thodg/totp-rs

diff --git a/examples/gen_secret.rs b/examples/gen_secret.rs
index d8c0878..527fc10 100644
--- a/examples/gen_secret.rs
+++ b/examples/gen_secret.rs
@@ -1,8 +1,7 @@
-#[cfg(not(feature = "gen_secret"))]
-compile_error!("requires feature gen_secret");
-
+#[cfg(all(feature = "gen_secret", feature = "otpauth"))]
 use totp_rs::{Secret, TOTP, Algorithm};
 
+#[cfg(all(feature = "gen_secret", feature = "otpauth"))]
 fn main () {
 
     let secret = Secret::generate_secret();
@@ -24,3 +23,6 @@ fn main () {
         totp.generate_current().unwrap()
     )
 }
+
+#[cfg(not(all(feature = "gen_secret", feature = "otpauth")))]
+fn main () {}
\ No newline at end of file
diff --git a/examples/rfc-6238.rs b/examples/rfc-6238.rs
index 12a9d59..4e3975c 100644
--- a/examples/rfc-6238.rs
+++ b/examples/rfc-6238.rs
@@ -1,5 +1,6 @@
 use totp_rs::{Rfc6238, TOTP};
 
+#[cfg(feature = "otpauth")]
 fn main () {
     let mut rfc = Rfc6238::with_defaults(
         "totp-sercret-123"
@@ -15,3 +16,18 @@ fn main () {
     let code = totp.generate_current().unwrap();
     println!("code: {}", code);
 }
+
+#[cfg(not(feature = "otpauth"))]
+fn main () {
+    let mut rfc = Rfc6238::with_defaults(
+        "totp-sercret-123"
+    ).unwrap();
+
+    // optional, set digits, issuer, account_name
+    rfc.digits(8).unwrap();
+
+    // create a TOTP from rfc
+    let totp = TOTP::from_rfc6238(rfc).unwrap();
+    let code = totp.generate_current().unwrap();
+    println!("code: {}", code);
+}
\ No newline at end of file
diff --git a/examples/secret.rs b/examples/secret.rs
index 5ff7276..adf1eaa 100644
--- a/examples/secret.rs
+++ b/examples/secret.rs
@@ -1,5 +1,6 @@
 use totp_rs::{Secret, TOTP, Algorithm};
 
+#[cfg(feature = "otpauth")]
 fn main () {
     // create TOTP from base32 secret
     let secret_b32 = Secret::Encoded(String::from("OBWGC2LOFVZXI4TJNZTS243FMNZGK5BNGEZDG"));
@@ -9,8 +10,8 @@ fn main () {
         1,
         30,
         secret_b32.to_bytes().unwrap(),
-        None,
-        "account".to_string(),
+        Some("issuer".to_string()),
+        "user-account".to_string(),
     ).unwrap();
 
     println!("base32 {} ; raw {}", secret_b32, secret_b32.to_raw().unwrap());
@@ -28,10 +29,43 @@ fn main () {
         1,
         30,
         secret_raw.to_bytes().unwrap(),
-        None,
-        "account".to_string(),
+        Some("issuer".to_string()),
+        "user-account".to_string(),
     ).unwrap();
 
     println!("raw {} ; base32 {}", secret_raw, secret_raw.to_encoded());
     println!("code from raw secret:\t{}", totp_raw.generate_current().unwrap());
 }
+
+#[cfg(not(feature = "otpauth"))]
+fn main () {
+    // create TOTP from base32 secret
+    let secret_b32 = Secret::Encoded(String::from("OBWGC2LOFVZXI4TJNZTS243FMNZGK5BNGEZDG"));
+    let totp_b32 = TOTP::new(
+        Algorithm::SHA1,
+        6,
+        1,
+        30,
+        secret_b32.to_bytes().unwrap(),
+    ).unwrap();
+
+    println!("base32 {} ; raw {}", secret_b32, secret_b32.to_raw().unwrap());
+    println!("code from base32:\t{}", totp_b32.generate_current().unwrap());
+
+    // create TOTP from raw binary value
+    let secret = [
+        0x70, 0x6c, 0x61, 0x69, 0x6e, 0x2d, 0x73, 0x74, 0x72, 0x69, 0x6e, 0x67, 0x2d, 0x73, 0x65,
+        0x63, 0x72, 0x65, 0x74, 0x2d, 0x31, 0x32, 0x33,
+    ];
+    let secret_raw = Secret::Raw(secret.to_vec());
+    let totp_raw = TOTP::new(
+        Algorithm::SHA1,
+        6,
+        1,
+        30,
+        secret_raw.to_bytes().unwrap(),
+    ).unwrap();
+
+    println!("raw {} ; base32 {}", secret_raw, secret_raw.to_encoded());
+    println!("code from raw secret:\t{}", totp_raw.generate_current().unwrap());
+}
\ No newline at end of file
diff --git a/examples/ttl.rs b/examples/ttl.rs
index 7554303..ec2c1a8 100644
--- a/examples/ttl.rs
+++ b/examples/ttl.rs
@@ -1,5 +1,6 @@
 use totp_rs::{Algorithm, TOTP};
 
