// scryptBlockMix implements the function described in RFC 7914, section 4. B'
// is written to |out|. |out| and |B| may not alias and must be each one scrypt
// block (2 * |r| Salsa20 blocks) long.
static void scryptBlockMix(block_t *out, const block_t *B, uint64_t r) {
assert(out != B);
block_t X;
OPENSSL_memcpy(&X, &B[r * 2 - 1], sizeof(X));
for (uint64_t i = 0; i < r * 2; i++) {
xor_block(&X, &X, &B[i]);
salsa208_word_specification(&X);
// This implements the permutation in step 3.
OPENSSL_memcpy(&out[i / 2 + (i & 1) * r], &X, sizeof(X));
}
}
static void scryptBlockMix(uint32_t *B_, uint32_t *B, uint64_t r)
{
uint64_t i, j;
uint32_t X[16], *pB;
memcpy(X, B + (r * 2 - 1) * 16, sizeof(X));
pB = B;
for (i = 0; i < r * 2; i++) {
for (j = 0; j < 16; j++)
X[j] ^= *pB++;
salsa208_word_specification(X);
memcpy(B_ + (i / 2 + (i & 1) * r) * 16, X, sizeof(X));
}
OPENSSL_cleanse(X, sizeof(X));
}
