    		return SSH_ERR_INVALID_ARGUMENT;
    	}
    
    	/* Decode type */
    	cp = *cpp;
    	space = strcspn(cp, " \t");
    	if (space == strlen(cp))
    		return SSH_ERR_INVALID_FORMAT;
    	if ((type = peek_type_nid(cp, space, &curve_nid)) == KEY_UNSPEC)
    		return SSH_ERR_INVALID_FORMAT;
    
    	/* skip whitespace */
    	for (cp += space; *cp == ' ' || *cp == '\t'; cp++)
    		;
    	if (*cp == '\0')
    		return SSH_ERR_INVALID_FORMAT;
    	if (ret->type != KEY_UNSPEC && ret->type != type)
    		return SSH_ERR_KEY_TYPE_MISMATCH;
    	if ((blob = sshbuf_new()) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    
    	/* find end of keyblob and decode */
    	space = strcspn(cp, " \t");
    	if ((blobcopy = strndup(cp, space)) == NULL) {
    		sshbuf_free(blob);
    		return SSH_ERR_ALLOC_FAIL;
    	}
    	if ((r = sshbuf_b64tod(blob, blobcopy)) != 0) {
    		free(blobcopy);
    		sshbuf_free(blob);
    		return r;
    	}
    	free(blobcopy);
    	if ((r = sshkey_fromb(blob, &k)) != 0) {
    		sshbuf_free(blob);
    		return r;
    	}
    	sshbuf_free(blob);
    
    	/* skip whitespace and leave cp at start of comment */
    	for (cp += space; *cp == ' ' || *cp == '\t'; cp++)
    		;
    
    	/* ensure type of blob matches type at start of line */
    	if (k->type != type) {
    		sshkey_free(k);
    		return SSH_ERR_KEY_TYPE_MISMATCH;
    	}
    	if (key_type_is_ecdsa_variant(type) && curve_nid != k->ecdsa_nid) {
    		sshkey_free(k);
    		return SSH_ERR_EC_CURVE_MISMATCH;
    	}
    
    	/* Fill in ret from parsed key */
    	ret->type = type;
    	if (sshkey_is_cert(ret)) {
    		if (!sshkey_is_cert(k)) {
    			sshkey_free(k);
    			return SSH_ERR_EXPECTED_CERT;
    		}
    		if (ret->cert != NULL)
    			cert_free(ret->cert);
    		ret->cert = k->cert;
    		k->cert = NULL;
    	}
    	switch (sshkey_type_plain(ret->type)) {
    #ifdef WITH_OPENSSL
    	case KEY_RSA:
    		RSA_free(ret->rsa);
    		ret->rsa = k->rsa;
    		k->rsa = NULL;
    #ifdef DEBUG_PK
    		RSA_print_fp(stderr, ret->rsa, 8);
    #endif
    		break;
    	case KEY_DSA:
    		DSA_free(ret->dsa);
    		ret->dsa = k->dsa;
    		k->dsa = NULL;
    #ifdef DEBUG_PK
    		DSA_print_fp(stderr, ret->dsa, 8);
    #endif
    		break;
    	case KEY_ECDSA:
    		EC_KEY_free(ret->ecdsa);
    		ret->ecdsa = k->ecdsa;
    		ret->ecdsa_nid = k->ecdsa_nid;
    		k->ecdsa = NULL;
    		k->ecdsa_nid = -1;
    #ifdef DEBUG_PK
    		sshkey_dump_ec_key(ret->ecdsa);
    #endif
    		break;
    	case KEY_ECDSA_SK:
    		EC_KEY_free(ret->ecdsa);
    		ret->ecdsa = k->ecdsa;
    		ret->ecdsa_nid = k->ecdsa_nid;
    		ret->sk_application = k->sk_application;
    		k->ecdsa = NULL;
    		k->ecdsa_nid = -1;
    		k->sk_application = NULL;
    #ifdef DEBUG_PK
    		sshkey_dump_ec_key(ret->ecdsa);
    		fprintf(stderr, "App: %s\n", ret->sk_application);
    #endif
    		break;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519:
    		freezero(ret->ed25519_pk, ED25519_PK_SZ);
    		ret->ed25519_pk = k->ed25519_pk;
    		k->ed25519_pk = NULL;
    #ifdef DEBUG_PK
    		/* XXX */
    #endif
    		break;
    	case KEY_ED25519_SK:
    		freezero(ret->ed25519_pk, ED25519_PK_SZ);
    		ret->ed25519_pk = k->ed25519_pk;
    		ret->sk_application = k->sk_application;
    		k->ed25519_pk = NULL;
    		k->sk_application = NULL;
    		break;
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    		free(ret->xmss_pk);
    		ret->xmss_pk = k->xmss_pk;
    		k->xmss_pk = NULL;
    		free(ret->xmss_state);
    		ret->xmss_state = k->xmss_state;
    		k->xmss_state = NULL;
    		free(ret->xmss_name);
    		ret->xmss_name = k->xmss_name;
    		k->xmss_name = NULL;
    		free(ret->xmss_filename);
    		ret->xmss_filename = k->xmss_filename;
    		k->xmss_filename = NULL;
    #ifdef DEBUG_PK
    		/* XXX */
    #endif
    		break;
    #endif /* WITH_XMSS */
    	default:
    		sshkey_free(k);
    		return SSH_ERR_INTERNAL_ERROR;
    	}
    	sshkey_free(k);
    
    	/* success */
    	*cpp = cp;
    	return 0;
    }
    
    int
    sshkey_to_base64(const struct sshkey *key, char **b64p)
    {
    	int r = SSH_ERR_INTERNAL_ERROR;
    	struct sshbuf *b = NULL;
    	char *uu = NULL;
    
    	if (b64p != NULL)
    		*b64p = NULL;
    	if ((b = sshbuf_new()) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    	if ((r = sshkey_putb(key, b)) != 0)
    		goto out;
    	if ((uu = sshbuf_dtob64_string(b, 0)) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	/* Success */
    	if (b64p != NULL) {
    		*b64p = uu;
    		uu = NULL;
    	}
    	r = 0;
     out:
    	sshbuf_free(b);
    	free(uu);
    	return r;
    }
    
    int
    sshkey_format_text(const struct sshkey *key, struct sshbuf *b)
    {
    	int r = SSH_ERR_INTERNAL_ERROR;
    	char *uu = NULL;
    
    	if ((r = sshkey_to_base64(key, &uu)) != 0)
    		goto out;
    	if ((r = sshbuf_putf(b, "%s %s",
    	    sshkey_ssh_name(key), uu)) != 0)
    		goto out;
    	r = 0;
     out:
    	free(uu);
    	return r;
    }
    
    int
    sshkey_write(const struct sshkey *key, FILE *f)
    {
    	struct sshbuf *b = NULL;
    	int r = SSH_ERR_INTERNAL_ERROR;
    
    	if ((b = sshbuf_new()) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    	if ((r = sshkey_format_text(key, b)) != 0)
    		goto out;
    	if (fwrite(sshbuf_ptr(b), sshbuf_len(b), 1, f) != 1) {
    		if (feof(f))
    			errno = EPIPE;
    		r = SSH_ERR_SYSTEM_ERROR;
    		goto out;
    	}
    	/* Success */
    	r = 0;
     out:
    	sshbuf_free(b);
    	return r;
    }
    
    const char *
    sshkey_cert_type(const struct sshkey *k)
    {
    	switch (k->cert->type) {
    	case SSH2_CERT_TYPE_USER:
    		return "user";
    	case SSH2_CERT_TYPE_HOST:
    		return "host";
    	default:
    		return "unknown";
    	}
    }
    
    #ifdef WITH_OPENSSL
    static int
    rsa_generate_private_key(u_int bits, RSA **rsap)
    {
    	RSA *private = NULL;
    	BIGNUM *f4 = NULL;
    	int ret = SSH_ERR_INTERNAL_ERROR;
    
    	if (rsap == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	if (bits < SSH_RSA_MINIMUM_MODULUS_SIZE ||
    	    bits > SSHBUF_MAX_BIGNUM * 8)
    		return SSH_ERR_KEY_LENGTH;
    	*rsap = NULL;
    	if ((private = RSA_new()) == NULL || (f4 = BN_new()) == NULL) {
    		ret = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if (!BN_set_word(f4, RSA_F4) ||
    	    !RSA_generate_key_ex(private, bits, f4, NULL)) {
    		ret = SSH_ERR_LIBCRYPTO_ERROR;
    		goto out;
    	}
    	*rsap = private;
    	private = NULL;
    	ret = 0;
     out:
    	RSA_free(private);
    	BN_free(f4);
    	return ret;
    }
    
    static int
    dsa_generate_private_key(u_int bits, DSA **dsap)
    {
    	DSA *private;
    	int ret = SSH_ERR_INTERNAL_ERROR;
    
    	if (dsap == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	if (bits != 1024)
    		return SSH_ERR_KEY_LENGTH;
    	if ((private = DSA_new()) == NULL) {
    		ret = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	*dsap = NULL;
    	if (!DSA_generate_parameters_ex(private, bits, NULL, 0, NULL,
    	    NULL, NULL) || !DSA_generate_key(private)) {
    		ret = SSH_ERR_LIBCRYPTO_ERROR;
    		goto out;
    	}
    	*dsap = private;
    	private = NULL;
    	ret = 0;
     out:
    	DSA_free(private);
    	return ret;
    }
    
    int
    sshkey_ecdsa_key_to_nid(EC_KEY *k)
    {
    	EC_GROUP *eg;
    	int nids[] = {
    		NID_X9_62_prime256v1,
    		NID_secp384r1,
    		NID_secp521r1,
    		-1
    	};
    	int nid;
    	u_int i;
    	const EC_GROUP *g = EC_KEY_get0_group(k);
    
    	/*
    	 * The group may be stored in a ASN.1 encoded private key in one of two
    	 * ways: as a "named group", which is reconstituted by ASN.1 object ID
    	 * or explicit group parameters encoded into the key blob. Only the
    	 * "named group" case sets the group NID for us, but we can figure
    	 * it out for the other case by comparing against all the groups that
    	 * are supported.
    	 */
    	if ((nid = EC_GROUP_get_curve_name(g)) > 0)
    		return nid;
    	for (i = 0; nids[i] != -1; i++) {
    		if ((eg = EC_GROUP_new_by_curve_name(nids[i])) == NULL)
    			return -1;
    		if (EC_GROUP_cmp(g, eg, NULL) == 0)
    			break;
    		EC_GROUP_free(eg);
    	}
    	if (nids[i] != -1) {
    		/* Use the group with the NID attached */
    		EC_GROUP_set_asn1_flag(eg, OPENSSL_EC_NAMED_CURVE);
    		if (EC_KEY_set_group(k, eg) != 1) {
    			EC_GROUP_free(eg);
    			return -1;
    		}
    	}
    	return nids[i];
    }
    
    static int
    ecdsa_generate_private_key(u_int bits, int *nid, EC_KEY **ecdsap)
    {
    	EC_KEY *private;
    	int ret = SSH_ERR_INTERNAL_ERROR;
    
    	if (nid == NULL || ecdsap == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	if ((*nid = sshkey_ecdsa_bits_to_nid(bits)) == -1)
    		return SSH_ERR_KEY_LENGTH;
    	*ecdsap = NULL;
    	if ((private = EC_KEY_new_by_curve_name(*nid)) == NULL) {
    		ret = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if (EC_KEY_generate_key(private) != 1) {
    		ret = SSH_ERR_LIBCRYPTO_ERROR;
    		goto out;
    	}
    	EC_KEY_set_asn1_flag(private, OPENSSL_EC_NAMED_CURVE);
    	*ecdsap = private;
    	private = NULL;
    	ret = 0;
     out:
    	EC_KEY_free(private);
    	return ret;
    }
    #endif /* WITH_OPENSSL */
    
    int
    sshkey_generate(int type, u_int bits, struct sshkey **keyp)
    {
    	struct sshkey *k;
    	int ret = SSH_ERR_INTERNAL_ERROR;
    
    	if (keyp == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	*keyp = NULL;
    	if ((k = sshkey_new(KEY_UNSPEC)) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    	switch (type) {
    	case KEY_ED25519:
    		if ((k->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL ||
    		    (k->ed25519_sk = malloc(ED25519_SK_SZ)) == NULL) {
    			ret = SSH_ERR_ALLOC_FAIL;
    			break;
    		}
    		crypto_sign_ed25519_keypair(k->ed25519_pk, k->ed25519_sk);
    		ret = 0;
    		break;
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    		ret = sshkey_xmss_generate_private_key(k, bits);
    		break;
    #endif /* WITH_XMSS */
    #ifdef WITH_OPENSSL
    	case KEY_DSA:
    		ret = dsa_generate_private_key(bits, &k->dsa);
    		break;
    	case KEY_ECDSA:
    		ret = ecdsa_generate_private_key(bits, &k->ecdsa_nid,
    		    &k->ecdsa);
    		break;
    	case KEY_RSA:
    		ret = rsa_generate_private_key(bits, &k->rsa);
    		break;
    #endif /* WITH_OPENSSL */
    	default:
    		ret = SSH_ERR_INVALID_ARGUMENT;
    	}
    	if (ret == 0) {
    		k->type = type;
    		*keyp = k;
    	} else
    		sshkey_free(k);
    	return ret;
    }
    
    int
    sshkey_cert_copy(const struct sshkey *from_key, struct sshkey *to_key)
    {
    	u_int i;
    	const struct sshkey_cert *from;
    	struct sshkey_cert *to;
    	int r = SSH_ERR_INTERNAL_ERROR;
    
    	if (to_key == NULL || (from = from_key->cert) == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    
    	if ((to = cert_new()) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    
    	if ((r = sshbuf_putb(to->certblob, from->certblob)) != 0 ||
    	    (r = sshbuf_putb(to->critical, from->critical)) != 0 ||
    	    (r = sshbuf_putb(to->extensions, from->extensions)) != 0)
    		goto out;
    
    	to->serial = from->serial;
    	to->type = from->type;
    	if (from->key_id == NULL)
    		to->key_id = NULL;
    	else if ((to->key_id = strdup(from->key_id)) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	to->valid_after = from->valid_after;
    	to->valid_before = from->valid_before;
    	if (from->signature_key == NULL)
    		to->signature_key = NULL;
    	else if ((r = sshkey_from_private(from->signature_key,
    	    &to->signature_key)) != 0)
    		goto out;
    	if (from->signature_type != NULL &&
    	    (to->signature_type = strdup(from->signature_type)) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if (from->nprincipals > SSHKEY_CERT_MAX_PRINCIPALS) {
    		r = SSH_ERR_INVALID_ARGUMENT;
    		goto out;
    	}
    	if (from->nprincipals > 0) {
    		if ((to->principals = calloc(from->nprincipals,
    		    sizeof(*to->principals))) == NULL) {
    			r = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		for (i = 0; i < from->nprincipals; i++) {
    			to->principals[i] = strdup(from->principals[i]);
    			if (to->principals[i] == NULL) {
    				to->nprincipals = i;
    				r = SSH_ERR_ALLOC_FAIL;
    				goto out;
    			}
    		}
    	}
    	to->nprincipals = from->nprincipals;
    
