ssh_hmac_init
if (ssh_hmac_init(ctx, key, klen) < 0 ||
int ssh_hmac_init(struct ssh_hmac_ctx *ctx, const void *key, size_t klen)
ssh_hmac_init(ctx, salt, len) < 0 ||
ssh_hmac_init(mac->hmac_ctx, mac->key, mac->key_len) < 0)
if (ssh_hmac_init(mac->hmac_ctx, NULL, 0) < 0 ||