kc3-lang/gnulib/doc/posix-functions/getentropy.texi

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• doc/posix-functions/getentropy.texi

• @node getentropy
  @subsection @code{getentropy}
  @findex getentropy
  
  POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9799919799/functions/getentropy.html}
  
  Documentation:
  @itemize
  @item
  @ifinfo
  @ref{Unpredictable Bytes,,Generating Unpredictable Bytes,libc},
  @end ifinfo
  @ifnotinfo
  @url{https://www.gnu.org/software/libc/manual/html_node/Unpredictable-Bytes.html},
  @end ifnotinfo
  @item
  @uref{https://www.kernel.org/doc/man-pages/online/pages/man3/getentropy.3.html,,man getentropy}.
  @end itemize
  
  Gnulib module: getentropy
  @mindex getentropy
  
  Portability problems fixed by Gnulib:
  @itemize
  @item
  This function is missing on some platforms:
  glibc 2.24, Mac OS X 10.11, FreeBSD 11.0, NetBSD 9.3, OpenBSD 5.5, Minix 3.3, AIX 7.1, HP-UX 11.31, Solaris 11.0, Cygwin 1.7.x, mingw, MSVC 14, Android 8.1.
  @item
  This function is declared in @code{<sys/random.h>}, not in @code{<unistd.h>},
  on some platforms:
  macOS 14, Solaris 11.4, Android 9.0.
  @end itemize
  
  Portability problems not fixed by Gnulib:
  @itemize
  @end itemize
  
  @noindent
  Although this function is intended to produce random data, the data's
  security properties may not be appropriate for your application.
  For example, identical ``random'' data streams might be produced by
  rebooted virtual machines.  If this is of concern you may need to use
  additional techniques such as hedging.@footnote{Ristenpart T, Yilek
  S@. @url{https://pages.cs.wisc.edu/~rist/papers/sslhedge.pdf, When good
  randomness goes bad: virtual machine vulnerabilities and hedging
  deployed cryptography}. NDSS 2010.}
  
  @mindex getrandom
  @mindex crypto/gc-random
  Related modules include @code{getrandom}, which has a more-flexible
  but more-complex API, and @code{crypto/gc-random}, which is likely a
  better match for code already using the other @code{crypto} APIs.
  

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