| 摘要 |
PROBLEM TO BE SOLVED: To provide a cryptograph system which can suppress deterioration in the cipher strength of a common key cipher system, an increase in a circuit scale, and a deterioration in a processing speed, and to provide a data transfer controller. SOLUTION: The cryptograph system 100 includes a cipher processing circuit 110, a key memory circuit 120 and a key selecting circuit 130. The cipher processing circuit 110 carries out cipher processing or decoding processing using a key for one set supplied by the common key cipher system. The key memory circuit 120 stores a plurality of key sets generated by the common cipher system from a plurality of common secret keys. The key selecting circuit 130 selects one key set from the plurality of key sets stored in the key memory circuit 120 on the basis of a given key selection signal, and supplies the set to the cipher processing circuit 110. COPYRIGHT: (C)2004,JPO
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