snapraid/cmdline/spooky2.c
Andrea Mazzoleni 09fa4af509 Add new memflip() function to fix block flipping a bit.
Unfortunately it takes too mutch time, about 80 seconds a call,
despite the optimization of saving the intermediate hash state.
2015-05-04 22:55:04 +02:00

344 lines
10 KiB
C

/*
* Copyright (C) 2013 Andrea Mazzoleni
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Derivative work from SpookyV2.cpp/h
*
* WARNING!!!! Note that this implementation doesn't use the short hash optimization
* resulting in different hashes for any length shorter than 192 bytes
*
* SpookyHash
* http://burtleburtle.net/bob/hash/spooky.html
*
* Exact source used as reference:
* http://burtleburtle.net/bob/c/SpookyV2.h
* http://burtleburtle.net/bob/c/SpookyV2.cpp
*/
// Spooky Hash
// A 128-bit noncryptographic hash, for checksums and table lookup
// By Bob Jenkins. Public domain.
// Oct 31 2010: published framework, disclaimer ShortHash isn't right
// Nov 7 2010: disabled ShortHash
// Oct 31 2011: replace End, ShortMix, ShortEnd, enable ShortHash again
// April 10 2012: buffer overflow on platforms without unaligned reads
// July 12 2012: was passing out variables in final to in/out in short
// July 30 2012: I reintroduced the buffer overflow
// August 5 2012: SpookyV2: d = should be d += in short hash, and remove extra mix from long hash
//
// Up to 3 bytes/cycle for long messages. Reasonably fast for short messages.
// All 1 or 2 bit deltas achieve avalanche within 1% bias per output bit.
//
// This was developed for and tested on 64-bit x86-compatible processors.
// It assumes the processor is little-endian. There is a macro
// controlling whether unaligned reads are allowed (by default they are).
// This should be an equally good hash on big-endian machines, but it will
// compute different results on them than on little-endian machines.
//
// Google's CityHash has similar specs to SpookyHash, and CityHash is faster
// on new Intel boxes. MD4 and MD5 also have similar specs, but they are orders
// of magnitude slower. CRCs are two or more times slower, but unlike
// SpookyHash, they have nice math for combining the CRCs of pieces to form
// the CRCs of wholes. There are also cryptographic hashes, but those are even
// slower than MD5.
//
#define Mix(data, s0, s1, s2, s3, s4, s5, s6, s7, s8, s9, s10, s11) \
s0 += data[0]; s2 ^= s10; s11 ^= s0; s0 = util_rotl64(s0, 11); s11 += s1; \
s1 += data[1]; s3 ^= s11; s0 ^= s1; s1 = util_rotl64(s1, 32); s0 += s2; \
s2 += data[2]; s4 ^= s0; s1 ^= s2; s2 = util_rotl64(s2, 43); s1 += s3; \
s3 += data[3]; s5 ^= s1; s2 ^= s3; s3 = util_rotl64(s3, 31); s2 += s4; \
s4 += data[4]; s6 ^= s2; s3 ^= s4; s4 = util_rotl64(s4, 17); s3 += s5; \
s5 += data[5]; s7 ^= s3; s4 ^= s5; s5 = util_rotl64(s5, 28); s4 += s6; \
s6 += data[6]; s8 ^= s4; s5 ^= s6; s6 = util_rotl64(s6, 39); s5 += s7; \
s7 += data[7]; s9 ^= s5; s6 ^= s7; s7 = util_rotl64(s7, 57); s6 += s8; \
s8 += data[8]; s10 ^= s6; s7 ^= s8; s8 = util_rotl64(s8, 55); s7 += s9; \
s9 += data[9]; s11 ^= s7; s8 ^= s9; s9 = util_rotl64(s9, 54); s8 += s10; \
s10 += data[10]; s0 ^= s8; s9 ^= s10; s10 = util_rotl64(s10, 22); s9 += s11; \
s11 += data[11]; s1 ^= s9; s10 ^= s11; s11 = util_rotl64(s11, 46); s10 += s0;
