tree f6d862fda8608a41677ec721f5dc280a1899a320
parent fb43f69401fef8ed2f72d7ea4a25910a0f2138bc
author Martin Willi <martin@strongswan.org> 1433159036 +0200
committer Herbert Xu <herbert@gondor.apana.org.au> 1433401489 +0800

crypto: chacha20 - Add a generic ChaCha20 stream cipher implementation

ChaCha20 is a high speed 256-bit key size stream cipher algorithm designed by
Daniel J. Bernstein. It is further specified in RFC7539 for use in IETF
protocols as a building block for the ChaCha20-Poly1305 AEAD.

This is a portable C implementation without any architecture specific
optimizations. It uses a 16-byte IV, which includes the 12-byte ChaCha20 nonce
prepended by the initial block counter. Some algorithms require an explicit
counter value, for example the mentioned AEAD construction.

Signed-off-by: Martin Willi <martin@strongswan.org>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>