| 摘要 |
PROBLEM TO BE SOLVED: To reduce reducible circuits while constituting a hash function circuit by a PGV construction method and securing safety. SOLUTION: A middle key K<SB>A</SB>is generated by setting an initial key K<SB>LO</SB>to all 0 or all 1 in a middle key generation part 20, and is stored in a register 32 as the initial value of a key data. A shift selector 33 selects and fetches a state in which the key data stored in the above register 32 are circulation-shifted to the left by 15 bits or 17 bits, and stores the state in the above register 32 again. A logic circuit 340 selectively outputs the key data in the above register 32 or the above initial key K<SB>LO</SB>as sub-keys k<SB>1</SB>to k<SB>18</SB>, kw<SB>1</SB>to kw<SB>4</SB>, kl<SB>1</SB>to kl<SB>4</SB>. Selection output control to the above logic circuit 340 and selection control to the above shift selector 33 are carried out by a sub-key control part 350 according to a sub-key generation algorithm. COPYRIGHT: (C)2008,JPO&INPIT
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