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pull/95/head
David G. Andersen 10 years ago
parent 4d493f6d4f
commit d744dd1be5
1 changed files with 63 additions and 10 deletions
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73
src/crypto/slow-hash.c
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@ -103,8 +103,16 @@
j = state_index(a); \
_c = _mm_load_si128(R128(&hp_state[j])); \
_a = _mm_load_si128(R128(a)); \
// dga's optimized scratchpad twiddling
/*
* An SSE-optimized implementation of the second half of CryptoNote step 3.
* After using AES to mix a scratchpad value into _c (done by the caller),
* this macro xors it with _b and stores the result back to the same index (j) that it
* loaded the scratchpad value from. It then performs a second random memory
* read/write from the scratchpad, but this time mixes the values using a 64
* bit multiply.
* This code is based upon an optimized implementation by dga.
*/
#define post_aes() \
_mm_store_si128(R128(c), _c); \
_b = _mm_xor_si128(_b, _c); \
@ -160,6 +168,10 @@ void cpuid(int CPUInfo[4], int InfoType)
}
#endif
/**
* @brief a = (a xor b), where a and b point to 128 bit values
*/
STATIC INLINE void xor_blocks(uint8_t *a, const uint8_t *b)
{
U64(a)[0] ^= U64(b)[0];
@ -218,7 +230,12 @@ STATIC INLINE void aes_256_assist2(__m128i* t1, __m128i * t3)
* of the AES encryption used to fill (and later, extract randomness from)
* the large 2MB buffer. Note that CryptoNight does not use a completely
* standard AES encryption for its buffer expansion, so do not copy this
* function outside of Monero without caution!
* function outside of Monero without caution! This version uses the hardware
* AESKEYGENASSIST instruction to speed key generation, and thus requires
* CPU AES support.
* For more information about these functions, see page 19 of Intel's AES instructions
* white paper:
* http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/aes-instructions-set-white-paper.pdf
*
* @param key the input 128 bit key
* @param expandedKey An output buffer to hold the generated key schedule
@ -274,6 +291,8 @@ STATIC INLINE void aes_expand_key(const uint8_t *key, uint8_t *expandedKey)
* in subsequent steps by aesenc_si128), and it does not use the simpler final round.
* Hence, this is a "pseudo" round - though the function actually implements 10 rounds together.
*
* Note that unlike aesb_pseudo_round, this function works on multiple data chunks.
*
* @param in a pointer to nblocks * 128 bits of data to be encrypted
* @param out a pointer to an nblocks * 128 bit buffer where the output will be stored
* @param expandedKey the expanded AES key
@ -304,6 +323,20 @@ STATIC INLINE void aes_pseudo_round(const uint8_t *in, uint8_t *out,
}
}
/*
* @brief aes_pseudo_round that loads data from *in and xors it with *xor first
*
* This function performs the same operations as aes_pseudo_round, but before
* performing the encryption of each 128 bit block from <in>, it xors
* it with the corresponding block from <xor>.
*
* @param in a pointer to nblocks * 128 bits of data to be encrypted
* @param out a pointer to an nblocks * 128 bit buffer where the output will be stored
* @param expandedKey the expanded AES key
* @param xor a pointer to an nblocks * 128 bit buffer that is xored into in before encryption (in is left unmodified)
* @param nblocks the number of 128 blocks of data to be encrypted
*/
STATIC INLINE void aes_pseudo_round_xor(const uint8_t *in, uint8_t *out,
const uint8_t *expandedKey, const uint8_t *xor, int nblocks)
{
@ -362,6 +395,18 @@ BOOL SetLockPagesPrivilege(HANDLE hProcess, BOOL bEnable)
}
#endif
/**
* @brief allocate the 2MB scratch buffer using OS support for huge pages, if available
*
* This function tries to allocate the 2MB scratch buffer using a single
* 2MB "huge page" (instead of the usual 4KB page sizes) to reduce TLB misses
* during the random accesses to the scratch buffer. This is one of the
* important speed optimizations needed to make CryptoNight faster.
*
* No parameters. Updates a thread-local pointer, hp_state, to point to
* the allocated buffer.
*/
void slow_hash_allocate_state(void)
{
int state = 0;
@ -391,6 +436,10 @@ void slow_hash_allocate_state(void)
}
}
/**
*@brief frees the state allocated by slow_hash_allocate_state
*/
void slow_hash_free_state(void)
{
if(hp_state == NULL)
@ -434,9 +483,12 @@ void slow_hash_free_state(void)
* core on 2013-era CPUs. When available, this implementation will use hardware
* AES support on x86 CPUs.
*
* A diagram of the inner loop of this function can be found at
* http://www.cs.cmu.edu/~dga/crypto/xmr/cryptonight.png
*
* @param data the data to hash
* @param length the length in bytes of the data
* @param hash a pointer to a buffer in which the final hash will be stored
* @param hash a pointer to a buffer in which the final 256 bit hash will be stored
*/
void cn_slow_hash(const void *data, size_t length, char *hash)
@ -507,14 +559,14 @@ void cn_slow_hash(const void *data, size_t length, char *hash)
*/
_b = _mm_load_si128(R128(b));
// this is ugly but the branching affects the loop somewhat so put it outside.
// Two independent versions, one with AES, one without, this to ensure that
// the useAes test is only performed once, not every iteration.
if(useAes)
{
for(i = 0; i < ITER / 2; i++)
{
pre_aes();
_c = _mm_aesenc_si128(_c, _a);
// post_aes(), optimized scratchpad twiddling (credits to dga)
post_aes();
}
}
@ -556,10 +608,11 @@ void cn_slow_hash(const void *data, size_t length, char *hash)
oaes_free((OAES_CTX **) &aes_ctx);
}
/* CryptoNight Step 5: Use the resulting data to select which of four
* finalizer hash functions to apply to the data (Blake, Groestl, JH, or Skein).
* Use this hash to squeeze the 200 byte pseudorandom state array down
* to the final hash output.
/* CryptoNight Step 5: Apply Keccak to the state again, and then
* use the resulting data to select which of four finalizer
* hash functions to apply to the data (Blake, Groestl, JH, or Skein).
* Use this hash to squeeze the state array down
* to the final 256 bit hash output.
*/
memcpy(state.init, text, INIT_SIZE_BYTE);

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