Mercurial > repos > blastem
diff hash.c @ 1305:5ceb316c479a
Allow games to be specified in ROM DB via sha1 instead of product ID. Added a new ROM DB memory map device type fixed for emulating simple fixed value copy protection registers. Used those two features to support Ya Se Chuan Shuo via a ROM DB entry.
author | Michael Pavone <pavone@retrodev.com> |
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date | Wed, 29 Mar 2017 00:29:44 -0700 |
parents | |
children | 0111c8344477 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hash.c Wed Mar 29 00:29:44 2017 -0700 @@ -0,0 +1,101 @@ +#include <stdint.h> +#include <string.h> + +//NOTE: This is only intended for use in file identification +//Please do not use this in a cryptographic setting as no attempts have been +//made at avoiding side channel attacks + +static uint32_t rotleft(uint32_t val, uint32_t shift) +{ + return val << shift | val >> (32-shift); +} + +static void sha1_step(uint32_t *state, uint32_t f, uint32_t k, uint32_t w) +{ + uint32_t tmp = rotleft(state[0], 5) + f + state[4] + k + w; + state[4] = state[3]; + state[3] = state[2]; + state[2] = rotleft(state[1], 30); + state[1] = state[0]; + state[0] = tmp; +} + +static void sha1_chunk(uint8_t *chunk, uint32_t *hash) +{ + uint32_t state[5], w[80]; + memcpy(state, hash, sizeof(state)); + for (uint32_t src = 0; src < 64; src += 4) + { + w[src >> 2] = chunk[src] << 24 | chunk[src+1] << 16 | chunk[src+2] << 8 | chunk[src+3]; + } + for (uint32_t cur = 16; cur < 80; cur++) + { + w[cur] = rotleft(w[cur-3] ^ w[cur-8] ^ w[cur-14] ^ w[cur-16], 1); + } + for (uint32_t cur = 0; cur < 20; cur++) + { + sha1_step(state, (state[1] & state[2]) | ((~state[1]) & state[3]), 0x5A827999, w[cur]); + } + for (uint32_t cur = 20; cur < 40; cur++) + { + sha1_step(state, state[1] ^ state[2] ^ state[3], 0x6ED9EBA1, w[cur]); + } + for (uint32_t cur = 40; cur < 60; cur++) + { + sha1_step(state, (state[1] & state[2]) | (state[1] & state[3]) | (state[2] & state[3]), 0x8F1BBCDC, w[cur]); + } + for (uint32_t cur = 60; cur < 80; cur++) + { + sha1_step(state, state[1] ^ state[2] ^ state[3], 0xCA62C1D6, w[cur]); + } + for (uint32_t i = 0; i < 5; i++) + { + hash[i] += state[i]; + } +} + +void sha1(uint8_t *data, uint64_t size, uint8_t *out) +{ + uint32_t hash[5] = {0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0}; + uint8_t last[128]; + uint32_t last_size = 0; + if ((size & 63) != 0) { + for (uint32_t src = size - (size & 63); src < size; src++) + { + last[last_size++] = data[src]; + } + } + uint64_t bitsize = size * 8; + size -= last_size; + last[last_size++] = 0x80; + while ((last_size & 63) != 56) + { + last[last_size++] = 0; + } + + last[last_size++] = bitsize >> 56; + last[last_size++] = bitsize >> 48; + last[last_size++] = bitsize >> 40; + last[last_size++] = bitsize >> 32; + last[last_size++] = bitsize >> 24; + last[last_size++] = bitsize >> 16; + last[last_size++] = bitsize >> 8; + last[last_size++] = bitsize; + + for (uint64_t cur = 0; cur < size; cur += 64) + { + sha1_chunk(data + cur, hash); + } + for (uint64_t cur = 0; cur < last_size; cur += 64) + { + sha1_chunk(last + cur, hash); + } + for (uint32_t cur = 0; cur < 20; cur += 4) + { + uint32_t val = hash[cur >> 2]; + out[cur] = val >> 24; + out[cur+1] = val >> 16; + out[cur+2] = val >> 8; + out[cur+3] = val; + } +}