Efficient Conditional Privacy-Preserving and Authentication Scheme for Secure Service Provision in VANET

Vehicle Ad hoc NETworks(VANET) can enhance traffic safety and improve traffic efficiency through cooperative communication among vehicles, roadside infrastructure, and traffic management centers. To guarantee secure service provision in VANET, message authentication is important. Moreover, a vehicle user's private information can also be leaked during service provision. A protection mechanism is needed to prevent such leakage. Therefore, we propose a conditional privacy-preserving and authentication scheme for secure service provision in VANETs. The proposed scheme not only satisfies the security requirements of VANETs, but also optimizes the calculation process of signature generation and verification. We carry out a detailed comparative analysis. The result shows that the proposed scheme is more efficient than existing schemes in terms of communication overhead and computational cost. Therefore, our scheme is suitable for secure service provision in VANETs.     

Efficient and Provably Secure Multi-Recipient Signcryption from Bilinear Pairings

0 Introduction Confidentiality, integrity, non-repudiation and au- thentication are the important requirements for many cryptographic applications. A traditional approach to achieve these requirements is to sign-then-encrypt the message. Signcryption, fir…     

基于多变量公钥密码体制的环签名方案

环签名可以让用户完全匿名地对消息进行签名.迄今为止所有的环签名都基于传统密码体制.然而随着量子计算机的出现,传统密码体制的安全性受到威胁.多变量公钥密码学是一种高效的密码体制,并且有可能成为后量子时代安全的密码体制.提出了一个基于多变量公钥密码体制的环签名方案,该方案满足无条件匿名性,在非适应性选择消息下满足不可为造性,且运算效率高.     

VANET中面向安全通信的隐私保护协议

车载网VANETs(vehicular ad hoc networks)的隐私安全问题,提出隐私保护安全通信协议PPSCP(privacy preserving secure communication protocol)。PPSCP匿名地认证安全消息,从而保护车辆隐私,阻止非法车辆跟踪,并且平衡了隐私与身份识别的关系。同时PPSCP采用了有效的撤销机制,降低了撤销列表的尺寸。此外,PPSCP能够防御重放攻击和拒绝服务攻击。通过与S3P的安全性能对比分析,结果表明,PPSCP有效地降低了安全消息处理时延,减少了撤销列表尺寸,占用带宽少,提高数据传输率。     

无双线性对的基于无证书的移动IP注册协议

目前大多数基于无证书的移动IP注册协议需要复杂的双线性对运算,这使得移动IP的注册过程开销较大,效率较低,不利于实时通信。基于无对运算的无证书签名方案,提出了高效安全的移动IP注册协议。由于在注册的过程中省去了复杂的对运算,所以减少了注册时间,提高了注册效率。此外,该协议通过在注册过程中用移动用户的临时身份代替真实身份实现了用户匿名性;通过使用临时随机数Nonce可以抵抗重放攻击。安全性分析的结果表明所提出的协议是高效的、安全的。此外,与同类协议进行的安全和性能比较结果证明在能提供同样高的安全性能级别的协议中,该协议所设计的IP注册过程的时延是最短的。     

A Practical Approach to Attaining Chosen Ciphertext Security

Strong security in public key cryptography is not enongh; the encryption has to be achieved in an efficient way. OAEP or SAEP is only suitable for special applications （e. g. key transport）, and securely transporting message of any length is a challenge. Motivated by the hybrid encryption, we present a practical approach to achieve the （adaptively） chosen eiphertext security. The time cost of encryption/decryption of proposed scheme is similar to OAEP and the bandwidth of message recovery is 92% for standard security parameter, while RSA-OAEP is 84%. The scheme is also provably secure against adaptively chosen ciphertext attacks in the random oracle model. We conclude that the approach is practical in more extensive application.     

两种无证书聚合签名方案的安全性分析及改进

大部分的聚合签名方案存在安全性缺陷和计算效率偏低的问题。通过对两种无证书聚合签名方案进行安全性分析,发现两种方案分别无法抵抗Type I和TypeⅡ的伪造性攻击。针对此类问题,提出了一个改进方案。该方案在签名过程中改变了参数的组合方式,在聚合签名验证中加强了对主密钥和公钥的约束。在计算性Diffie-Hellman困难问题假设下,证明了方案在适应性选择消息攻击下具有不可伪造性。效率分析表明,方案在签名与验证过程中只需要4个双线性对运算,签名的长度是固定的,与同类安全的无证书聚合签名方案相比,改进的方案效率更高。     

带消息恢复的指定接收者的代理盲签名方案

基于离散对数难题,提出了一种具有消息恢复且只有指定接收者才能恢复消息并验证签名的代理盲签名方案.对方案做了安全性分析和计算效率分析,指出方案在满足可验证性、强不可伪造性、不可链接性、保密性等安全性要求的同时具有较高的计算效率,是一个高效安全的代理强盲签名方案.     

