Cryptographic processor with dynamic update of encryption state

Abstract

An efficient implementation of a cryptographic processor that dynamically updates the encryption state is described. The cryptographic processor can be implemented with a minimal number of gates, yet still perform cryptographic operations quickly. The cryptographic processor has an interface, a memory, a pseudorandom permutation block and control logic. The interface receives input data blocks and returns cryptographically processed data blocks. The memory is used to store an encryption state of the cryptographic processor. The pseudorandom permutation block transforms a portion of the encryption state that is modified for each input data block by at least the input data block and a previously transformed data block. The control logic routes data in the cryptographic processor to return cryptographically processed data blocks at the interface and update dynamically the encryption state stored in memory using the transformed data blocks from the pseudorandom permutation block.