    	/* success */
    	cert_free(to_key->cert);
    	to_key->cert = to;
    	to = NULL;
    	r = 0;
     out:
    	cert_free(to);
    	return r;
    }
    
    int
    sshkey_from_private(const struct sshkey *k, struct sshkey **pkp)
    {
    	struct sshkey *n = NULL;
    	int r = SSH_ERR_INTERNAL_ERROR;
    #ifdef WITH_OPENSSL
    	const BIGNUM *rsa_n, *rsa_e;
    	BIGNUM *rsa_n_dup = NULL, *rsa_e_dup = NULL;
    	const BIGNUM *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
    	BIGNUM *dsa_p_dup = NULL, *dsa_q_dup = NULL, *dsa_g_dup = NULL;
    	BIGNUM *dsa_pub_key_dup = NULL;
    #endif /* WITH_OPENSSL */
    
    	*pkp = NULL;
    	if ((n = sshkey_new(k->type)) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	switch (k->type) {
    #ifdef WITH_OPENSSL
    	case KEY_DSA:
    	case KEY_DSA_CERT:
    		DSA_get0_pqg(k->dsa, &dsa_p, &dsa_q, &dsa_g);
    		DSA_get0_key(k->dsa, &dsa_pub_key, NULL);
    		if ((dsa_p_dup = BN_dup(dsa_p)) == NULL ||
    		    (dsa_q_dup = BN_dup(dsa_q)) == NULL ||
    		    (dsa_g_dup = BN_dup(dsa_g)) == NULL ||
    		    (dsa_pub_key_dup = BN_dup(dsa_pub_key)) == NULL) {
    			r = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		if (!DSA_set0_pqg(n->dsa, dsa_p_dup, dsa_q_dup, dsa_g_dup)) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		dsa_p_dup = dsa_q_dup = dsa_g_dup = NULL; /* transferred */
    		if (!DSA_set0_key(n->dsa, dsa_pub_key_dup, NULL)) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		dsa_pub_key_dup = NULL; /* transferred */
    
    		break;
    	case KEY_ECDSA:
    	case KEY_ECDSA_CERT:
    	case KEY_ECDSA_SK:
    	case KEY_ECDSA_SK_CERT:
    		n->ecdsa_nid = k->ecdsa_nid;
    		n->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid);
    		if (n->ecdsa == NULL) {
    			r = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		if (EC_KEY_set_public_key(n->ecdsa,
    		    EC_KEY_get0_public_key(k->ecdsa)) != 1) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		if (k->type != KEY_ECDSA_SK && k->type != KEY_ECDSA_SK_CERT)
    			break;
    		/* Append security-key application string */
    		if ((n->sk_application = strdup(k->sk_application)) == NULL)
    			goto out;
    		break;
    	case KEY_RSA:
    	case KEY_RSA_CERT:
    		RSA_get0_key(k->rsa, &rsa_n, &rsa_e, NULL);
    		if ((rsa_n_dup = BN_dup(rsa_n)) == NULL ||
    		    (rsa_e_dup = BN_dup(rsa_e)) == NULL) {
    			r = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		if (!RSA_set0_key(n->rsa, rsa_n_dup, rsa_e_dup, NULL)) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		rsa_n_dup = rsa_e_dup = NULL; /* transferred */
    		break;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519:
    	case KEY_ED25519_CERT:
    	case KEY_ED25519_SK:
    	case KEY_ED25519_SK_CERT:
    		if (k->ed25519_pk != NULL) {
    			if ((n->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) {
    				r = SSH_ERR_ALLOC_FAIL;
    				goto out;
    			}
    			memcpy(n->ed25519_pk, k->ed25519_pk, ED25519_PK_SZ);
    		}
    		if (k->type != KEY_ED25519_SK &&
    		    k->type != KEY_ED25519_SK_CERT)
    			break;
    		/* Append security-key application string */
    		if ((n->sk_application = strdup(k->sk_application)) == NULL)
    			goto out;
    		break;
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    	case KEY_XMSS_CERT:
    		if ((r = sshkey_xmss_init(n, k->xmss_name)) != 0)
    			goto out;
    		if (k->xmss_pk != NULL) {
    			u_int32_t left;
    			size_t pklen = sshkey_xmss_pklen(k);
    			if (pklen == 0 || sshkey_xmss_pklen(n) != pklen) {
    				r = SSH_ERR_INTERNAL_ERROR;
    				goto out;
    			}
    			if ((n->xmss_pk = malloc(pklen)) == NULL) {
    				r = SSH_ERR_ALLOC_FAIL;
    				goto out;
    			}
    			memcpy(n->xmss_pk, k->xmss_pk, pklen);
    			/* simulate number of signatures left on pubkey */
    			left = sshkey_xmss_signatures_left(k);
    			if (left)
    				sshkey_xmss_enable_maxsign(n, left);
    		}
    		break;
    #endif /* WITH_XMSS */
    	default:
    		r = SSH_ERR_KEY_TYPE_UNKNOWN;
    		goto out;
    	}
    	if (sshkey_is_cert(k) && (r = sshkey_cert_copy(k, n)) != 0)
    		goto out;
    	/* success */
    	*pkp = n;
    	n = NULL;
    	r = 0;
     out:
    	sshkey_free(n);
    #ifdef WITH_OPENSSL
    	BN_clear_free(rsa_n_dup);
    	BN_clear_free(rsa_e_dup);
    	BN_clear_free(dsa_p_dup);
    	BN_clear_free(dsa_q_dup);
    	BN_clear_free(dsa_g_dup);
    	BN_clear_free(dsa_pub_key_dup);
    #endif /* WITH_OPENSSL */
    
    	return r;
    }
    
    int
    sshkey_is_shielded(struct sshkey *k)
    {
    	return k != NULL && k->shielded_private != NULL;
    }
    
    int
    sshkey_shield_private(struct sshkey *k)
    {
    	struct sshbuf *prvbuf = NULL;
    	u_char *prekey = NULL, *enc = NULL, keyiv[SSH_DIGEST_MAX_LENGTH];
    	struct sshcipher_ctx *cctx = NULL;
    	const struct sshcipher *cipher;
    	size_t i, enclen = 0;
    	struct sshkey *kswap = NULL, tmp;
    	int r = SSH_ERR_INTERNAL_ERROR;
    
    #ifdef DEBUG_PK
    	fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k));
    #endif
    	if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) {
    		r = SSH_ERR_INVALID_ARGUMENT;
    		goto out;
    	}
    	if (cipher_keylen(cipher) + cipher_ivlen(cipher) >
    	    ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) {
    		r = SSH_ERR_INTERNAL_ERROR;
    		goto out;
    	}
    
    	/* Prepare a random pre-key, and from it an ephemeral key */
    	if ((prekey = malloc(SSHKEY_SHIELD_PREKEY_LEN)) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	arc4random_buf(prekey, SSHKEY_SHIELD_PREKEY_LEN);
    	if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH,
    	    prekey, SSHKEY_SHIELD_PREKEY_LEN,
    	    keyiv, SSH_DIGEST_MAX_LENGTH)) != 0)
    		goto out;
    #ifdef DEBUG_PK
    	fprintf(stderr, "%s: key+iv\n", __func__);
    	sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH),
    	    stderr);
    #endif
    	if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher),
    	    keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 1)) != 0)
    		goto out;
    
    	/* Serialise and encrypt the private key using the ephemeral key */
    	if ((prvbuf = sshbuf_new()) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if (sshkey_is_shielded(k) && (r = sshkey_unshield_private(k)) != 0)
    		goto out;
    	if ((r = sshkey_private_serialize_opt(k, prvbuf,
    	     SSHKEY_SERIALIZE_SHIELD)) != 0)
    		goto out;
    	/* pad to cipher blocksize */
    	i = 0;
    	while (sshbuf_len(prvbuf) % cipher_blocksize(cipher)) {
    		if ((r = sshbuf_put_u8(prvbuf, ++i & 0xff)) != 0)
    			goto out;
    	}
    #ifdef DEBUG_PK
    	fprintf(stderr, "%s: serialised\n", __func__);
    	sshbuf_dump(prvbuf, stderr);
    #endif
    	/* encrypt */
    	enclen = sshbuf_len(prvbuf);
    	if ((enc = malloc(enclen)) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if ((r = cipher_crypt(cctx, 0, enc,
    	    sshbuf_ptr(prvbuf), sshbuf_len(prvbuf), 0, 0)) != 0)
    		goto out;
    #ifdef DEBUG_PK
    	fprintf(stderr, "%s: encrypted\n", __func__);
    	sshbuf_dump_data(enc, enclen, stderr);
    #endif
    
    	/* Make a scrubbed, public-only copy of our private key argument */
    	if ((r = sshkey_from_private(k, &kswap)) != 0)
    		goto out;
    
    	/* Swap the private key out (it will be destroyed below) */
    	tmp = *kswap;
    	*kswap = *k;
    	*k = tmp;
    
    	/* Insert the shielded key into our argument */
    	k->shielded_private = enc;
    	k->shielded_len = enclen;
    	k->shield_prekey = prekey;
    	k->shield_prekey_len = SSHKEY_SHIELD_PREKEY_LEN;
    	enc = prekey = NULL; /* transferred */
    	enclen = 0;
    
    	/* preserve key fields that are required for correct operation */
    	k->sk_flags = kswap->sk_flags;
    
    	/* success */
    	r = 0;
    
     out:
    	/* XXX behaviour on error - invalidate original private key? */
    	cipher_free(cctx);
    	explicit_bzero(keyiv, sizeof(keyiv));
    	explicit_bzero(&tmp, sizeof(tmp));
    	freezero(enc, enclen);
    	freezero(prekey, SSHKEY_SHIELD_PREKEY_LEN);
    	sshkey_free(kswap);
    	sshbuf_free(prvbuf);
    	return r;
    }
    
    int
    sshkey_unshield_private(struct sshkey *k)
    {
    	struct sshbuf *prvbuf = NULL;
    	u_char pad, *cp, keyiv[SSH_DIGEST_MAX_LENGTH];
    	struct sshcipher_ctx *cctx = NULL;
    	const struct sshcipher *cipher;
    	size_t i;
    	struct sshkey *kswap = NULL, tmp;
    	int r = SSH_ERR_INTERNAL_ERROR;
    
    #ifdef DEBUG_PK
    	fprintf(stderr, "%s: entering for %s\n", __func__, sshkey_ssh_name(k));
    #endif
    	if (!sshkey_is_shielded(k))
    		return 0; /* nothing to do */
    
    	if ((cipher = cipher_by_name(SSHKEY_SHIELD_CIPHER)) == NULL) {
    		r = SSH_ERR_INVALID_ARGUMENT;
    		goto out;
    	}
    	if (cipher_keylen(cipher) + cipher_ivlen(cipher) >
    	    ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH)) {
    		r = SSH_ERR_INTERNAL_ERROR;
    		goto out;
    	}
    	/* check size of shielded key blob */
    	if (k->shielded_len < cipher_blocksize(cipher) ||
    	    (k->shielded_len % cipher_blocksize(cipher)) != 0) {
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    
    	/* Calculate the ephemeral key from the prekey */
    	if ((r = ssh_digest_memory(SSHKEY_SHIELD_PREKEY_HASH,
    	    k->shield_prekey, k->shield_prekey_len,
    	    keyiv, SSH_DIGEST_MAX_LENGTH)) != 0)
    		goto out;
    	if ((r = cipher_init(&cctx, cipher, keyiv, cipher_keylen(cipher),
    	    keyiv + cipher_keylen(cipher), cipher_ivlen(cipher), 0)) != 0)
    		goto out;
    #ifdef DEBUG_PK
    	fprintf(stderr, "%s: key+iv\n", __func__);
    	sshbuf_dump_data(keyiv, ssh_digest_bytes(SSHKEY_SHIELD_PREKEY_HASH),
    	    stderr);
    #endif
    
    	/* Decrypt and parse the shielded private key using the ephemeral key */
    	if ((prvbuf = sshbuf_new()) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if ((r = sshbuf_reserve(prvbuf, k->shielded_len, &cp)) != 0)
    		goto out;
    	/* decrypt */
    #ifdef DEBUG_PK
    	fprintf(stderr, "%s: encrypted\n", __func__);
    	sshbuf_dump_data(k->shielded_private, k->shielded_len, stderr);
    #endif
    	if ((r = cipher_crypt(cctx, 0, cp,
    	    k->shielded_private, k->shielded_len, 0, 0)) != 0)
    		goto out;
    #ifdef DEBUG_PK
    	fprintf(stderr, "%s: serialised\n", __func__);
    	sshbuf_dump(prvbuf, stderr);
    #endif
    	/* Parse private key */
    	if ((r = sshkey_private_deserialize(prvbuf, &kswap)) != 0)
    		goto out;
    	/* Check deterministic padding */
    	i = 0;
    	while (sshbuf_len(prvbuf)) {
    		if ((r = sshbuf_get_u8(prvbuf, &pad)) != 0)
    			goto out;
    		if (pad != (++i & 0xff)) {
    			r = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    	}
    
    	/* Swap the parsed key back into place */
    	tmp = *kswap;
    	*kswap = *k;
    	*k = tmp;
    
    	/* success */
    	r = 0;
    
     out:
    	cipher_free(cctx);
    	explicit_bzero(keyiv, sizeof(keyiv));
    	explicit_bzero(&tmp, sizeof(tmp));
    	sshkey_free(kswap);
    	sshbuf_free(prvbuf);
    	return r;
    }
    
    static int
    cert_parse(struct sshbuf *b, struct sshkey *key, struct sshbuf *certbuf)
    {
    	struct sshbuf *principals = NULL, *crit = NULL;
    	struct sshbuf *exts = NULL, *ca = NULL;
    	u_char *sig = NULL;
    	size_t signed_len = 0, slen = 0, kidlen = 0;
    	int ret = SSH_ERR_INTERNAL_ERROR;
    
    	/* Copy the entire key blob for verification and later serialisation */
    	if ((ret = sshbuf_putb(key->cert->certblob, certbuf)) != 0)
    		return ret;
    
    	/* Parse body of certificate up to signature */
    	if ((ret = sshbuf_get_u64(b, &key->cert->serial)) != 0 ||
    	    (ret = sshbuf_get_u32(b, &key->cert->type)) != 0 ||
    	    (ret = sshbuf_get_cstring(b, &key->cert->key_id, &kidlen)) != 0 ||
    	    (ret = sshbuf_froms(b, &principals)) != 0 ||
    	    (ret = sshbuf_get_u64(b, &key->cert->valid_after)) != 0 ||
    	    (ret = sshbuf_get_u64(b, &key->cert->valid_before)) != 0 ||
    	    (ret = sshbuf_froms(b, &crit)) != 0 ||
    	    (ret = sshbuf_froms(b, &exts)) != 0 ||
    	    (ret = sshbuf_get_string_direct(b, NULL, NULL)) != 0 ||
    	    (ret = sshbuf_froms(b, &ca)) != 0) {
    		/* XXX debug print error for ret */
    		ret = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    
    	/* Signature is left in the buffer so we can calculate this length */
    	signed_len = sshbuf_len(key->cert->certblob) - sshbuf_len(b);
    
    	if ((ret = sshbuf_get_string(b, &sig, &slen)) != 0) {
    		ret = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    
    	if (key->cert->type != SSH2_CERT_TYPE_USER &&
    	    key->cert->type != SSH2_CERT_TYPE_HOST) {
    		ret = SSH_ERR_KEY_CERT_UNKNOWN_TYPE;
    		goto out;
    	}
    