+#[cfg(not(feature = "otpauth"))]
 fn main() {
     let totp = TOTP::new(
         Algorithm::SHA1,
@@ -7,8 +8,30 @@ fn main() {
         1,
         30,
         "my-secret".to_string(),
-        None,
-        "account".to_string(),
+    ).unwrap();
+
+    loop {
+        println!(
+            "code {}\t ttl {}\t valid until: {}",
+            totp.generate_current().unwrap(),
+            totp.ttl().unwrap(),
+            totp.next_step_current().unwrap()
+        );
+        std::thread::sleep(std::time::Duration::from_secs(1));
+    }
+}
+
+
+#[cfg(feature = "otpauth")]
+fn main() {
+    let totp = TOTP::new(
+        Algorithm::SHA1,
+        6,
+        1,
+        30,
+        "my-secret".to_string(),
+        Some("Github".to_string()),
+        "constantoine@github.com".to_string()
     ).unwrap();
 
     loop {
diff --git a/src/lib.rs b/src/lib.rs
index c33e800..382585c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -9,20 +9,22 @@
 //! # Examples
 //!
 //! ```rust
+//! # #[cfg(feature = "otpauth")] {
 //! use std::time::SystemTime;
-//! use totp_rs::{Algorithm, TOTP};
+//! use totp_rs::{Algorithm, TOTP, Secret};
 //!
 //! let totp = TOTP::new(
 //!     Algorithm::SHA1,
 //!     6,
 //!     1,
 //!     30,
-//!     "supersecret_topsecret",
+//!     Secret::Raw("TestSecretSuperSecret".as_bytes().to_vec()).to_bytes().unwrap(),
 //!     Some("Github".to_string()),
 //!     "constantoine@github.com".to_string(),
 //! ).unwrap();
 //! let token = totp.generate_current().unwrap();
 //! println!("{}", token);
+//! # }
 //! ```
 //!
 //! ```rust
@@ -142,10 +144,12 @@ pub struct TOTP<T = Vec<u8>> {
     ///
     /// non-encoded value
     pub secret: T,
+    #[cfg(feature = "otpauth")]
     /// The "Github" part of "Github:constantoine@github.com". Must not contain a colon `:`
     /// For example, the name of your service/website.
     /// Not mandatory, but strongly recommended!
     pub issuer: Option<String>,
+    #[cfg(feature = "otpauth")]
     /// The "constantoine@github.com" part of "Github:constantoine@github.com". Must not contain a colon `:`
     /// For example, the name of your user's account.
     pub account_name: String
@@ -171,7 +175,23 @@ impl <T: AsRef<[u8]>> PartialEq for TOTP<T> {
     }
 }
 
+#[cfg(all(feature = "gen_secret", not(feature = "otpauth")))]
+impl Default for TOTP {
+    fn default() -> Self {
+        return TOTP::new(Algorithm::SHA1, 6, 1, 30, Secret::generate_secret().to_bytes().unwrap()).unwrap()
+    }
+}
+
+#[cfg(all(feature = "gen_secret", feature = "otpauth"))]
+impl Default for TOTP {
+    fn default() -> Self {
+        return TOTP::new(Algorithm::SHA1, 6, 1, 30, Secret::generate_secret().to_bytes().unwrap(), None, "".to_string()).unwrap()
+    }
+}
+
 impl<T: AsRef<[u8]>> TOTP<T> {
+
+    #[cfg(feature = "otpauth")]
     /// Will create a new instance of TOTP with given parameters. See [the doc](struct.TOTP.html#fields) for reference as to how to choose those values
     ///
     /// # Description
@@ -210,6 +230,35 @@ impl<T: AsRef<[u8]>> TOTP<T> {
         })
     }
 
