[git commit] sha3: cosmetic tweaks to various names, comments. No logic changes.
Denys Vlasenko
vda.linux at googlemail.com
Tue Jan 15 18:52:30 UTC 2013
commit: http://git.busybox.net/busybox/commit/?id=5b7f50f37210706c0f508788991de88244c7b29b
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
libbb/hash_md5_sha.c | 124 +++++++++++++++++++++++++------------------------
1 files changed, 63 insertions(+), 61 deletions(-)
diff --git a/libbb/hash_md5_sha.c b/libbb/hash_md5_sha.c
index 4cd2244..18e4260 100644
--- a/libbb/hash_md5_sha.c
+++ b/libbb/hash_md5_sha.c
@@ -926,66 +926,67 @@ void FAST_FUNC sha512_end(sha512_ctx_t *ctx, void *resbuf)
# define SHA3_SMALL CONFIG_SHA3_SMALL
#endif
-#define ARCH_IS_64BIT (sizeof(long) >= sizeof(uint64_t))
-
enum {
- cKeccakR_SizeInBytes = 576 / 8,
- cKeccakNumberOfRounds = 24,
+ KECCAK_IBLK_BYTES = 576 / 8,
+ KECCAK_NROUNDS = 24,
};
/* Elements should be 64-bit, but top half is always zero or 0x80000000.
- * It is encoded as a separate word below.
- * Same is true for 31th bits.
+ * We encode 63rd bits in a separate word below.
+ * 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] = {
- 0x0001UL,
- 0x8082UL,
- 0x808aUL,
- 0x8000UL,
- 0x808bUL,
- 0x0001UL,
- 0x8081UL,
- 0x8009UL,
- 0x008aUL,
- 0x0088UL,
- 0x8009UL,
- 0x000aUL,
- 0x808bUL,
- 0x008bUL,
- 0x8089UL,
- 0x8003UL,
- 0x8002UL,
- 0x0080UL,
- 0x800aUL,
- 0x000aUL,
- 0x8081UL,
- 0x8080UL,
- 0x0001UL,
- 0x8008UL
+static const uint16_t KECCAK_IOTA_CONST[KECCAK_NROUNDS] = {
+ 0x0001U,
+ 0x8082U,
+ 0x808aU,
+ 0x8000U,
+ 0x808bU,
+ 0x0001U,
+ 0x8081U,
+ 0x8009U,
+ 0x008aU,
+ 0x0088U,
+ 0x8009U,
+ 0x000aU,
+ 0x808bU,
+ 0x008bU,
+ 0x8089U,
+ 0x8003U,
+ 0x8002U,
+ 0x0080U,
+ 0x800aU,
+ 0x000aU,
+ 0x8081U,
+ 0x8080U,
+ 0x0001U,
+ 0x8008U,
};
-/* 0th first - 0011 0011 0000 0111 1101 1101: */
-#define KeccakF_RoundConstantBit63 ((uint32_t)(0x3307dd00))
-/* 0th first - 0001 0110 0011 1000 0001 1011: */
-#define KeccakF_RoundConstantBit31 ((uint32_t)(0x16381b00))
+/* bit from CONST[0] is msb: 0011 0011 0000 0111 1101 1101 */
+#define KECCAK_IOTA_CONST_bit63 ((uint32_t)(0x3307dd00))
+/* bit from CONST[0] is msb: 0001 0110 0011 1000 0001 1011 */
+#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,
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,
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
};
+#define ARCH_IS_64BIT (sizeof(long) >= sizeof(uint64_t))
+
static void KeccakF(uint64_t *state)
{
- uint8_t x, y;
- int round;
+ unsigned x, y;
+ unsigned round;
if (BB_BIG_ENDIAN) {
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 */
{
uint64_t BC[10];
@@ -1003,7 +1004,7 @@ static void KeccakF(uint64_t *state)
^ state[x + 15] ^ state[x + 20];
}
/* 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_.
