From 1b06460aa967e3afcfa6fc8d664874134ab6c739 Mon Sep 17 00:00:00 2001 From: Matthias Schiffer Date: Sat, 16 Nov 2013 22:13:38 +0100 Subject: ghash: builtin: use bytewise lookup table --- src/crypto/mac/ghash/builtin/ghash_builtin.c | 46 ++++++++++++++++------------ 1 file changed, 26 insertions(+), 20 deletions(-) (limited to 'src') diff --git a/src/crypto/mac/ghash/builtin/ghash_builtin.c b/src/crypto/mac/ghash/builtin/ghash_builtin.c index 34e118a..947dc34 100644 --- a/src/crypto/mac/ghash/builtin/ghash_builtin.c +++ b/src/crypto/mac/ghash/builtin/ghash_builtin.c @@ -28,7 +28,7 @@ struct fastd_mac_state { - fastd_block128_t H[32][16]; + fastd_block128_t H[16][256]; }; @@ -40,22 +40,30 @@ static inline uint8_t shr(fastd_block128_t *out, const fastd_block128_t *in, int uint8_t c = 0; for (i = 0; i < sizeof(fastd_block128_t); i++) { - uint8_t c2 = in->b[i] << (8-n); out->b[i] = (in->b[i] >> n) | c; - c = c2; + c = in->b[i] << (8-n); } return (c >> (8-n)); } +static inline uint8_t shr8(fastd_block128_t *out, const fastd_block128_t *in) { + size_t i; + + out->b[0] = 0; + + for (i = 1; i < sizeof(fastd_block128_t); i++) + out->b[i] = in->b[i-1]; + + return in->b[sizeof(fastd_block128_t)-1]; +} + static inline void mulH_a(fastd_block128_t *x, const fastd_mac_state_t *cstate) { fastd_block128_t out = {}; int i; - for (i = 0; i < 16; i++) { - xor_a(&out, &cstate->H[2*i][x->b[i]>>4]); - xor_a(&out, &cstate->H[2*i+1][x->b[i]&0xf]); - } + for (i = 0; i < 16; i++) + xor_a(&out, &cstate->H[i][x->b[i]]); *x = out; } @@ -70,16 +78,16 @@ static size_t ghash_key_length(fastd_context_t *ctx UNUSED, const fastd_mac_cont } static fastd_mac_state_t* ghash_init_state(fastd_context_t *ctx UNUSED, const fastd_mac_context_t *mctx UNUSED, const uint8_t *key) { - fastd_mac_state_t *state = malloc(sizeof(fastd_mac_state_t)); + fastd_mac_state_t *state = calloc(1, sizeof(fastd_mac_state_t)); - fastd_block128_t Hbase[4]; - fastd_block128_t Rbase[4]; + fastd_block128_t Hbase[8]; + fastd_block128_t Rbase[8]; memcpy(&Hbase[0], key, sizeof(fastd_block128_t)); Rbase[0] = r; int i; - for (i = 1; i < 4; i++) { + for (i = 1; i < 8; i++) { uint8_t carry = shr(&Hbase[i], &Hbase[i-1], 1); if (carry) xor_a(&Hbase[i], &r); @@ -87,25 +95,23 @@ static fastd_mac_state_t* ghash_init_state(fastd_context_t *ctx UNUSED, const fa shr(&Rbase[i], &Rbase[i-1], 1); } - fastd_block128_t R[16]; - memset(state->H, 0, sizeof(state->H)); - memset(R, 0, sizeof(R)); + fastd_block128_t R[256] = {}; - for (i = 0; i < 16; i++) { + for (i = 0; i < 256; i++) { int j; - for (j = 0; j < 4; j++) { - if (i & (8 >> j)) { + for (j = 0; j < 8; j++) { + if (i & (0x80 >> j)) { xor_a(&state->H[0][i], &Hbase[j]); xor_a(&R[i], &Rbase[j]); } } } - for (i = 1; i < 32; i++) { + for (i = 1; i < 16; i++) { int j; - for (j = 0; j < 16; j++) { - uint8_t carry = shr(&state->H[i][j], &state->H[i-1][j], 4); + for (j = 0; j < 256; j++) { + uint8_t carry = shr8(&state->H[i][j], &state->H[i-1][j]); xor_a(&state->H[i][j], &R[carry]); } } -- cgit v1.2.3