+    #[cfg(not(feature = "otpauth"))]
+    /// Will create a new instance of TOTP with given parameters. See [the doc](struct.TOTP.html#fields) for reference as to how to choose those values
+    ///
+    /// # Description
+    /// * `secret`: expect a non-encoded value, to pass in base32 string use `Secret::Encoded(String)`
+    ///
+    /// ```rust
+    /// use totp_rs::{Secret, TOTP, Algorithm};
+    /// let secret = Secret::Encoded("OBWGC2LOFVZXI4TJNZTS243FMNZGK5BNGEZDG".to_string());
+    /// let totp = TOTP::new(Algorithm::SHA1, 6, 1, 30, secret.to_bytes().unwrap()).unwrap();
+    /// ```
+    /// * `digits`: MUST be between 6 & 8
+    /// * `secret`: Must have bitsize of at least 128
+    ///
+    /// # Errors
+    ///
+    /// Will return an error in case issuer or label contain the character ':'
+    pub fn new(algorithm: Algorithm, digits: usize,skew: u8, step: u64, secret: T) -> Result<TOTP<T>, TotpUrlError> {
+        crate::rfc::assert_digits(&digits)?;
+        crate::rfc::assert_secret_length(secret.as_ref())?;
+        Ok(TOTP {
+            algorithm,
+            digits,
+            skew,
+            step,
+            secret,
+        })
+    }
+
     /// Will create a new instance of TOTP from the given [Rfc6238](struct.Rfc6238.html) struct
     ///
     /// # Errors
@@ -462,6 +511,17 @@ mod tests {
     use super::*;
 
     #[test]
+    #[cfg(feature = "gen_secret")]
+    fn default_values() {
+        let totp = TOTP::default();
+        assert_eq!(totp.algorithm, Algorithm::SHA1);
+        assert_eq!(totp.digits, 6);
+        assert_eq!(totp.skew, 1);
+        assert_eq!(totp.step, 30)
+    }
+
+    #[test]
+    #[cfg(feature = "otpauth")]
     fn new_wrong_issuer() {
         let totp = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github:".to_string()), "constantoine@github.com".to_string());
         assert!(totp.is_err());
@@ -469,6 +529,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg(feature = "otpauth")]
     fn new_wrong_account_name() {
         let totp = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine:github.com".to_string());
         assert!(totp.is_err());
@@ -476,6 +537,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg(feature = "otpauth")]
     fn new_wrong_account_name_no_issuer() {
         let totp = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", None, "constantoine:github.com".to_string());
         assert!(totp.is_err());
@@ -483,6 +545,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg(feature = "otpauth")]
     fn comparison_ok() {
         let reference = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
         let test = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
@@ -490,37 +553,42 @@ mod tests {
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn comparison_different_algo() {
-        let reference = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
-        let test = TOTP::new(Algorithm::SHA256, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let reference = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret").unwrap();
+        let test = TOTP::new(Algorithm::SHA256, 6, 1, 1, "TestSecretSuperSecret").unwrap();
         assert_ne!(reference, test);
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn comparison_different_digits() {
-        let reference = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
-        let test = TOTP::new(Algorithm::SHA1, 8, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let reference = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret").unwrap();
+        let test = TOTP::new(Algorithm::SHA1, 8, 1, 1, "TestSecretSuperSecret").unwrap();
         assert_ne!(reference, test);
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn comparison_different_skew() {
-        let reference = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
-        let test = TOTP::new(Algorithm::SHA1, 6, 0, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let reference = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret").unwrap();
+        let test = TOTP::new(Algorithm::SHA1, 6, 0, 1, "TestSecretSuperSecret").unwrap();
         assert_ne!(reference, test);
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn comparison_different_step() {
-        let reference = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
-        let test = TOTP::new(Algorithm::SHA1, 6, 1, 30, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let reference = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret").unwrap();
+        let test = TOTP::new(Algorithm::SHA1, 6, 1, 30, "TestSecretSuperSecret").unwrap();
         assert_ne!(reference, test);
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn comparison_different_secret() {
-        let reference = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
-        let test = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretDifferentSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let reference = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret").unwrap();
+        let test = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretDifferentSecret").unwrap();
         assert_ne!(reference, test);
     }
 
