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 .