antonmeep / pbkdf2

pbkdf2

This is a PBKDF2 algorithm implemented in Ada, tested against RFC6070 test vectors. Currently PBKDF2_HMAC_SHA_1, PBKDF2_HMAC_SHA_256 and PBKDF2_HMAC_SHA_512 are implemented using respective hmac, sha{1,2} crates. It is easy to use the generic interface to define new PBKDF2 functions for other hash functions.

pbkdf2's Issues

Extremely slow due to the underlying SHA implementation

Because this seems to be extremely slow compared, to say, OpenSSL. While clearly it would benefit from optimizations similar to what fastpbkdf2 uses, biggest bottleneck seems to be GNAT.SHA* modules. Ideally, I would prefer to have a separate crate for sha and hmac that would implement these algorithms in a platform-independent, portable and hopefully faster manner.

Example of a simple benchmark on 2^10 iterations:

Implementation	Time (s)
PBKDF2	5.527577500
OpenSSL	1.494409900

Mark the package as Pure, Preelaborate

Because of the internal dependency on GNAT.SHA*, PBKDF2 package cannot be marked as Pure, Preelaborate. This is a great shame since cryptography functions are inherently Pure (same function called with the same parameters will always return same result) and don't usually have any initialization needed that would affect elaboration order.
Only solution - use an external sha and hmac implementation, as per #1