利用组合加解密方案改进SET协议的研究

文章首先对电子商务的安全体系进行了分析,针对SET协议对加解密算法的限制,提出一种采用组合加解密方案来提高SET协议的适应性和安全性,同时,又给出多证书和多数字签名的生成和认证方法。     

Definitions and properties of zero-knowledge proof systems

In this paper we investigate some properties of zero-knowledge proofs, a notion introduced by Goldwasser, Micali, and Rackoff. We introduce and classify two definitions of zero-knowledge: auxiliary-input zero-knowledge and blackbox-simulation zero-knowledge. We explain why auxiliary-input zero-knowledge is a definition more suitable for cryptographic applications than the original [GMR1] definition. In particular, we show that any protocol solely composed of subprotocols which are auxiliary-input zero-knowledge is itself auxiliary-input zero-knowledge. We show that blackbox-simulation zero-knowledge implies auxiliary-input zero-knowledge (which in turn implies the [GMR1] definition). We argue that all known zero-knowledge proofs are in fact blackbox-simulation zero-knowledge (i.e., we proved zero-knowledge using blackbox-simulation of the verifier). As a result, all known zero-knowledge proof systems are shown to be auxiliary-input zero-knowledge and can be used for cryptographic applications such as those in [GMW2].We demonstrate the triviality of certain classes of zero-knowledge proof systems, in the sense that only languages in BPP have zero-knowledge proofs of these classes. In particular, we show that any language having a Las Vegas zero-knowledge proof system necessarily belongs to RP. We show that randomness of both the verifier and the prover, and nontriviality of the interaction are essential properties of (nontrivial) auxiliary-input zero-knowledge proofs.This research was partially supported by the Fund for Basic Research Administered by the Israeli Academy of Sciences and Humanities. Preliminary versions of this work have appeared in [O1] and [O2].     

密码协议的设计准则

介绍了密码协议的设计准则，并通过具体实例加以说明，针对公钥协议，特别是协议中的签名和加密顺序问题，指出某些准则的局限性。     

On the Relative Soundness of the Free Algebra Model for Public Key Encryption

Formal systems for cryptographic protocol analysis typically model cryptosystems in terms of free algebras. Modeling the behavior of a cryptosystem in terms of rewrite rules is more expressive, however, and there are some attacks that can only be discovered when rewrite rules are used. But free algebras are more efficient, and appear to be sound for “most” protocols. In [J. Millen, “On the freedom of decryption”, Information Processing Letters 86 (6) (June 2003) 329–333] Millen formalizes this intuition for shared key cryptography and provides conditions under which it holds; that is, conditions under which security for a free algebra version of the protocol implies security of the version using rewrite rules. Moreover, these conditions fit well with accepted best practice for protocol design. However, he left public key cryptography as an open problem. In this paper, we show how Millen's approach can be extended to public key cryptography, giving conditions under which security for the free algebra model implies security for the rewrite rule model. As in the case for shared key cryptography, our conditions correspond to standard best practice for protocol design.     

G.Vigna加密跟踪改进方法

G．Vigna提出的加密跟踪方法是一种比较有代表性的保护Mobile Agent不受恶意主机或其他Agent写攻击的软件方法。该文针对G．Vigna加密跟踪方法的不足提出一种改进方法，使Mobile Agent的检测变得及时、主动，减少存储量和消息数，并使检测的比较结果直接化。     

Linux加密文件系统:CryPt-FS

随着便携式计算设备的普及，保存数据的存储设备失窃或遗失的可能性增大。在这种情况下，能够保证敏感数据不被泄露的唯一方案是使用数据加密技术。相对于其它加密方式，使用加密文件系统对用户透明、可靠，有着不容忽视的优势。文章在Linux2．4操作系统上设计和实现了一个加密文件系统——Crypt-FS，并对其进行了介绍。     

Construction of Cryptographically Important Boolean Permutations

In this paper a new general methodology is developed to construct Boolean permutations such that any non-trivial linear combination of their components has the largest algebraic degree.This work was supported by Natural Science Foundation of China no.90304007Acknowledgement The authors would like to express their deep gratitude to the anonymous referees for their valuable comments on this short paper.     

Analysis of e-commerce protocols: Adapting a traditional technique

We present the adaptation of our model for the validation of key distribution and authentication protocols to address some of the specific needs of protocols for electronic commerce. The two models defer in both the threat scenario and in the protocol formalization. We demonstrate the suitability of our adaptation by analyzing a specific version of the Internet Billing Server protocol introduced by Carnegie Mellon University. Our analysis shows that, while the security properties a key distribution or authentication protocol shall provide are well understood, it is often not clear which properties an electronic commerce protocol can or shall provide. We use the automatic theorem proving software Otter developed at Argonne National Laboratories for state space exploration.     

Networked cryptographic devices resilient to capture

We present a simple technique by which a device that performs private key operations (signatures or decryptions) in networked applications and whose local private key is activated with a password or PIN can be immunized to offline dictionary attacks in case the device is captured. Our techniques do not assume tamper resistance of the device but rather exploit the networked nature of the device in that the devices private key operations are performed using a simple interaction with a remote server. This server, however, is untrusted – its compromise does not reduce the security of the devices private key unless the device is also captured – and need not have a prior relationship with the device. We further extend this approach with support for key disabling, by which the rightful owner of a stolen device can disable the devices private key even if the attacker already knows the users password.     

Windows 2000平台下CSP模块的替换方法研究

要将自行开发的CSP模块替换Windows2000系统中自带的CSP模块,必须将自己开发的CSP动态库发送给微软签名,但是在开发CSP时必需对开发的模块进行测试,本文给出了两种在测试时简单替换Windows2000系统中CSP的方法,且这些方法简单易行。