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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/cha-internals.texi | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/doc/cha-internals.texi b/doc/cha-internals.texi index 532057d51a..4cb3364d8c 100644 --- a/doc/cha-internals.texi +++ b/doc/cha-internals.texi @@ -527,7 +527,13 @@ For more information see @ref{Hardware security modules and abstract key types}. @node Random Number Generators-internals @section Random Number Generators -@subheading Inner workings +@subheading About the generators + +GnuTLS provides two random generators. The default, and the AES-DRBG random +generator which is only used when the library is compiled with support for +FIPS140-2 and the system is in FIPS140-2 mode. + +@subheading The default generator - inner workings The random number generator levels in @code{gnutls_rnd_level_t} map to two CHACHA-based random generators which are initially seeded using the OS random device, e.g., @code{/dev/urandom} @@ -575,6 +581,17 @@ a re-key of the PRNG using its own output, is additionally performed. That ensur the recovery of the PRNG state will not be sufficient to recover previously generated values. +@subheading The AES-DRBG generator - inner workings + +Similar with the default generator, the random number generator levels in @code{gnutls_rnd_level_t} map to two +AES-DRBG random generators which are initially seeded using the OS random device, +e.g., @code{/dev/urandom} or @code{getrandom()}. These random generators are +unique per thread, and are automatically re-seeded when a fork is detected. + +The AES-DRBG generator is based on the AES cipher in counter mode and is +re-seeded after a fixed amount of bytes are generated. + + @subheading Defense against PRNG attacks This section describes the counter-measures available in the Pseudo-random number generator (PRNG) |