    	/* Parse principals section */
    	while (sshbuf_len(principals) > 0) {
    		char *principal = NULL;
    		char **oprincipals = NULL;
    
    		if (key->cert->nprincipals >= SSHKEY_CERT_MAX_PRINCIPALS) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		if ((ret = sshbuf_get_cstring(principals, &principal,
    		    NULL)) != 0) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		oprincipals = key->cert->principals;
    		key->cert->principals = recallocarray(key->cert->principals,
    		    key->cert->nprincipals, key->cert->nprincipals + 1,
    		    sizeof(*key->cert->principals));
    		if (key->cert->principals == NULL) {
    			free(principal);
    			key->cert->principals = oprincipals;
    			ret = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		key->cert->principals[key->cert->nprincipals++] = principal;
    	}
    
    	/*
    	 * Stash a copies of the critical options and extensions sections
    	 * for later use.
    	 */
    	if ((ret = sshbuf_putb(key->cert->critical, crit)) != 0 ||
    	    (exts != NULL &&
    	    (ret = sshbuf_putb(key->cert->extensions, exts)) != 0))
    		goto out;
    
    	/*
    	 * Validate critical options and extensions sections format.
    	 */
    	while (sshbuf_len(crit) != 0) {
    		if ((ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0 ||
    		    (ret = sshbuf_get_string_direct(crit, NULL, NULL)) != 0) {
    			sshbuf_reset(key->cert->critical);
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    	}
    	while (exts != NULL && sshbuf_len(exts) != 0) {
    		if ((ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0 ||
    		    (ret = sshbuf_get_string_direct(exts, NULL, NULL)) != 0) {
    			sshbuf_reset(key->cert->extensions);
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    	}
    
    	/* Parse CA key and check signature */
    	if (sshkey_from_blob_internal(ca, &key->cert->signature_key, 0) != 0) {
    		ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
    		goto out;
    	}
    	if (!sshkey_type_is_valid_ca(key->cert->signature_key->type)) {
    		ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
    		goto out;
    	}
    	if ((ret = sshkey_verify(key->cert->signature_key, sig, slen,
    	    sshbuf_ptr(key->cert->certblob), signed_len, NULL, 0, NULL)) != 0)
    		goto out;
    	if ((ret = sshkey_get_sigtype(sig, slen,
    	    &key->cert->signature_type)) != 0)
    		goto out;
    
    	/* Success */
    	ret = 0;
     out:
    	sshbuf_free(ca);
    	sshbuf_free(crit);
    	sshbuf_free(exts);
    	sshbuf_free(principals);
    	free(sig);
    	return ret;
    }
    
    #ifdef WITH_OPENSSL
    static int
    check_rsa_length(const RSA *rsa)
    {
    	const BIGNUM *rsa_n;
    
    	RSA_get0_key(rsa, &rsa_n, NULL, NULL);
    	if (BN_num_bits(rsa_n) < SSH_RSA_MINIMUM_MODULUS_SIZE)
    		return SSH_ERR_KEY_LENGTH;
    	return 0;
    }
    #endif /* WITH_OPENSSL */
    
    static int
    sshkey_from_blob_internal(struct sshbuf *b, struct sshkey **keyp,
        int allow_cert)
    {
    	int type, ret = SSH_ERR_INTERNAL_ERROR;
    	char *ktype = NULL, *curve = NULL, *xmss_name = NULL;
    	struct sshkey *key = NULL;
    	size_t len;
    	u_char *pk = NULL;
    	struct sshbuf *copy;
    #ifdef WITH_OPENSSL
    	EC_POINT *q = NULL;
    	BIGNUM *rsa_n = NULL, *rsa_e = NULL;
    	BIGNUM *dsa_p = NULL, *dsa_q = NULL, *dsa_g = NULL, *dsa_pub_key = NULL;
    #endif /* WITH_OPENSSL */
    
    #ifdef DEBUG_PK /* XXX */
    	sshbuf_dump(b, stderr);
    #endif
    	if (keyp != NULL)
    		*keyp = NULL;
    	if ((copy = sshbuf_fromb(b)) == NULL) {
    		ret = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if (sshbuf_get_cstring(b, &ktype, NULL) != 0) {
    		ret = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    
    	type = sshkey_type_from_name(ktype);
    	if (!allow_cert && sshkey_type_is_cert(type)) {
    		ret = SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
    		goto out;
    	}
    	switch (type) {
    #ifdef WITH_OPENSSL
    	case KEY_RSA_CERT:
    		/* Skip nonce */
    		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		/* FALLTHROUGH */
    	case KEY_RSA:
    		if ((key = sshkey_new(type)) == NULL) {
    			ret = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		if (sshbuf_get_bignum2(b, &rsa_e) != 0 ||
    		    sshbuf_get_bignum2(b, &rsa_n) != 0) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		if (!RSA_set0_key(key->rsa, rsa_n, rsa_e, NULL)) {
    			ret = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		rsa_n = rsa_e = NULL; /* transferred */
    		if ((ret = check_rsa_length(key->rsa)) != 0)
    			goto out;
    #ifdef DEBUG_PK
    		RSA_print_fp(stderr, key->rsa, 8);
    #endif
    		break;
    	case KEY_DSA_CERT:
    		/* Skip nonce */
    		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		/* FALLTHROUGH */
    	case KEY_DSA:
    		if ((key = sshkey_new(type)) == NULL) {
    			ret = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		if (sshbuf_get_bignum2(b, &dsa_p) != 0 ||
    		    sshbuf_get_bignum2(b, &dsa_q) != 0 ||
    		    sshbuf_get_bignum2(b, &dsa_g) != 0 ||
    		    sshbuf_get_bignum2(b, &dsa_pub_key) != 0) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		if (!DSA_set0_pqg(key->dsa, dsa_p, dsa_q, dsa_g)) {
    			ret = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		dsa_p = dsa_q = dsa_g = NULL; /* transferred */
    		if (!DSA_set0_key(key->dsa, dsa_pub_key, NULL)) {
    			ret = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		dsa_pub_key = NULL; /* transferred */
    #ifdef DEBUG_PK
    		DSA_print_fp(stderr, key->dsa, 8);
    #endif
    		break;
    	case KEY_ECDSA_CERT:
    	case KEY_ECDSA_SK_CERT:
    		/* Skip nonce */
    		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		/* FALLTHROUGH */
    	case KEY_ECDSA:
    	case KEY_ECDSA_SK:
    		if ((key = sshkey_new(type)) == NULL) {
    			ret = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		key->ecdsa_nid = sshkey_ecdsa_nid_from_name(ktype);
    		if (sshbuf_get_cstring(b, &curve, NULL) != 0) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		if (key->ecdsa_nid != sshkey_curve_name_to_nid(curve)) {
    			ret = SSH_ERR_EC_CURVE_MISMATCH;
    			goto out;
    		}
    		EC_KEY_free(key->ecdsa);
    		if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid))
    		    == NULL) {
    			ret = SSH_ERR_EC_CURVE_INVALID;
    			goto out;
    		}
    		if ((q = EC_POINT_new(EC_KEY_get0_group(key->ecdsa))) == NULL) {
    			ret = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		if (sshbuf_get_ec(b, q, EC_KEY_get0_group(key->ecdsa)) != 0) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		if (sshkey_ec_validate_public(EC_KEY_get0_group(key->ecdsa),
    		    q) != 0) {
    			ret = SSH_ERR_KEY_INVALID_EC_VALUE;
    			goto out;
    		}
    		if (EC_KEY_set_public_key(key->ecdsa, q) != 1) {
    			/* XXX assume it is a allocation error */
    			ret = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    #ifdef DEBUG_PK
    		sshkey_dump_ec_point(EC_KEY_get0_group(key->ecdsa), q);
    #endif
    		if (type == KEY_ECDSA_SK || type == KEY_ECDSA_SK_CERT) {
    			/* Parse additional security-key application string */
    			if (sshbuf_get_cstring(b, &key->sk_application,
    			    NULL) != 0) {
    				ret = SSH_ERR_INVALID_FORMAT;
    				goto out;
    			}
    #ifdef DEBUG_PK
    			fprintf(stderr, "App: %s\n", key->sk_application);
    #endif
    		}
    		break;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519_CERT:
    	case KEY_ED25519_SK_CERT:
    		/* Skip nonce */
    		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		/* FALLTHROUGH */
    	case KEY_ED25519:
    	case KEY_ED25519_SK:
    		if ((ret = sshbuf_get_string(b, &pk, &len)) != 0)
    			goto out;
    		if (len != ED25519_PK_SZ) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		if ((key = sshkey_new(type)) == NULL) {
    			ret = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		if (type == KEY_ED25519_SK || type == KEY_ED25519_SK_CERT) {
    			/* Parse additional security-key application string */
    			if (sshbuf_get_cstring(b, &key->sk_application,
    			    NULL) != 0) {
    				ret = SSH_ERR_INVALID_FORMAT;
    				goto out;
    			}
    #ifdef DEBUG_PK
    			fprintf(stderr, "App: %s\n", key->sk_application);
    #endif
    		}
    		key->ed25519_pk = pk;
    		pk = NULL;
    		break;
    #ifdef WITH_XMSS
    	case KEY_XMSS_CERT:
    		/* Skip nonce */
    		if (sshbuf_get_string_direct(b, NULL, NULL) != 0) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		/* FALLTHROUGH */
    	case KEY_XMSS:
    		if ((ret = sshbuf_get_cstring(b, &xmss_name, NULL)) != 0)
    			goto out;
    		if ((key = sshkey_new(type)) == NULL) {
    			ret = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		if ((ret = sshkey_xmss_init(key, xmss_name)) != 0)
    			goto out;
    		if ((ret = sshbuf_get_string(b, &pk, &len)) != 0)
    			goto out;
    		if (len == 0 || len != sshkey_xmss_pklen(key)) {
    			ret = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		key->xmss_pk = pk;
    		pk = NULL;
    		if (type != KEY_XMSS_CERT &&
    		    (ret = sshkey_xmss_deserialize_pk_info(key, b)) != 0)
    			goto out;
    		break;
    #endif /* WITH_XMSS */
    	case KEY_UNSPEC:
    	default:
    		ret = SSH_ERR_KEY_TYPE_UNKNOWN;
    		goto out;
    	}
    
    	/* Parse certificate potion */
    	if (sshkey_is_cert(key) && (ret = cert_parse(b, key, copy)) != 0)
    		goto out;
    
    	if (key != NULL && sshbuf_len(b) != 0) {
    		ret = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    	ret = 0;
    	if (keyp != NULL) {
    		*keyp = key;
    		key = NULL;
    	}
     out:
    	sshbuf_free(copy);
    	sshkey_free(key);
    	free(xmss_name);
    	free(ktype);
    	free(curve);
    	free(pk);
    #ifdef WITH_OPENSSL
    	EC_POINT_free(q);
    	BN_clear_free(rsa_n);
    	BN_clear_free(rsa_e);
    	BN_clear_free(dsa_p);
    	BN_clear_free(dsa_q);
    	BN_clear_free(dsa_g);
    	BN_clear_free(dsa_pub_key);
    #endif /* WITH_OPENSSL */
    	return ret;
    }
    
    int
    sshkey_from_blob(const u_char *blob, size_t blen, struct sshkey **keyp)
    {
    	struct sshbuf *b;
    	int r;
    
    	if ((b = sshbuf_from(blob, blen)) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    	r = sshkey_from_blob_internal(b, keyp, 1);
    	sshbuf_free(b);
    	return r;
    }
    
    int
    sshkey_fromb(struct sshbuf *b, struct sshkey **keyp)
    {
    	return sshkey_from_blob_internal(b, keyp, 1);
    }
    
    int
    sshkey_froms(struct sshbuf *buf, struct sshkey **keyp)
    {
    	struct sshbuf *b;
    	int r;
    
    	if ((r = sshbuf_froms(buf, &b)) != 0)
    		return r;
    	r = sshkey_from_blob_internal(b, keyp, 1);
    	sshbuf_free(b);
    	return r;
    }
    
    int
    sshkey_get_sigtype(const u_char *sig, size_t siglen, char **sigtypep)
    {
    	int r;
    	struct sshbuf *b = NULL;
    	char *sigtype = NULL;
    
    	if (sigtypep != NULL)
    		*sigtypep = NULL;
    	if ((b = sshbuf_from(sig, siglen)) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    	if ((r = sshbuf_get_cstring(b, &sigtype, NULL)) != 0)
    		goto out;
    	/* success */
    	if (sigtypep != NULL) {
    		*sigtypep = sigtype;
    		sigtype = NULL;
    	}
    	r = 0;
     out:
    	free(sigtype);
    	sshbuf_free(b);
    	return r;
    }
    
    /*
     *
     * Checks whether a certificate's signature type is allowed.
     * Returns 0 (success) if the certificate signature type appears in the
     * "allowed" pattern-list, or the key is not a certificate to begin with.
     * Otherwise returns a ssherr.h code.
     */
    int
    sshkey_check_cert_sigtype(const struct sshkey *key, const char *allowed)
    {
    	if (key == NULL || allowed == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	if (!sshkey_type_is_cert(key->type))
    		return 0;
    	if (key->cert == NULL || key->cert->signature_type == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	if (match_pattern_list(key->cert->signature_type, allowed, 0) != 1)
    		return SSH_ERR_SIGN_ALG_UNSUPPORTED;
    	return 0;
    }
    
    /*
     * Returns the expected signature algorithm for a given public key algorithm.
     */
    const char *
    sshkey_sigalg_by_name(const char *name)
    {
    	const struct keytype *kt;
    
    	for (kt = keytypes; kt->type != -1; kt++) {
    		if (strcmp(kt->name, name) != 0)
    			continue;
    		if (kt->sigalg != NULL)
    			return kt->sigalg;
    		if (!kt->cert)
    			return kt->name;
    		return sshkey_ssh_name_from_type_nid(
    		    sshkey_type_plain(kt->type), kt->nid);
    	}
    	return NULL;
    }
    