#define EndPartial(h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11) \
h11 += h1; h2 ^= h11; h1 = util_rotl64(h1, 44); \
h0 += h2; h3 ^= h0; h2 = util_rotl64(h2, 15); \
h1 += h3; h4 ^= h1; h3 = util_rotl64(h3, 34); \
h2 += h4; h5 ^= h2; h4 = util_rotl64(h4, 21); \
h3 += h5; h6 ^= h3; h5 = util_rotl64(h5, 38); \
h4 += h6; h7 ^= h4; h6 = util_rotl64(h6, 33); \
h5 += h7; h8 ^= h5; h7 = util_rotl64(h7, 10); \
h6 += h8; h9 ^= h6; h8 = util_rotl64(h8, 13); \
h7 += h9; h10 ^= h7; h9 = util_rotl64(h9, 38); \
h8 += h10; h11 ^= h8; h10 = util_rotl64(h10, 53); \
h9 += h11; h0 ^= h9; h11 = util_rotl64(h11, 42); \
h10 += h0; h1 ^= h10; h0 = util_rotl64(h0, 54);
#define End(data, h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11) \
h0 += data[0]; h1 += data[1]; h2 += data[2]; h3 += data[3]; \
h4 += data[4]; h5 += data[5]; h6 += data[6]; h7 += data[7]; \
h8 += data[8]; h9 += data[9]; h10 += data[10]; h11 += data[11]; \
EndPartial(h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11); \
EndPartial(h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11); \
EndPartial(h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11);
// number of uint64_t's in internal state
#define sc_numVars 12
// size of the internal state
#define sc_blockSize (sc_numVars * 8)
// sc_const: a constant which:
// * is not zero
// * is odd
// * is a not-very-regular mix of 1's and 0's
// * does not need any other special mathematical properties
//
#define sc_const 0xdeadbeefdeadbeefLL
#define SPOOKY2_BLOCK_SIZE sc_blockSize
struct spooky2_context {
uint64_t h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11;
};
void spooky2_init(struct spooky2_context* ctx, const uint8_t* seed)
{
ctx->h9 = ((const uint64_t*)seed)[0];
ctx->h10 = ((const uint64_t*)seed)[1];
#if WORDS_BIGENDIAN
ctx->h9 = util_swap64(ctx->h9);
ctx->h10 = util_swap64(ctx->h10);
#endif
ctx->h0 = ctx->h3 = ctx->h6 = ctx->h9;
ctx->h1 = ctx->h4 = ctx->h7 = ctx->h10;
ctx->h2 = ctx->h5 = ctx->h8 = ctx->h11 = sc_const;
}
void spooky2_block(struct spooky2_context* ctx, const void* data, size_t size)
{
uint64_t h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11;
#if WORDS_BIGENDIAN
uint64_t buf[sc_numVars];
size_t i;
#endif
size_t nblocks;
const uint64_t* blocks;
const uint64_t* end;
assert(size % SPOOKY2_BLOCK_SIZE == 0);
blocks = (const uint64_t*)data;
nblocks = size / SPOOKY2_BLOCK_SIZE;
end = blocks + nblocks * sc_numVars;
h0 = ctx->h0;
h1 = ctx->h1;
h2 = ctx->h2;
h3 = ctx->h3;
h4 = ctx->h4;
h5 = ctx->h5;
h6 = ctx->h6;
h7 = ctx->h7;
h8 = ctx->h8;
h9 = ctx->h9;
h10 = ctx->h10;
h11 = ctx->h11;
/* body */
while (blocks < end) {
#if WORDS_BIGENDIAN
for (i = 0; i < sc_numVars; ++i)
buf[i] = util_swap64(blocks[i]);
Mix(buf, h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11);
#else
Mix(blocks, h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11);
#endif
blocks += sc_numVars;
}
ctx->h0 = h0;
ctx->h1 = h1;
ctx->h2 = h2;
ctx->h3 = h3;
ctx->h4 = h4;
ctx->h5 = h5;
ctx->h6 = h6;
ctx->h7 = h7;
ctx->h8 = h8;
ctx->h9 = h9;
ctx->h10 = h10;
ctx->h11 = h11;
}
void spooky2_final(struct spooky2_context* ctx, const void* data, size_t size, void* digest)
{
