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Code Issues Releases Wiki Activity

Simplified sha256_Final/sha512_Last

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- Fix the bug where we zero too many bytes in sha512_Last
  (SHORT_BLOCK_LENGTH != BLOCK_LENGTH -2).
- Get rid of an if branch.
- Don't reverse the last two words in 512_Last that are written later.
- make 256_Final and 512_Last look the same.
This commit is contained in:
Jochen Hoenicke 2016-08-29 21:41:23 +02:00
parent b3e6eecfce
commit 19a1f501c4
No known key found for this signature in database
GPG Key ID: 65B10C0466560648
1 changed files with 17 additions and 23 deletions
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40
sha2.c
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@ -488,13 +488,9 @@ void sha256_Final(SHA256_CTX* context, sha2_byte digest[]) {
/* Begin padding with a 1 bit: */
((uint8_t*)context->buffer)[usedspace++] = 0x80;
if (usedspace <= SHA256_SHORT_BLOCK_LENGTH) {
/* Set-up for the last transform: */
MEMSET_BZERO(((uint8_t*)context->buffer) + usedspace, SHA256_SHORT_BLOCK_LENGTH - usedspace);
} else {
if (usedspace < SHA256_BLOCK_LENGTH) {
MEMSET_BZERO(((uint8_t*)context->buffer) + usedspace, SHA256_BLOCK_LENGTH - usedspace);
}
if (usedspace > SHA256_SHORT_BLOCK_LENGTH) {
MEMSET_BZERO(((uint8_t*)context->buffer) + usedspace, SHA256_BLOCK_LENGTH - usedspace);
#if BYTE_ORDER == LITTLE_ENDIAN
/* Convert TO host byte order */
for (int j = 0; j < 16; j++) {
@ -504,9 +500,11 @@ void sha256_Final(SHA256_CTX* context, sha2_byte digest[]) {
/* Do second-to-last transform: */
sha256_Transform(context->state, context->buffer, context->state);
/* And set-up for the last transform: */
MEMSET_BZERO(context->buffer, SHA256_SHORT_BLOCK_LENGTH);
/* And prepare the last transform: */
usedspace = 0;
}
/* Set-up for the last transform: */
MEMSET_BZERO(((uint8_t*)context->buffer) + usedspace, SHA256_SHORT_BLOCK_LENGTH - usedspace);
#if BYTE_ORDER == LITTLE_ENDIAN
/* Convert TO host byte order */
@ -793,13 +791,9 @@ static void sha512_Last(SHA512_CTX* context) {
/* Begin padding with a 1 bit: */
((uint8_t*)context->buffer)[usedspace++] = 0x80;
if (usedspace <= SHA512_SHORT_BLOCK_LENGTH) {
/* Set-up for the last transform: */
MEMSET_BZERO(((uint8_t*)context->buffer) + usedspace, SHA512_SHORT_BLOCK_LENGTH - usedspace);
} else {
if (usedspace < SHA512_BLOCK_LENGTH) {
MEMSET_BZERO(((uint8_t*)context->buffer) + usedspace, SHA512_BLOCK_LENGTH - usedspace);
}
if (usedspace > SHA512_SHORT_BLOCK_LENGTH) {
MEMSET_BZERO(((uint8_t*)context->buffer) + usedspace, SHA512_BLOCK_LENGTH - usedspace);
#if BYTE_ORDER == LITTLE_ENDIAN
/* Convert TO host byte order */
for (int j = 0; j < 16; j++) {
@ -809,21 +803,21 @@ static void sha512_Last(SHA512_CTX* context) {
/* Do second-to-last transform: */
sha512_Transform(context->state, context->buffer, context->state);
/* And set-up for the last transform: */
MEMSET_BZERO(context->buffer, SHA512_BLOCK_LENGTH - 2);
/* And prepare the last transform: */
usedspace = 0;
}
/* Set-up for the last transform: */
MEMSET_BZERO(((uint8_t*)context->buffer) + usedspace, SHA512_SHORT_BLOCK_LENGTH - usedspace);
#if BYTE_ORDER == LITTLE_ENDIAN
/* Convert TO host byte order */
for (int j = 0; j < 16; j++) {
for (int j = 0; j < 14; j++) {
REVERSE64(context->buffer[j],context->buffer[j]);
}
#endif
/* Store the length of input data (in bits): */
sha2_word64 *t;
t = &context->buffer[SHA512_SHORT_BLOCK_LENGTH/sizeof(sha2_word64)];
t[0] = context->bitcount[1];
t[1] = context->bitcount[0];
context->buffer[14] = context->bitcount[1];
context->buffer[15] = context->bitcount[0];
/* Final transform: */
sha512_Transform(context->state, context->buffer, context->state);