    /*
     * Verifies that the signature algorithm appearing inside the signature blob
     * matches that which was requested.
     */
    int
    sshkey_check_sigtype(const u_char *sig, size_t siglen,
        const char *requested_alg)
    {
    	const char *expected_alg;
    	char *sigtype = NULL;
    	int r;
    
    	if (requested_alg == NULL)
    		return 0;
    	if ((expected_alg = sshkey_sigalg_by_name(requested_alg)) == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	if ((r = sshkey_get_sigtype(sig, siglen, &sigtype)) != 0)
    		return r;
    	r = strcmp(expected_alg, sigtype) == 0;
    	free(sigtype);
    	return r ? 0 : SSH_ERR_SIGN_ALG_UNSUPPORTED;
    }
    
    int
    sshkey_sign(struct sshkey *key,
        u_char **sigp, size_t *lenp,
        const u_char *data, size_t datalen,
        const char *alg, const char *sk_provider, u_int compat)
    {
    	int was_shielded = sshkey_is_shielded(key);
    	int r2, r = SSH_ERR_INTERNAL_ERROR;
    
    	if (sigp != NULL)
    		*sigp = NULL;
    	if (lenp != NULL)
    		*lenp = 0;
    	if (datalen > SSH_KEY_MAX_SIGN_DATA_SIZE)
    		return SSH_ERR_INVALID_ARGUMENT;
    	if ((r = sshkey_unshield_private(key)) != 0)
    		return r;
    	switch (key->type) {
    #ifdef WITH_OPENSSL
    	case KEY_DSA_CERT:
    	case KEY_DSA:
    		r = ssh_dss_sign(key, sigp, lenp, data, datalen, compat);
    		break;
    	case KEY_ECDSA_CERT:
    	case KEY_ECDSA:
    		r = ssh_ecdsa_sign(key, sigp, lenp, data, datalen, compat);
    		break;
    	case KEY_RSA_CERT:
    	case KEY_RSA:
    		r = ssh_rsa_sign(key, sigp, lenp, data, datalen, alg);
    		break;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519:
    	case KEY_ED25519_CERT:
    		r = ssh_ed25519_sign(key, sigp, lenp, data, datalen, compat);
    		break;
    	case KEY_ED25519_SK:
    	case KEY_ED25519_SK_CERT:
    	case KEY_ECDSA_SK_CERT:
    	case KEY_ECDSA_SK:
    		r = sshsk_sign(sk_provider, key, sigp, lenp, data,
    		    datalen, compat, /* XXX PIN */ NULL);
    		break;
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    	case KEY_XMSS_CERT:
    		r = ssh_xmss_sign(key, sigp, lenp, data, datalen, compat);
    		break;
    #endif /* WITH_XMSS */
    	default:
    		r = SSH_ERR_KEY_TYPE_UNKNOWN;
    		break;
    	}
    	if (was_shielded && (r2 = sshkey_shield_private(key)) != 0)
    		return r2;
    	return r;
    }
    
    /*
     * ssh_key_verify returns 0 for a correct signature  and < 0 on error.
     * If "alg" specified, then the signature must use that algorithm.
     */
    int
    sshkey_verify(const struct sshkey *key,
        const u_char *sig, size_t siglen,
        const u_char *data, size_t dlen, const char *alg, u_int compat,
        struct sshkey_sig_details **detailsp)
    {
    	if (detailsp != NULL)
    		*detailsp = NULL;
    	if (siglen == 0 || dlen > SSH_KEY_MAX_SIGN_DATA_SIZE)
    		return SSH_ERR_INVALID_ARGUMENT;
    	switch (key->type) {
    #ifdef WITH_OPENSSL
    	case KEY_DSA_CERT:
    	case KEY_DSA:
    		return ssh_dss_verify(key, sig, siglen, data, dlen, compat);
    	case KEY_ECDSA_CERT:
    	case KEY_ECDSA:
    		return ssh_ecdsa_verify(key, sig, siglen, data, dlen, compat);
    	case KEY_ECDSA_SK_CERT:
    	case KEY_ECDSA_SK:
    		return ssh_ecdsa_sk_verify(key, sig, siglen, data, dlen,
    		    compat, detailsp);
    	case KEY_RSA_CERT:
    	case KEY_RSA:
    		return ssh_rsa_verify(key, sig, siglen, data, dlen, alg);
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519:
    	case KEY_ED25519_CERT:
    		return ssh_ed25519_verify(key, sig, siglen, data, dlen, compat);
    	case KEY_ED25519_SK:
    	case KEY_ED25519_SK_CERT:
    		return ssh_ed25519_sk_verify(key, sig, siglen, data, dlen,
    		    compat, detailsp);
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    	case KEY_XMSS_CERT:
    		return ssh_xmss_verify(key, sig, siglen, data, dlen, compat);
    #endif /* WITH_XMSS */
    	default:
    		return SSH_ERR_KEY_TYPE_UNKNOWN;
    	}
    }
    
    /* Convert a plain key to their _CERT equivalent */
    int
    sshkey_to_certified(struct sshkey *k)
    {
    	int newtype;
    
    	switch (k->type) {
    #ifdef WITH_OPENSSL
    	case KEY_RSA:
    		newtype = KEY_RSA_CERT;
    		break;
    	case KEY_DSA:
    		newtype = KEY_DSA_CERT;
    		break;
    	case KEY_ECDSA:
    		newtype = KEY_ECDSA_CERT;
    		break;
    	case KEY_ECDSA_SK:
    		newtype = KEY_ECDSA_SK_CERT;
    		break;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519_SK:
    		newtype = KEY_ED25519_SK_CERT;
    		break;
    	case KEY_ED25519:
    		newtype = KEY_ED25519_CERT;
    		break;
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    		newtype = KEY_XMSS_CERT;
    		break;
    #endif /* WITH_XMSS */
    	default:
    		return SSH_ERR_INVALID_ARGUMENT;
    	}
    	if ((k->cert = cert_new()) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    	k->type = newtype;
    	return 0;
    }
    
    /* Convert a certificate to its raw key equivalent */
    int
    sshkey_drop_cert(struct sshkey *k)
    {
    	if (!sshkey_type_is_cert(k->type))
    		return SSH_ERR_KEY_TYPE_UNKNOWN;
    	cert_free(k->cert);
    	k->cert = NULL;
    	k->type = sshkey_type_plain(k->type);
    	return 0;
    }
    
    /* Sign a certified key, (re-)generating the signed certblob. */
    int
    sshkey_certify_custom(struct sshkey *k, struct sshkey *ca, const char *alg,
        const char *sk_provider, sshkey_certify_signer *signer, void *signer_ctx)
    {
    	struct sshbuf *principals = NULL;
    	u_char *ca_blob = NULL, *sig_blob = NULL, nonce[32];
    	size_t i, ca_len, sig_len;
    	int ret = SSH_ERR_INTERNAL_ERROR;
    	struct sshbuf *cert = NULL;
    	char *sigtype = NULL;
    #ifdef WITH_OPENSSL
    	const BIGNUM *rsa_n, *rsa_e, *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key;
    #endif /* WITH_OPENSSL */
    
    	if (k == NULL || k->cert == NULL ||
    	    k->cert->certblob == NULL || ca == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	if (!sshkey_is_cert(k))
    		return SSH_ERR_KEY_TYPE_UNKNOWN;
    	if (!sshkey_type_is_valid_ca(ca->type))
    		return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
    
    	/*
    	 * If no alg specified as argument but a signature_type was set,
    	 * then prefer that. If both were specified, then they must match.
    	 */
    	if (alg == NULL)
    		alg = k->cert->signature_type;
    	else if (k->cert->signature_type != NULL &&
    	    strcmp(alg, k->cert->signature_type) != 0)
    		return SSH_ERR_INVALID_ARGUMENT;
    
    	/*
    	 * If no signing algorithm or signature_type was specified and we're
    	 * using a RSA key, then default to a good signature algorithm.
    	 */
    	if (alg == NULL && ca->type == KEY_RSA)
    		alg = "rsa-sha2-512";
    
    	if ((ret = sshkey_to_blob(ca, &ca_blob, &ca_len)) != 0)
    		return SSH_ERR_KEY_CERT_INVALID_SIGN_KEY;
    
    	cert = k->cert->certblob; /* for readability */
    	sshbuf_reset(cert);
    	if ((ret = sshbuf_put_cstring(cert, sshkey_ssh_name(k))) != 0)
    		goto out;
    
    	/* -v01 certs put nonce first */
    	arc4random_buf(&nonce, sizeof(nonce));
    	if ((ret = sshbuf_put_string(cert, nonce, sizeof(nonce))) != 0)
    		goto out;
    
    	/* XXX this substantially duplicates to_blob(); refactor */
    	switch (k->type) {
    #ifdef WITH_OPENSSL
    	case KEY_DSA_CERT:
    		DSA_get0_pqg(k->dsa, &dsa_p, &dsa_q, &dsa_g);
    		DSA_get0_key(k->dsa, &dsa_pub_key, NULL);
    		if ((ret = sshbuf_put_bignum2(cert, dsa_p)) != 0 ||
    		    (ret = sshbuf_put_bignum2(cert, dsa_q)) != 0 ||
    		    (ret = sshbuf_put_bignum2(cert, dsa_g)) != 0 ||
    		    (ret = sshbuf_put_bignum2(cert, dsa_pub_key)) != 0)
    			goto out;
    		break;
    	case KEY_ECDSA_CERT:
    	case KEY_ECDSA_SK_CERT:
    		if ((ret = sshbuf_put_cstring(cert,
    		    sshkey_curve_nid_to_name(k->ecdsa_nid))) != 0 ||
    		    (ret = sshbuf_put_ec(cert,
    		    EC_KEY_get0_public_key(k->ecdsa),
    		    EC_KEY_get0_group(k->ecdsa))) != 0)
    			goto out;
    		if (k->type == KEY_ECDSA_SK_CERT) {
    			if ((ret = sshbuf_put_cstring(cert,
    			    k->sk_application)) != 0)
    				goto out;
    		}
    		break;
    	case KEY_RSA_CERT:
    		RSA_get0_key(k->rsa, &rsa_n, &rsa_e, NULL);
    		if ((ret = sshbuf_put_bignum2(cert, rsa_e)) != 0 ||
    		    (ret = sshbuf_put_bignum2(cert, rsa_n)) != 0)
    			goto out;
    		break;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519_CERT:
    	case KEY_ED25519_SK_CERT:
    		if ((ret = sshbuf_put_string(cert,
    		    k->ed25519_pk, ED25519_PK_SZ)) != 0)
    			goto out;
    		if (k->type == KEY_ED25519_SK_CERT) {
    			if ((ret = sshbuf_put_cstring(cert,
    			    k->sk_application)) != 0)
    				goto out;
    		}
    		break;
    #ifdef WITH_XMSS
    	case KEY_XMSS_CERT:
    		if (k->xmss_name == NULL) {
    			ret = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		if ((ret = sshbuf_put_cstring(cert, k->xmss_name)) ||
    		    (ret = sshbuf_put_string(cert,
    		    k->xmss_pk, sshkey_xmss_pklen(k))) != 0)
    			goto out;
    		break;
    #endif /* WITH_XMSS */
    	default:
    		ret = SSH_ERR_INVALID_ARGUMENT;
    		goto out;
    	}
    
    	if ((ret = sshbuf_put_u64(cert, k->cert->serial)) != 0 ||
    	    (ret = sshbuf_put_u32(cert, k->cert->type)) != 0 ||
    	    (ret = sshbuf_put_cstring(cert, k->cert->key_id)) != 0)
    		goto out;
    
    	if ((principals = sshbuf_new()) == NULL) {
    		ret = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	for (i = 0; i < k->cert->nprincipals; i++) {
    		if ((ret = sshbuf_put_cstring(principals,
    		    k->cert->principals[i])) != 0)
    			goto out;
    	}
    	if ((ret = sshbuf_put_stringb(cert, principals)) != 0 ||
    	    (ret = sshbuf_put_u64(cert, k->cert->valid_after)) != 0 ||
    	    (ret = sshbuf_put_u64(cert, k->cert->valid_before)) != 0 ||
    	    (ret = sshbuf_put_stringb(cert, k->cert->critical)) != 0 ||
    	    (ret = sshbuf_put_stringb(cert, k->cert->extensions)) != 0 ||
    	    (ret = sshbuf_put_string(cert, NULL, 0)) != 0 || /* Reserved */
    	    (ret = sshbuf_put_string(cert, ca_blob, ca_len)) != 0)
    		goto out;
    
    	/* Sign the whole mess */
    	if ((ret = signer(ca, &sig_blob, &sig_len, sshbuf_ptr(cert),
    	    sshbuf_len(cert), alg, sk_provider, 0, signer_ctx)) != 0)
    		goto out;
    	/* Check and update signature_type against what was actually used */
    	if ((ret = sshkey_get_sigtype(sig_blob, sig_len, &sigtype)) != 0)
    		goto out;
    	if (alg != NULL && strcmp(alg, sigtype) != 0) {
    		ret = SSH_ERR_SIGN_ALG_UNSUPPORTED;
    		goto out;
    	}
    	if (k->cert->signature_type == NULL) {
    		k->cert->signature_type = sigtype;
    		sigtype = NULL;
    	}
    	/* Append signature and we are done */
    	if ((ret = sshbuf_put_string(cert, sig_blob, sig_len)) != 0)
    		goto out;
    	ret = 0;
     out:
    	if (ret != 0)
    		sshbuf_reset(cert);
    	free(sig_blob);
    	free(ca_blob);
    	free(sigtype);
    	sshbuf_free(principals);
    	return ret;
    }
    
    static int
    default_key_sign(struct sshkey *key, u_char **sigp, size_t *lenp,
        const u_char *data, size_t datalen,
        const char *alg, const char *sk_provider, u_int compat, void *ctx)
    {
    	if (ctx != NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	return sshkey_sign(key, sigp, lenp, data, datalen, alg,
    	    sk_provider, compat);
    }
    
    int
    sshkey_certify(struct sshkey *k, struct sshkey *ca, const char *alg,
        const char *sk_provider)
    {
    	return sshkey_certify_custom(k, ca, alg, sk_provider,
    	    default_key_sign, NULL);
    }
    
    int
    sshkey_cert_check_authority(const struct sshkey *k,
        int want_host, int require_principal,
        const char *name, const char **reason)
    {
    	u_int i, principal_matches;
    	time_t now = time(NULL);
    
    	if (reason == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    
    	if (want_host) {
    		if (k->cert->type != SSH2_CERT_TYPE_HOST) {
    			*reason = "Certificate invalid: not a host certificate";
    			return SSH_ERR_KEY_CERT_INVALID;
    		}
    	} else {
    		if (k->cert->type != SSH2_CERT_TYPE_USER) {
    			*reason = "Certificate invalid: not a user certificate";
    			return SSH_ERR_KEY_CERT_INVALID;
    		}
    	}
    	if (now < 0) {
    		/* yikes - system clock before epoch! */
    		*reason = "Certificate invalid: not yet valid";
    		return SSH_ERR_KEY_CERT_INVALID;
    	}
    	if ((u_int64_t)now < k->cert->valid_after) {
    		*reason = "Certificate invalid: not yet valid";
    		return SSH_ERR_KEY_CERT_INVALID;
    	}
    	if ((u_int64_t)now >= k->cert->valid_before) {
    		*reason = "Certificate invalid: expired";
    		return SSH_ERR_KEY_CERT_INVALID;
    	}
    	if (k->cert->nprincipals == 0) {
    		if (require_principal) {
    			*reason = "Certificate lacks principal list";
    			return SSH_ERR_KEY_CERT_INVALID;
    		}
    	} else if (name != NULL) {
    		principal_matches = 0;
    		for (i = 0; i < k->cert->nprincipals; i++) {
    			if (strcmp(name, k->cert->principals[i]) == 0) {
    				principal_matches = 1;
    				break;
    			}
    		}
    		if (!principal_matches) {
    			*reason = "Certificate invalid: name is not a listed "
    			    "principal";
    			return SSH_ERR_KEY_CERT_INVALID;
    		}
    	}
    	return 0;
    }
    
    size_t
    sshkey_format_cert_validity(const struct sshkey_cert *cert, char *s, size_t l)
    {
    	char from[32], to[32], ret[64];
    	time_t tt;
    	struct tm *tm;
    
