Mathematics / Matematik
Permanent URI for this collectionhttps://hdl.handle.net/11147/8
Browse
2 results
Search Results
Article Citation - WoS: 22Anonymity and One-Way Authentication in Key Exchange Protocols(Springer Verlag, 2013) Goldberg, Ian; Stebila, Douglas; Ustaoğlu, BerkantKey establishment is a crucial cryptographic primitive for building secure communication channels between two parties in a network. It has been studied extensively in theory and widely deployed in practice. In the research literature a typical protocol in the public-key setting aims for key secrecy and mutual authentication. However, there are many important practical scenarios where mutual authentication is undesirable, such as in anonymity networks like Tor, or is difficult to achieve due to insufficient public-key infrastructure at the user level, as is the case on the Internet today. In this work we are concerned with the scenario where two parties establish a private shared session key, but only one party authenticates to the other; in fact, the unauthenticated party may wish to have strong anonymity guarantees. We present a desirable set of security, authentication, and anonymity goals for this setting and develop a model which captures these properties. Our approach allows for clients to choose among different levels of authentication. We also describe an attack on a previous protocol of Øverlier and Syverson, and present a new, efficient key exchange protocol that provides one-way authentication and anonymity. © 2012 Springer Science+Business Media, LLC.Conference Object Citation - WoS: 28Strongly Secure Authenticated Key Exchange Without Naxos' Approach(Springer Verlag, 2009) Kim, Minkyu; Fujioka, Atsushi; Ustaoğlu, BerkantLaMacchia, Lauter and Mityagin [15] proposed the extended Canetti-Krawczyk (eCK) model and an AKE protocol, called NAXOS. Unlike previous security models, the adversary in the eCK model is allowed to obtain ephemeral secret information related to the test session, which makes the security proof difficult. To overcome this NAXOS combines an ephemeral private key x with a static private key a to generate an ephemeral public key X; more precisely X∈=∈g H(x,a). As a result, no one is able to query the discrete logarithm of X without knowing both the ephemeral and static private keys. In other words, the discrete logarithm of an ephemeral public key, which is typically the ephemeral secret, is hidden via an additional random oracle. In this paper, we show that it is possible to construct eCK-secure protocol without the NAXOS' approach by proposing two eCK-secure protocols. One is secure under the GDH assumption and the other under the CDH assumption; their efficiency and security assurances are comparable to the well-known HMQV [12] protocol. Furthermore, they are at least as secure as protocols that use the NAXOS' approach but unlike them and HMQV, the use of the random oracle is minimized and restricted to the key derivation function. © 2009 Springer-Verlag Berlin Heidelberg.