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sha3: cosmetic tweaks to various names, comments. No logic changes.

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2013-01-15 19:52:30 +01:00
parent ac4100e103
commit 5b7f50f372
1 changed files with 63 additions and 61 deletions
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124
libbb/hash_md5_sha.c
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@ -926,66 +926,67 @@ void FAST_FUNC sha512_end(sha512_ctx_t *ctx, void *resbuf)
# define SHA3_SMALL CONFIG_SHA3_SMALL # define SHA3_SMALL CONFIG_SHA3_SMALL
#endif #endif
#define ARCH_IS_64BIT (sizeof(long) >= sizeof(uint64_t))
enum { enum {
cKeccakR_SizeInBytes = 576 / 8, KECCAK_IBLK_BYTES = 576 / 8,
cKeccakNumberOfRounds = 24, KECCAK_NROUNDS = 24,
}; };
/* Elements should be 64-bit, but top half is always zero or 0x80000000. /* Elements should be 64-bit, but top half is always zero or 0x80000000.
* It is encoded as a separate word below. * We encode 63rd bits in a separate word below.
* Same is true for 31th bits. * Same is true for 31th bits, which lets us use 16-bit table instead of 64-bit.
* The speed penalty is lost in the noise.
*/ */
static const uint16_t KeccakF_RoundConstants[cKeccakNumberOfRounds] = { static const uint16_t KECCAK_IOTA_CONST[KECCAK_NROUNDS] = {
0x0001UL, 0x0001U,
0x8082UL, 0x8082U,
0x808aUL, 0x808aU,
0x8000UL, 0x8000U,
0x808bUL, 0x808bU,
0x0001UL, 0x0001U,
0x8081UL, 0x8081U,
0x8009UL, 0x8009U,
0x008aUL, 0x008aU,
0x0088UL, 0x0088U,
0x8009UL, 0x8009U,
0x000aUL, 0x000aU,
0x808bUL, 0x808bU,
0x008bUL, 0x008bU,
0x8089UL, 0x8089U,
0x8003UL, 0x8003U,
0x8002UL, 0x8002U,
0x0080UL, 0x0080U,
0x800aUL, 0x800aU,
0x000aUL, 0x000aU,
0x8081UL, 0x8081U,
0x8080UL, 0x8080U,
0x0001UL, 0x0001U,
0x8008UL 0x8008U,
}; };
/* 0th first - 0011 0011 0000 0111 1101 1101: */ /* bit from CONST[0] is msb: 0011 0011 0000 0111 1101 1101 */
#define KeccakF_RoundConstantBit63 ((uint32_t)(0x3307dd00)) #define KECCAK_IOTA_CONST_bit63 ((uint32_t)(0x3307dd00))
/* 0th first - 0001 0110 0011 1000 0001 1011: */ /* bit from CONST[0] is msb: 0001 0110 0011 1000 0001 1011 */
#define KeccakF_RoundConstantBit31 ((uint32_t)(0x16381b00)) #define KECCAK_IOTA_CONST_bit31 ((uint32_t)(0x16381b00))
static const uint8_t KeccakF_RotationConstants[25] = { static const uint8_t KECCAK_ROT_CONST[25] = {
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 2, 14, 27, 41, 56, 8, 25, 43, 62, 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 2, 14, 27, 41, 56, 8, 25, 43, 62,
18, 39, 61, 20, 44 18, 39, 61, 20, 44
}; };
static const uint8_t KeccakF_PiLane[25] = { static const uint8_t KECCAK_PI_LANE[25] = {
10, 7, 11, 17, 18, 3, 5, 16, 8, 21, 24, 4, 15, 23, 19, 13, 12, 2, 20, 10, 7, 11, 17, 18, 3, 5, 16, 8, 21, 24, 4, 15, 23, 19, 13, 12, 2, 20,
14, 22, 9, 6, 1 14, 22, 9, 6, 1
}; };
static const uint8_t KeccakF_Mod5[10] = { static const uint8_t MOD5[10] = {
0, 1, 2, 3, 4, 0, 1, 2, 3, 4 0, 1, 2, 3, 4, 0, 1, 2, 3, 4
}; };
#define ARCH_IS_64BIT (sizeof(long) >= sizeof(uint64_t))
static void KeccakF(uint64_t *state) static void KeccakF(uint64_t *state)
{ {
uint8_t x, y; unsigned x, y;
int round; unsigned round;
if (BB_BIG_ENDIAN) { if (BB_BIG_ENDIAN) {
for (x = 0; x < 25; x++) { for (x = 0; x < 25; x++) {
@ -993,7 +994,7 @@ static void KeccakF(uint64_t *state)
} }
} }
for (round = 0; round < cKeccakNumberOfRounds; ++round) { for (round = 0; round < KECCAK_NROUNDS; ++round) {
/* Theta */ /* Theta */
{ {
uint64_t BC[10]; uint64_t BC[10];
@ -1003,7 +1004,7 @@ static void KeccakF(uint64_t *state)
^ state[x + 15] ^ state[x + 20]; ^ state[x + 15] ^ state[x + 20];
} }
/* Using 2x5 vector above eliminates the need to use /* Using 2x5 vector above eliminates the need to use
* [Mod5[x+N]] index trick below to calculate (x+N) % 5, * BC[MOD5[x+N]] trick below to fetch BC[(x+N) % 5],
* and the code is a bit _smaller_. * and the code is a bit _smaller_.
