一个安全可追踪的策略隐藏属性基加密方案

A SECURE AND TRACEABLE ATTRIBUTE-BASED ENCRYPTION SCHEME WITH ACCESS STRUCTURES

传统的属性基加密方案中存在着访问策略所包含的属性会泄露用户的敏感信息、恶意用户泄露私钥获取非法利益而不会被追责的问题,同时私钥长度、密文长度和解密运算量均会随属性数量增加而带来较大的通信开销和计算开销。对现有多种隐藏策略的属性基加密方案和可追踪的属性基加密方案分别进行深入研究,采用多属性值的方法,并引入一个安全的签名机制,提出了一个用户私钥长度、密文长度和解密运算量均固定的支持可追踪和隐藏策略的密文属性基加密方案,即STH-CP-ABE方案。并基于DBDH(Decisional Bilinear Diffie-Hellman)假设,在标准模型下证明了方案的安全性。

Referring to the problem that the traditional attribute-based Encryption schemes could not trace the malicious use and hide access structures at the same time,and the shortage that length of ciphertext and secret key increased with the number of attributes and large computing in decryption,large researches were put into several attribute-based encryption schemes with traitor tracing and hidden access structures separately. Combined with secure signature mechanism and the method of multi attribute value,a ciphertext-policy attribute-based encryption scheme supporting traitor tracing and hidden access structures was proposed. Based on the decisional bilinear Diffie-Hellman（DBDH） assumption,the scheme was proved fully secure. Moreover,it achieves constant size of private key and ciphertext and constant number of pairing computations.