Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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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: 9Citation - Scopus: 24Modeling Leakage of Ephemeral Secrets in Tripartite/Group Key Exchange(Springer Verlag, 2010) Manulis, Mark; Suzuki, Koutarou; Ustaoğlu, BerkantRecent advances in the design and analysis of secure two-party key exchange (2KE) such as the leakage of ephemeral secrets used during the attacked sessions remained unnoticed by the current models for group key exchange (GKE). Focusing on a special case of GKE - the tripartite key exchange (3KE) - that allows for efficient one-round protocols, we demonstrate how to incorporate these advances to the multi-party setting. From this perspective our work closes the most pronounced gap between provably secure 2KE and GKE protocols. The proposed 3KE protocol is an implicitly authenticated protocol with one communication round which remains secure even in the event of ephemeral secret leakage. It also significantly improves upon currently known 3KE protocols, many of which are insecure. An optional key confirmation round can be added to our proposal to achieve the explicitly authenticated protocol variant. © 2010 Springer-Verlag.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.Conference Object Security Arguments for the Um Key Agreement Protocol in the Nist Sp 800-56a Standard(Association for Computing Machinery (ACM), 2008) Menezes, Alfred; Ustaoğlu, BerkantThe Unified Model (UM) key agreement protocol is an efficient Diffie-Hellman scheme that has been included in many cryptographic standards, most recently in the NIST SP 800-56A standard. The UM protocol is believed to possess all important security attributes including key authentication and secrecy, resistance to unknown key-share attacks, forward secrecy, resistance to known-session key attacks, and resistance to leakage of ephemeral private keys, but is known to succumb to key-compromise impersonation attacks. In this paper we present a strengthening of the Canetti-Krawczyk security definition for key agreement that captures resistance to all important attacks that have been identified in the literature with the exception of key-compromise impersonation attacks. We then present a reductionist security proof that the UM protocol satisfies this new definition in the random oracle model under the Gap Diffie-Hellman assumption. Copyright 2008 ACM.Conference Object Citation - Scopus: 5A Distributed Wakening Based Target Tracking Protocol for Wireless Sensor Networks(Institute of Electrical and Electronics Engineers Inc., 2010) Alaybeyoğlu, Ayşegül; Dağdeviren, Orhan; Kantarcı, Aylin; Erciyeş, KayhanWe propose a two layer protocol for tracking fast targets in sensor networks. At the lower layer, the Distributed Spanning Tree Algorithm (DSTA) [12] partitions the network into clusters with controllable diameter and constructs a spanning tree backbone of clusterheads rooted at the sink. At the upper layer, we propose a target tracking algorithm which wakes clusters of nodes by using the estimated trajectory beforehand, which is different from existing studies [3] in which target can be detected only when the nodes close to the target are awake. We provide the simulation results and show the effect of fore-waking operation by comparing error and miss ratios of existing approaches with our proposed target tracking algorithm. © 2010 IEEE.Conference Object Citation - WoS: 13Citation - Scopus: 14Performance Evaluation of Cluster-Based Target Tracking Protocols for Wireless Sensor Networks(Institute of Electrical and Electronics Engineers Inc., 2009) Alaybeyoğlu, Ayşegül; Dağdeviren, Orhan; Erciyeş, Kayhan; Kantarcı, AylinTarget tracking is an important application type for wireless sensor networks (WSN). Recently, various approaches [1-11] are proposed to maintain the accurate tracking of the targets as well as low energy consumption. Clustering is a fundamental technique to manage the scarce network resources [12-19]. The message complexity of an application can be significantly decreased when it is redesigned on top of a clustered network. Clustering has provided an efficient infrastructure in many existing studies [1-8]. The clusters can be constructed before the target enters the region which is called the static method [1-4] or clusters are created by using received signal strength (RSS) from target which is called the dynamic method [5-8]. In this paper we provide simulations of static and dynamic clustering algorithms against various mobility models and target speeds. The mobility models that we applied are Random Waypoint Model, Random Direct Model and Gauss Markov Model. We provide metrics to measure the tracking performance of both approaches. We show that the dynamic clustering is favorable in terms of tracking accuracy whereas the energy consumption of static clustering is significantly smaller. We also show that the target moving with Gauss Markov Model can be tracked more accurately than the other models.Conference Object Citation - WoS: 6Citation - Scopus: 8A Cluster-Based Dynamic Load Balancing Middleware Protocol for Grids(Springer Verlag, 2005) Erciyeş, Kayhan; Payli, Reşat ÜmitWe describe a hierarchical dynamic load balancing protocol for Grids. The Grid consists of clusters and each cluster is represented by a coordinator. Each coordinator first attempts to balance the load in its cluster and if this fails, communicates with the other coordinators to perform transfer or reception of load. This process is repetaed periodically. We show the implementation and analyze the performance and scalability of the proposed protocol.Conference Object Citation - WoS: 4Citation - Scopus: 4Merging Clustering Algorithms in Mobile Ad Hoc Networks(Springer Verlag, 2005) Dağdeviren, Orhan; Erciyeş, Kayhan; Çokuslu, DenizClustering is a widely used approach to ease implementation of various problems such as routing and resource management in mobile ad hoc networks (MANET)s. We first look at minimum spanning tree(MST) based algorithms and then propose a new algorithm for clustering in MANETs. The algorithm we propose merges clusters to form higher level clusters by increasing their levels. We show the operation of the algorithm and analyze its time and message complexities.