Symmetric encryption/decryption routine using AES

The following is a symmetric encryption/decryption routine using AES in GCM mode. This code operates in the application layer and is meant to receive user-specific and confidential information and encrypt it, after which it is stored in a separate database server. It also is called upon to decrypt encrypted information from the database.

The full description of the AES in GCM mode can be found in this document produced by David A. McGrew and John Viega The Galois/Counter Mode of Operation (GCM)