强前向安全的提名多代理签名方案

针对前向安全技术存在攻击者在得到第i周期的私钥后,可以伪造本阶段和以后阶段签名的缺陷,将强前向安全技术、提名思想与多代理签名理论结合,利用Hash函数叠加,提出一个强前向安全的提名多代理签名方案.对其正确性和安全性的分析结果表明,该方案不仅具有强前向安全性,还具有多人分享代理权和提名验证人验证签名的特性.     

A New Forward-Secure Authenticated Encryption Scheme with Message Linkages

Yoon and Yoo recently proposed a robust authenticated encryption scheme and claimed their scheme has the properties of forward secrecy and confidentiality. The current paper, however, points out that Yoon-Yoo＇s scheme also can not provide forward secrecy and confidentiality such that any adversary can easily recover the transferred message. Based on intractability of reversing the one-way hash function and discrete logarithm problem, an improved authenticated encryption scheme with messages linkage is proposed. The above security faults get solved perfectly. The new scheme is proven to satisfy all the basic security requirements of the authenticated encryption scheme. And by the concrete comparison, it has the similar efficiency of the original scheme.     

基于椭圆曲线密码体制的前向安全代理签名

在代理签名、椭圆曲线密码体制和前向安全签名的基础上，提出一种基于椭圆密码体制的前向安全代理签名方案，保证了系统在泄露密钥（或撤销密钥）后以前所做签名的有效性问题，并讨论其方案的正确性和安全性．     

一个基于GDH群的前向安全分布式数字签名方案

将一个基于GDH群的数字签名方案扩展到分布式数字签名中,并将前向安全的概念扩展到该签名方案中,提出一个有效的前向安全分布式签名方案.使用部分签名密钥安全前向更新,使集体签名安全前向更新,使得任何成员都不可能单独控制签名密钥的更新.增强密钥的安全性,使签名方案具有前向安全性.     

前向安全的签密方案

提出了一个基于Schnorr签名体制的、具有前向安全性质的签密方案,弥补已有签密方案大多不具备前向安全性的缺陷,该方案能够实现即使签密者的密钥泄漏,以前产生的签密仍然有效的目标.同时还证明了方案的正确性,并对方案的安全性进行了分析,得出该方案是有效的,且满足不可伪造性和保密性.     

A Signature Scheme with Non-Repudiation

Based on the Schnorr signature scheme, a new signature scheme with non-repudiation is proposed. In this scheme, only the signer and the designated receiver can verify the signature signed by the signer, and if necessary, both the signer and the designated receiver can prove and show the validity of the signature signed by the signer. The proof of the validity of the signature is noninteractive and transferable. To verify and prove the validity of the signature, the signer and the nominated receiver needn＇t store extra information besides the signature. At the same time, neither the signer nor the designated receiver can deny a valid signature signed. Then, there is no repudiation in this new signature scheme. According to the security analysis of this scheme, it is found the proposed scheme is secure against existential forgery on adaptive chosen message attack.     

双线性配对的前向安全环签名方案

前向安全的签名方案在当前签名密钥泄漏后,也能确保用户此前所作签名的合法性;而环签名能保证签名用户的无条件匿名性。基于保护前向安全性和无条件匿名性的要求,本文利用双线性对提出了一种新的前向安全的环签名方案,并在标准模型下证明其能抵抗伪造签名攻击,适用于对安全性能要求较高且匿名的场合。     

Efficient Identity Based Signcryption Scheme with Public Verifiability and Forward Security

In this paper, we point out that Libert and Quisquater‘s signeryption scheme cannot provide public verifiability. Then we present a new identity based signcryption scheme using quadratic residue and pairings over elliptic curves. It combines the functionalities of both public verifiability and forward security at the same time. Under the Bilinear Diffie-Hellman and quadratic residue assumption, we describe the new scheme that is more secure and can be some what more efficient than Libert and Quisquater‘s one.     

Merkle Tree Digital Signature and Trusted Computing Platform

0 IntroductionDigital signatureis a key technique to provide datainteg-rity andsource authenticationcapabilities to enhance da-ta trustworthiness in trusted computing platform. Most cur-rent digital signature schemes are based on complex mathe-matical problems , such as integer factoring, discrete log-arithm,and discrete logarithm on elliptic curves . The hard-ness of these underlying mathematical problems is really un-certain at present . Merkle treeis a method used for authenti-cation and di…     

Verifiable （ t, n） Threshold Signature Scheme Based on Elliptic Curve

Based on the difficulty of solving the ECDLP (elliptic curve discrete logarithm problem) on the finite field, we present a (t, n) threshold signature scheme and a verifiable key agreement scheme without trusted party. Applying a modified elliptic curve signature equation, we get a more efficient signature scheme than the existing ECDSA (ellipticcurve digital signature algorithm) from the computability and security view. Our scheme has a shorter key, faster computation, and better security.     

