Key Generators Can Strengthen Block Ciphers

The notion of key generators is introduced to symmetric cryptography. Key generators help eliminate the dependence of a block cipher’s security on a single, static key. If one of the dynamic keys is leaked to the adversary, then this compromise does not reveal future keys and prior keys used by the block cipher to encrypt distinct blocks of plaintext. A practical, key generator updating algorithm is provided that enhances the cryptographic strength of block ciphers and in particular the AES block cipher.