| 摘要 |
PROBLEM TO BE SOLVED: To attain high efficiency of whole processing while achieving safety equal to that in the conventional EME mode. SOLUTION: In encryption device 10, the interaction between blocks needed in the EME mode is achieved by exclusive-OR functions (XOR42 to XOR44) with a second mask data 2M to 8M to thereby provide safety equal to that in the conventional method. In the encryption device 10, according to the conventional EME mode, bit slice reverse conversion is not performed in bit slice mounting for a part corresponding to an encryption part (ECB1) of the conventional first layer, bit slice conversion is not performed in bit slice mounting for a part corresponding to an encryption part (ECB2) of the conventional second layer. Therefore, as compared with the case of applying the bit slice method to the EME mode of the conventional method as it is, bit slice reverse conversion (I-BS) and bit slice conversion (BS) can be reduced by one layer each so that the processing efficiency can be improved. COPYRIGHT: (C)2009,JPO&INPIT
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