    	*from = *to = '\0';
    	if (cert->valid_after == 0 &&
    	    cert->valid_before == 0xffffffffffffffffULL)
    		return strlcpy(s, "forever", l);
    
    	if (cert->valid_after != 0) {
    		/* XXX revisit INT_MAX in 2038 :) */
    		tt = cert->valid_after > INT_MAX ?
    		    INT_MAX : cert->valid_after;
    		tm = localtime(&tt);
    		strftime(from, sizeof(from), "%Y-%m-%dT%H:%M:%S", tm);
    	}
    	if (cert->valid_before != 0xffffffffffffffffULL) {
    		/* XXX revisit INT_MAX in 2038 :) */
    		tt = cert->valid_before > INT_MAX ?
    		    INT_MAX : cert->valid_before;
    		tm = localtime(&tt);
    		strftime(to, sizeof(to), "%Y-%m-%dT%H:%M:%S", tm);
    	}
    
    	if (cert->valid_after == 0)
    		snprintf(ret, sizeof(ret), "before %s", to);
    	else if (cert->valid_before == 0xffffffffffffffffULL)
    		snprintf(ret, sizeof(ret), "after %s", from);
    	else
    		snprintf(ret, sizeof(ret), "from %s to %s", from, to);
    
    	return strlcpy(s, ret, l);
    }
    
    int
    sshkey_private_serialize_opt(struct sshkey *key, struct sshbuf *buf,
        enum sshkey_serialize_rep opts)
    {
    	int r = SSH_ERR_INTERNAL_ERROR;
    	int was_shielded = sshkey_is_shielded(key);
    	struct sshbuf *b = NULL;
    #ifdef WITH_OPENSSL
    	const BIGNUM *rsa_n, *rsa_e, *rsa_d, *rsa_iqmp, *rsa_p, *rsa_q;
    	const BIGNUM *dsa_p, *dsa_q, *dsa_g, *dsa_pub_key, *dsa_priv_key;
    #endif /* WITH_OPENSSL */
    
    	if ((r = sshkey_unshield_private(key)) != 0)
    		return r;
    	if ((b = sshbuf_new()) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    	if ((r = sshbuf_put_cstring(b, sshkey_ssh_name(key))) != 0)
    		goto out;
    	switch (key->type) {
    #ifdef WITH_OPENSSL
    	case KEY_RSA:
    		RSA_get0_key(key->rsa, &rsa_n, &rsa_e, &rsa_d);
    		RSA_get0_factors(key->rsa, &rsa_p, &rsa_q);
    		RSA_get0_crt_params(key->rsa, NULL, NULL, &rsa_iqmp);
    		if ((r = sshbuf_put_bignum2(b, rsa_n)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, rsa_e)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, rsa_d)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, rsa_iqmp)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, rsa_p)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, rsa_q)) != 0)
    			goto out;
    		break;
    	case KEY_RSA_CERT:
    		if (key->cert == NULL || sshbuf_len(key->cert->certblob) == 0) {
    			r = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		RSA_get0_key(key->rsa, NULL, NULL, &rsa_d);
    		RSA_get0_factors(key->rsa, &rsa_p, &rsa_q);
    		RSA_get0_crt_params(key->rsa, NULL, NULL, &rsa_iqmp);
    		if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, rsa_d)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, rsa_iqmp)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, rsa_p)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, rsa_q)) != 0)
    			goto out;
    		break;
    	case KEY_DSA:
    		DSA_get0_pqg(key->dsa, &dsa_p, &dsa_q, &dsa_g);
    		DSA_get0_key(key->dsa, &dsa_pub_key, &dsa_priv_key);
    		if ((r = sshbuf_put_bignum2(b, dsa_p)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, dsa_q)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, dsa_g)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, dsa_pub_key)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, dsa_priv_key)) != 0)
    			goto out;
    		break;
    	case KEY_DSA_CERT:
    		if (key->cert == NULL || sshbuf_len(key->cert->certblob) == 0) {
    			r = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		DSA_get0_key(key->dsa, NULL, &dsa_priv_key);
    		if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0 ||
    		    (r = sshbuf_put_bignum2(b, dsa_priv_key)) != 0)
    			goto out;
    		break;
    	case KEY_ECDSA:
    		if ((r = sshbuf_put_cstring(b,
    		    sshkey_curve_nid_to_name(key->ecdsa_nid))) != 0 ||
    		    (r = sshbuf_put_eckey(b, key->ecdsa)) != 0 ||
    		    (r = sshbuf_put_bignum2(b,
    		    EC_KEY_get0_private_key(key->ecdsa))) != 0)
    			goto out;
    		break;
    	case KEY_ECDSA_CERT:
    		if (key->cert == NULL || sshbuf_len(key->cert->certblob) == 0) {
    			r = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0 ||
    		    (r = sshbuf_put_bignum2(b,
    		    EC_KEY_get0_private_key(key->ecdsa))) != 0)
    			goto out;
    		break;
    	case KEY_ECDSA_SK:
    		if ((r = sshbuf_put_cstring(b,
    		    sshkey_curve_nid_to_name(key->ecdsa_nid))) != 0 ||
    		    (r = sshbuf_put_eckey(b, key->ecdsa)) != 0 ||
    		    (r = sshbuf_put_cstring(b, key->sk_application)) != 0 ||
    		    (r = sshbuf_put_u8(b, key->sk_flags)) != 0 ||
    		    (r = sshbuf_put_stringb(b, key->sk_key_handle)) != 0 ||
    		    (r = sshbuf_put_stringb(b, key->sk_reserved)) != 0)
    			goto out;
    		break;
    	case KEY_ECDSA_SK_CERT:
    		if (key->cert == NULL || sshbuf_len(key->cert->certblob) == 0) {
    			r = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0 ||
    		    (r = sshbuf_put_cstring(b, key->sk_application)) != 0 ||
    		    (r = sshbuf_put_u8(b, key->sk_flags)) != 0 ||
    		    (r = sshbuf_put_stringb(b, key->sk_key_handle)) != 0 ||
    		    (r = sshbuf_put_stringb(b, key->sk_reserved)) != 0)
    			goto out;
    		break;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519:
    		if ((r = sshbuf_put_string(b, key->ed25519_pk,
    		    ED25519_PK_SZ)) != 0 ||
    		    (r = sshbuf_put_string(b, key->ed25519_sk,
    		    ED25519_SK_SZ)) != 0)
    			goto out;
    		break;
    	case KEY_ED25519_CERT:
    		if (key->cert == NULL || sshbuf_len(key->cert->certblob) == 0) {
    			r = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0 ||
    		    (r = sshbuf_put_string(b, key->ed25519_pk,
    		    ED25519_PK_SZ)) != 0 ||
    		    (r = sshbuf_put_string(b, key->ed25519_sk,
    		    ED25519_SK_SZ)) != 0)
    			goto out;
    		break;
    	case KEY_ED25519_SK:
    		if ((r = sshbuf_put_string(b, key->ed25519_pk,
    		    ED25519_PK_SZ)) != 0 ||
    		    (r = sshbuf_put_cstring(b, key->sk_application)) != 0 ||
    		    (r = sshbuf_put_u8(b, key->sk_flags)) != 0 ||
    		    (r = sshbuf_put_stringb(b, key->sk_key_handle)) != 0 ||
    		    (r = sshbuf_put_stringb(b, key->sk_reserved)) != 0)
    			goto out;
    		break;
    	case KEY_ED25519_SK_CERT:
    		if (key->cert == NULL || sshbuf_len(key->cert->certblob) == 0) {
    			r = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0 ||
    		    (r = sshbuf_put_string(b, key->ed25519_pk,
    		    ED25519_PK_SZ)) != 0 ||
    		    (r = sshbuf_put_cstring(b, key->sk_application)) != 0 ||
    		    (r = sshbuf_put_u8(b, key->sk_flags)) != 0 ||
    		    (r = sshbuf_put_stringb(b, key->sk_key_handle)) != 0 ||
    		    (r = sshbuf_put_stringb(b, key->sk_reserved)) != 0)
    			goto out;
    		break;
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    		if (key->xmss_name == NULL) {
    			r = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		if ((r = sshbuf_put_cstring(b, key->xmss_name)) != 0 ||
    		    (r = sshbuf_put_string(b, key->xmss_pk,
    		    sshkey_xmss_pklen(key))) != 0 ||
    		    (r = sshbuf_put_string(b, key->xmss_sk,
    		    sshkey_xmss_sklen(key))) != 0 ||
    		    (r = sshkey_xmss_serialize_state_opt(key, b, opts)) != 0)
    			goto out;
    		break;
    	case KEY_XMSS_CERT:
    		if (key->cert == NULL || sshbuf_len(key->cert->certblob) == 0 ||
    		    key->xmss_name == NULL) {
    			r = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		if ((r = sshbuf_put_stringb(b, key->cert->certblob)) != 0 ||
    		    (r = sshbuf_put_cstring(b, key->xmss_name)) != 0 ||
    		    (r = sshbuf_put_string(b, key->xmss_pk,
    		    sshkey_xmss_pklen(key))) != 0 ||
    		    (r = sshbuf_put_string(b, key->xmss_sk,
    		    sshkey_xmss_sklen(key))) != 0 ||
    		    (r = sshkey_xmss_serialize_state_opt(key, b, opts)) != 0)
    			goto out;
    		break;
    #endif /* WITH_XMSS */
    	default:
    		r = SSH_ERR_INVALID_ARGUMENT;
    		goto out;
    	}
    	/*
    	 * success (but we still need to append the output to buf after
    	 * possibly re-shielding the private key)
    	 */
    	r = 0;
     out:
    	if (was_shielded)
    		r = sshkey_shield_private(key);
    	if (r == 0)
    		r = sshbuf_putb(buf, b);
    	sshbuf_free(b);
    
    	return r;
    }
    
    int
    sshkey_private_serialize(struct sshkey *key, struct sshbuf *b)
    {
    	return sshkey_private_serialize_opt(key, b,
    	    SSHKEY_SERIALIZE_DEFAULT);
    }
    
    int
    sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
    {
    	char *tname = NULL, *curve = NULL, *xmss_name = NULL;
    	struct sshkey *k = NULL;
    	size_t pklen = 0, sklen = 0;
    	int type, r = SSH_ERR_INTERNAL_ERROR;
    	u_char *ed25519_pk = NULL, *ed25519_sk = NULL;
    	u_char *xmss_pk = NULL, *xmss_sk = NULL;
    #ifdef WITH_OPENSSL
    	BIGNUM *exponent = NULL;
    	BIGNUM *rsa_n = NULL, *rsa_e = NULL, *rsa_d = NULL;
    	BIGNUM *rsa_iqmp = NULL, *rsa_p = NULL, *rsa_q = NULL;
    	BIGNUM *dsa_p = NULL, *dsa_q = NULL, *dsa_g = NULL;
    	BIGNUM *dsa_pub_key = NULL, *dsa_priv_key = NULL;
    #endif /* WITH_OPENSSL */
    
