AES-GCM is an authenticated encryption block cipher mode which provides data confidentiality, integrity and origin authentication at potentially very high data rates, and is therefore an alternative to modes such as CCM, EAX & OCB. It is described formally in NIST Special Publication 800-38D. This particular implementation of GCM targets medium throughput applications with emphasis on low resource usage, and ease of use via a byte-wide interface.
The Helion AES-GCM core integrates all of the underlying functions required to implement AES in GCM mode including round-key expansion, counter mode logic, hash length counters, final block padding, and tag appending and checking features. The only external logic required is to form the Nonce block from various application specific packet header fields. Support is provided for both optional header and zero-length payload, and configurable tag length, making the core suitable for IPsec (RFC4106), MACsec (IEEE802.1ae) and Tape Storage (IEEE1619.1) applications.