@conference {
	title = {New Algorithm for the Design of Topology Aware Hypercube in Multi-hop Ad hoc Networks},
	author = {Striki, Maria., Manousakis, Kyriakos., Baras, John S.},
	year = {2009},
	month = {03/2009},
	abstract = {Securing group communications in resource constrained, infrastructure-less environments such as Mobile Ad Hoc Networks (MANETs) has become one of the most challenging research directions in the areas of wireless network security. MANETs are emerging as the desired environment for an increasing number of commercial and military applications, addressing also an increasing number of users. Security, on the other hand, is becoming an indispensable requirement of our modern life for all these applications. The inherent limitations of such dynamic and resource-constraint networks impose major difficulties in establishing a suitable secure group communications framework. This is even more so for the operation of Key Agreement (KA), under which all parties contribute equally to the group key. The logical design of efficient KA protocols has been the main focus of the related research to-date. Such a consideration, however, gives only a partial account on the actual performance of a KA protocol in a multi-hop network. This is because protocols have been evaluated only in terms of the group key related messaging in isolation from the underlying network functions that interact with the logical scheme and support its correct execution (i.e. routing). In recent work, we contributed towards efficiently extending a number of Diffie-Hellman (DH)-based group KA protocols in wireless multi-hop ad-hoc networks. Towards this end, we introduced a number of new algorithms to efficiently estimate the combined routing {\textendash} communication costs. We then improved these protocols with the addition of a new communication schedule subject to the underlying routing. Indeed, the resulting protocols were significantly more efficient in some or all of the metrics of interest, as our analytical and simulation results indicated. In this work, we contribute towards the latter, by extending an existing KA scheme that was left out in our previous work: Hypercube. Through our analysis and simulations, we demonstrate the superiority of the new, {\textquotedblleft}enriched{\textquotedblright} Hypercube that takes into account the underlying routing via the application of a topologically aware communications schedule.},
	address = {Gosier Guadeloupe, France},
	booktitle = {8th International Conference on Networks ICN 2009},
	pages = {pp.236-244}
}
@conference {
	title = {Fault-Tolerant Extension of Hypercube for Secure and Reliable Group Communications},
	author = {Striki, Maria., Baras, John S., Manousakis, Kyriakos.},
	year = {2008},
	month = {04/2008},
	abstract = {Securing group communications in resource constrained, infrastructure-less Mobile Ad Hoc Networks (MANETs) has become one of the most challenging research directions in the areas of wireless networking and security. MANETs are emerging as the desired environment for an increasing number of commercial and military applications, addressing also an increasing number of users. Security, on the other hand, is becoming an indispensable requirement of our modern life for all these applications. The inherent limitations of MANETs impose major difficulties on establishing a suitable secure group communications framework. We contribute to the latter by extending Hypercube, an existing key agreement (KA) scheme - all parties contribute equally to the group key - to tolerate multiple member failures with low cost. We achieve this by enhancing Hypercube with a novel adaptively proactive algorithm. Members are assumed to be already authenticated via some underlying mechanism and we only focus on the design and analysis of a fault-tolerant scheme. Our algorithm has been evaluated and compared with the existing approach. Through our analysis and simulations, we demonstrate its superiority in terms of robustness and efficiency.},
	address = {Cancun, Mexico},
	booktitle = {Seventh International Conference on Networking (ICN 2008)},
	pages = {pp. 223-231}
}
@conference {
	title = {New Algorithms for the Efficient Design of Topology-Oriented Key Agreement Protocols in Multi-hop Ad Hoc Networks},
	author = {Striki, Maria., Baras, John S., Manousakis, Kyriakos.},
	year = {2008},
	month = {03/2008},