uint64_t h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11;
uint64_t buf[sc_numVars];
#if WORDS_BIGENDIAN
size_t i;
#endif
assert(size < SPOOKY2_BLOCK_SIZE);
/* tail */
memcpy(buf, data, size);
memset(((uint8_t*)buf) + size, 0, SPOOKY2_BLOCK_SIZE - size);
((uint8_t*)buf)[SPOOKY2_BLOCK_SIZE - 1] = size;
/* finalization */
#if WORDS_BIGENDIAN
for (i = 0; i < sc_numVars; ++i)
buf[i] = util_swap64(buf[i]);
#endif
h0 = ctx->h0;
h1 = ctx->h1;
h2 = ctx->h2;
h3 = ctx->h3;
h4 = ctx->h4;
h5 = ctx->h5;
h6 = ctx->h6;
h7 = ctx->h7;
h8 = ctx->h8;
h9 = ctx->h9;
h10 = ctx->h10;
h11 = ctx->h11;
End(buf, h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11);
#if WORDS_BIGENDIAN
h0 = util_swap64(h0);
h1 = util_swap64(h1);
#endif
((uint64_t*)digest)[0] = h0;
((uint64_t*)digest)[1] = h1;
}
void spooky2(const void* data, size_t size, const uint8_t* seed, uint8_t* digest)
{
uint64_t h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11;
uint64_t buf[sc_numVars];
#if WORDS_BIGENDIAN
size_t i;
#endif
size_t nblocks;
const uint64_t* blocks;
const uint64_t* end;
size_t remainder;
h9 = ((const uint64_t*)seed)[0];
h10 = ((const uint64_t*)seed)[1];
#if WORDS_BIGENDIAN
h9 = util_swap64(h9);
h10 = util_swap64(h10);
#endif
h0 = h3 = h6 = h9;
h1 = h4 = h7 = h10;
h2 = h5 = h8 = h11 = sc_const;
blocks = (const uint64_t*)data;
nblocks = size / SPOOKY2_BLOCK_SIZE;
end = blocks + nblocks * sc_numVars;
/* body */
while (blocks < end) {
#if WORDS_BIGENDIAN
for (i = 0; i < sc_numVars; ++i)
buf[i] = util_swap64(u.p64[i]);
Mix(buf, h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11);
#else
Mix(blocks, h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11);
#endif
blocks += sc_numVars;
}
/* tail */
remainder = (size - ((const uint8_t*)end - (const uint8_t*)data));
memcpy(buf, end, remainder);
memset(((uint8_t*)buf) + remainder, 0, sc_blockSize - remainder);
((uint8_t*)buf)[sc_blockSize - 1] = remainder;
/* finalization */
#if WORDS_BIGENDIAN
for (i = 0; i < sc_numVars; ++i)
buf[i] = util_swap64(buf[i]);
#endif
End(buf, h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11);
#if WORDS_BIGENDIAN
h0 = util_swap64(h0);
h1 = util_swap64(h1);
#endif
((uint64_t*)digest)[0] = h0;
((uint64_t*)digest)[1] = h1;
}
int spooky2_flip(void* void_data, uint32_t size, const uint8_t* seed, const void* digest)
{
struct spooky2_context last_ctx;
size_t last_off;
size_t off;
uint8_t* data = (uint8_t*)void_data;
uint32_t tail = size % SPOOKY2_BLOCK_SIZE;
uint32_t body = size - tail;
spooky2_init(&last_ctx, seed);
last_off = 0;
for (off = 0; off < size; ++off) {
unsigned bit;
if (off == last_off + SPOOKY2_BLOCK_SIZE) {
/* process one more block */
spooky2_block(&last_ctx, data + last_off, SPOOKY2_BLOCK_SIZE);
last_off += SPOOKY2_BLOCK_SIZE;
}
/* try all bits */
for (bit = 0; bit < 8; ++bit) {
struct spooky2_context ctx;
uint8_t out[16];
/* flip the bit */
data[off] ^= 1 << bit;
/* restore the latest context */
ctx = last_ctx;
/* compute the new hash from this point */
spooky2_block(&last_ctx, data + last_off, body - last_off);
spooky2_final(&ctx, data + body, tail, out);
/* check if the digest is correct */
if (memcmp(digest, out, 16) == 0)
return 0;
/* restore the bit */
data[off] ^= 1 << bit;
}
}
return -1;
}