*/ */
for (x = 0; x < 5; ++x) { for (x = 0; x < 5; ++x) {
@ -1027,22 +1028,24 @@ static void KeccakF(uint64_t *state)
if (SHA3_SMALL) { if (SHA3_SMALL) {
uint64_t t1 = state[1]; uint64_t t1 = state[1];
for (x = 0; x < 24; ++x) { for (x = 0; x < 24; ++x) {
uint64_t t0 = state[KeccakF_PiLane[x]]; uint64_t t0 = state[KECCAK_PI_LANE[x]];
state[KeccakF_PiLane[x]] = rotl64(t1, KeccakF_RotationConstants[x]); state[KECCAK_PI_LANE[x]] = rotl64(t1, KECCAK_ROT_CONST[x]);
t1 = t0; t1 = t0;
} }
} else { } else {
/* Especially large benefit for 32-bit arch (75% faster): /* Especially large benefit for 32-bit arch (75% faster):
* 64-bit rotations by non-constant usually are SLOW on those. * 64-bit rotations by non-constant usually are SLOW on those.
* We resort to unrolling here. * We resort to unrolling here.
* This optimizes out KeccakF_PiLane[] and KeccakF_RotationConstants[], * This optimizes out KECCAK_PI_LANE[] and KECCAK_ROT_CONST[],
* but generates 300-500 more bytes of code. * but generates 300-500 more bytes of code.
*/ */
uint64_t t0; uint64_t t0;
uint64_t t1 = state[1]; uint64_t t1 = state[1];
#define RhoPi_twice(x) \ #define RhoPi_twice(x) \
t0 = state[KeccakF_PiLane[x ]]; state[KeccakF_PiLane[x ]] = rotl64(t1, KeccakF_RotationConstants[x ]); \ t0 = state[KECCAK_PI_LANE[x ]]; \
t1 = state[KeccakF_PiLane[x+1]]; state[KeccakF_PiLane[x+1]] = rotl64(t0, KeccakF_RotationConstants[x+1]); state[KECCAK_PI_LANE[x ]] = rotl64(t1, KECCAK_ROT_CONST[x ]); \
t1 = state[KECCAK_PI_LANE[x+1]]; \
state[KECCAK_PI_LANE[x+1]] = rotl64(t0, KECCAK_ROT_CONST[x+1]);
RhoPi_twice(0); RhoPi_twice(2); RhoPi_twice(0); RhoPi_twice(2);
RhoPi_twice(4); RhoPi_twice(6); RhoPi_twice(4); RhoPi_twice(6);
RhoPi_twice(8); RhoPi_twice(10); RhoPi_twice(8); RhoPi_twice(10);
@ -1063,8 +1066,8 @@ static void KeccakF(uint64_t *state)
BC[4] = state[y + 4]; BC[4] = state[y + 4];
for (x = 0; x < 5; ++x) { for (x = 0; x < 5; ++x) {
state[y + x] = state[y + x] =
BC[x] ^ ((~BC[KeccakF_Mod5[x + 1]]) & BC[x] ^ ((~BC[MOD5[x + 1]]) &
BC[KeccakF_Mod5[x + 2]]); BC[MOD5[x + 2]]);
} }
} else { } else {
/* 32-bit x86: +50 bytes code, 10% faster */ /* 32-bit x86: +50 bytes code, 10% faster */
@ -1083,9 +1086,9 @@ static void KeccakF(uint64_t *state)
} }
/* Iota */ /* Iota */
state[0] ^= KeccakF_RoundConstants[round] state[0] ^= KECCAK_IOTA_CONST[round]
