NIST - draft Special Publication 800-38D, Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) for Confidentiality and Authentication
The document specifies the Galois/Counter Mode (GCM), an authenticated encryption mode of the Advanced Encryption Standard (AES) algorithm. GCM provides assurance of confidentiality of data using a variation of the Counter mode of operation for encryption. GCM provides assurance of authenticity of the confidential data using a universal hash function that is defined over a binary Galois (i.e., finite) field. GCM can also provide authentication assurance for additional data that is not encrypted.