一种适合云数据共享的身份代理重加密方案

目前云数据安全存储方案中，数据拥有者加密数据上传到云中，但却不能很好的支持加密数据分享，尤其是分享给多个用户时，可扩展性不强。针对这个问题本文提出一种基于身份的代理重加密方案，该方案不需要云完全可信但却又能灵活地进行数据安全共享。在具体构造上，结合基于身份的加密，用一个强不可伪造的一次签名方案使被转化后的密文具有公开验证性，且能达到被转化后的密文在标准模型下具有选择密文安全性。由于该类方案无需使用公钥证书、能支持细粒度的访问控制且可扩展性较好，因此可以较好的适用于安全云数据共享。

An identity based proxy re-encryption scheme for secure cloud data sharing

Currently most of the solutions of cloud data security storage require the data owner encrypts his data before outsourcing the data to the cloud, but this method cannot support flexible data sharing, especially for the multi-user setting. Aimed at solving this problem, this paper proposes a new identity based proxy re-encryption scheme, which does not need the cloud to be completely trusted, but can also be used to share the data safely. In the concrete construction, we use a strongly non-forgeable signature scheme to let the encrypted ciphertexts be publicly verifiable, our scheme can also be chosen ciphertext secure in the standard model. For our scheme can be used without certificate, support fine-grained access control and be very scalable, thus it can be used for secure data sharing in the cloud.