	abstract = {Securing group communications in resource constrained, infrastructure-less environments such as Mobile Ad Hoc Networks (MANETs) has become one of the most challenging research directions in the areas of wireless network security. MANETs are emerging as the desired environment for an increasing number of commercial and military applications, addressing also an increasing number of users. Security, on the other hand, is an indispensable requirement of our modern life for all these applications. The inherent limitations of such dynamic and resource-constraint networks impose major difficulties in establishing a suitable secure group communications framework. This is even more so for the task of Key Agreement (KA), under which all parties contribute equally to the group key. The logical design of efficient KA protocols has been the main focus of the related research to-date. Such a consideration, however, gives only a partial account on the feasibility and actual performance of a KA protocol in a real multi-hop network. This is because protocols have been evaluated only in terms of the group key related messaging in isolation from the underlying network functions that interact with the logical scheme and support its correct execution (i.e. routing). In this work, we contribute towards efficiently extending a number of Diffie-Hellman (DH)-based group KA protocols in wireless multi-hop ad-hoc networks, and measuring their actual performance over these networks. Towards this end, we introduce a number of new algorithms that intelligently blend the logical protocol design with the underlying routing and network topology, to produce schemes that substantially improve on the metrics of interest. Indeed, the resulting protocols accomplish this goal, as our analytical and simulation results indicate.},
	address = {Berlin, Germany},
	booktitle = {6th International Symposium on Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt{\textquoteright}08)},
	pages = {pp. 384-393}
}
@conference {
	title = {Modeling Key Agreement in Multi-Hop Ad Hoc Networks},
	author = {Crescenzo, Giovanni Di., Striki, Maria., Baras, John S.},
	year = {2006},
	month = {07/2006},
	abstract = {Securing multicast communications in ad hoc networks has become one of the most challenging research directions in the areas of wireless networking and security. This is especially true as ad hoc networks are emerging as the desired environment for an increasing number of civilian, commercial and military applications, also addressing an increasingly large number of users. In this paper we study a very basic security question for Ad Hoc Networks: Key Agreement against passive adversaries. Despite being a widely studied area in wired networks, the problem becomes significantly more challenging for ad hoc networks, and even more for sensor networks, due to lack of trusted entities, infrastructures, full connectivity, routing structures, and due to severe limitations on the resources and capabilities of network nodes. In this paper we perform a comprehensive investigation of Key Agreement over resource constrained ad hoc networks. First, we formally model the key agreement problem over multi-hop ad hop networks, and we directly extend known key agreement protocols for wired networks, and evaluate the efficiency of such approaches. We then go beyond natural extensions of such protocols, by proposing non-trivial extensions based on efficient topology-driven simulations of logical networks over an arbitrary physical network, in order to optimize the most significant metrics of interest for such networks: i.e. bandwidth, latency, processing cost. Indeed, the resulting protocols are significantly more efficient in some or all of the above metrics, as our analytical results indicate},
	address = {Vancouver, Canada},
	booktitle = {2006 International Wireless Communications and Mobile Computing Conference},
	pages = {pp. 39-44}
}
@conference {
	title = {A Robust Distributed TGDH-based Scheme for Secure Group Communications in MANET{\textquoteright}s},
	author = {Striki, Maria., Baras, John S., Manousakis, Kyriakos.},
	year = {2006},
	month = {06/2006},
	abstract = {Securing multicast communications in Mobile Ad Hoc Networks (MANET) is considered among the most challenging research directions in the areas of wireless networking and security. MANET is emerging as the desired environment for an increasing number of commercial and military applications, addressing also a growing number of users. Security, on the other hand, is now an indispensable requirement for these applications. However, the limitations of the dynamic, infrastructure-less nature of MANET impose major difficulties in establishing a secure framework suitable for such services. The design of efficient key management (KM) schemes for MANET is of paramount importance since the performance of the KM functions imposes an upper limit on the efficiency and scalability of the whole secure group communication system. In this work, we contribute towards this direction by extending TGDH to a novel distributed scheme: DS-TGDH. Our aim is to modify TGDH to: a) be feasible in the most general resource-constrained MANET where no nodes with special capabilities exist, b) produce considerably lower overhead for the network nodes involved, c) handle disruptions with low cost. We consider the underlying routing protocol in our design, and we apply a distributed TGDH version over a robust schedule, optimizing parameters of interest. We focus on the design and analysis of the {\textquotedblleft}stealthy{\textquotedblright} TGDH and compare it with the original. Through our analysis and results, we shed insight on the actual feasibility of these protocols for MANET and provide realistic and fair comparison results that more accurately advocate the pros and cons of each protocol over the environment of study.},