    	if (kp != NULL)
    		*kp = NULL;
    	if ((r = sshbuf_get_cstring(buf, &tname, NULL)) != 0)
    		goto out;
    	type = sshkey_type_from_name(tname);
    	if (sshkey_type_is_cert(type)) {
    		/*
    		 * Certificate key private keys begin with the certificate
    		 * itself. Make sure this matches the type of the enclosing
    		 * private key.
    		 */
    		if ((r = sshkey_froms(buf, &k)) != 0)
    			goto out;
    		if (k->type != type) {
    			r = SSH_ERR_KEY_CERT_MISMATCH;
    			goto out;
    		}
    		/* For ECDSA keys, the group must match too */
    		if (k->type == KEY_ECDSA &&
    		    k->ecdsa_nid != sshkey_ecdsa_nid_from_name(tname)) {
    			r = SSH_ERR_KEY_CERT_MISMATCH;
    			goto out;
    		}
    	} else {
    		if ((k = sshkey_new(type)) == NULL) {
    			r = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    	}
    	switch (type) {
    #ifdef WITH_OPENSSL
    	case KEY_DSA:
    		if ((r = sshbuf_get_bignum2(buf, &dsa_p)) != 0 ||
    		    (r = sshbuf_get_bignum2(buf, &dsa_q)) != 0 ||
    		    (r = sshbuf_get_bignum2(buf, &dsa_g)) != 0 ||
    		    (r = sshbuf_get_bignum2(buf, &dsa_pub_key)) != 0)
    			goto out;
    		if (!DSA_set0_pqg(k->dsa, dsa_p, dsa_q, dsa_g)) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		dsa_p = dsa_q = dsa_g = NULL; /* transferred */
    		if (!DSA_set0_key(k->dsa, dsa_pub_key, NULL)) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		dsa_pub_key = NULL; /* transferred */
    		/* FALLTHROUGH */
    	case KEY_DSA_CERT:
    		if ((r = sshbuf_get_bignum2(buf, &dsa_priv_key)) != 0)
    			goto out;
    		if (!DSA_set0_key(k->dsa, NULL, dsa_priv_key)) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		dsa_priv_key = NULL; /* transferred */
    		break;
    	case KEY_ECDSA:
    		if ((k->ecdsa_nid = sshkey_ecdsa_nid_from_name(tname)) == -1) {
    			r = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		if ((r = sshbuf_get_cstring(buf, &curve, NULL)) != 0)
    			goto out;
    		if (k->ecdsa_nid != sshkey_curve_name_to_nid(curve)) {
    			r = SSH_ERR_EC_CURVE_MISMATCH;
    			goto out;
    		}
    		k->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid);
    		if (k->ecdsa  == NULL) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		if ((r = sshbuf_get_eckey(buf, k->ecdsa)) != 0)
    			goto out;
    		/* FALLTHROUGH */
    	case KEY_ECDSA_CERT:
    		if ((r = sshbuf_get_bignum2(buf, &exponent)) != 0)
    			goto out;
    		if (EC_KEY_set_private_key(k->ecdsa, exponent) != 1) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		if ((r = sshkey_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
    		    EC_KEY_get0_public_key(k->ecdsa))) != 0 ||
    		    (r = sshkey_ec_validate_private(k->ecdsa)) != 0)
    			goto out;
    		break;
    	case KEY_ECDSA_SK:
    		if ((k->ecdsa_nid = sshkey_ecdsa_nid_from_name(tname)) == -1) {
    			r = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		if ((r = sshbuf_get_cstring(buf, &curve, NULL)) != 0)
    			goto out;
    		if (k->ecdsa_nid != sshkey_curve_name_to_nid(curve)) {
    			r = SSH_ERR_EC_CURVE_MISMATCH;
    			goto out;
    		}
    		if ((k->sk_key_handle = sshbuf_new()) == NULL ||
    		    (k->sk_reserved = sshbuf_new()) == NULL) {
    			r = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		k->ecdsa = EC_KEY_new_by_curve_name(k->ecdsa_nid);
    		if (k->ecdsa  == NULL) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		if ((r = sshbuf_get_eckey(buf, k->ecdsa)) != 0 ||
    		    (r = sshbuf_get_cstring(buf, &k->sk_application,
    		    NULL)) != 0 ||
    		    (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 ||
    		    (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 ||
    		    (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0)
    			goto out;
    		if ((r = sshkey_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
    		    EC_KEY_get0_public_key(k->ecdsa))) != 0)
    			goto out;
    		break;
    	case KEY_ECDSA_SK_CERT:
    		if ((k->sk_key_handle = sshbuf_new()) == NULL ||
    		    (k->sk_reserved = sshbuf_new()) == NULL) {
    			r = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		if ((r = sshbuf_get_cstring(buf, &k->sk_application,
    		    NULL)) != 0 ||
    		    (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 ||
    		    (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 ||
    		    (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0)
    			goto out;
    		if ((r = sshkey_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
    		    EC_KEY_get0_public_key(k->ecdsa))) != 0)
    			goto out;
    		break;
    	case KEY_RSA:
    		if ((r = sshbuf_get_bignum2(buf, &rsa_n)) != 0 ||
    		    (r = sshbuf_get_bignum2(buf, &rsa_e)) != 0)
    			goto out;
    		if (!RSA_set0_key(k->rsa, rsa_n, rsa_e, NULL)) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		rsa_n = rsa_e = NULL; /* transferred */
    		/* FALLTHROUGH */
    	case KEY_RSA_CERT:
    		if ((r = sshbuf_get_bignum2(buf, &rsa_d)) != 0 ||
    		    (r = sshbuf_get_bignum2(buf, &rsa_iqmp)) != 0 ||
    		    (r = sshbuf_get_bignum2(buf, &rsa_p)) != 0 ||
    		    (r = sshbuf_get_bignum2(buf, &rsa_q)) != 0)
    			goto out;
    		if (!RSA_set0_key(k->rsa, NULL, NULL, rsa_d)) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		rsa_d = NULL; /* transferred */
    		if (!RSA_set0_factors(k->rsa, rsa_p, rsa_q)) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		rsa_p = rsa_q = NULL; /* transferred */
    		if ((r = check_rsa_length(k->rsa)) != 0)
    			goto out;
    		if ((r = ssh_rsa_complete_crt_parameters(k, rsa_iqmp)) != 0)
    			goto out;
    		break;
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519:
    	case KEY_ED25519_CERT:
    		if ((r = sshbuf_get_string(buf, &ed25519_pk, &pklen)) != 0 ||
    		    (r = sshbuf_get_string(buf, &ed25519_sk, &sklen)) != 0)
    			goto out;
    		if (pklen != ED25519_PK_SZ || sklen != ED25519_SK_SZ) {
    			r = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		k->ed25519_pk = ed25519_pk;
    		k->ed25519_sk = ed25519_sk;
    		ed25519_pk = ed25519_sk = NULL; /* transferred */
    		break;
    	case KEY_ED25519_SK:
    	case KEY_ED25519_SK_CERT:
    		if ((r = sshbuf_get_string(buf, &ed25519_pk, &pklen)) != 0)
    			goto out;
    		if (pklen != ED25519_PK_SZ) {
    			r = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		if ((k->sk_key_handle = sshbuf_new()) == NULL ||
    		    (k->sk_reserved = sshbuf_new()) == NULL) {
    			r = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		if ((r = sshbuf_get_cstring(buf, &k->sk_application,
    		    NULL)) != 0 ||
    		    (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 ||
    		    (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 ||
    		    (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0)
    			goto out;
    		k->ed25519_pk = ed25519_pk;
    		ed25519_pk = NULL; /* transferred */
    		break;
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    	case KEY_XMSS_CERT:
    		if ((r = sshbuf_get_cstring(buf, &xmss_name, NULL)) != 0 ||
    		    (r = sshbuf_get_string(buf, &xmss_pk, &pklen)) != 0 ||
    		    (r = sshbuf_get_string(buf, &xmss_sk, &sklen)) != 0)
    			goto out;
    		if (type == KEY_XMSS &&
    		    (r = sshkey_xmss_init(k, xmss_name)) != 0)
    			goto out;
    		if (pklen != sshkey_xmss_pklen(k) ||
    		    sklen != sshkey_xmss_sklen(k)) {
    			r = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    		k->xmss_pk = xmss_pk;
    		k->xmss_sk = xmss_sk;
    		xmss_pk = xmss_sk = NULL;
    		/* optional internal state */
    		if ((r = sshkey_xmss_deserialize_state_opt(k, buf)) != 0)
    			goto out;
    		break;
    #endif /* WITH_XMSS */
    	default:
    		r = SSH_ERR_KEY_TYPE_UNKNOWN;
    		goto out;
    	}
    #ifdef WITH_OPENSSL
    	/* enable blinding */
    	switch (k->type) {
    	case KEY_RSA:
    	case KEY_RSA_CERT:
    		if (RSA_blinding_on(k->rsa, NULL) != 1) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		break;
    	}
    #endif /* WITH_OPENSSL */
    	/* success */
    	r = 0;
    	if (kp != NULL) {
    		*kp = k;
    		k = NULL;
    	}
     out:
    	free(tname);
    	free(curve);
    #ifdef WITH_OPENSSL
    	BN_clear_free(exponent);
    	BN_clear_free(dsa_p);
    	BN_clear_free(dsa_q);
    	BN_clear_free(dsa_g);
    	BN_clear_free(dsa_pub_key);
    	BN_clear_free(dsa_priv_key);
    	BN_clear_free(rsa_n);
    	BN_clear_free(rsa_e);
    	BN_clear_free(rsa_d);
    	BN_clear_free(rsa_p);
    	BN_clear_free(rsa_q);
    	BN_clear_free(rsa_iqmp);
    #endif /* WITH_OPENSSL */
    	sshkey_free(k);
    	freezero(ed25519_pk, pklen);
    	freezero(ed25519_sk, sklen);
    	free(xmss_name);
    	freezero(xmss_pk, pklen);
    	freezero(xmss_sk, sklen);
    	return r;
    }
    
    #ifdef WITH_OPENSSL
    int
    sshkey_ec_validate_public(const EC_GROUP *group, const EC_POINT *public)
    {
    	EC_POINT *nq = NULL;
    	BIGNUM *order = NULL, *x = NULL, *y = NULL, *tmp = NULL;
    	int ret = SSH_ERR_KEY_INVALID_EC_VALUE;
    
    	/*
    	 * NB. This assumes OpenSSL has already verified that the public
    	 * point lies on the curve. This is done by EC_POINT_oct2point()
    	 * implicitly calling EC_POINT_is_on_curve(). If this code is ever
    	 * reachable with public points not unmarshalled using
    	 * EC_POINT_oct2point then the caller will need to explicitly check.
    	 */
    
    	/*
    	 * We shouldn't ever hit this case because bignum_get_ecpoint()
    	 * refuses to load GF2m points.
    	 */
    	if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
    	    NID_X9_62_prime_field)
    		goto out;
    
    	/* Q != infinity */
    	if (EC_POINT_is_at_infinity(group, public))
    		goto out;
    
    	if ((x = BN_new()) == NULL ||
    	    (y = BN_new()) == NULL ||
    	    (order = BN_new()) == NULL ||
    	    (tmp = BN_new()) == NULL) {
    		ret = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    
    	/* log2(x) > log2(order)/2, log2(y) > log2(order)/2 */
    	if (EC_GROUP_get_order(group, order, NULL) != 1 ||
    	    EC_POINT_get_affine_coordinates_GFp(group, public,
    	    x, y, NULL) != 1) {
    		ret = SSH_ERR_LIBCRYPTO_ERROR;
    		goto out;
    	}
    	if (BN_num_bits(x) <= BN_num_bits(order) / 2 ||
    	    BN_num_bits(y) <= BN_num_bits(order) / 2)
    		goto out;
    
    	/* nQ == infinity (n == order of subgroup) */
    	if ((nq = EC_POINT_new(group)) == NULL) {
    		ret = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if (EC_POINT_mul(group, nq, NULL, public, order, NULL) != 1) {
    		ret = SSH_ERR_LIBCRYPTO_ERROR;
    		goto out;
    	}
    	if (EC_POINT_is_at_infinity(group, nq) != 1)
    		goto out;
    
    	/* x < order - 1, y < order - 1 */
    	if (!BN_sub(tmp, order, BN_value_one())) {
    		ret = SSH_ERR_LIBCRYPTO_ERROR;
    		goto out;
    	}
    	if (BN_cmp(x, tmp) >= 0 || BN_cmp(y, tmp) >= 0)
    		goto out;
    	ret = 0;
     out:
    	BN_clear_free(x);
    	BN_clear_free(y);
    	BN_clear_free(order);
    	BN_clear_free(tmp);
    	EC_POINT_free(nq);
    	return ret;
    }
    
    int
    sshkey_ec_validate_private(const EC_KEY *key)
    {
    	BIGNUM *order = NULL, *tmp = NULL;
    	int ret = SSH_ERR_KEY_INVALID_EC_VALUE;
    
    	if ((order = BN_new()) == NULL || (tmp = BN_new()) == NULL) {
    		ret = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    
    	/* log2(private) > log2(order)/2 */
    	if (EC_GROUP_get_order(EC_KEY_get0_group(key), order, NULL) != 1) {
    		ret = SSH_ERR_LIBCRYPTO_ERROR;
    		goto out;
    	}
    	if (BN_num_bits(EC_KEY_get0_private_key(key)) <=
    	    BN_num_bits(order) / 2)
    		goto out;
    
    	/* private < order - 1 */
    	if (!BN_sub(tmp, order, BN_value_one())) {
    		ret = SSH_ERR_LIBCRYPTO_ERROR;
    		goto out;
    	}
    	if (BN_cmp(EC_KEY_get0_private_key(key), tmp) >= 0)
    		goto out;
    	ret = 0;
     out:
    	BN_clear_free(order);
    	BN_clear_free(tmp);
    	return ret;
    }
    
    void
    sshkey_dump_ec_point(const EC_GROUP *group, const EC_POINT *point)
    {
    	BIGNUM *x = NULL, *y = NULL;
    
    	if (point == NULL) {
    		fputs("point=(NULL)\n", stderr);
    		return;
    	}
    	if ((x = BN_new()) == NULL || (y = BN_new()) == NULL) {
    		fprintf(stderr, "%s: BN_new failed\n", __func__);
    		goto out;
    	}
    	if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) !=
    	    NID_X9_62_prime_field) {
    		fprintf(stderr, "%s: group is not a prime field\n", __func__);
    		goto out;
    	}
    	if (EC_POINT_get_affine_coordinates_GFp(group, point,
    	    x, y, NULL) != 1) {
    		fprintf(stderr, "%s: EC_POINT_get_affine_coordinates_GFp\n",
    		    __func__);
    		goto out;
    	}
    	fputs("x=", stderr);
    	BN_print_fp(stderr, x);
    	fputs("\ny=", stderr);
    	BN_print_fp(stderr, y);
    	fputs("\n", stderr);
     out:
    	BN_clear_free(x);
    	BN_clear_free(y);
    }
    
    void
    sshkey_dump_ec_key(const EC_KEY *key)
    {
    	const BIGNUM *exponent;
    
    	sshkey_dump_ec_point(EC_KEY_get0_group(key),
    	    EC_KEY_get0_public_key(key));
    	fputs("exponent=", stderr);
    	if ((exponent = EC_KEY_get0_private_key(key)) == NULL)
    		fputs("(NULL)", stderr);
    	else
    		BN_print_fp(stderr, EC_KEY_get0_private_key(key));
    	fputs("\n", stderr);
    }
    #endif /* WITH_OPENSSL */
    
    static int
    sshkey_private_to_blob2(struct sshkey *prv, struct sshbuf *blob,
        const char *passphrase, const char *comment, const char *ciphername,
        int rounds)
    {
    	u_char *cp, *key = NULL, *pubkeyblob = NULL;
    	u_char salt[SALT_LEN];
    	char *b64 = NULL;
    	size_t i, pubkeylen, keylen, ivlen, blocksize, authlen;
    	u_int check;
    	int r = SSH_ERR_INTERNAL_ERROR;
    	struct sshcipher_ctx *ciphercontext = NULL;
    	const struct sshcipher *cipher;
    	const char *kdfname = KDFNAME;
    	struct sshbuf *encoded = NULL, *encrypted = NULL, *kdf = NULL;
    
    	if (rounds <= 0)
    		rounds = DEFAULT_ROUNDS;
    	if (passphrase == NULL || !strlen(passphrase)) {
    		ciphername = "none";
    		kdfname = "none";
    	} else if (ciphername == NULL)
    		ciphername = DEFAULT_CIPHERNAME;
    	if ((cipher = cipher_by_name(ciphername)) == NULL) {
    		r = SSH_ERR_INVALID_ARGUMENT;
    		goto out;
    	}
    
    	if ((kdf = sshbuf_new()) == NULL ||
    	    (encoded = sshbuf_new()) == NULL ||
    	    (encrypted = sshbuf_new()) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	blocksize = cipher_blocksize(cipher);
    	keylen = cipher_keylen(cipher);
    	ivlen = cipher_ivlen(cipher);
    	authlen = cipher_authlen(cipher);
    	if ((key = calloc(1, keylen + ivlen)) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if (strcmp(kdfname, "bcrypt") == 0) {
    		arc4random_buf(salt, SALT_LEN);
    		if (bcrypt_pbkdf(passphrase, strlen(passphrase),
    		    salt, SALT_LEN, key, keylen + ivlen, rounds) < 0) {
    			r = SSH_ERR_INVALID_ARGUMENT;
    			goto out;
    		}
    		if ((r = sshbuf_put_string(kdf, salt, SALT_LEN)) != 0 ||
    		    (r = sshbuf_put_u32(kdf, rounds)) != 0)
    			goto out;
    	} else if (strcmp(kdfname, "none") != 0) {
    		/* Unsupported KDF type */
    		r = SSH_ERR_KEY_UNKNOWN_CIPHER;
    		goto out;
    	}
    	if ((r = cipher_init(&ciphercontext, cipher, key, keylen,
    	    key + keylen, ivlen, 1)) != 0)
    		goto out;
    
    	if ((r = sshbuf_put(encoded, AUTH_MAGIC, sizeof(AUTH_MAGIC))) != 0 ||
    	    (r = sshbuf_put_cstring(encoded, ciphername)) != 0 ||
    	    (r = sshbuf_put_cstring(encoded, kdfname)) != 0 ||
    	    (r = sshbuf_put_stringb(encoded, kdf)) != 0 ||
    	    (r = sshbuf_put_u32(encoded, 1)) != 0 ||	/* number of keys */
    	    (r = sshkey_to_blob(prv, &pubkeyblob, &pubkeylen)) != 0 ||
    	    (r = sshbuf_put_string(encoded, pubkeyblob, pubkeylen)) != 0)
    		goto out;
    
