static bool prf_xor(int nid, const char *secret, size_t secretlen, char *seed, size_t seedlen, char *out, ssize_t outlen) {
digest_t *digest = digest_open_by_nid(nid, -1);
static bool prf_xor(int nid, const char *secret, size_t secretlen, char *seed, size_t seedlen, char *out, ssize_t outlen) {
digest_t *digest = digest_open_by_nid(nid, -1);