+ * EXAMPLE
+ *
+ * SilcMac hmac;
+ *
+ * // Allocate HMAC
+ * silc_mac_alloc(SILC_MAC_HMAC_SHA256, &hmac);
+ *
+ * // Set secret key to the MAC
+ * silc_mac_set_key(hmac, key, key_len);
+ *
+ * // Compute MAC
+ * unsigned char mac[SILC_MAC_MAXLEN];
+ * SilcUInt32 mac_len;
+ *
+ * silc_mac_make(hmac, data, data_len, digest, &mac_len);
+ *
+ * // Free MAC
+ * silc_mac_free(hmac);
+ *