    	/* set up the buffer that will be encrypted */
    
    	/* Random check bytes */
    	check = arc4random();
    	if ((r = sshbuf_put_u32(encrypted, check)) != 0 ||
    	    (r = sshbuf_put_u32(encrypted, check)) != 0)
    		goto out;
    
    	/* append private key and comment*/
    	if ((r = sshkey_private_serialize_opt(prv, encrypted,
    	     SSHKEY_SERIALIZE_FULL)) != 0 ||
    	    (r = sshbuf_put_cstring(encrypted, comment)) != 0)
    		goto out;
    
    	/* padding */
    	i = 0;
    	while (sshbuf_len(encrypted) % blocksize) {
    		if ((r = sshbuf_put_u8(encrypted, ++i & 0xff)) != 0)
    			goto out;
    	}
    
    	/* length in destination buffer */
    	if ((r = sshbuf_put_u32(encoded, sshbuf_len(encrypted))) != 0)
    		goto out;
    
    	/* encrypt */
    	if ((r = sshbuf_reserve(encoded,
    	    sshbuf_len(encrypted) + authlen, &cp)) != 0)
    		goto out;
    	if ((r = cipher_crypt(ciphercontext, 0, cp,
    	    sshbuf_ptr(encrypted), sshbuf_len(encrypted), 0, authlen)) != 0)
    		goto out;
    
    	sshbuf_reset(blob);
    
    	/* assemble uuencoded key */
    	if ((r = sshbuf_put(blob, MARK_BEGIN, MARK_BEGIN_LEN)) != 0 ||
    	    (r = sshbuf_dtob64(encoded, blob, 1)) != 0 ||
    	    (r = sshbuf_put(blob, MARK_END, MARK_END_LEN)) != 0)
    		goto out;
    
    	/* success */
    	r = 0;
    
     out:
    	sshbuf_free(kdf);
    	sshbuf_free(encoded);
    	sshbuf_free(encrypted);
    	cipher_free(ciphercontext);
    	explicit_bzero(salt, sizeof(salt));
    	if (key != NULL)
    		freezero(key, keylen + ivlen);
    	if (pubkeyblob != NULL) 
    		freezero(pubkeyblob, pubkeylen);
    	if (b64 != NULL) 
    		freezero(b64, strlen(b64));
    	return r;
    }
    
    static int
    private2_uudecode(struct sshbuf *blob, struct sshbuf **decodedp)
    {
    	const u_char *cp;
    	size_t encoded_len;
    	int r;
    	u_char last;
    	struct sshbuf *encoded = NULL, *decoded = NULL;
    
    	if (blob == NULL || decodedp == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    
    	*decodedp = NULL;
    
    	if ((encoded = sshbuf_new()) == NULL ||
    	    (decoded = sshbuf_new()) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    
    	/* check preamble */
    	cp = sshbuf_ptr(blob);
    	encoded_len = sshbuf_len(blob);
    	if (encoded_len < (MARK_BEGIN_LEN + MARK_END_LEN) ||
    	    memcmp(cp, MARK_BEGIN, MARK_BEGIN_LEN) != 0) {
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    	cp += MARK_BEGIN_LEN;
    	encoded_len -= MARK_BEGIN_LEN;
    
    	/* Look for end marker, removing whitespace as we go */
    	while (encoded_len > 0) {
    		if (*cp != '\n' && *cp != '\r') {
    			if ((r = sshbuf_put_u8(encoded, *cp)) != 0)
    				goto out;
    		}
    		last = *cp;
    		encoded_len--;
    		cp++;
    		if (last == '\n') {
    			if (encoded_len >= MARK_END_LEN &&
    			    memcmp(cp, MARK_END, MARK_END_LEN) == 0) {
    				/* \0 terminate */
    				if ((r = sshbuf_put_u8(encoded, 0)) != 0)
    					goto out;
    				break;
    			}
    		}
    	}
    	if (encoded_len == 0) {
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    
    	/* decode base64 */
    	if ((r = sshbuf_b64tod(decoded, (char *)sshbuf_ptr(encoded))) != 0)
    		goto out;
    
    	/* check magic */
    	if (sshbuf_len(decoded) < sizeof(AUTH_MAGIC) ||
    	    memcmp(sshbuf_ptr(decoded), AUTH_MAGIC, sizeof(AUTH_MAGIC))) {
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    	/* success */
    	*decodedp = decoded;
    	decoded = NULL;
    	r = 0;
     out:
    	sshbuf_free(encoded);
    	sshbuf_free(decoded);
    	return r;
    }
    
    static int
    private2_decrypt(struct sshbuf *decoded, const char *passphrase,
        struct sshbuf **decryptedp, struct sshkey **pubkeyp)
    {
    	char *ciphername = NULL, *kdfname = NULL;
    	const struct sshcipher *cipher = NULL;
    	int r = SSH_ERR_INTERNAL_ERROR;
    	size_t keylen = 0, ivlen = 0, authlen = 0, slen = 0;
    	struct sshbuf *kdf = NULL, *decrypted = NULL;
    	struct sshcipher_ctx *ciphercontext = NULL;
    	struct sshkey *pubkey = NULL;
    	u_char *key = NULL, *salt = NULL, *dp;
    	u_int blocksize, rounds, nkeys, encrypted_len, check1, check2;
    
    	if (decoded == NULL || decryptedp == NULL || pubkeyp == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    
    	*decryptedp = NULL;
    	*pubkeyp = NULL;
    
    	if ((decrypted = sshbuf_new()) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    
    	/* parse public portion of key */
    	if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 ||
    	    (r = sshbuf_get_cstring(decoded, &ciphername, NULL)) != 0 ||
    	    (r = sshbuf_get_cstring(decoded, &kdfname, NULL)) != 0 ||
    	    (r = sshbuf_froms(decoded, &kdf)) != 0 ||
    	    (r = sshbuf_get_u32(decoded, &nkeys)) != 0)
    		goto out;
    
    	if (nkeys != 1) {
    		/* XXX only one key supported at present */
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    
    	if ((r = sshkey_froms(decoded, &pubkey)) != 0 ||
    	    (r = sshbuf_get_u32(decoded, &encrypted_len)) != 0)
    		goto out;
    
    	if ((cipher = cipher_by_name(ciphername)) == NULL) {
    		r = SSH_ERR_KEY_UNKNOWN_CIPHER;
    		goto out;
    	}
    	if (strcmp(kdfname, "none") != 0 && strcmp(kdfname, "bcrypt") != 0) {
    		r = SSH_ERR_KEY_UNKNOWN_CIPHER;
    		goto out;
    	}
    	if (strcmp(kdfname, "none") == 0 && strcmp(ciphername, "none") != 0) {
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    	if ((passphrase == NULL || strlen(passphrase) == 0) &&
    	    strcmp(kdfname, "none") != 0) {
    		/* passphrase required */
    		r = SSH_ERR_KEY_WRONG_PASSPHRASE;
    		goto out;
    	}
    
    	/* check size of encrypted key blob */
    	blocksize = cipher_blocksize(cipher);
    	if (encrypted_len < blocksize || (encrypted_len % blocksize) != 0) {
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    
    	/* setup key */
    	keylen = cipher_keylen(cipher);
    	ivlen = cipher_ivlen(cipher);
    	authlen = cipher_authlen(cipher);
    	if ((key = calloc(1, keylen + ivlen)) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if (strcmp(kdfname, "bcrypt") == 0) {
    		if ((r = sshbuf_get_string(kdf, &salt, &slen)) != 0 ||
    		    (r = sshbuf_get_u32(kdf, &rounds)) != 0)
    			goto out;
    		if (bcrypt_pbkdf(passphrase, strlen(passphrase), salt, slen,
    		    key, keylen + ivlen, rounds) < 0) {
    			r = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    	}
    
    	/* check that an appropriate amount of auth data is present */
    	if (sshbuf_len(decoded) < authlen ||
    	    sshbuf_len(decoded) - authlen < encrypted_len) {
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    
    	/* decrypt private portion of key */
    	if ((r = sshbuf_reserve(decrypted, encrypted_len, &dp)) != 0 ||
    	    (r = cipher_init(&ciphercontext, cipher, key, keylen,
    	    key + keylen, ivlen, 0)) != 0)
    		goto out;
    	if ((r = cipher_crypt(ciphercontext, 0, dp, sshbuf_ptr(decoded),
    	    encrypted_len, 0, authlen)) != 0) {
    		/* an integrity error here indicates an incorrect passphrase */
    		if (r == SSH_ERR_MAC_INVALID)
    			r = SSH_ERR_KEY_WRONG_PASSPHRASE;
    		goto out;
    	}
    	if ((r = sshbuf_consume(decoded, encrypted_len + authlen)) != 0)
    		goto out;
    	/* there should be no trailing data */
    	if (sshbuf_len(decoded) != 0) {
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    
    	/* check check bytes */
    	if ((r = sshbuf_get_u32(decrypted, &check1)) != 0 ||
    	    (r = sshbuf_get_u32(decrypted, &check2)) != 0)
    		goto out;
    	if (check1 != check2) {
    		r = SSH_ERR_KEY_WRONG_PASSPHRASE;
    		goto out;
    	}
    	/* success */
    	*decryptedp = decrypted;
    	decrypted = NULL;
    	*pubkeyp = pubkey;
    	pubkey = NULL;
    	r = 0;
     out:
    	cipher_free(ciphercontext);
    	free(ciphername);
    	free(kdfname);
    	sshkey_free(pubkey);
    	if (salt != NULL) {
    		explicit_bzero(salt, slen);
    		free(salt);
    	}
    	if (key != NULL) {
    		explicit_bzero(key, keylen + ivlen);
    		free(key);
    	}
    	sshbuf_free(kdf);
    	sshbuf_free(decrypted);
    	return r;
    }
    
    /* Check deterministic padding after private key */
    static int
    private2_check_padding(struct sshbuf *decrypted)
    {
    	u_char pad;
    	size_t i;
    	int r = SSH_ERR_INTERNAL_ERROR;
    
    	i = 0;
    	while (sshbuf_len(decrypted)) {
    		if ((r = sshbuf_get_u8(decrypted, &pad)) != 0)
    			goto out;
    		if (pad != (++i & 0xff)) {
    			r = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    	}
    	/* success */
    	r = 0;
     out:
    	explicit_bzero(&pad, sizeof(pad));
    	explicit_bzero(&i, sizeof(i));
    	return r;
    }
    
    static int
    sshkey_parse_private2(struct sshbuf *blob, int type, const char *passphrase,
        struct sshkey **keyp, char **commentp)
    {
    	char *comment = NULL;
    	int r = SSH_ERR_INTERNAL_ERROR;
    	struct sshbuf *decoded = NULL, *decrypted = NULL;
    	struct sshkey *k = NULL, *pubkey = NULL;
    
    	if (keyp != NULL)
    		*keyp = NULL;
    	if (commentp != NULL)
    		*commentp = NULL;
    
    	/* Undo base64 encoding and decrypt the private section */
    	if ((r = private2_uudecode(blob, &decoded)) != 0 ||
    	    (r = private2_decrypt(decoded, passphrase,
    	    &decrypted, &pubkey)) != 0)
    		goto out;
    
    	if (type != KEY_UNSPEC &&
    	    sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) {
    		r = SSH_ERR_KEY_TYPE_MISMATCH;
    		goto out;
    	}
    
    	/* Load the private key and comment */
    	if ((r = sshkey_private_deserialize(decrypted, &k)) != 0 ||
    	    (r = sshbuf_get_cstring(decrypted, &comment, NULL)) != 0)
    		goto out;
    
    	/* Check deterministic padding after private section */
    	if ((r = private2_check_padding(decrypted)) != 0)
    		goto out;
    
    	/* Check that the public key in the envelope matches the private key */
    	if (!sshkey_equal(pubkey, k)) {
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    
    	/* success */
    	r = 0;
    	if (keyp != NULL) {
    		*keyp = k;
    		k = NULL;
    	}
    	if (commentp != NULL) {
    		*commentp = comment;
    		comment = NULL;
    	}
     out:
    	free(comment);
    	sshbuf_free(decoded);
    	sshbuf_free(decrypted);
    	sshkey_free(k);
    	sshkey_free(pubkey);
    	return r;
    }
    
    static int
    sshkey_parse_private2_pubkey(struct sshbuf *blob, int type,
        struct sshkey **keyp)
    {
    	int r = SSH_ERR_INTERNAL_ERROR;
    	struct sshbuf *decoded = NULL;
    	struct sshkey *pubkey = NULL;
    	u_int nkeys = 0;
    
    	if (keyp != NULL)
    		*keyp = NULL;
    
    	if ((r = private2_uudecode(blob, &decoded)) != 0)
    		goto out;
    	/* parse public key from unencrypted envelope */
    	if ((r = sshbuf_consume(decoded, sizeof(AUTH_MAGIC))) != 0 ||
    	    (r = sshbuf_skip_string(decoded)) != 0 || /* cipher */
    	    (r = sshbuf_skip_string(decoded)) != 0 || /* KDF alg */
    	    (r = sshbuf_skip_string(decoded)) != 0 || /* KDF hint */
    	    (r = sshbuf_get_u32(decoded, &nkeys)) != 0)
    		goto out;
    
    	if (nkeys != 1) {
    		/* XXX only one key supported at present */
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    
    	/* Parse the public key */
    	if ((r = sshkey_froms(decoded, &pubkey)) != 0)
    		goto out;
    
    	if (type != KEY_UNSPEC &&
    	    sshkey_type_plain(type) != sshkey_type_plain(pubkey->type)) {
    		r = SSH_ERR_KEY_TYPE_MISMATCH;
    		goto out;
    	}
    
    	/* success */
    	r = 0;
    	if (keyp != NULL) {
    		*keyp = pubkey;
    		pubkey = NULL;
    	}
     out:
    	sshbuf_free(decoded);
    	sshkey_free(pubkey);
    	return r;
    }
    
