A Public Verifiable Identity Based Signcryption in the Random Oracle Model

Since Libert and Quisquater's identity based signcryption scheme cannot provide public verifiability after research, the paper proposes a new identity based signcryption scheme. The scheme uses quadratic residue and pairings over elliptic curves to realize public verifiability. By analysis the scheme is proved to be more efficient than Libert and Quisquater's scheme. Moreover, a security proof of the original scheme is presented in the random oracle model.     

A new efficient blind signcryption

In a blind signcryption, besides the functions of digital signature and encryption algorithm for authentication and confidentiality, a user can delegates another user＇s capability with the anonymity of the participants guaranteed. Some blind signcryptions were proposed but without a blind signcryption with public public verifiability. In this paper, verifiability that is proved to be efficient and secure is proposed. Through the security analysis, we proved that the scheme can offer confidentiality, integrity, unforgeability, non-repudiation and public verifiability. The coming research direction is also summarized.     

A Generic Solution to Realize Public Verifiability of Signcryption

0 IntroductionIn 1997 , Zheng[1]proposed a new pri mitive called sign-cryption, which si multaneously provides authenticity andconfidentiality within a single logic step.Signcryptionis moreefficient than the conventional“sign-then-encrypt”approach.Many signcryption schemes[2-5]have been proposed so far .For more details about the development of signcryption we re-fer the readers to Ref .[6] .Asecure signcryptionscheme should satisfy public verifi-ability (including non-repudiation)[1]. Wef…     

基于身份的前向安全和可公开验证签密方案

针对具有前向安全性和可公开验证的签密方案进行研究,基于Liber 和Quisquater的签密方案,给出了一个新的签密方案,并对所提出方案的安全性和效率进行了分析.结果表明:文章给出的签密方案实现了同时提供前向安全性和可公开验证性;而基于身份公钥密码和双线性对技术,使该方案又具有密钥长度短和密钥管理简单的特点,使其具有与LQ签密方案相当的效率.这种高效性和高安全性签密方案的提出,不仅对相关公开问题的解决具有一定理论意义,同时文中签密方案能更好的满足电子商务等实际应用的高安全需求,因此也具有一定应用价值.     

一种公开验证和前向安全的签密方案

利用椭圆曲线上双线性映射的特性,提出了一种基于身份的签密方案。分析结果表明,该方案除了满足一般签密方案的安全性外,还满足公开验证性和前向安全性。当发送方与接收方发生争议时,任何第3方都可以验证签名的有效性,但只有指定的接收者才可以解密恢复出消息明文。     

A signcryption scheme based on self-certified cryptography

Self-certified signcryption can remove key escrow problem and certification management problem. Based on Boneh and Boyen＇s short signature scheme, a secure self-certified sign- cryption scheme is proposed. Under the strong Diffie-Hellman assumption, the new scheme is proved secure, in which it satisfies public verifiability and existential unforgeablity. Furthermore, performance analysis shows that the proposed scheme only re- quires two pairing evaluations, so it can be used in the power and bandwidth limited environments.     

基于Zheng签密和SK签密的改进方案

近年来针对孤立目标的微动特征提取技术已较为成熟,但针对群目标的分辨与微动特征提取技术尚有待深入研究。以空间自旋微动群目标为例,提出了一种基于正弦调频傅里叶变换的自旋微动群目标分辨方法。建立了自旋微动群目标的回波模型,在此基础上采用正弦调频傅里叶变换来提取回波中的微多普勒特征分量。针对正弦调频傅里叶变换在分析多分量正弦调频信号时所特有的交叉项问题,提出了一种有效的交叉项抑制方法。结合交叉项抑制方法,利用正弦调频傅里叶变换处理自旋群目标微动信号,实现了对自旋微动群目标的分辨,并准确地提取出各子目标自旋频率特征。     

Public Key Cryptography Based on Ergodic Matrices over Finite Field

A new public key encryption scheme is proposed in this paper, which is based on a hard problem over ergodic matrices. The security of this scheme is equal to the MQ-problem： multivariate quadratic equations over finite fields. This problem has been shown to be NP-complete and can＇t be solved with polynomial time algorithm.     

A New ID-Based Proxy Multi-Signature Scheme from Bilinear Pairings

ID-based public key cryptosystem can be a good alternative for certifieate-based public key setting. This paper provides an efficient ID-based proxy multi signature scheme from pairings. In the random oracle model, we prove that our new scheme is secure against existential delegation forgery with the assumption that Hess＇s scheme-1 is existential unforgeable, and that our new scheme is secure against existential proxy multi-signature forgery under the hardness assumption of the computational Diffie-Hellman problem.     

关于不使用Hash和Redundancy函数签密方案的分析与改进

在实际应用中,前向安全性和公开验证性对密码系统来说是非常重要的.分析了不使用Hash和Redundancy函数的签密方案的前向安全性和公开验证性,分析表明该方案不具备前向安全性和公开验证性.分别就其前向安全性和公开验证性提出了相应的改进方案,并对方案进行了理论上的证明.改进方案克服了原方案中不具备前向安全性或公开验证性的缺陷;而且从效率上来分析,并没有明显增加计算量或传输量.     