@@ -557,20 +625,23 @@ mod tests {
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn returns_base32() {
-        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret").unwrap();
         assert_eq!(totp.get_secret_base32().as_str(), "KRSXG5CTMVRXEZLUKN2XAZLSKNSWG4TFOQ");
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn generate_token() {
-        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret").unwrap();
         assert_eq!(totp.generate(1000).as_str(), "659761");
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn generate_token_current() {
-        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret").unwrap();
         let time = SystemTime::now()
             .duration_since(SystemTime::UNIX_EPOCH).unwrap()
             .as_secs();
@@ -578,49 +649,56 @@ mod tests {
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn generates_token_sha256() {
-        let totp = TOTP::new(Algorithm::SHA256, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let totp = TOTP::new(Algorithm::SHA256, 6, 1, 1, "TestSecretSuperSecret").unwrap();
         assert_eq!(totp.generate(1000).as_str(), "076417");
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn generates_token_sha512() {
-        let totp = TOTP::new(Algorithm::SHA512, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let totp = TOTP::new(Algorithm::SHA512, 6, 1, 1, "TestSecretSuperSecret").unwrap();
         assert_eq!(totp.generate(1000).as_str(), "473536");
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn checks_token() {
-        let totp = TOTP::new(Algorithm::SHA1, 6, 0, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let totp = TOTP::new(Algorithm::SHA1, 6, 0, 1, "TestSecretSuperSecret").unwrap();
         assert!(totp.check("659761", 1000));
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn checks_token_current() {
-        let totp = TOTP::new(Algorithm::SHA1, 6, 0, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let totp = TOTP::new(Algorithm::SHA1, 6, 0, 1, "TestSecretSuperSecret").unwrap();
         assert!(totp.check_current(&totp.generate_current().unwrap()).unwrap());
         assert!(!totp.check_current("bogus").unwrap());
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn checks_token_with_skew() {
-        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 1, "TestSecretSuperSecret").unwrap();
         assert!(
             totp.check("174269", 1000) && totp.check("659761", 1000) && totp.check("260393", 1000)
         );
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn next_step() {
-        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 30, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 30, "TestSecretSuperSecret").unwrap();
         assert!(totp.next_step(0) == 30);
         assert!(totp.next_step(29) == 30);
         assert!(totp.next_step(30) == 60);
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn next_step_current() {
-        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 30, "TestSecretSuperSecret", Some("Github".to_string()), "constantoine@github.com".to_string()).unwrap();
+        let totp = TOTP::new(Algorithm::SHA1, 6, 1, 30, "TestSecretSuperSecret").unwrap();
         let t = system_time().unwrap();
         assert!(totp.next_step_current().unwrap() == totp.next_step(t));
     }
@@ -689,7 +767,7 @@ mod tests {
     #[test]
     #[cfg(feature = "otpauth")]
     fn from_url_query_different_issuers() {
-        let totp = TOTP::<Vec<u8>>::from_url("otpauth://totp/GitHub:test?issuer=Gitlab&secret=TestSecretSuperSecret&digits=8&period=60&algorithm=SHA256");
+        let totp = TOTP::<Vec<u8>>::from_url("otpauth://totp/GitHub:test?issuer=Gitlab&secret=KRSXG5CTMVRXEZLUKN2XAZLSKNSWG4TFOQ&digits=8&period=60&algorithm=SHA256");
         assert!(totp.is_err());
         assert!(matches!(totp.unwrap_err(), TotpUrlError::IssuerMistmatch(_, _)));
     }
diff --git a/src/rfc.rs b/src/rfc.rs
index 808a1e2..f5f763c 100644
--- a/src/rfc.rs
+++ b/src/rfc.rs
@@ -59,8 +59,6 @@ pub fn assert_secret_length(secret: &[u8]) -> Result<(), Rfc6238Error> {
 ///
 /// // optional, set digits, issuer, account_name
 /// rfc.digits(8).unwrap();
-/// rfc.issuer("issuer".to_string());
-/// rfc.account_name("user-account".to_string());
 ///
 /// let totp = TOTP::from_rfc6238(rfc).unwrap();
 /// ```
@@ -77,10 +75,12 @@ pub struct Rfc6238<T = Vec<u8>> {
     step: u64,
     /// As per [rfc-4226](https://tools.ietf.org/html/rfc4226#section-4) the secret should come from a strong source, most likely a CSPRNG. It should be at least 128 bits, but 160 are recommended
     secret: T,
+    #[cfg(feature = "otpauth")]
     /// The "Github" part of "Github:constantoine@github.com". Must not contain a colon `:`
     /// For example, the name of your service/website.
     /// Not mandatory, but strongly recommended!
     issuer: Option<String>,
+    #[cfg(feature = "otpauth")]
     /// The "constantoine@github.com" part of "Github:constantoine@github.com". Must not contain a colon `:`
     /// For example, the name of your user's account.
     account_name: String,
@@ -94,6 +94,7 @@ impl<T: AsRef<[u8]>> Rfc6238<T> {
     /// will return a [Rfc6238Error](enum.Rfc6238Error.html) when
     /// - `digits` is lower than 6 or higher than 8
     /// - `secret` is smaller than 128 bits (16 characters)
+    #[cfg(feature = "otpauth")]
     pub fn new(
         digits: usize,
         secret: T,
@@ -113,6 +114,22 @@ impl<T: AsRef<[u8]>> Rfc6238<T> {
             account_name,
         })
     }
+    #[cfg(not(feature = "otpauth"))]
+    pub fn new(
+        digits: usize,
+        secret: T,
+    ) -> Result<Rfc6238<T>, Rfc6238Error> {
+        assert_digits(&digits)?;
+        assert_secret_length(secret.as_ref())?;
+        
+        Ok(Rfc6238 {
+            algorithm: Algorithm::SHA1,
+            digits,
+            skew: 1,
+            step: 30,
+            secret,
+        })
+    }
 