    #ifdef WITH_OPENSSL
    /* convert SSH v2 key to PEM or PKCS#8 format */
    static int
    sshkey_private_to_blob_pem_pkcs8(struct sshkey *key, struct sshbuf *buf,
        int format, const char *_passphrase, const char *comment)
    {
    	int was_shielded = sshkey_is_shielded(key);
    	int success, r;
    	int blen, len = strlen(_passphrase);
    	u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL;
    	const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL;
    	char *bptr;
    	BIO *bio = NULL;
    	struct sshbuf *blob;
    	EVP_PKEY *pkey = NULL;
    
    	if (len > 0 && len <= 4)
    		return SSH_ERR_PASSPHRASE_TOO_SHORT;
    	if ((blob = sshbuf_new()) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    	if ((bio = BIO_new(BIO_s_mem())) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if (format == SSHKEY_PRIVATE_PKCS8 && (pkey = EVP_PKEY_new()) == NULL) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    	if ((r = sshkey_unshield_private(key)) != 0)
    		goto out;
    
    	switch (key->type) {
    	case KEY_DSA:
    		if (format == SSHKEY_PRIVATE_PEM) {
    			success = PEM_write_bio_DSAPrivateKey(bio, key->dsa,
    			    cipher, passphrase, len, NULL, NULL);
    		} else {
    			success = EVP_PKEY_set1_DSA(pkey, key->dsa);
    		}
    		break;
    	case KEY_ECDSA:
    		if (format == SSHKEY_PRIVATE_PEM) {
    			success = PEM_write_bio_ECPrivateKey(bio, key->ecdsa,
    			    cipher, passphrase, len, NULL, NULL);
    		} else {
    			success = EVP_PKEY_set1_EC_KEY(pkey, key->ecdsa);
    		}
    		break;
    	case KEY_RSA:
    		if (format == SSHKEY_PRIVATE_PEM) {
    			success = PEM_write_bio_RSAPrivateKey(bio, key->rsa,
    			    cipher, passphrase, len, NULL, NULL);
    		} else {
    			success = EVP_PKEY_set1_RSA(pkey, key->rsa);
    		}
    		break;
    	default:
    		success = 0;
    		break;
    	}
    	if (success == 0) {
    		r = SSH_ERR_LIBCRYPTO_ERROR;
    		goto out;
    	}
    	if (format == SSHKEY_PRIVATE_PKCS8) {
    		if ((success = PEM_write_bio_PrivateKey(bio, pkey, cipher,
    		    passphrase, len, NULL, NULL)) == 0) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    	}
    	if ((blen = BIO_get_mem_data(bio, &bptr)) <= 0) {
    		r = SSH_ERR_INTERNAL_ERROR;
    		goto out;
    	}
    	if ((r = sshbuf_put(blob, bptr, blen)) != 0)
    		goto out;
    	r = 0;
     out:
    	if (was_shielded)
    		r = sshkey_shield_private(key);
    	if (r == 0)
    		r = sshbuf_putb(buf, blob);
    
    	EVP_PKEY_free(pkey);
    	sshbuf_free(blob);
    	BIO_free(bio);
    	return r;
    }
    #endif /* WITH_OPENSSL */
    
    /* Serialise "key" to buffer "blob" */
    int
    sshkey_private_to_fileblob(struct sshkey *key, struct sshbuf *blob,
        const char *passphrase, const char *comment,
        int format, const char *openssh_format_cipher, int openssh_format_rounds)
    {
    	switch (key->type) {
    #ifdef WITH_OPENSSL
    	case KEY_DSA:
    	case KEY_ECDSA:
    	case KEY_RSA:
    		break; /* see below */
    #endif /* WITH_OPENSSL */
    	case KEY_ED25519:
    	case KEY_ED25519_SK:
    #ifdef WITH_XMSS
    	case KEY_XMSS:
    #endif /* WITH_XMSS */
    #ifdef WITH_OPENSSL
    	case KEY_ECDSA_SK:
    #endif /* WITH_OPENSSL */
    		return sshkey_private_to_blob2(key, blob, passphrase,
    		    comment, openssh_format_cipher, openssh_format_rounds);
    	default:
    		return SSH_ERR_KEY_TYPE_UNKNOWN;
    	}
    
    #ifdef WITH_OPENSSL
    	switch (format) {
    	case SSHKEY_PRIVATE_OPENSSH:
    		return sshkey_private_to_blob2(key, blob, passphrase,
    		    comment, openssh_format_cipher, openssh_format_rounds);
    	case SSHKEY_PRIVATE_PEM:
    	case SSHKEY_PRIVATE_PKCS8:
    		return sshkey_private_to_blob_pem_pkcs8(key, blob,
    		    format, passphrase, comment);
    	default:
    		return SSH_ERR_INVALID_ARGUMENT;
    	}
    #endif /* WITH_OPENSSL */
    }
    
    #ifdef WITH_OPENSSL
    static int
    translate_libcrypto_error(unsigned long pem_err)
    {
    	int pem_reason = ERR_GET_REASON(pem_err);
    
    	switch (ERR_GET_LIB(pem_err)) {
    	case ERR_LIB_PEM:
    		switch (pem_reason) {
    		case PEM_R_BAD_PASSWORD_READ:
    		case PEM_R_PROBLEMS_GETTING_PASSWORD:
    		case PEM_R_BAD_DECRYPT:
    			return SSH_ERR_KEY_WRONG_PASSPHRASE;
    		default:
    			return SSH_ERR_INVALID_FORMAT;
    		}
    	case ERR_LIB_EVP:
    		switch (pem_reason) {
    		case EVP_R_BAD_DECRYPT:
    			return SSH_ERR_KEY_WRONG_PASSPHRASE;
    #ifdef EVP_R_BN_DECODE_ERROR
    		case EVP_R_BN_DECODE_ERROR:
    #endif
    		case EVP_R_DECODE_ERROR:
    #ifdef EVP_R_PRIVATE_KEY_DECODE_ERROR
    		case EVP_R_PRIVATE_KEY_DECODE_ERROR:
    #endif
    			return SSH_ERR_INVALID_FORMAT;
    		default:
    			return SSH_ERR_LIBCRYPTO_ERROR;
    		}
    	case ERR_LIB_ASN1:
    		return SSH_ERR_INVALID_FORMAT;
    	}
    	return SSH_ERR_LIBCRYPTO_ERROR;
    }
    
    static void
    clear_libcrypto_errors(void)
    {
    	while (ERR_get_error() != 0)
    		;
    }
    
    /*
     * Translate OpenSSL error codes to determine whether
     * passphrase is required/incorrect.
     */
    static int
    convert_libcrypto_error(void)
    {
    	/*
    	 * Some password errors are reported at the beginning
    	 * of the error queue.
    	 */
    	if (translate_libcrypto_error(ERR_peek_error()) ==
    	    SSH_ERR_KEY_WRONG_PASSPHRASE)
    		return SSH_ERR_KEY_WRONG_PASSPHRASE;
    	return translate_libcrypto_error(ERR_peek_last_error());
    }
    
    static int
    sshkey_parse_private_pem_fileblob(struct sshbuf *blob, int type,
        const char *passphrase, struct sshkey **keyp)
    {
    	EVP_PKEY *pk = NULL;
    	struct sshkey *prv = NULL;
    	BIO *bio = NULL;
    	int r;
    
    	if (keyp != NULL)
    		*keyp = NULL;
    
    	if ((bio = BIO_new(BIO_s_mem())) == NULL || sshbuf_len(blob) > INT_MAX)
    		return SSH_ERR_ALLOC_FAIL;
    	if (BIO_write(bio, sshbuf_ptr(blob), sshbuf_len(blob)) !=
    	    (int)sshbuf_len(blob)) {
    		r = SSH_ERR_ALLOC_FAIL;
    		goto out;
    	}
    
    	clear_libcrypto_errors();
    	if ((pk = PEM_read_bio_PrivateKey(bio, NULL, NULL,
    	    (char *)passphrase)) == NULL) {
    	       /*
    		* libcrypto may return various ASN.1 errors when attempting
    		* to parse a key with an incorrect passphrase.
    		* Treat all format errors as "incorrect passphrase" if a
    		* passphrase was supplied.
    		*/
    		if (passphrase != NULL && *passphrase != '\0')
    			r = SSH_ERR_KEY_WRONG_PASSPHRASE;
    		else
    			r = convert_libcrypto_error();
    		goto out;
    	}
    	if (EVP_PKEY_base_id(pk) == EVP_PKEY_RSA &&
    	    (type == KEY_UNSPEC || type == KEY_RSA)) {
    		if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
    			r = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		prv->rsa = EVP_PKEY_get1_RSA(pk);
    		prv->type = KEY_RSA;
    #ifdef DEBUG_PK
    		RSA_print_fp(stderr, prv->rsa, 8);
    #endif
    		if (RSA_blinding_on(prv->rsa, NULL) != 1) {
    			r = SSH_ERR_LIBCRYPTO_ERROR;
    			goto out;
    		}
    		if ((r = check_rsa_length(prv->rsa)) != 0)
    			goto out;
    	} else if (EVP_PKEY_base_id(pk) == EVP_PKEY_DSA &&
    	    (type == KEY_UNSPEC || type == KEY_DSA)) {
    		if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
    			r = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		prv->dsa = EVP_PKEY_get1_DSA(pk);
    		prv->type = KEY_DSA;
    #ifdef DEBUG_PK
    		DSA_print_fp(stderr, prv->dsa, 8);
    #endif
    	} else if (EVP_PKEY_base_id(pk) == EVP_PKEY_EC &&
    	    (type == KEY_UNSPEC || type == KEY_ECDSA)) {
    		if ((prv = sshkey_new(KEY_UNSPEC)) == NULL) {
    			r = SSH_ERR_ALLOC_FAIL;
    			goto out;
    		}
    		prv->ecdsa = EVP_PKEY_get1_EC_KEY(pk);
    		prv->type = KEY_ECDSA;
    		prv->ecdsa_nid = sshkey_ecdsa_key_to_nid(prv->ecdsa);
    		if (prv->ecdsa_nid == -1 ||
    		    sshkey_curve_nid_to_name(prv->ecdsa_nid) == NULL ||
    		    sshkey_ec_validate_public(EC_KEY_get0_group(prv->ecdsa),
    		    EC_KEY_get0_public_key(prv->ecdsa)) != 0 ||
    		    sshkey_ec_validate_private(prv->ecdsa) != 0) {
    			r = SSH_ERR_INVALID_FORMAT;
    			goto out;
    		}
    #ifdef DEBUG_PK
    		if (prv != NULL && prv->ecdsa != NULL)
    			sshkey_dump_ec_key(prv->ecdsa);
    #endif
    	} else {
    		r = SSH_ERR_INVALID_FORMAT;
    		goto out;
    	}
    	r = 0;
    	if (keyp != NULL) {
    		*keyp = prv;
    		prv = NULL;
    	}
     out:
    	BIO_free(bio);
    	EVP_PKEY_free(pk);
    	sshkey_free(prv);
    	return r;
    }
    #endif /* WITH_OPENSSL */
    
    int
    sshkey_parse_private_fileblob_type(struct sshbuf *blob, int type,
        const char *passphrase, struct sshkey **keyp, char **commentp)
    {
    	int r = SSH_ERR_INTERNAL_ERROR;
    
    	if (keyp != NULL)
    		*keyp = NULL;
    	if (commentp != NULL)
    		*commentp = NULL;
    
    	switch (type) {
    	case KEY_ED25519:
    	case KEY_XMSS:
    		/* No fallback for new-format-only keys */
    		return sshkey_parse_private2(blob, type, passphrase,
    		    keyp, commentp);
    	default:
    		r = sshkey_parse_private2(blob, type, passphrase, keyp,
    		    commentp);
    		/* Only fallback to PEM parser if a format error occurred. */
    		if (r != SSH_ERR_INVALID_FORMAT)
    			return r;
    #ifdef WITH_OPENSSL
    		return sshkey_parse_private_pem_fileblob(blob, type,
    		    passphrase, keyp);
    #else
    		return SSH_ERR_INVALID_FORMAT;
    #endif /* WITH_OPENSSL */
    	}
    }
    
    int
    sshkey_parse_private_fileblob(struct sshbuf *buffer, const char *passphrase,
        struct sshkey **keyp, char **commentp)
    {
    	if (keyp != NULL)
    		*keyp = NULL;
    	if (commentp != NULL)
    		*commentp = NULL;
    
    	return sshkey_parse_private_fileblob_type(buffer, KEY_UNSPEC,
    	    passphrase, keyp, commentp);
    }
    
    void
    sshkey_sig_details_free(struct sshkey_sig_details *details)
    {
    	freezero(details, sizeof(*details));
    }
    
    int
    sshkey_parse_pubkey_from_private_fileblob_type(struct sshbuf *blob, int type,
        struct sshkey **pubkeyp)
    {
    	int r = SSH_ERR_INTERNAL_ERROR;
    
    	if (pubkeyp != NULL)
    		*pubkeyp = NULL;
    	/* only new-format private keys bundle a public key inside */
    	if ((r = sshkey_parse_private2_pubkey(blob, type, pubkeyp)) != 0)
    		return r;
    	return 0;
    }
    
    #ifdef WITH_XMSS
    /*
     * serialize the key with the current state and forward the state
     * maxsign times.
     */
    int
    sshkey_private_serialize_maxsign(struct sshkey *k, struct sshbuf *b,
        u_int32_t maxsign, sshkey_printfn *pr)
    {
    	int r, rupdate;
    
    	if (maxsign == 0 ||
    	    sshkey_type_plain(k->type) != KEY_XMSS)
    		return sshkey_private_serialize_opt(k, b,
    		    SSHKEY_SERIALIZE_DEFAULT);
    	if ((r = sshkey_xmss_get_state(k, pr)) != 0 ||
    	    (r = sshkey_private_serialize_opt(k, b,
    	    SSHKEY_SERIALIZE_STATE)) != 0 ||
    	    (r = sshkey_xmss_forward_state(k, maxsign)) != 0)
    		goto out;
    	r = 0;
    out:
    	if ((rupdate = sshkey_xmss_update_state(k, pr)) != 0) {
    		if (r == 0)
    			r = rupdate;
    	}
    	return r;
    }
    
    u_int32_t
    sshkey_signatures_left(const struct sshkey *k)
    {
    	if (sshkey_type_plain(k->type) == KEY_XMSS)
    		return sshkey_xmss_signatures_left(k);
    	return 0;
    }
    
    int
    sshkey_enable_maxsign(struct sshkey *k, u_int32_t maxsign)
    {
    	if (sshkey_type_plain(k->type) != KEY_XMSS)
    		return SSH_ERR_INVALID_ARGUMENT;
    	return sshkey_xmss_enable_maxsign(k, maxsign);
    }
    
    int
    sshkey_set_filename(struct sshkey *k, const char *filename)
    {
    	if (k == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	if (sshkey_type_plain(k->type) != KEY_XMSS)
    		return 0;
    	if (filename == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	if ((k->xmss_filename = strdup(filename)) == NULL)
    		return SSH_ERR_ALLOC_FAIL;
    	return 0;
    }
    #else
    int
    sshkey_private_serialize_maxsign(struct sshkey *k, struct sshbuf *b,
        u_int32_t maxsign, sshkey_printfn *pr)
    {
    	return sshkey_private_serialize_opt(k, b, SSHKEY_SERIALIZE_DEFAULT);
    }
    
    u_int32_t
    sshkey_signatures_left(const struct sshkey *k)
    {
    	return 0;
    }
    
    int
    sshkey_enable_maxsign(struct sshkey *k, u_int32_t maxsign)
    {
    	return SSH_ERR_INVALID_ARGUMENT;
    }
    
    int
    sshkey_set_filename(struct sshkey *k, const char *filename)
    {
    	if (k == NULL)
    		return SSH_ERR_INVALID_ARGUMENT;
    	return 0;
    }
    #endif /* WITH_XMSS */