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.<>     

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.     

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.     

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.     

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.     

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     

Toward a national public key infrastructure

Reliance on electronic communications makes information more vulnerable, and users will require confidentiality, message integrity, sender authentication, and sender non-repudiation. Public key cryptography will play an important role in providing these services     

公钥密码体制研究与进展

公钥密码体制的思想是密码史上一个重要的里程碑。本文详细的介绍了公钥密码体制的研究发展及实现应用,其中着重讨论了目前已有的几个比较重要的、有代表性的公钥密码体制如RSA、ECC、XTR的攻击现状,介绍了它们长期的安全性、标准化及其实现状况。最后我们简单的介绍了最近所提出的一些公钥密码体制如基于辫群的密码体制,量子公钥密码体制等。     

公钥密码体制RSA算法

介绍了RSA密码算法原理及在生成注册码方面的应用,并对RSA算法的安全性、缺点进行了简单的分析。     

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.<>     

Immunizing public key cryptosystems against chosen ciphertextattacks

Three methods for strengthening public key cryptosystems in such a way that they become secure against adaptively chosen ciphertext attacks are presented. In an adaptively chosen ciphertext attack, an attacker can query the deciphering algorithm with any ciphertext except for the exact object ciphertext to be cryptanalyzed. The first strengthening method is based on the use of one-way hash functions, the second on the use of universal hash functions, and the third on the use of digital signature schemes. Each method is illustrated by an example of a public key cryptosystem based on the intractability of computing discrete logarithms in finite fields. Security of the three example cryptosystems is formally proved. Two other issues, namely, applications of the methods to public key cryptosystems based on other intractable problems and enhancement of information authentication capability to the cryptosystems, are also discussed     

Vehicular implementations of public key cryptographic techniques

The author discusses public key cryptography techniques offering solutions to the unique problems associated with transaction authentication procedures using the open communication channel between a vehicle and an unprotected ground terminal. Valuable secrets embedded in costly security modules are not kept at the terminals. Playback of recorded taped communications or attempts at rehashing messages would be useless, and will not assist illicit falsification or forging of subsequent transactions. To prevent the unauthorized use of the crediting facility of a vehicle, an integral part of this facility is to be carried by the driver when the vehicle is not in operation. This can be integrated into existing electronic ignition keys. A public key cryptographic module installed in a vehicle can also be used for theft prevention by enhancing both ignition security and remote controlled door locking/unlocking mechanisms. The same device can be used for authenticating smartcard-based prepayment systems for parking or toll-road usage. This methodology is described