| 摘要 |
PURPOSE:To increase the secrecy of information by several steps by preparing conversion rules different for every plural users and producing the new cipher information applying said conversion rules to the old cipher information. CONSTITUTION:Conversion rules f1-fn are prepared for user names U1-Un respectively. When the name U1, for example, is supplied by a cipher information input device 4, a conversion processor 3 reads the corresponding conversion rule f1 out of a conversion rule memory 2. Furthermore the processor 3 reads the existing cipher information out of a cipher information memory 1 and then applies the conversion rule to the existing cipher information to produce the new cipher information. While the user U1 memorizes the old cipher information and produces the new cipher information with the rule f1 to feed it through an input device 4. Then the permission is given for processing of secret information when the coincidence is obtained from comparison between both cipher information. |
