• Eric Biggers's avatar
    crypto: chacha20-generic - refactor to allow varying number of rounds · 1ca1b917
    Eric Biggers authored
    In preparation for adding XChaCha12 support, rename/refactor
    chacha20-generic to support different numbers of rounds.  The
    justification for needing XChaCha12 support is explained in more detail
    in the patch "crypto: chacha - add XChaCha12 support".
    
    The only difference between ChaCha{8,12,20} are the number of rounds
    itself; all other parts of the algorithm are the same.  Therefore,
    remove the "20" from all definitions, structures, functions, files, etc.
    that will be shared by all ChaCha versions.
    
    Also make ->setkey() store the round count in the chacha_ctx (previously
    chacha20_ctx).  The generic code then passes the round count through to
    chacha_block().  There will be a ->setkey() function for each explicitly
    allowed round count; the encrypt/decrypt functions will be the same.  I
    decided not to do it the opposite way (same ->setkey() function for all
    round counts, with different encrypt/decrypt functions) because that
    would have required more boilerplate code in architecture-specific
    implementations of ChaCha and XChaCha.
    Reviewed-by: 's avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
    Acked-by: 's avatarMartin Willi <martin@strongswan.org>
    Signed-off-by: 's avatarEric Biggers <ebiggers@google.com>
    Signed-off-by: 's avatarHerbert Xu <herbert@gondor.apana.org.au>
    1ca1b917
chacha20poly1305.c 19.4 KB