A block-cipher based encryption scheme providing both privacy and authenticity that encrypts an arbitrary-length message into a minimal-length ciphertext. In one embodiment, “OCB”, a message is encrypted using a nonce by partitioning it into 128-bit message blocks and a possibly shorter message fragment....http://www.google.com/patents/US7046802?utm_source=gb-gplus-sharePatent US7046802 - Method and apparatus for facilitating efficient authenticated encryption
