research-article Share on Analytical Models for the Scalability of Dynamic Group-key Agreement Protocols and Secure File Sharing Systems Authors: Gokcan Cantali Dept. of Computer Engineering, Bogazici University, Istanbul, Turkey Dept. of Computer Engineering, Bogazici University, Istanbul, TurkeyView Profile , Orhan Ermis Dept. of Computer Engineering, Bogazici University and EURECOM, Sophia-Antipolis, France, Dept. of Computer Engineering, Bogazici University and EURECOM, Sophia-Antipolis, France,View Profile , Mehmet Ufuk Çağlayan Dept. of Computer Engineering, Yasar University, Izmir, Turkey Dept. of Computer Engineering, Yasar University, Izmir, TurkeyView Profile , Cem Ersoy Dept. of Computer Engineering, Bogazici University, Istanbul, Turkey Dept. of Computer Engineering, Bogazici University, Istanbul, TurkeyView Profile Authors Info & Claims ACM Transactions on Privacy and SecurityVolume 22Issue 4November 2019 Article No.: 20pp 1–36https://doi.org/10.1145/3342998Published:25 September 2019Publication History 0citation349DownloadsMetricsTotal Citations0Total Downloads349Last 12 Months22Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access

With the pervasive use of communications technologies, security of multiparty communication systems becomes crucial more than ever. However, providing a secure communication in distributed and dynamic networks is a challenging issue. Dynamic group key agreement protocols are one of the best candidates to overcome this issue. In dynamic group key agreement protocols, each participant in a group involves into the key computation. Moreover, dynamic group key agreement protocols provide auxiliary dynamic group operations for updating the group key when the set of participants is updated. In this paper, a comparative study on the scalability of dynamic group key agreement protocols is presented to show the best possible group key agreement protocol for specific-sized networks. Furthermore, we present simulations for scalability analysis of dynamic group key agreement protocols. Finally, we analyze and compare the performance of protocols regarding computational and communications costs.

Abstract As a natural consequence of the multibillion dollar annual losses incurred as a result of credit card fraud, banks attach great importance to credit card fraud detection. In this paper, we proposed the use of six known models, namely, decision tree, random forest, Bayesian network, Naïve Bayes, support vector machine, and K* models, to form an ensemble for the detection of credit card fraud. We focused on the voting mechanisms used by the ensemble and proposed optimistic, pessimistic, and weighted voting strategies. The proposed model is called optimistic, pessimistic, and weighted voting in an ensemble of models. A dataset of real credit card transactions from a leading bank in Turkey was used to evaluate the performance of optimistic, pessimistic, and weighted voting in an ensemble of models. The results showed that the optimistic voting strategy enables the detection of 31.59% of fraudulent transactions with a false alarm rate of only 0.10%, the pessimistic voting strategy detects 93.92% of fraudulent transactions with a false alarm rate of 13.72%, and the weighted voting strategy detects 64.02% of fraudulent transactions with a false alarm rate of 0.75%. Banks can choose among these voting mechanisms depending on their preferred strategies for fraud detection and desired false alarm rates.

Radio Frequency Identification (RFID) protocols should have a secret updating phase in order to protect the privacy of RFID tags against tag tracing attacks. In the literature, there are many lightweight RFID authentication protocols that try to provide key updating with lightweight cryptographic primitives. In this paper, we analyze the security of two recently proposed lightweight RFID authentication protocol against desynchronization attacks. We show that secret values shared between the back-end server and any given tag can be easily desynchronized. This weakness stems from the insufficient design of these protocols.

Abstract Because of its low cost and ease of deployment, radio frequency identification (RFID) technology offers great potential for all applications that require identification. Main obstacle for wide adoption of this technology is the concerns about its security and privacy issues. Many RFID authentication protocols have been proposed to provide desired security and privacy level for RFID systems. Recently, Benssalah et al. have proposed a chaotic map‐based RFID security protocol. In this paper, we analyze the security of this protocol and discover its vulnerabilities. We show that message generation arises some weaknesses, and this protocol is vulnerable to tracking, tag impersonation, and de‐synchronization attacks. The success probabilities of the proposed attacks are significant, and their complexities are polynomial. Furthermore, we propose an RFID authentication protocol. Our protocol utilizes the Chebyshev chaotic map hard problem and conforms to the EPCglobal Class 1 Generation 2 (EPC C1‐G2) standard. Our protocol eliminates the weaknesses of the protocol of Benssalah et al. Copyright © 2015 John Wiley & Sons, Ltd.

