Converter encryption/decryption system, multi-stage converter, converting method, multi-stage converting method, program, and information recording medium

摘要

A converter 101 uses a predetermined parameter a. A generating unit 102 accepts generated inputs x1,..., xn, and generates generated outputs, y1, ..., yn, using recurrence formulas, y1 = F1 (x1, a) and yi+1 = Fi+1 (xi+1, yi) (1≤i≤n-1). A key accepting unit 103 accepts key inputs, k1,..., kn, and gives them as generated inputs to said generating unit 102. A repetition controller 104 gives the generated outputs as generated inputs to said generating unit 102, for an "m" (m≥0 number of times, and sets one of the generated outputs to be given at the end as a random number string, r1,..., rn. The data accepting unit 105 accepts data inputs, d1,..., dn. The converting unit 106 converts data using, ei = di ri, and, outputs data outputs, e1, ..., en. The converter 101 can be used both for encrypting and decrypting data.