可支持属性撤销的基于 CP-ABE 可搜索加密方案

针对目前基于属性的可搜索加密方案存在密钥泄露以及不支持属性撤销的问题，提出了一种云环境下，安全高效、可支持属性撤销的基于 CP-ABE （ciphertext-policy attribute based encryption）的可搜索加密方案。该方案不仅可支持细粒度的访问控制，具有较高的计算效率，且用户密钥使用随机值盲化后提交服务器，保证了用户密钥的保密性和安全性。该方案支持用户属性的撤销，并在属性撤销过程中，将密文更新的大部分工作转移给云服务提供商完成，方案在保证安全性的前提下，进一步降低了用户的计算代价。方案的安全性基于 DL（decisional linear）假设，在通用模型下具有选择明文攻击安全，抗合谋攻击，前向安全和后向安全。

CP-ABE based searchable encryption with attribute revocation

Against the drawback of present searchable encryistion based attribute in secret key leak and non-supported attribute revocation, a secure and efficient CP-ABE ( ciphertext-policy attribute based ercryption) searchable encryption scheme supporting attribute revocation is presented. It supports fine-grained access control, and has perfect computational efficiency. Moreover, the secret key is blinded by using a random number before submitting to sever. In the process of attribute revocation, the work of re-encryption ciphertext is completed by the cloud sever. Furthermore, the analysis shows that the security can be proved under the Decisional Linear assumption. And in the general model, the formula can achieve chosen plaintext attack security. Moreover it can resist collusion attack and has forward and backward secrecy.