From 1dc19a0714d3e58b9fbbe1838137002254ba87c1 Mon Sep 17 00:00:00 2001 From: Daiki Ueno Date: Sat, 23 Mar 2024 17:58:21 +0900 Subject: [PATCH 2/3] shake256: Rename sha3_256_shake_output to sha3_shake256_output This adds a new family of functions to deal with SHAKE256. The original sha3_256_shake is deprecated in favor of this, and re-implemented using the new functions. Signed-off-by: Daiki Ueno --- sha3.h | 36 ++++++++++++++++++++++++++--------- shake256.c | 40 +++++++++++++++++++++++---------------- testsuite/shake256-test.c | 10 +++++----- 3 files changed, 56 insertions(+), 30 deletions(-) diff --git a/sha3.h b/sha3.h index 4b7e186c..87cbb879 100644 --- a/sha3.h +++ b/sha3.h @@ -49,7 +49,9 @@ extern "C" { #define sha3_256_update nettle_sha3_256_update #define sha3_256_digest nettle_sha3_256_digest #define sha3_256_shake nettle_sha3_256_shake -#define sha3_256_shake_output nettle_sha3_256_shake_output +#define sha3_shake256_init nettle_sha3_shake256_init +#define sha3_shake256_update nettle_sha3_shake256_update +#define sha3_shake256_output nettle_sha3_shake256_output #define sha3_384_init nettle_sha3_384_init #define sha3_384_update nettle_sha3_384_update #define sha3_384_digest nettle_sha3_384_digest @@ -91,6 +93,8 @@ sha3_permute (struct sha3_state *state); #define SHA3_512_DIGEST_SIZE 64 #define SHA3_512_BLOCK_SIZE 72 +#define SHA3_SHAKE256_BLOCK_SIZE SHA3_256_BLOCK_SIZE + /* For backwards compatibility */ #define SHA3_224_DATA_SIZE SHA3_224_BLOCK_SIZE #define SHA3_256_DATA_SIZE SHA3_256_BLOCK_SIZE @@ -137,17 +141,31 @@ sha3_256_digest(struct sha3_256_ctx *ctx, size_t length, uint8_t *digest); -/* Alternative digest function implementing shake256, with arbitrary - digest size */ +/* This function is deprecated; consider migrating to sha3_shake256_* + interface. */ void -sha3_256_shake(struct sha3_256_ctx *ctx, - size_t length, - uint8_t *digest); +sha3_256_shake (struct sha3_256_ctx *ctx, + size_t length, + uint8_t *digest); + +/* Alternative interface implementing SHAKE256, with arbitrary digest size. */ +struct sha3_shake256_ctx +{ + struct sha3_state state; + unsigned index; + uint8_t block[SHA3_SHAKE256_BLOCK_SIZE]; +}; + +void +sha3_shake256_init (struct sha3_shake256_ctx *ctx); + +void +sha3_shake256_update (struct sha3_shake256_ctx *ctx, + size_t length, + const uint8_t *data); -/* Unlike sha3_256_shake, this function can be called multiple times - to retrieve output from shake256 in an incremental manner */ void -sha3_256_shake_output(struct sha3_256_ctx *ctx, +sha3_shake256_output (struct sha3_shake256_ctx *ctx, size_t length, uint8_t *digest); diff --git a/shake256.c b/shake256.c index 11d34d5e..879c0935 100644 --- a/shake256.c +++ b/shake256.c @@ -49,27 +49,25 @@ #define INDEX_HIGH_BIT (~((UINT_MAX) >> 1)) void -sha3_256_shake (struct sha3_256_ctx *ctx, - size_t length, - uint8_t *dst) +sha3_shake256_init (struct sha3_shake256_ctx *ctx) { - _sha3_pad_shake (&ctx->state, SHA3_256_BLOCK_SIZE, ctx->block, ctx->index); - while (length > SHA3_256_BLOCK_SIZE) - { - _nettle_write_le64 (SHA3_256_BLOCK_SIZE, dst, ctx->state.a); - length -= SHA3_256_BLOCK_SIZE; - dst += SHA3_256_BLOCK_SIZE; - sha3_permute (&ctx->state); - } - _nettle_write_le64 (length, dst, ctx->state.a); + memset (ctx, 0, offsetof (struct sha3_shake256_ctx, block)); +} - sha3_256_init (ctx); +void +sha3_shake256_update (struct sha3_shake256_ctx *ctx, + size_t length, + const uint8_t *data) +{ + ctx->index = _nettle_sha3_update (&ctx->state, + SHA3_256_BLOCK_SIZE, ctx->block, + ctx->index, length, data); } void -sha3_256_shake_output (struct sha3_256_ctx *ctx, - size_t length, - uint8_t *digest) +sha3_shake256_output (struct sha3_shake256_ctx *ctx, + size_t length, + uint8_t *digest) { unsigned index, left; @@ -126,3 +124,13 @@ sha3_256_shake_output (struct sha3_256_ctx *ctx, } ctx->index = ~length; } + +void +sha3_256_shake (struct sha3_256_ctx *ctx, + size_t length, + uint8_t *dst) +{ + struct sha3_shake256_ctx *shake = (struct sha3_shake256_ctx *) ctx; + sha3_shake256_output (shake, length, dst); + sha3_shake256_init (shake); +} diff --git a/testsuite/shake256-test.c b/testsuite/shake256-test.c index 016060e8..38326466 100644 --- a/testsuite/shake256-test.c +++ b/testsuite/shake256-test.c @@ -39,7 +39,7 @@ const struct nettle_hash nettle_shake256 = { "shake256", - sizeof(struct sha3_256_ctx), + sizeof(struct sha3_shake256_ctx), 0, SHA3_256_BLOCK_SIZE, (nettle_hash_init_func *) sha3_256_init, @@ -52,18 +52,18 @@ test_incremental (const struct tstring *msg, const struct tstring *digest, size_t interval) { - struct sha3_256_ctx ctx; + struct sha3_shake256_ctx ctx; size_t offset = 0; uint8_t *buffer = xalloc (digest->length); - sha3_256_init (&ctx); - sha3_256_update (&ctx, msg->length, msg->data); + sha3_shake256_init (&ctx); + sha3_shake256_update (&ctx, msg->length, msg->data); while (offset < digest->length) { size_t to_read = MIN(digest->length - offset, interval); - sha3_256_shake_output (&ctx, to_read, buffer + offset); + sha3_shake256_output (&ctx, to_read, buffer + offset); offset += to_read; } -- 2.44.0