| 摘要 |
PROBLEM TO BE SOLVED: To provide an encrypting/decoding device which ensures safety, while preventing increase of circuits due to countermeasures against attacks by DPA. SOLUTION: The encrypting/decoding device is provided with: a random-number supply portion 12 which generates and supplies a certain random number beforehand; an arithmetic circuit 11 which performs arithmetic processing to be determined by a certain encrypting/decoding system; a first exclusive-OR circuit 13 for performing the exclusive-OR operations of data on an arithmetic processing results from the arithmetic circuit and the random numbers supplied from the random-number supply portion; a data register circuit 14 which is provided with a plurality of data retention portions 33-1, 33-2, writes and retains data from the first circuit 13 on a selected data retention portion on the basis of a selection signal for designating one of the plurality of data retention portions, every time a selection signal is inputted; and a second exclusive-OR circuit 15 which performs the exclusive-OR operations of the data retained in the one data retention portion of the data register circuit and the random numbers supplied from the random-number supply portion, and outputs it to the arithmetic circuit. COPYRIGHT: (C)2007,JPO&INPIT
|
