From dd333449d0fb667c5250c42488a7e90470e16c77 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Fri, 16 Nov 2018 17:26:18 -0800 Subject: crypto: chacha20-generic - add HChaCha20 library function Refactor the unkeyed permutation part of chacha20_block() into its own function, then add hchacha20_block() which is the ChaCha equivalent of HSalsa20 and is an intermediate step towards XChaCha20 (see https://cr.yp.to/snuffle/xsalsa-20081128.pdf). HChaCha20 skips the final addition of the initial state, and outputs only certain words of the state. It should not be used for streaming directly. Reviewed-by: Ard Biesheuvel Acked-by: Martin Willi Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu --- include/crypto/chacha20.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/crypto') diff --git a/include/crypto/chacha20.h b/include/crypto/chacha20.h index 2d3129442a52..56073814eef0 100644 --- a/include/crypto/chacha20.h +++ b/include/crypto/chacha20.h @@ -20,6 +20,8 @@ struct chacha20_ctx { }; void chacha20_block(u32 *state, u8 *stream); +void hchacha20_block(const u32 *in, u32 *out); + void crypto_chacha20_init(u32 *state, struct chacha20_ctx *ctx, u8 *iv); int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key, unsigned int keysize); -- cgit v1.2.3-55-g7522