An efficient identity-based anonymous signcryption scheme

Signcryption is a cryptographic primitive that performs encryption and signature in a single logical step more efficiently than sign-then-encrypt approach. Till now, various kinds of signcryption schemes have been proposed. Among them, the requirement of signcrypter＇s privacy protection is needful in some practical applications. In this paper, a new identity-based anonymous signcryption scheme from hilinear pairings, which is the organic combination of identity-based ring signature and encryption scheme, is proposed. The proposed scheme is indistinguishable against the chosen ciphertext attack under the Decisional Bilinear Diffie-Hellman assumption in the random oracle model. Its unforgeability relies on the computational Diffieellman problem. Compared with the previous schemes, the new scheme is more efficient in computation.     

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.     

Cryptanalysis and Improvement of Signcryption Schemes on Elliptic Curves

In this paper, we analyze two signcryption schemes on elliptic curves proposed by Zheng Yu liang and Hideki lmai. We point out a serious problem with the schemes that the elliptic curve based signcryption schemes lose confidentiality to gain non repudiation. We also propose two improvement versions that not only overcome the security leak inherenl in the schemes but also provide public verifiability or forward security. Our improvement versions require smaller computing cost than that required by signature-thenencryption methods.     

A New （ t, n） Threshold Signature Scheme Withstanding the Conspiracy Attack

A conspiracy attack is proposed to show that Wang-Li‘s scheme is insecure, because any t or more group members can impersonate other t members to sign any message without holding the responsibility. To avoid the conspiracy attack, this paper presents a new (t, n) threshold signature scheme with traceable signers.     

新的无证书签密方案

提出了一种新的无证书的签密方案,新方案在签密过程中只需要1次配对运算,在解签密过程中仅需要4次配对运算.与已有方案相比,新方案具有更高的效率.在安全性方面,新方案满足机密性、不可伪造性和可公开验证性.     

Applying evolutionary algorithm to public key cryptosystems

A best algorithm generated scheme is proposed in the paper by making use of the thought of evolutionary algorithm, which can generate dynamically the best algorithm of generating primes in RSA cryptography under different conditions. Taking into account the factors of time, space and security integrated, this scheme possessed strong practicability. The paper also proposed a model of multi-degree parallel evolutionary algorithm to evaluate synthetically the efficiency and security of the public key cryptography. The model contributes to designing public key cryptography system too. Foundation item: Supported by the Hi-Tech Research and Development Foundation item: Supported by the Hi-Tech Research and Development Biography; Tu Hang (1975-), male, Ph. D candidate, research directions: Biography; Tu Hang (1975-), male, Ph. D candidate, research directions:     

New multivariate-based certificateless hybrid signcryption scheme for multi-recipient

With the development of quantum computer,multivariate public key cryptography withstanding quantum attack has became one of the research focus.The existed signcryption schemes from discrete logarithm and bilinear paring are facing the serious threats.Based on multivariate public key cryptography,a new certificateless multi-receiver hybrid signcryption scheme has been proposed.The proposal reduced the cipher text and could handle arbitrary length messages by employing randomness reusing and hybrid encryption,as well as keeping security.In the random oracle model,the scheme’s confidentiality could withstand the IND-CCA2 adversary and its unforgeability could withstand the UF-CMA adversary under the hardness of multivariate quadratic(MQ)problem and isomorphism of polynomials(IP)assumption.It has less computation overhead and higher transmission efficiency than others.It reduced 33%cipher data compared with the existed similar scheme.     

A secure and efficient ( t, n ) multi-secret sharing scheme

Based on Shamir's secret sharing, a (t, n) multi-secret sharing scheme is proposed in this paper.p secrets can be shared amongn participants, andt or more participants can co-operate to reconstruct these secrets at the same time, butt−1 or fewer participants can derive nothing about these secrets. Each participant's secret shadow is as short as each secret. Compared with the existing schemes, the proposed scheme is characterized by the lower complexity of the secret reconstruction and less public information. The security of this scheme is the same as that of Shamir's threshold scheme. Analyses show that this scheme is an efficient, computationally secure scheme. Foundation item: Supported by the Special Funds for Major State Basic Research Program of China (973 Program) (G19990358-04) Biography: PANG Liao-jun(1978-), male, Ph. D candidate, research direction: Internet security, cryptography, secure mobile agent system and e-commerce security technology.     

An efficient certificateless ring signature scheme

To overcome the drawbacks such as high computational cost, unreasonable security model and long signature length in existing certificateless ring signature schemes, we propose an efficient certificateless ring signature scheme in this paper. Our construction is inspired by some efficient ID-based ring signature schemes, and uses bilinear pairings as a basic tool. Using a reasonable security model, the unforgeability of the proposed scheme is proven based on the intractability of the computational Diffie-Hellman （CDH） problem. The signature length of the new scheme is only ｜G2｜＋n｜G1｜ （｜Gi｜ is the bit length of an element in group Gi, i =1, 2）. Compared with other existing certificateless ring signature schemes, the newly proposed scheme has a shorter signature length and is more efficient and practical.     

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.