	address = {Istanbul, Turkey},
	booktitle = {ICC2006 - IEEE International Conference on Communications},
	pages = {pp. 2249-2255}
}
@conference {
	title = {Distributed Certification Authority Generation to Enhance Autonomous Key Management for Group Communications in MANETs},
	author = {Striki, Maria., Baras, John S.},
	year = {2004},
	month = {11/2004},
	abstract = {A MANET is a collection of wireless mobile nodes dynamically forming a temporary network, without the use of fixed infrastructure or centralized entities, and this is exactly the environment envisioned for military operations by the Objective Force. Military command and control rely on secure (multicast) communications, and thus key management (KM) schemes that ensure secure communications under MANET constraints are required. However, without fixed infrastructure, e.g. trusted third parties (TTPs), Certification Authorities (CAs), the design of KM becomes particularly difficult, since its most fundamental service {\textendash} entity authentication, privileges update/revocation - rely on these entities to establish trust among nodes, terminate or renew participation to secure operations in a pre-agreed, global manner. Without this guarantee, all subsequent KM operations make no sense. So, it is of paramount importance to provide a secure authentication service that detects misbehavior and defends against dishonest users in the network. Thus, the challenge lies in dynamically generating mechanisms that provide individual nodes and KM groups with functionalities similar to those of the original CAs of fixed infrastructure, under MANET constraints. In this work, we develop distributed, scalable, robust and efficient mechanisms for dynamically generating CAs in MANETs, by distributing the tasks of a CA among legitimate members of existing (preferably hierarchical) KM groups. We will show how the features of our scheme render it superior in performance and resilience and how properties of KM groups are exploited to avoid impractical heavy bandwidth-delay solutions of other proposals in the literature.},
	address = {Orlando, Florida},
	booktitle = {24th Army Science Conference (ASC2004)}
}
@conference {
	title = {Towards Integrating Key Distribution with Entity Authentication for Efficient, Scalable and Secure Group Communication in MANETs},
	author = {Striki, Maria., Baras, John S.},
	year = {2004},
	month = {06/2004},
	abstract = {We focus on the design of key management (KM) schemes tailored for the environment of Mobile Ad Hoc Networks (MANETs). A MANET is a collection of wireless mobile nodes, communicating among themselves over possibly multi-hop paths, without the help of any infrastructure such as base stations or access points. The fact that no central authorization entity is assumed at all times for all nodes makes the task of network operations more difficult and indicates the need for distributed algorithms to provide the functions of centralized entities. KM ensures communication security among nodes and the capability of their cooperation as a secure group. It consists of key generation, user authentication and key distribution services. In this work we address key distribution, group key generation, entity authentication: we emphasize that entity authentication should be designed with key distribution algorithms in mind and vice versa, to achieve efficient and scalable KM schemes for MANETs. We present an entity authentication scheme based on the Merkle Tree algorithm, applied on a key generation protocol recently developed - MOT- to produce an efficient, scalable and secure KM scheme.},
	address = {Paris, France},
	booktitle = {2004 IEEE International Conference on Communications},
	pages = {pg. 4377-4381}
}
@conference {
	title = {Key Distribution Protocols for Secure Multicast Communication Survivable in MANETs},
	author = {Striki, Maria., Baras, John S.},
	year = {2003},
	month = {10/2003},
