标准模型下高效安全的基于身份多签密方案.doc

标准模型下高效安全的基于身份多签密方案 摘要:针对已提出的基于身份多签密方案效率不高的问题，提出了一种高效安全的基于身份多签密方案。新方案消除了多次乘法运算，增加了密钥验证过程，并在标准模型下进行安全性分析及效率分析，证明了新方案可归约于cdh困难假定，计算量减少。与现有方案相比，新方案的安全性和多签密效率都得到了提高。 关键词:多签密；基于身份；标准模型；双线性对；可证安全 efficient and secure identity.based multi.signcryption scheme in standard model li cong*, yan de.qin, zheng hong.liang school of computer science and information technology, liaoning normal university, dalian liaoning 116081, chinaabstract: faced with inefficiency problem of current identity-based multi-signcryption schemes, an efficient and secure identity-based multi-signcryption scheme is proposed. the new scheme eliminates numbers of multiplicative operation, increases the course of verification key. furthermore, through security and efficiency analysis in the standard model, the new scheme is proved secure under computation diffie-hellman assumption and reduces the calculation work. compared with the known schemes ,the new sheme is more secure and efficient. faced with the inefficiency problem of current identity.based multi.signcryption schemes, an efficient and secure identity.based multi.signcryption scheme was proposed. the new scheme eliminated the number of multiplicative operations, and increased the procedure of key verification. furthermore, through security and efficiency analysis in the standard model, the new scheme is proved secure under computational diffie.hellman assumption and reduces the calculation work. compared with the known schemes, the new scheme is more secure and efficient. key words: multi.signcryption；identity.based；standard model；bilinear pairing；provable security0引言 shamir在1984年提出了基于身份的密码体制［1］，其主要思想是将能标识用户的身份信息作为公钥，如身份证号码、邮箱地址等,这就解决了传统使用公钥证书带来的各种问题。2004年，boneh等［2］提出了在标准模型下的基于身份的加密方案，如果要攻破方案，就相当于攻破公认的困难问题假定，显然，安全性问题是有保证的。 1997年，zheng提出了一种签密思想［3］，能同时完成签名和加密两种操作，降低了先签名后加密分步进行带来的高消耗。2002年，malone.lee最先提出了完整的基于身份的签密方案［4］，但chow等［5］指出基于身份的签密方案应该给出公开可证明性和前向安全性。直到2009年，yu等［6］提出了第一个在标准模型下的基于身份的签密方案。 为了适应多方参与的发展形势，2001年，mitomi等［7］提出了一种多签密方案，但是没有提供该方案安全性。201