由于现有聚合签名方案多数是基于双线性映射构造,存在计算效率低的不足。针对不同的网络环境,提出了2种不使用双线性映射的无证书聚合签名方案CLAS-Ⅰ和CLAS-Ⅱ,并在随机预言机模型下,基于离散对数困难问题证明了方案的不可伪造性;同时,分析了该方案所具有的公开验证性等安全属性。与现有方案相比较,由于未使用双线性映射运算,该方案具有更高的计算效率。由于方案CLAS-Ⅰ的聚合签名长度较长,将用于带宽较高的网络环境;CLAS-Ⅱ具有较短的签名长度,且长度与用户数无关,将用于带宽较低的网络环境。
Almost all existing aggregate signature schemes are based on bilinear pairing which leads to high computational cost. In order to solve this problem under different network environment, two new certificateless aggregate signature schemes without bilinear pairing CLAS-Ⅰ and CLAS-Ⅱ are proposed in this paper. The proposed schemes are provably unforgeable in the random oracle model under the discrete logarithm assumption, and also have the security properties of public verifiability. Moreover, compared with other existing aggregate signature schemes in the computationally complexity, the proposal are more efficient. Meanwhile, the scheme CLAS-Ⅰ can be used for high bandwidth network environment because the length of signature is long, and the scheme CLAS-II can be used in a narrow bandwidth network environment since it is the shortest certificateless aggregate signature and the number of users does not correlate to the length of the signatures generated by CLAS-Ⅱ,.