Cisco Systems This document specifies algorithms for authenticated encryption with additional authenticated data (AEAD) that are based on the composition of the Advanced Encryption Standard (AES) in the Cipher Block Chaining (CBC) mode of operation for encryption, and the HMAC- SHA1 message authentication code (MAC). It also separately defines a generic composition method that can be used with other MACs and randomized ciphers. These algorithms are randomized, and thus are suitable for use with applications that cannot provide distinct nonces to each invocation of the AEAD encrypt operation.