Improvement of Identity-Based Threshold Proxy Signature Scheme with Known Signers

0 IntroductionIdentity-based (ID-based) cryptography[1]is rapidly emer-gingin recent years .The concept of the proxy signature scheme was first in-troduced by Mamboet al[2]in 1996 .The concept of thresholdproxy signature was proposed[3 ,4]. Apractical and secure (t,n) threshold proxy signature scheme should satisfy the secre-cy,the proxy protected,the unforgeability,the non-repudia-tion,the ti me constraint ,andthe known signers[5].In 2006 , Baoet al[6]proposed an ID-based thresholdproxy si…     

一个新的具有前向安全有代理的多重数字签名方案

文章在研究有代理的多重数字签名的基础上,将前向安全的概念引人在有代理多重数字签名中,提出了一个具有前向安全性的有代理多重数字签名方案,在这种多重签名中,允许部分签名人委托其代理人进行签名．同时该方案能实现即使所有签名人的签名密钥被泄露,攻击者也无法伪造前阶段签名,以前所产生的有代理多重数字签名依然有效．     

Efficient hierarchical identity based signature scheme in the standard model

Hierarchical identity based cryptography is a generalization of identity based encryption that mirrors an organizational hierarchy. It allows a root public key generator to distribute the workload by delegating public key generation and identity authentication to lower-level public key generators. Most hierarchical identity based signature schemes are provably secure in the random oracle model or the weak models without random oracles such as gauntlet-ID model. Currently, there is no hierarchical identity based signature scheme that is fully secure in the standard model, with short public parameters and a tight reduction. In this paper, a hierarchical identity based signature scheme based on the q-SDH problem that is fully secure in the standard model is proposed. The signature size is independent of the level of the hierarchy. Moreover, our scheme has short public parameters, high efficiency and a tight reduction.     

安全加密的环签名混淆器

构造了一个安全的混淆器来实现对特殊的加密的环签名功能的混淆。这个特殊的加密的环签名功能是由waters的环签名方案和线性加密方案组合实现的。在标准模型下,构造的混淆器满足有关联预言的平均情况虚拟黑盒性质(ACVBP w.r.t.dependent oracles)。有了这个性质,即使敌手在获得混淆后的具有加密的环签名功能程序,环签名依然是匿名的和不可伪造的。     

A Secure Anonymous Internet Electronic Voting Scheme Based on the Polynomial

In this paper, we use the polynomial function and Chaum＇s RSA （Rivest, Shamir, Adleman） blind signature scheme to construct a secure anonymous internet electronic voting scheme. In our scheme, each vote does not need to be revealed in the tallying phase. The ballot number of each candidate gets is counted by computing the degrees of two polynomials＇ greatest common divisor. Our scheme does not require a special voting channel and communication can occur entirely over the current internet.     

前向安全的指定接收者恢复消息的部分盲签名方案

在指定接收者恢复消息签名方案的基础上加入了前向安全性,提出一种新的部分盲签名方案.新方案能够减少通信量,避免因密钥的泄露而导致以前的所有签名无效,只有指定的接收者才能恢复原始消息,进一步加强了消息的隐秘性.新方案中签名发起人和签名者合作完成签名,签名密钥按周期更新,在签名过程中加入了最终可恢复消息的接收者的信息.安全性分析表明新方案满足部分盲性、前向安全性和不可伪造性等安全性要求.     

前向安全门限签名方案

提出了一个新的前向安全门限签名方案,方案采用乘法共享的方法,实现十分简单,使用的密钥长度也很短,在参与成员n=t＋1时,可抵御收买t个成员的窃听敌手．假设因式分解是难解的,证明了方案在随机预言模型中是前向安全的．最后,给出了抵御恶意敌手的方法．     

Comment Fail-Stop Blind Signature Scheme Design Based on Pairings

Fail-stop signature schemes provide security for a signer against forgeries of an enemy with unlimited computational power by enabling the signer to provide a proof of forgery when a forgery happens. Chang et al proposed a robust fail-stop blind signature scheme based on bilinear pairings. However, in this paper, it will be found that there are several mistakes in Chang et al＇s fail-stop blind signature scheme. Moreover, it will be pointed out that this scheme doesn＇t meet the property of a fail-stop signature： unconditionally secure for a signer. In Chang et al＇s scheme, a forger can forge a valid signature that can＇t be proved by a signer using the ＂proof of forgery＂. The scheme also doesn＇t possess the unlinkability property of a blind signature.     

完全安全匿名的身份型广播加密方案

针对现有的广播加密方案效率与安全性难以兼顾的事实,利用Waters双系统密码技术及混合阶群双线性运算的正交性,提出了一个双系统密码技术下的公钥匿名的身份型广播加密方案.该方案建立在标准模型下,具有尺寸固定的短的密文与密钥,更无需使用任何哈希函数及随机标签,具有较高的计算效率与存储效率,其安全性依赖于3个简单的静态假设.证明结果显示,所提出的方案达到了匿名性及完全安全性的高安全级别要求.     

一类ELGamal数字签名方案的安全性分析

对一类原子原型的ELGamal签名变形方案进行有效的存在性伪造攻击,指出该类方案在实用中不可取.根据方案中是否应用杂凑函数将ELGamal签名体制分为两类,深入探讨了杂凑函数在签名中的作用.综述了基于ELGamal签名体制的可证明安全的一般方法,指出对基于ELGamal签名体制的实用签名方案的改进,应规定在带杂凑函数的三元组ELGamal签名方案中.