*/
for (x = 0; x < 5; ++x) {
@@ -1027,22 +1028,24 @@ static void KeccakF(uint64_t *state)
if (SHA3_SMALL) {
uint64_t t1 = state[1];
for (x = 0; x < 24; ++x) {
- uint64_t t0 = state[KeccakF_PiLane[x]];
- state[KeccakF_PiLane[x]] = rotl64(t1, KeccakF_RotationConstants[x]);
+ uint64_t t0 = state[KECCAK_PI_LANE[x]];
+ state[KECCAK_PI_LANE[x]] = rotl64(t1, KECCAK_ROT_CONST[x]);
t1 = t0;
}
} else {
/* Especially large benefit for 32-bit arch (75% faster):
* 64-bit rotations by non-constant usually are SLOW on those.
* 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.
*/
uint64_t t0;
uint64_t t1 = state[1];
#define RhoPi_twice(x) \
- t0 = state[KeccakF_PiLane[x ]]; state[KeccakF_PiLane[x ]] = rotl64(t1, KeccakF_RotationConstants[x ]); \
- t1 = state[KeccakF_PiLane[x+1]]; state[KeccakF_PiLane[x+1]] = rotl64(t0, KeccakF_RotationConstants[x+1]);
+ t0 = state[KECCAK_PI_LANE[x ]]; \
+ 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(4); RhoPi_twice(6);
RhoPi_twice(8); RhoPi_twice(10);
@@ -1063,8 +1066,8 @@ static void KeccakF(uint64_t *state)
BC[4] = state[y + 4];
for (x = 0; x < 5; ++x) {
state[y + x] =
- BC[x] ^ ((~BC[KeccakF_Mod5[x + 1]]) &
- BC[KeccakF_Mod5[x + 2]]);
+ BC[x] ^ ((~BC[MOD5[x + 1]]) &
+ BC[MOD5[x + 2]]);
}
} else {
/* 32-bit x86: +50 bytes code, 10% faster */
@@ -1083,9 +1086,9 @@ static void KeccakF(uint64_t *state)
}
/* Iota */
- state[0] ^= KeccakF_RoundConstants[round]
- | (uint32_t)((KeccakF_RoundConstantBit31 << round) & 0x80000000)
- | (uint64_t)((KeccakF_RoundConstantBit63 << round) & 0x80000000) << 32;
+ state[0] ^= KECCAK_IOTA_CONST[round]
+ | (uint32_t)((KECCAK_IOTA_CONST_bit31 << round) & 0x80000000)
+ | (uint64_t)((KECCAK_IOTA_CONST_bit63 << round) & 0x80000000) << 32;
}
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)
{
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++;
bytes--;
ctx->bytes_queued++;
- if (ctx->bytes_queued == cKeccakR_SizeInBytes) {
+ if (ctx->bytes_queued == KECCAK_IBLK_BYTES) {
KeccakF(ctx->state);
ctx->bytes_queued = 0;
}
}
/* Absorb complete blocks */
- while (bytes >= cKeccakR_SizeInBytes) {
+ while (bytes >= KECCAK_IBLK_BYTES) {
/* XOR data onto beginning of state[].
* We try to be efficient - operate on word at a time, not byte.
* 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;
do {
long v;
@@ -1132,7 +1137,7 @@ void FAST_FUNC sha3_hash(sha3_ctx_t *ctx, const void *buf, size_t bytes)
} while (--count);
KeccakF(ctx->state);
- bytes -= cKeccakR_SizeInBytes;
+ bytes -= KECCAK_IBLK_BYTES;
}
/* Queue remaining data bytes */
@@ -1148,11 +1153,8 @@ void FAST_FUNC sha3_end(sha3_ctx_t *ctx, uint8_t *hashval)
{
/* Padding */
uint8_t *buffer = (uint8_t*)ctx->state;
- /* 0 is the number of bits in last, incomplete byte
- * (that is, zero: we never have incomplete bytes):
- */
- buffer[ctx->bytes_queued] ^= 1 << 0;
- buffer[cKeccakR_SizeInBytes - 1] ^= 0x80;
+ buffer[ctx->bytes_queued] ^= 1;
+ buffer[KECCAK_IBLK_BYTES - 1] ^= 0x80;
KeccakF(ctx->state);
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