Date Added: Jun 2009
Message Authentication Code (MAC) is a fixed length information used to en-sure data integrity and authenticity, and is widely used in network and security protocols, such as IPSec, SNMP, and SSL/TLS. This paper develops several new techniques of cryptanalyzing MACs based on block ciphers, and is divided into two parts. The first part presents new distinguishers of the MAC construction ALRED and its specific instance ALPHA-MAC based on AES. For the ALRED construction, the authors first describe a general distinguishing attack which leads to a forgery attack directly with the complexity of the birthday attack.