     /// Create an [rfc-6238](https://tools.ietf.org/html/rfc6238) compliant set of options that can be turned into a [TOTP](struct.TOTP.html),
     /// with a default value of 6 for `digits`, None `issuer` and an empty account
@@ -122,8 +139,14 @@ impl<T: AsRef<[u8]>> Rfc6238<T> {
     /// will return a [Rfc6238Error](enum.Rfc6238Error.html) when
     /// - `digits` is lower than 6 or higher than 8
     /// - `secret` is smaller than 128 bits (16 characters)
+    #[cfg(feature = "otpauth")]
     pub fn with_defaults(secret: T) -> Result<Rfc6238<T>, Rfc6238Error> {
-        Rfc6238::new(6, secret, None, "".to_string())
+        Rfc6238::new(6, secret, Some("".to_string()), "".to_string())
+    }
+
+    #[cfg(not(feature = "otpauth"))]
+    pub fn with_defaults(secret: T) -> Result<Rfc6238<T>, Rfc6238Error> {
+        Rfc6238::new(6, secret)
     }
 
     /// Set the `digits`
@@ -133,17 +156,36 @@ impl<T: AsRef<[u8]>> Rfc6238<T> {
         Ok(())
     }
 
+    #[cfg(feature = "otpauth")]
     /// Set the `issuer`
     pub fn issuer(&mut self, value: String) {
         self.issuer = Some(value);
     }
 
-    /// Seet the `account_name`
+    #[cfg(feature = "otpauth")]
+    /// Set the `account_name`
     pub fn account_name(&mut self, value: String) {
         self.account_name = value;
     }
 }
 
+#[cfg(not(feature = "otpauth"))]
+impl<T: AsRef<[u8]>> TryFrom<Rfc6238<T>> for TOTP<T> {
+    type Error = TotpUrlError;
+
+    /// Try to create a [TOTP](struct.TOTP.html) from a [Rfc6238](struct.Rfc6238.html) config
+    fn try_from(rfc: Rfc6238<T>) -> Result<Self, Self::Error> {
+        TOTP::new(
+            rfc.algorithm,
+            rfc.digits,
+            rfc.skew,
+            rfc.step,
+            rfc.secret,
+        )
+    }
+}
+
+#[cfg(feature = "otpauth")]
 impl<T: AsRef<[u8]>> TryFrom<Rfc6238<T>> for TOTP<T> {
     type Error = TotpUrlError;
 
@@ -156,30 +198,39 @@ impl<T: AsRef<[u8]>> TryFrom<Rfc6238<T>> for TOTP<T> {
             rfc.step,
             rfc.secret,
             rfc.issuer,
-            rfc.account_name,
+            rfc.account_name
         )
     }
 }
 
 #[cfg(test)]
 mod tests {
+    #[cfg(feature = "otpauth")]
     use crate::TotpUrlError;
 
