crypto_init_iv
crypto_init_iv (ks, buf, xf->blocksize);
crypto_init_iv (ks, iv, xf->blocksize);
extern void crypto_init_iv(struct keystate *, u_int8_t *, size_t);
crypto_init_iv(exchange->keystate, hash->digest,
crypto_init_iv(ks, hash->digest, ks->xf->blocksize);