ENCRYPTING A PLAINTEXT MESSAGE WITH AUTHENTICATION

摘要

An encryption and authentication technique that achieves enhanced integrity verification through assured error-propagation using a multistage sequence of pseudorandom permutations. The present invention generates intermediate data-dependent cryptographic variables at each stage, which are systematically combined into feedback loops. The encryption technique also generates an authentication tag without any further steps that is N times longer than the block size where N is the number of pseudorandom permutations used in the encipherment of each block. The authentication tag provides a unique mapping to the plaintext for any number of plaintext blocks that is less than or equal to N. In addition to being a stand alone encryption algorithm, the disclosed technique is applicable to any mode that uses pseudorandom permutations such as, key dependent lookup tables, S-Boxes, and block ciphers such as RC5, TEA, and AES.