diff --git a/src/crypto-support/enc-tlv.hpp b/src/crypto-support/enc-tlv.hpp
index 030be07..9e207c0 100644
--- a/src/crypto-support/enc-tlv.hpp
+++ b/src/crypto-support/enc-tlv.hpp
@@ -26,12 +26,31 @@
 namespace ndn {
 namespace ndncert {
 
+/**
+ * Encode the payload into TLV block with Authenticated GCM 128 Encryption
+ * @p tlv_type, intput, the TLV TYPE of the encoded block, either ApplicationParameters or Content
+ * @p key, intput, 16 Bytes, the AES key used for encryption
+ * @p payload, input, the plaintext payload
+ * @p payloadSize, input, the size of the plaintext payload
+ * @p associatedData, input, associated data used for authentication
+ * @p associatedDataSize, input, the size of associated data
+ * @return the TLV block with @p tlv_type TLV TYPE
+ */
 Block
 encodeBlockWithAesGcm128(uint32_t tlv_type, const uint8_t* key, const uint8_t* payload, size_t payloadSize,
                          const uint8_t* associatedData, size_t associatedDataSize);
 
+/**
+ * Decode the payload from TLV block with Authenticated GCM 128 Encryption
+ * @p block, intput, the TLV block in the format of NDNCERT protocol
+ * @p key, intput, 16 Bytes, the AES key used for encryption
+ * @p associatedData, input, associated data used for authentication
+ * @p associatedDataSize, input, the size of associated data
+ * @return the plaintext buffer
+ */
 Buffer
-decodeBlockWithAesGcm128(const Block& block, const uint8_t* key, const uint8_t* associatedData, size_t associatedDataSize);
+decodeBlockWithAesGcm128(const Block& block, const uint8_t* key,
+                         const uint8_t* associatedData, size_t associatedDataSize);
 
 } // namespace ndncert
 } // namespace ndn