364 research outputs found

    Multiple Signatures in Cryptographic Message Syntax (CMS)

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    The Value of User-Visible Internet Cryptography

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    Cryptographic mechanisms are used in a wide range of applications, including email clients, web browsers, document and asset management systems, where typical users are not cryptography experts. A number of empirical studies have demonstrated that explicit, user-visible cryptographic mechanisms are not widely used by non-expert users, and as a result arguments have been made that cryptographic mechanisms need to be better hidden or embedded in end-user processes and tools. Other mechanisms, such as HTTPS, have cryptography built-in and only become visible to the user when a dialogue appears due to a (potential) problem. This paper surveys deployed and potential technologies in use, examines the social and legal context of broad classes of users, and from there, assesses the value and issues for those users

    Optimizing secure communication standards for disadvantaged networks

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    Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 137-140).We present methods for optimizing standardized cryptographic message protocols for use on disadvantaged network links. We first provide an assessment of current secure communication message packing standards and their relevance to disadvantaged networks. Then we offer methods to reduce message overhead in packing Cryptographic Message Syntax (CMS) structures by using ZLIB compression and using a Lite version of CMS. Finally, we offer a few extensions to the Extensible Messaging and Presence Protocol (XMPP) to wrap secure group messages for chat on disadvantaged networks and to reduce XMPP message overhead in secure group transmissions. We present the design and implementation of these optimizations and the results that these optimizations have on message overhead, extensibility, and usability of both CMS and XMPP. We have developed these methods to extend CMS and XMPP with the ultimate goal of establishing standards for securing communications in disadvantaged networks.by Stephen Hiroshi Okano.M.Eng

    High-level Cryptographic Abstractions

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    The interfaces exposed by commonly used cryptographic libraries are clumsy, complicated, and assume an understanding of cryptographic algorithms. The challenge is to design high-level abstractions that require minimum knowledge and effort to use while also allowing maximum control when needed. This paper proposes such high-level abstractions consisting of simple cryptographic primitives and full declarative configuration. These abstractions can be implemented on top of any cryptographic library in any language. We have implemented these abstractions in Python, and used them to write a wide variety of well-known security protocols, including Signal, Kerberos, and TLS. We show that programs using our abstractions are much smaller and easier to write than using low-level libraries, where size of security protocols implemented is reduced by about a third on average. We show our implementation incurs a small overhead, less than 5 microseconds for shared key operations and less than 341 microseconds (< 1%) for public key operations. We also show our abstractions are safe against main types of cryptographic misuse reported in the literature

    Traceable Anonymous Certificate

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    Kerberos realm crossover

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    Proceedings of the 2nd International Workshop on Security in Mobile Multiagent Systems

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    This report contains the Proceedings of the Second Workshop on Security on Security of Mobile Multiagent Systems (SEMAS2002). The Workshop was held in Montreal, Canada as a satellite event to the 5th International Conference on Autonomous Agents in 2001. The far reaching influence of the Internet has resulted in an increased interest in agent technologies, which are poised to play a key role in the implementation of successful Internet and WWW-based applications in the future. While there is still considerable hype concerning agent technologies, there is also an increasing awareness of the problems involved. In particular, that these applications will not be successful unless security issues can be adequately handled. Although there is a large body of work on cryptographic techniques that provide basic building-blocks to solve specific security problems, relatively little work has been done in investigating security in the multiagent system context. Related problems are secure communication between agents, implementation of trust models/authentication procedures or even reflections of agents on security mechanisms. The introduction of mobile software agents significantly increases the risks involved in Internet and WWW-based applications. For example, if we allow agents to enter our hosts or private networks, we must offer the agents a platform so that they can execute correctly but at the same time ensure that they will not have deleterious effects on our hosts or any other agents / processes in our network. If we send out mobile agents, we should also be able to provide guarantees about specific aspects of their behaviour, i.e., we are not only interested in whether the agents carry out-out their intended task correctly. They must defend themselves against attacks initiated by other agents, and survive in potentially malicious environments. Agent technologies can also be used to support network security. For example in the context of intrusion detection, intelligent guardian agents may be used to analyse the behaviour of agents on a firewall or intelligent monitoring agents can be used to analyse the behaviour of agents migrating through a network. Part of the inspiration for such multi-agent systems comes from primitive animal behaviour, such as that of guardian ants protecting their hill or from biological immune systems

    SECURE E-MAIL SYSTEM USING S/MIME AND IB-PKC

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    Although e-mail security solutions have been introduced for more than two decades, most of the e-mail messages are sent nowadays without being secured by any of these techniques. This is due to the complexity of using these secure e-mail systems and protocols. The complexity mainly arises from the difficulty associated with managing certificates and public keys. The main objective of this study was to find a solution that can make secure e-mail systems easier to use while maintaining the same level of security. This paper proposes a secure e-mail system that is based on the S/MIME standard where the public key and signature algorithms have been replaced by their Identity-Based Cryptography analogue algorithms. Using Identity-Based Cryptography has eliminated the need for digital certificates, and provided a solution to the usability problem present in the existing secure e-mail systems. Users can determine the public key of the recipient without having to contact any trusted third party, and can start encrypting or verifying messages as long as they have the public system parameters that can be publicly available. Users need to contact the Private Key Generator (PKG) only once in order to retrieve their private key before being able to decrypt or sign messages
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