Binary digit string generation device, binary digit string generation method and program

摘要

P To perform an arithmetic operation of a mask generation function for certifying whether the function is safe or not in the sense of Indifferentiability which is one of the criteria for evaluation of the safety of a mask generating function. PSOLUTION: For each count value i, a hash value y (i) of hash input information u (i) including an optional value x is generated. Each hash value y (i) and/or a bit string of a part of the hash value y (i) are bit-connected to generate a bit string having optional bit length L. The hash input information u (i) corresponding to at least some of the count value i further includes a hash chain value v (j (i)) corresponding to the count value j (i) (j (i) belong to 0,, Max}). The hash chain value v (j (i)) is the hash value of the information including the hash chain value v (m (i)) corresponding to the count value m (i) (m (i)≠ j (i)) or a bit string of a part of it. Hash input information u (p (i)) corresponding to the count value p (i) (p (i)≠ i) further includes a hash chain value v (m (i)). Fig.1 is a block diagram for explaining the constitution of a bit string generating device in the first embodiment. The bit string generating device 100 in this embodiment includes a control section 101, a memory 102a, an initial value memory 102b and an input section 103, a parameter computing section 104, a counter 105, hash operation sections 106, bit cut-out sections 107, and a bit connecting section 108. PCOPYRIGHT: (C)2011 and JPO& INPIT