Remarks on LUC public key system

Recently, Smith and Lennon (1993) proposed a new public key system LUC in which the trapdoor is based on the defined Lucas function instead of exponentiation. The authors present some remarkable properties of the Lucas function, which may or may not be disadvantages of the LUC system.<>     

替代LUC系统的一种新公钥系统

新公钥系统是利用Dickson的另外两类多项式,替代生成LUC系统的Lucas序列,利用一个新的算法构造的公钥系统。与LUC系统相比,新公钥系统具有相同的安全性,但是计算量减少,效率相对提高,比LUC系统实用性更强。     

基于公钥密码体制的网络认证技术

网络认证技术是“互联网+”行动计划应用推广的关键安全保障,基于公钥密码体制的数字签名已经成为身份与信息认证的主要手段,而数字签名有赖于认证中心(CA)及其基础设施(PKI).目前,认证中心依然存在身份认证不能互信互认、投入高、安全控制及运维难度大等问题.提出一种在不降低安全程度的情况下,缩短公钥密码长度,实现公钥可视化的技术,这种技术可以不再完全依赖第三方的认证机构,是去除认证中心当前存在问题的一种有效途径.     

基于身份的组合公钥认证体制

在三大主要的认证体制PKI,IBE和CPK中,基于身份标识的组合公钥体制CPK拥有我国自主知识产权,解决了大规模认证中密钥管理、离线验证和跨域认证等难题。首先,介绍CPK算法原理;其次,详细分析CPK的体系结构、密钥产生、密钥分发和管理、密钥存储以及密钥更新等问题;再次,对CPK各版本的演进进行介绍;最后,指出CPK有自身的优势应用,其主要运用于身份认证、离线认证、多域和跨域认证。总之,CPK作为一项推动我国信息安全发展的核心技术,有广泛的应用前景。     

Implementation of Mitre public key cryptographic system

The letter presents an observation of theoretical interest regarding exponentiation in a finite field. The result can be applied towards reducing the time required for the first of two exponentiations specified by the Mitre public key cryptographic system.     

Short cycling in the Kravitz-Reed public key encryption system

The Kravitz-Reed public key encryption system, a variant of the MIT system based on Galois fields, is interesting because it offers the potential of high security with efficient implementation. In the letter we demonstrate that high security and efficient implementation are not, in reality, compatible goals with this algorithm. Efficient implementation is subject to a short cycling attack that exposes the secret key to computation. If the parameters of the algorithm are selected for high security, then the algorithm cannot be efficiently implemented.     

Remarks on KRA key recovery block format

The introduction of a plethora of key recovery (KR) schemes and the lack of a standard has led to interoperability problems between dissimilar mechanisms. To overcome these problems the key recovery alliance (KRA) has proposed a common key recovery block (KRB) format. The authors identify some cases in which the mechanism fails to achieve its objectives     

The use of public key cryptography in communication system design

Since the time of Caesar, cryptography has been used in the design of secure communications systems. Recently, Diffie and Hellman [2] have introduced a new type of cryptographic method, based on "trapdoor" functions, which promises to be of great value in the design of such systems. We present a review of public key cryptosystems, followed by examples of communications systems which make particularly elegant use of their properties.     

破解HFEM公钥密码方案

为设计后量子公钥密码,赵永哲等人提出了一种基于BMQ问题新的公钥方案。利用有限域上遍历矩阵的性质,从该方案公钥能够直接求出其等价私钥,从而破解了该HFEM公钥密码方案。     

HFEM公钥密码方案的设计与实现

基于BMQ问题的困难性,以及有限域上的矩阵与向量之间的关系,提出了一种新的公钥密码方案,即隐藏域上遍历矩阵的公钥密码.给出了有关矩阵集合的约束条件以及利用遍历矩阵来构造满足条件之矩阵集合的方法.与已有MPKC方案相比,HFEM具有陷门设计新颖、算法简单、不涉及任何乘幂及复杂运算、加/解密算法效率相当、中心映射难以抽象、密钥/明文/密文空间大等特点.     

Specialised attack on Chor-Rivest public key cryptosystem

The Chor-Rivest public key cryptosystem (PKC) is a knapsack-type crypto-system based on arithmetic in finite fields GF (p/sup h/). It uses large fields, such as GF (197/sup 24/), where it is possible to compute discrete logarithms, which must be carried out at system configuration. The author presents a 'specialised attack' on the Chor-Rivest PKC which exploits an inherent algebraic property of the system.<>     

Security of the Cao-Li public key cryptosystem

The author shows that the Cao-Li cryptosystem proposed [1991] is not secure. Its private key can be reconstructed from its public key using elementary means such as LU-decomposition and the Euclidean algorithm     

对REESSE1公钥算法的攻击

最近国内的学者提出了一个名叫REESSEI的公钥算法,其中包括公钥加解密算法和数字签名算法。本文对公钥加解密算法进行了一系列的分析:密钥长度,密钥长度的下界,加解密的算法复杂度。同时指出了该公钥算法所用密钥长度过长,所以并不实用。而当密钥长度取最小时,我们又找到了一种攻击方法,从已知的公钥中完全恢复了私钥。     

Password-only authenticated key establishment protocol without public key cryptography

A scenario in which a user and a server can authenticate each other and generate a strong session key through a symmetric cipher by their shared weak (low-entropy) password in an insecure channel is considered. Until now, designing a secure protocol in this scenario has been an open problem due to the offline dictionary attack. A protocol to resolve this problem is proposed. The idea is to ensure that people must participate to verify each guessed password in the offline dictionary attack. Therefore, this attack cannot succeed in a reasonable time for the proposed protocol.     

Remarks on system simplification using the Routh stability array

A novel method employing the Routh stability array is presented for obtaining a stable approximant for a stable system.     

Fast public key cryptosystem based on matrix rings

A public key cryptosystem is proposed, which is based on the assumption that finding the square root of an element in a large finite ring is computationally infeasible in the absence of a knowledge of the ring structure. The encryption and decryption operations are very fast, and the data expansion is 1:2.     

具有固定公钥和私钥长度的广播加密方案

利用双线性配对技术提出一个新的基于身份的广播加密方案。在标准模型下,证明了该方案具有适应性攻击安全模型下选择明文安全性。方案中的公钥参数和用户私钥均为固定长度,密文长度较短,并且,新方案还满足完全抗同谋攻击。与现有的广播加密方案相比,新方案更适用于存储量小的系统。     

Variation of Cramer-Shoup public key scheme

Demonstrates an adaptive chosen ciphertext attack against the variation of Cramer-Shoup's public-key encryption scheme as proposed in the original paper [see ibid., vol. 35, no. 14, p. 1150, 1999]     

Algorithm engineering for public key algorithms

Methods of implementing public key algorithms based on modular integer arithmetic (RSA) and finite-field arithmetic (Diffie-Hellman, El Gamal) are examined. Architectures for VLSI implementations are emphasized.<>     

Variation of Cramer-Shoup public key scheme

A variation of the Cramer-Shoup public key scheme is presented. It is shown that the new public key scheme is also secure against adaptive chosen cipher-text attack. In addition the new scheme is simpler and requires less computation than the original scheme