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trezor-firmware/pbkdf2.c
2013-12-09 18:16:33 +01:00

36 lines
956 B
C

#include <string.h>
#include "pbkdf2.h"
#include "hmac.h"
#define HMACFUNC hmac_sha512
#define HMACLEN (512/8)
void pbkdf2(const uint8_t *pass, int passlen, uint8_t *salt, int saltlen, uint32_t iterations, uint8_t *key, int keylen)
{
uint32_t i, j, k;
uint8_t f[HMACLEN], g[HMACLEN];
uint32_t blocks = keylen / HMACLEN;
if (keylen & (HMACLEN - 1)) {
blocks++;
}
for (i = 1; i <= blocks; i++) {
salt[saltlen ] = (i >> 24) & 0xFF;
salt[saltlen + 1] = (i >> 16) & 0xFF;
salt[saltlen + 2] = (i >> 8) & 0xFF;
salt[saltlen + 3] = i & 0xFF;
HMACFUNC(pass, passlen, salt, saltlen + 4, g);
memcpy(f, g, HMACLEN);
for (j = 1; j < iterations; j++) {
HMACFUNC(pass, passlen, g, HMACLEN, g);
for (k = 0; k < HMACLEN; k++) {
f[k] ^= g[k];
}
}
if (i == blocks - 1 && (keylen & (HMACLEN - 1))) {
memcpy(key + HMACLEN * (i - 1), f, keylen & (HMACLEN - 1));
} else {
memcpy(key + HMACLEN * (i - 1), f, HMACLEN);
}
}
}