	abstract = {In this paper, we develop a secure, robust and scalable key management scheme for multicast communications in Mobile Ad Hoc Networks (MANETs). Most key distribution protocols of today are primarily designed for wire-line networks. Frequent node failures, network partitions, inefficient computational and communication capabilities of wireless nodes, network delay, bad quality of signal etc, are some of the reasons why they fail to work properly in MANETs. We classify existing and newly developed protocols in two families, contributory and non-contributory. We evaluate them and compare their performance. We focus on studying and developing key distribution techniques that achieve scalability and high performance within our framework without sacrificing the security level of the network. We also describe a hierarchical two-level hybrid key management scheme that utilizes some of the above protocols in the appropriate combinations to further reduce the storage, communication and computation costs of nodes.},
	address = {Boston, Massachusetts},
	booktitle = {MILCOM 2003},
	pages = {pp. 1-6}
}
@conference {
	title = {Efficient Scalable Key Agreement Protocols for Secure Multicast Communication in MANETs},
	author = {Striki, Maria., Baras, John S.},
	year = {2003},
	month = {04/2003},
	abstract = {In this paper protocols for group key distribution are compared and evaluated from the point of view of Mobile Ad Hoc Networks (MANETs). A MANET is a collection of wireless mobile nodes, communicating among themselves over possibly multihop paths, without the help of any infrastructure such as base stations or access points. So the need to render those networks as autonomous and secure as possible, since no central authorization can be assumed at all times, becomes emergent. Key management is the service that ensures the security of communication among nodes, and the capability of their cooperation as a secure group. It consists of three important services: key generation, user authentication and key distribution. In this work we assume that the participating users have already been authenticated with some mechanism, and we are focused only on studying and comparing protocols for group key establishment in MANETs. We distinguish the protocols in two families, the contributory and noncontributory and we evaluate them from the point of view of MANETs.},
	address = {College Park, Maryland},
	booktitle = {Collaborative Technology Alliances (CTA) Communications \&amp; Networks (C\&amp;N) Alliance - 2003 Annual Symposium},
	organization = {University of Maryland Conference Center}
}
@conference {
	title = {Fault-tolerance and efficiency considerations for key distribution ~protocols in MANETs},
	author = {Striki, Maria., Baras, John S.},
	year = {2003},
	month = {03/2003},
	abstract = {In this paper we address the Fault-Tolerance and Efficiency of key distribution protocols for group communications in Mobile AdHoc Networks. Most key distribution protocols that exist today are primarily designed for wireline networks. These protocols either fail to work as intended or cannot work at all when they are applied to the demanding environment of MANETs. The main reasons for this are: frequent node failures, network partitions and merges, inefficient computational and communication capabilities of certain wireless nodes, network delay, bad quality of signal etc. We determine the framework under which protocols can efficiently work in MANETs, design new protocols or modify existing ones, so that they can be robust, scalable and applicable in this environment. We classify these protocols in two families: contributory and non-contributory. We evaluate them from the point of view of MANETs and compare their performance.},
	address = {Baltimore, Maryland},
	booktitle = {37th Conference on Information Sciences and Systems(CISS)},
	organization = {Johns Hopkins University}
}
@conference {
	title = {Two Level Hybrid key Scheme for Efficient Key Distribution in Mobile Ad-Hoc Networks},
	author = {Baras, John S., Striki, Maria.},
	year = {2002},
	month = {12/2002},
	abstract = {Military command and control require that information be communicated to the appropriate groups and only with the utmost security. At the same time the environment envisioned by the Objective Force is mobile ad-hoc and consists of a large number of heterogeneous nodes deployed in a hostile field of limited bandwidth and unreliable channels. The nodes of the network may present severe bandwidth, energy, capacity and processing constraints (vary from Satellites, PDAs, laptops, to GPS devices, cellphones and pagers). In this work we develop a secure, robust and scalable key management scheme for multicast communications. This service is very important in determining the security and efficiency of the network. It consists of key generation, entity authentication and key distribution. We assume that the nodes are already authenticated and focus on studying and developing key distribution techniques with the aim to achieve scalability and high performance of our key distribution framework without sacrificing the security level of the network. For that we need to reduce the total storage, communication and computation cost of the nodes, resulting from the key distribution protocol we apply to our network. The new key distribution framework we designed is a hierarchical, two-level hybrid key management scheme.},
