Patent ID: 8023643
Filing Date: 2011-09-20
Classification: H04L

Abstract:
1. An encryption/decryption apparatus comprising: a random number supply unit configured to supply a random number; a first Exclusive OR circuit configured to perform an Exclusive OR between input data and the random number; an operation circuit configured to perform an operation of one of encryption or decryption of output data from the first Exclusive OR circuit; a selection signal generation unit configured to repeatedly generate a selection signal in synchronization with output timing of data from the operation circuit; a data register circuit having a plurality of data hold units, the data register circuit configured to hold data from the operation circuit in one data hold unit in response to the selection signal, the selection signal selectively indicating the one data hold unit from among the plurality of data hold units, the data register circuit further configured to supply the data from the one data hold unit to the operation circuit; and a second Exclusive OR circuit configured to perform an Exclusive OR between the data supplied from the data register circuit and the random number; wherein the operation circuit is further configured to recursively perform the one operation on the data supplied from the data register circuit and to output operated data to the data register circuit.