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Optimization to reduce code size of derive_u_ripemd160. Useful for boatloader.

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This commit is contained in:
Mounir IDRASSI 2014-10-05 00:34:41 +02:00
parent 0178a6d33f
commit 50ca9fe46f
1 changed files with 20 additions and 25 deletions
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45
src/Common/Pkcs5.c
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@ -247,8 +247,20 @@ void derive_u_ripemd160 (BOOL bNotTest, char *pwd, int pwd_len, char *salt, int
char j[RIPEMD160_DIGESTSIZE], k[RIPEMD160_DIGESTSIZE];
char init[128];
char counter[4];
int c, i, l;
int EnhanceSecurityLoops = (bNotTest)? 20 : 1;
uint32 c;
int i;
if (bNotTest)
{
if (iterations == 32767)
c = 655331;
else
c = 327661;
}
else
{
c = iterations;
}
/* iteration 1 */
memset (counter, 0, 4);
@ -259,34 +271,17 @@ void derive_u_ripemd160 (BOOL bNotTest, char *pwd, int pwd_len, char *salt, int
memcpy (u, j, RIPEMD160_DIGESTSIZE);
/* remaining iterations */
for (l = 0; l < EnhanceSecurityLoops; l++)
while ( c > 1)
{
for (c = 1; c < iterations; c++)
hmac_ripemd160 (pwd, pwd_len, j, RIPEMD160_DIGESTSIZE, k);
for (i = 0; i < RIPEMD160_DIGESTSIZE; i++)
{
hmac_ripemd160 (pwd, pwd_len, j, RIPEMD160_DIGESTSIZE, k);
for (i = 0; i < RIPEMD160_DIGESTSIZE; i++)
{
u[i] ^= k[i];
j[i] = k[i];
}
u[i] ^= k[i];
j[i] = k[i];
}
c--;
}
/* add extra 10 loops to ensure backward compatibilty with the previous count (327661 for boot, 655331 for normal) */
if (iterations == 32767)
{
/* case of normal partition : add 10 iterations to have a total of 655331 = (32767 - 1)*20 + 1 + 10 */
for (c = 0; c < 10; c++)
{
hmac_ripemd160 (pwd, pwd_len, j, RIPEMD160_DIGESTSIZE, k);
for (i = 0; i < RIPEMD160_DIGESTSIZE; i++)
{
u[i] ^= k[i];
j[i] = k[i];
}
}
}
/* Prevent possible leaks. */
burn (j, sizeof(j));
burn (k, sizeof(k));