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hmac/256 -> hmac512/256 in randombytes_salsa20_random_stir() to make code smaller.

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This commit is contained in:
Frank Denis
2013-05-13 16:59:57 -07:00
parent 1a0a89df33
commit ab2e1ab140
1 changed files with 19 additions and 21 deletions
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src/libsodium/randombytes/salsa20/randombytes_salsa20_random.c
+19 -21
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@@ -13,7 +13,7 @@
#include <unistd.h>
#include "crypto_core_salsa20.h"
#include "crypto_hash_sha256.h"
#include "crypto_auth_hmacsha512256.h"
#include "crypto_stream_salsa20.h"
#include "randombytes.h"
#include "randombytes_salsa20_random.h"
@@ -26,8 +26,8 @@
#endif
#define SALSA20_RANDOM_BLOCK_SIZE crypto_core_salsa20_OUTPUTBYTES
#define SHA256_BLOCK_SIZE 64U
#define SHA256_MIN_PAD_SIZE (1U + 8U)
#define SHA512_BLOCK_SIZE 128U
#define SHA512_MIN_PAD_SIZE (1U + 16U)
#define COMPILER_ASSERT(X) (void) sizeof(char[(X) ? 1 : -1])
typedef struct Salsa20Random_ {
@@ -149,12 +149,16 @@ randombytes_salsa20_random_init(void)
void
randombytes_salsa20_random_stir(void)
{
unsigned char m0[3U * SHA256_BLOCK_SIZE - SHA256_MIN_PAD_SIZE];
unsigned char m1[SHA256_BLOCK_SIZE + crypto_hash_sha256_BYTES];
unsigned char *k0 = m0 + SHA256_BLOCK_SIZE;
unsigned char *k1 = m1 + SHA256_BLOCK_SIZE;
const unsigned char s[crypto_auth_hmacsha512256_KEYBYTES] = {
'T', 'h', 'i', 's', 'I', 's', 'J', 'u', 's', 't', 'A', 'T',
'h', 'i', 'r', 't', 'y', 'T', 'w', 'o', 'B', 'y', 't', 'e',
's', 'S', 'e', 'e', 'd', '.', '.', '.'
};
unsigned char m0[crypto_auth_hmacsha512256_BYTES +
2U * SHA512_BLOCK_SIZE - SHA512_MIN_PAD_SIZE];
unsigned char *k0 = m0 + crypto_auth_hmacsha512256_BYTES;
size_t i;
size_t sizeof_k0 = sizeof m0 - SHA256_BLOCK_SIZE;
size_t sizeof_k0 = sizeof m0 - crypto_auth_hmacsha512256_BYTES;
memset(stream.rnd32, 0, sizeof stream.rnd32);
stream.rnd32_outleft = (size_t) 0U;
@@ -162,27 +166,21 @@ randombytes_salsa20_random_stir(void)
randombytes_salsa20_random_init();
stream.initialized = 1;
}
memset(m0, 0x69, SHA256_BLOCK_SIZE);
memset(m1, 0x42, SHA256_BLOCK_SIZE);
#ifndef _WIN32
if (safe_read(stream.random_data_source_fd, k0,
sizeof_k0) != (ssize_t) sizeof_k0) {
if (safe_read(stream.random_data_source_fd, m0,
sizeof m0) != (ssize_t) sizeof m0) {
abort();
}
#else /* _WIN32 */
if (! CryptGenRandom(stream.hcrypt_prov, sizeof_k0, k0)) {
if (! CryptGenRandom(stream.hcrypt_prov, sizeof m0, m0)) {
abort();
}
#endif
COMPILER_ASSERT(sizeof m0 >= 2U * SHA256_BLOCK_SIZE);
crypto_hash_sha256(k1, m0, sizeof m0);
COMPILER_ASSERT(sizeof m1 >= SHA256_BLOCK_SIZE + crypto_hash_sha256_BYTES);
crypto_hash_sha256(stream.key, m1, sizeof m1);
sodium_memzero(m1, sizeof m1);
COMPILER_ASSERT(sizeof stream.key == crypto_hash_sha256_BYTES);
assert(sizeof stream.key <= sizeof_k0);
COMPILER_ASSERT(sizeof stream.key == crypto_auth_hmacsha512256_BYTES);
crypto_auth_hmacsha512256(stream.key, k0, sizeof_k0, s);
COMPILER_ASSERT(sizeof stream.key <= sizeof m0);
for (i = (size_t) 0U; i < sizeof stream.key; i++) {
stream.key[i] ^= k0[i];
stream.key[i] ^= m0[i];
}
sodium_memzero(m0, sizeof m0);
}