-    use super::{Rfc6238, Rfc6238Error, TOTP};
+    use super::{Rfc6238, TOTP};
+
+    #[cfg(not(feature = "otpauth"))]
+    use super::Rfc6238Error;
+
+    #[cfg(not(feature = "otpauth"))]
+    use crate::Secret;
 
     const GOOD_SECRET: &str = "01234567890123456789";
+    #[cfg(feature = "otpauth")]
     const ISSUER: Option<&str> = None;
+    #[cfg(feature = "otpauth")]
     const ACCOUNT: &str = "valid-account";
+    #[cfg(feature = "otpauth")]
     const INVALID_ACCOUNT: &str = ":invalid-account";
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn new_rfc_digits() {
         for x in 0..=20 {
             let rfc = Rfc6238::new(
                 x,
                 GOOD_SECRET.to_string(),
-                ISSUER.map(str::to_string),
-                ACCOUNT.to_string(),
             );
             if !(6..=8).contains(&x) {
                 assert!(rfc.is_err());
@@ -191,6 +242,7 @@ mod tests {
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn new_rfc_secret() {
         let mut secret = String::from("");
         for _ in 0..=20 {
@@ -198,8 +250,6 @@ mod tests {
             let rfc = Rfc6238::new(
                 6,
                 secret.clone(),
-                ISSUER.map(str::to_string),
-                ACCOUNT.to_string(),
             );
             let rfc_default = Rfc6238::with_defaults(secret.clone());
             if secret.len() < 16 {
@@ -215,12 +265,11 @@ mod tests {
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn rfc_to_totp_ok() {
         let rfc = Rfc6238::new(
             8,
             GOOD_SECRET.to_string(),
-            ISSUER.map(str::to_string),
-            ACCOUNT.to_string(),
         )
         .unwrap();
         let totp = TOTP::try_from(rfc);
@@ -228,14 +277,29 @@ mod tests {
         let otp = totp.unwrap();
         assert_eq!(&otp.secret, GOOD_SECRET);
         assert_eq!(otp.algorithm, crate::Algorithm::SHA1);
-        assert_eq!(&otp.account_name, ACCOUNT);
         assert_eq!(otp.digits, 8);
-        assert_eq!(otp.issuer, ISSUER.map(str::to_string));
         assert_eq!(otp.skew, 1);
         assert_eq!(otp.step, 30)
     }
 
     #[test]
+    #[cfg(not(feature = "otpauth"))]
+    fn rfc_to_totp_ok_2() {
+        let rfc = Rfc6238::with_defaults(
+            Secret::Encoded("KRSXG5CTMVRXEZLUKN2XAZLSKNSWG4TFOQ".to_string()).to_bytes().unwrap(),
+        )
+        .unwrap();
+        let totp = TOTP::try_from(rfc);
+        assert!(totp.is_ok());
+        let otp = totp.unwrap();
+        assert_eq!(otp.algorithm, crate::Algorithm::SHA1);
+        assert_eq!(otp.digits, 6);
+        assert_eq!(otp.skew, 1);
+        assert_eq!(otp.step, 30)
+    }
+
+    #[test]
+    #[cfg(feature = "otpauth")]
     fn rfc_to_totp_fail() {
         let rfc = Rfc6238::new(
             8,
@@ -250,14 +314,23 @@ mod tests {
     }
 
     #[test]
+    #[cfg(feature = "otpauth")]
+    fn rfc_to_totp_ok() {
+        let rfc = Rfc6238::new(
+            8,
+            GOOD_SECRET.to_string(),
+            ISSUER.map(str::to_string),
+            ACCOUNT.to_string(),
+        )
+        .unwrap();
+        let totp = TOTP::try_from(rfc);
+        assert!(!totp.is_err());
+    }
+
+    #[test]
+    #[cfg(not(feature = "otpauth"))]
     fn rfc_with_default_set_values() {
-        let new_account = "new-account";
-        let new_issuer = String::from("new-issuer");
         let mut rfc = Rfc6238::with_defaults(GOOD_SECRET.to_string()).unwrap();
-        rfc.issuer(new_issuer.clone());
-        assert_eq!(rfc.issuer, Some(new_issuer));
-        rfc.account_name(new_account.to_string());
-        assert_eq!(rfc.account_name, new_account.to_string());
         let fail = rfc.digits(4);
         assert!(fail.is_err());
         assert!(matches!(fail.unwrap_err(), Rfc6238Error::InvalidDigits(_)));