完整内部安全的混合签密方案设计与分析

设计达到完整内部安全的混合签密方案(HSC)是目前亟待解决的重要问题,而如何实现高效安全的签密密钥封装机制(SC-KEM)则是解决该问题的关键。为此,先设计一种带标签的签密密钥封装机制(SC-tag-KEM)的通用构造方案(SCtK_std),该方案通过签名绑定标签与密钥封装报文,将得到的签名和临时密钥使用消息认证码进行绑定。在标准模型下进行的安全性分析表明SCtK_std方案可达到DM-IND-iCCA安全和DM-SUF-iCMA安全,进而为达成完整内部安全奠定基础。然后,将SCtK_std方案与被动安全对称加密机制结合,构造了一种可达完整内部安全的混合签密的通用构造方案(HSC_std)。在标准模型下进行的安全性分析表明HSC_std方案同时具备IND-CCA2安全与SUF-CMA安全,进而达到完整内部安全。     

隐匿性签名方案

普通的数字签名体制无法有效地应对密钥泄漏攻击.为此,基于离散对数和大数分解困难性,保留一个秘密的备用公钥和相应的签名验证方程,在Schnorr签名中隐藏一个秘密的签名,给出一种新型的签名方案,即隐匿性签名方案.该方案能够在当前的签名密钥泄漏的情况下通过公开附加一些新的参数再次挽救签名系统.同时,为进一步分析方案的安全性,给出了相应的安全模型.方案在适应性选择消息和密钥泄漏攻击下可证明是安全的.该签名系统可用于诸如银行等安全级别要求较高的部门.     

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.     

两个标准模型下签名方案的密码学分析

为了分析和设计标准模型下安全的签名方案, 避免签名方案的设计中出现类似的安全性问题。 通过对标准模型下的无证书签名方案和前向安全的基于证书签名方案的分析, 发现该签名方案容易受到替换公钥攻击和后门攻击, 攻击者可以对任意的消息产生一个有效签名。 对这些攻击给出了具体分析, 同时探讨了克服这类攻击的方法。 研究结果表明, 这些攻击方法对于同类签名的分析与设计有借鉴意义。     

A practical identity-based signature scheme

Many identity-based signature （IBS） schemes solving key escrow were proposed, But the updating of the private keys wasn＇t discussed in these literatures. For the problem of key update, an identity-based key-insulated signature scheme with secure key-updates has been proposed. But their scheme inherited the key escrow property. In this paper, we propose a new identity-based strong key-insulated signature scheme without key escrow. It makes the IBS scheme more applicable to the real world. After analyzing the security and the performance, an application example in E-passport passive authentication scenario is described.     

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.     

基于DLP的指定验证人的代理签名

代理签名与指定验证人签名都是非常有用的密码学工具，在实际生活中有着广泛的应用。在代理签名中，原始签名人能将其数字签名的权力委托给代理签名人；而在指定验证人签名方案中，对于验证人却是有所限制的。文章结合两者的优点，利用基于离散对数的Schnorr签名方案构造了一个指定验证人的代理签名方案。本方案与其他方案相比，除了满足所必需的安全性之外，在代价及计算量上更为高效。     

指定验证人的门限环签名研究

将指定验证人的思想引入门限环签名,利用双线性映射构造了一个基于ID的指定验证人(t,n)门限环签名方案.在该方案中,不少于t个用户合作才能产生有效的环签名,且只有指定的验证人可以验证签名的有效性,任何人无法确定t个签名人的身份.因此该方案在随机预言模型下能抵抗适应性选择消息和身份攻击,且计算高效,签名过程不涉及映射运算,验证签名只需n+1次映射运算.     

Identity-based blind signature from lattices

Blind signature allows a user to get a signature of a signer on an arbitrary message,and the verifier can convince that the signature is indeed signed by the signer without leaking any information about the message.This property is necessary when the user’s privacy needs protection,such as a bank bill,a trade secret,etc.As an alternative of public key infrastructure,the identity-based system can simplify the key management procedures in certificate-based public key systems.Inspired by the requirement of identity-based blind signature in the post quantum world,we research on identity-based blind signature based on hard lattice problems under the random Oracle model.We propose a construction built upon the blind signature by Rückert,and it is proved to be one-more unforgeable against selective identity and chosen message attacks(s ID-CMA)and unconditionally blind.The proposed scheme has 2 moves,and its security can be reduced to the small integer solution(SIS)problem.     

一种新型弱仲裁量子签名方案

弱仲裁量子签名的安全性依赖于量子力学的一些基本原理,其不仅比传统的数字签名具有更好的安全性,而且比仲裁量子签名计算效率较高.为此,给出了一种新型弱仲裁量子签名,该签名具有以下特点:(1)仲裁者并不参与签名的产生和验证过程,只在发生纠纷时,仲裁者才参与纠纷的解决;(2)通过利用签名者身份信息以及与密钥绑定的旋转算子对签名进行认证,可以抵抗伪造攻击,并具有不可否认性;(3)该签名方案具有基于身份的数字签名方案的优点,即用户的身份信息直接用作公钥,无须量子公钥证书,这将给用户提供更多的方便.     

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。