云计算中高效可即时撤销的无证书签名方案

Efficient revocable certificateless signature scheme for cloud computing

针对云计算中无证书签名方案计算代价高、撤销不即时的缺点,提出一种基于椭圆曲线加密的可即时撤销签名方案。采用椭圆曲线标量乘运算降低计算开销,KGC(key generation center)将时间参数加密与系统主密钥结合生成时间密钥,当出现用户密钥泄漏或身份过期时,KGC立即更新撤销时间表中未被撤销用户的时间密钥,防止用户的隐私泄露。理论与仿真分析结果表明,方案在随机预言模型下被证明是安全的,并且能够抵抗已撤销用户的攻击。

Aiming at the certificateless signature schemes which have the shortcomings of high computational cost and unimme-diate revocation,an efficient and immediate revocable signature scheme was proposed based on elliptic curve cryptography.Elliptic curve scalar multiplication was used to reduce computational overhead.To prevent the user’s privacy from leaking,time parameter and system master key were combined to generate the time key.When a user’s key leaked or his identity expired,the time key in the revocation schedule was updated immediately by key generation center for those users who had not been revoked.Theoretical and simulation results show that the proposed scheme is secure under the random oracle model against the attack of revoked users.