PROBLEM TO BE SOLVED: To provide a proxy re-encryption system, at least one of convenience and safety of which is enhanced.;SOLUTION: A universal re-encryption key generation device 700 generates a universal re-encryption key urkS, by converting a user private key skS so that an original cipher text octF, that can be decrypted by the user private key skS, cannot be decrypted. A re-encryption key generation device 300 generates a re-encryption key rkS→F' for changing the decodable range of a cipher text, that can be decrypted by the user private key skS, and in which the information indicating the decodable range of the cipher text is set, from the universal re-encryption key urkS, without using the user private key skS and a master secret key msk.;SELECTED DRAWING: Figure 1;COPYRIGHT: (C)2016,JPO&INPIT
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机译：解决的问题：提供一种代理重加密系统，至少增强了其便利性和安全性。解决方案：通用重加密密钥生成设备700生成通用重加密密钥urk S ，方法是转换用户私钥sk S ，以便可以由用户私钥sk S解密的原始密文oct F ，无法解密。重新加密密钥生成设备300生成用于改变密文的可解码范围的重新加密密钥rk S→F'，该密文可被用户私钥sk S解密，并且在其中设置了指示密文的可解码范围的信息，该信息是从通用重新加密密钥urk S 中获得的，无需使用用户私钥sk S < / Sub>和一个主密钥msk 。;选定的图纸：图1;版权：（C）2016，JPO＆INPIT
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