The Galois/Counter Mode (GCM) is a typical block cipher modes of operation using block cipher algorithm. In this version, Advanced Encryption Standard (AES) processing ability is provided. The cipherkey length for AES should be 128/192/256 bits. The implementation takes a fix-sized (128 bits per block) payload and additional authenticated data (AAD) streams, but the text might have a variety of length in different situation. Thus, you need to provide the length in bits accompany with the data or the AAD. Meanwhile, the ciphers, which is the output of the primitive also comply to this pattern.