摘要:
多重签密是指2个以上参与方对同一则消息进行签密,并且要求签密结果不能因为签密者数目增多而呈线性增长.普通的ElGamal型多重签名虽然具有不可伪造性,但不能抵制多个签名者的联合攻击.为了克服现有ElGamal型多重签名的缺点,将ElGamal型多重签名和公钥签密组合在一起研究.提出了一种新的ElGamal型广播多重签密(ElGamal broadcasting multi-signcryption, EBMSC)协议,并给出了该协议的算法定义和安全模型,也在随机预言模型中证明了该协议在离散对数和计算性Diffie-Hellman假设下是语义安全的;然后在通用可复合框架下定义了ElGamal型广播多重签密协议的理想函数和现实协议,进而证明了现实协议能够实现广播多重签密协议的理想功能,同时还证明了现实协议是满足选择消息攻击下的不可伪造性;最后给出了ElGamal型广播多重签密协议与其他协议的效率比较.结果表明：该协议不仅在效率上要优于现有方案,而且在通用可复合框架下实现了多重签密功能.该协议适合应用在电子商务、合同签署、网上交易和财务出账等方面.
Abstract:
Multi-signcryption means two or more parties sign the same message, moreover, the length of signcryption cannot linearly increase for the increasing of the number of signers. Although ordinary ElGamal multi-signature satisfies the unforgeability, however, it can’t resist joint attack of multiple signers. In order to overcome the shortcomings of existing ElGamal multi-signature, the authors integrate the techniques of ElGamal multi-signature and signcryption to present a new ElGamal broadcasting multi-signcryption (EBMSC) protocol. We also describe its algorithm definition and security model, and prove its semantical security under the discrete logarithm (DL) and computation Diffie-Hellman (CDH) assumptions in the random oracle model (ROM). At the same time, we define the ideal function and the real protocol of EBMSC protocol under the universally composalble (UC) security framework, and then prove that the real protocol can realize the ideal function of EBMSC protocol. It also proves that the real protocol is unforgeable under unforgeability against adaptive chosen message attacks. Finally, the efficiency comparison between EBMSC protocol and existing protocols is given. Analysis results show our protocol not only is more efficient than existing protocols but also implements the function of multi-signcryption in UC security framework. Our protocol can be suitable for applications in e-commerce, contract signing, online transaction and financial accounting.
百度学术
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