| 摘要 |
PROBLEM TO BE SOLVED: To provide certified re-encipherment shuffle having a certificating method and a verifying method in which calculation quantity can be made proportional to the number of input cipher texts and the calculation quantity can be made small, and to provided a method for verifying this certified re-encipherment shuffle. SOLUTION: Re-encipherment is expressed as a kind of general conversion, and the authentication of re-encipherment shuffle can be constituted of the authentication of the possession of conversion information and the authentication of a condition fulfilled by the conversion. The two kinds of authentication can be made short, without having to depend on the number of input cipher texts, and as for the authentication of the possession of the conversion information, a response is generated depending on the conversion from a challenge value, so that the condition fulfilled by the conversion can be reflected on a relation between the response and the challenge value, and a relational expression between the response independently of the challenge value and the challenge value is present, so that the condition fulfilled by the conversion can be authenticated based on this establishment. Also, the authentication of the re-encipherment shuffle can be constituted with both authentications by selecting a condition fulfilled by the conversion, corresponding to the re-encipherment shuffle as a condition to be authenticated.
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