[digest] Add HMAC-SHA1 based pseudorandom function and PBKDF2
Both of these routines are used by 802.11 WPA, but they are generic
and could be needed by other protocols as well.
Signed-off-by: Marty Connor <mdc@etherboot.org>
[crypto] Split crypto_algorithm into {digest,cipher,pubkey}_algorithm
The various types of cryptographic algorithm are fundamentally
different, and it was probably a mistake to try to handle them via a
single common type.
pubkey_algorithm is a placeholder type for now.