	address = {Orlando, Florida},
	booktitle = {23rd Army Science Conference}
}
@techreport {
	title = {A Robust, Distributed TGDH-based Scheme for Secure Group Communications in MANETs},
	author = {Striki, Maria.},
	year = {2005},
	month = {01/2005},
	abstract = {Through our analysis and results we shed more insight on the actual feasibility of these protocols for MANETs and provide more realistic and {\textquotedblleft}fair{\textquotedblright} comparison results that more accurately advocate the pros and cons of each protocol over the environment of interest.},
	number = {Number: CSHCN TR 2005-9}
}
@techreport {
	title = {Fault-Tolerant Extension of Hypercube Algorithm for Efficient, Robust Group Communications in MANETs},
	author = {Striki, Maria.},
	year = {2005},
	month = {01/2005},
	abstract = {Securing multicast communications in Mobile Ad Hoc Networks (MANETs) has become one of the most challenging research directions in the areas of wireless networking and security. MANETs are emerging as the desired environment for an increasing number of commercial and military applications, addressing also an increasing number of users. Security on the other hand, is becoming an indispensable requirement of our modern life for all these applications. However, the limitations of the dynamic, infrastructure-less nature of MANETs impose major difficulties in establishing a secure framework suitable for group communications. The design of efficient key management (KM) schemes for MANET is of paramount importance, since the performance of the KM functions (key generation, entity authentication, key distribution/agreement) imposes an upper limit on the efficiency and scalability of the whole secure group communication system. In this work, we contribute towards efficient, robust and scalable, secure group communications for MANETs, by extending an existing key agreement (KA) scheme (where all parties contribute equally to group key generation) {\textendash}Hypercube - to tolerate multiple member failures with low cost, through its integration with a novel adaptively proactive algorithm. We assume that the participating users have already been authenticated via some underlying mechanism and we focus on the design and analysis of a fault-tolerant Hypercube, with the aim to contribute to the robustness and efficiency of Octopus-based schemes (an efficient group of KA protocols for MANETs using Hypercube as backbone). We compare our algorithm with the existing approach, and we evaluate the results of our analysis. Through our analysis and simulation results we demonstrate how the new Hypercube algorithm enhances the robustness of the Octopus schemes maintaining their feasibility in MANETs at the same time.},
	number = {Number: CSHCN TR 2005-108}
}
@techreport {
	title = {Key Distribution Protocols for Multicast Group Communication in MANETs},
	author = {Striki, Maria.},
	year = {2003},
	month = {01/2003},
	abstract = {In this work we will attempt to combine these protocols with all the possible combinations into a two-layered hybrid scheme that exploits adavantages of both protocols and reduces possibly their overhead. We will develop models of these combinations, redefine their function principles and we will do a mathematical analysis to derive all costs. The analytical formulae of these models will provide us with the tools for comparisons among them, and push the research towards the best behaving models.},
	number = {Number: CSHCN TR 2003-10}
}
@techreport {
	title = {Scalable and Efficient Key Agreement Protocols for Secure Multicast Communication in MANETs},
	author = {Striki, Maria.},
	year = {2002},
	month = {01/2002},
	abstract = {In this paper protocols for group key distribution are compared and evaluated from the point of view of Mobile Ad Hoc Networks (MANETs). A MANET is a collection of wireless mobile nodes, communicating among themselves over possibly multihop paths, without the help of any infrastructure such as base stations or access points. So the need to render those networks as autonomous and secure as possible, since no central authorization can be assumed at all times, becomes emergent. Key management is the service that ensures the security of communication among nodes, and the capability of their cooperation as a secure group. It consists of three important services: key generation, user authentication and key distribution. In this work we assume that the participating users have already been authenticated with some mechanism, and we are focused only on studying and comparing protocols for group key establishment in MANETs. We distinguish the protocols in two families, the contributory and non-contributory and we evaluate them from the point of view of MANETs.},
	number = {Number: CSHCN TR 2002-28}
}
