Data encryption apparatus, data converting method, data converting program, recording medium and integrated circuit

A data converting method used in an encryption processing apparatus that encrypts n-bit input data with use of pre-provided key data,

• the encryption processing apparatus including an input data converting unit, a first combining unit, a scramble unit, a second combining unit, and an output unit, the data converting method comprising the steps of:
• generating n-bit converted data constituted from a first block group including one or more data blocks and a second block group including one or more data blocks, by causing the input data converting unit to convert the input data with use of the pre-provided key data:
• generating a third block group with use of the second block group by causing the first combining unit to, for each of the one or more data blocks in the second block group, XOR the data block with a duplicated data block duplicated from among the one or more data blocks in the first block group,
• generating a fourth block group with use of the first block group and generating a fifth block group with use of the third block group by causing the scramble unit to, for each of the one or more data blocks in the first block group and each of the one or more data blocks in the third block group, duplicate the data blocks to generate two or more duplicated data blocks, shift-rotate each duplicated data block to generate a shifted data block, and XOR the shifted data blocks together;
• generating a sixth block group with use of the fourth block group by causing the second combining unit to, for each of the one or more data blocks in the fourth block group, XOR the data block with a duplicated data block duplicated from among the one or more data blocks in the fifth block group;
• and
• outputting n-bit output data by causing the output unit to output the output data, the output data including the data blocks in the fifth block group and the data blocks in the sixth block group.

A non-transitory computer-readable recording medium storing a data converting program used in an encryption processing apparatus that encrypts n-bit input data with use of pre-provided key data, the encryption processing apparatus including an input data converting unit, a first combining unit, a scramble unit, a second combining unit, and an output unit, the data converting program causing the encryption processing apparatus to perform the steps of:

• generating n-bit converted data constituted from a first block group including one or more data blocks and a second block group including one or more data blocks, by causing the input data converting unit to convert the input data with use of the pre-provided key data;
• generating a third block group with use of the second block group by causing the first combining unit to, for each of the one or more data blocks in the second block group, XOR the data block with a duplicated data block duplicated from among the one or more data blocks in the first block group;
• generating a fourth block group with use of the first block and generating a fifth block group with use of the third block group by causing the scramble unit to, for each of the one or more data blocks in the first block group and each of the one or more data blocks in the third block group, duplicate data blocks to generate two or more duplicated data blocks, shift-rotate each duplicated data block to generate a shifted data block, and XOR the shifted data blocks together;
• generating a sixth block group with use of the fourth block second combining unit to, for each of the one or more data blocks in the fourth block group, XOR the data block with a duplicated data block duplicated from among the one or more data blocks in the fifth block group;
• and
• outputting n-bit output data by causing the output unit to output the output data, the output data including the data blocks in the fifth block group and the data blocks in the sixth block group.

An integrated circuit used in an encryption processing apparatus that includes a data converting unit encrypts n-bit input data with use of pre-provided key data, the integrated circuit comprising:

• an input data converting unit operable to generate n-bit converted data constituted from a first block group including one or more data blocks and a second block group including one or more data blocks, by converting the input data with use of the pre-provided key data;
• at least one processor configured to operate as a first combining unit operable to generate a third block group with use of the second block group by, for each of the one or more data blocks in the second block group, XORing the data block with a duplicated data block duplicated from among the one or more data blocks in the first block group;
• a scramble unit operable to generate a fourth block group with use of the first block group and generate a fifth block group with use of the third block group by, for each of the one or more data blocks in the first block group and each of the one or more data blocks in the third block group, duplicating the data blocks to generate two or more duplicated data blocks, shift-rotating each duplicated data block to generate a shifted data block, and XORing the shifted data blocks together;
• a second combining unit operable to generate a sixth block group with use of the fourth block group by, for each of the one or more data blocks in the fourth block group, XORing the data block with a duplicated data block duplicated from among the one or more data blocks in the fifth block group;
• and
• an output unit operable to output n-bit output data, the output data including the data blocks in the fifth block group and the data blocks in the sixth block group.