[crypto] Add parentheses around len argument in blocksize assert
This fixes an issue where passing a length as a compound expression
(e.g. using `hdrlen + datalen') would trigger compiler warnings and
potentially precedence-related errors.
Signed-off-by: Marty Connor <mdc@etherboot.org>
[crypto] Change cipher_{en,de}crypt() to void functions
It is a programming error, not a runtime error, if we attempt to use
block ciphers with an incorrect blocksize, so use an assert() rather
than an error status return.
[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.