| (uint32_t)((KeccakF_RoundConstantBit31 << round) & 0x80000000) | (uint32_t)((KECCAK_IOTA_CONST_bit31 << round) & 0x80000000)
| (uint64_t)((KeccakF_RoundConstantBit63 << round) & 0x80000000) << 32; | (uint64_t)((KECCAK_IOTA_CONST_bit63 << round) & 0x80000000) << 32;
} }
if (BB_BIG_ENDIAN) { if (BB_BIG_ENDIAN) {
@ -1095,6 +1098,8 @@ static void KeccakF(uint64_t *state)
} }
} }
#undef ARCH_IS_64BIT
void FAST_FUNC sha3_begin(sha3_ctx_t *ctx) void FAST_FUNC sha3_begin(sha3_ctx_t *ctx)
{ {
memset(ctx, 0, sizeof(*ctx)); memset(ctx, 0, sizeof(*ctx));
@ -1110,19 +1115,19 @@ void FAST_FUNC sha3_hash(sha3_ctx_t *ctx, const void *buf, size_t bytes)
buffer[ctx->bytes_queued] ^= *data++; buffer[ctx->bytes_queued] ^= *data++;
bytes--; bytes--;
ctx->bytes_queued++; ctx->bytes_queued++;
if (ctx->bytes_queued == cKeccakR_SizeInBytes) { if (ctx->bytes_queued == KECCAK_IBLK_BYTES) {
KeccakF(ctx->state); KeccakF(ctx->state);
ctx->bytes_queued = 0; ctx->bytes_queued = 0;
} }
} }
/* Absorb complete blocks */ /* Absorb complete blocks */
while (bytes >= cKeccakR_SizeInBytes) { while (bytes >= KECCAK_IBLK_BYTES) {
/* XOR data onto beginning of state[]. /* XOR data onto beginning of state[].
* We try to be efficient - operate on word at a time, not byte. * We try to be efficient - operate on word at a time, not byte.
* Yet safe wrt unaligned access: can't just use "*(long*)data"... * Yet safe wrt unaligned access: can't just use "*(long*)data"...
*/ */
unsigned count = cKeccakR_SizeInBytes / sizeof(long); unsigned count = KECCAK_IBLK_BYTES / sizeof(long);
long *buffer = (long*)ctx->state; long *buffer = (long*)ctx->state;
do { do {
long v; long v;
@ -1132,7 +1137,7 @@ void FAST_FUNC sha3_hash(sha3_ctx_t *ctx, const void *buf, size_t bytes)
} while (--count); } while (--count);
KeccakF(ctx->state); KeccakF(ctx->state);
bytes -= cKeccakR_SizeInBytes; bytes -= KECCAK_IBLK_BYTES;
} }
/* Queue remaining data bytes */ /* Queue remaining data bytes */
@ -1148,11 +1153,8 @@ void FAST_FUNC sha3_end(sha3_ctx_t *ctx, uint8_t *hashval)
{ {
/* Padding */ /* Padding */
uint8_t *buffer = (uint8_t*)ctx->state; uint8_t *buffer = (uint8_t*)ctx->state;
/* 0 is the number of bits in last, incomplete byte buffer[ctx->bytes_queued] ^= 1;
* (that is, zero: we never have incomplete bytes): buffer[KECCAK_IBLK_BYTES - 1] ^= 0x80;
*/
buffer[ctx->bytes_queued] ^= 1 << 0;
buffer[cKeccakR_SizeInBytes - 1] ^= 0x80;
KeccakF(ctx->state); KeccakF(ctx->state);