Abstract Information system security is receiving increasing attention every day because a security problem can cause serious financial loss or even loss of lives. Some of these security problems occur as a result of poor design practices, where important security functionality is not designed properly and is directly implemented later in the development cycle in an unmethodical way. Researchers have put a great deal of effort into defining processes and tools to design and develop more secure information systems. However, verification of the designed and developed security functionality is of utmost importance. In some cases, designs and codes also need to be formally or semi‐formally verified and certified by authorities. The Common Criteria is one of the widely used universal frameworks for evaluating the security functionality of information systems. In this paper, we propose a new framework, model driven security framework, for the analysis, design, and evaluation of security properties of information systems. Our aim is to support information system developers and evaluation authorities who implement the higher‐level Common Criteria (levels 6 and 7) security assurance process using formal methods based on Unified Modelling Language, Object Constraint Language, Promela, and Spin. Copyright © 2015 John Wiley & Sons, Ltd.

Abstract The pervasive usage of the Internet has made secure group communications a significant issue. Conference‐key agreement protocols provide secure group communications with lower computational cost. Providing key agreements and updates of dynamic groups in an efficient manner is a significant challenge for conference‐key agreement protocols. Auxiliary key agreement operations are needed to solve the challenge. In this paper, we propose an improved conference‐key agreement protocol, called Dynamic Conference‐Key Agreement Protocol, that consists of Initial Conference‐Key Agreement Protocol and Auxiliary Conference‐Key Agreement operations. Dynamic Conference‐Key Agreement Protocol has operations to handle dynamic groups. The proposed protocol has better fault correction and provides the same security level with the existing ones. Copyright © 2014 John Wiley & Sons, Ltd.

Many RFID authentication protocols have been proposed to provide desired security and privacy level for RFID systems. Almost all of these protocols are based on symmetric cryptography because of the limited resources of RFID tags. Recently Cheng et. Al have proposed an RFID security protocol based on chaotic maps. In this paper, we analyse the security of this protocol and discover its vulnerabilities. We firstly present a de-synchronization attack in which a passive adversary makes the shared secrets out-of-synchronization by eavesdropping just one protocol session. We secondly present a secret disclosure attack in which a passive adversary extracts secrets of a tag by eavesdropping just one protocol session. An adversary having the secrets of the tag can launch some other attacks. Finally, we propose modifications to Cheng et. Al's protocol to eliminate its vulnerabilities.

The pervasive usage of the Internet has made secure group communications a significant issue. Conference key agreement protocols provide secure group communications against some attacks with lower computational cost in the Internet. However, forward secrecy is a challenging issue in the existing protocols, where it is preserved either the long-term key of a participant is compromised. In this study, we propose an improved conference key agreement protocol with forward secrecy. Besides providing forward secrecy, the proposed protocol preserves the same security level with existing ones.

ABSTRACT We present XFPM‐RBAC (XML‐based formal policy language for mobility with role‐based access control), an XML‐based specification language for specification of domain and interdomain security policies with location and mobility constraints based on role‐based access control. XFPM‐RBAC supports specification of locations, mobility, interdomain access rights, role mapping, and separation of duty (SOD) aspects of security policies. XFPM‐RBAC builds upon the FPM‐RBAC security policy model that we have recently proposed. XFPM‐RBAC consists of XML schemas, which define domain security policy, interdomain security policy, locations, mobility, and SOD constructs. A Security Policy Management Interface application is also developed for specification and administration of security policies as a prototype implementation of XFPM‐RBAC. XFPM‐RBAC supports extraction of formal specifications from security policies for the purpose of automated verification of security policies. Automated extraction of formal specifications is based on XSLT (Extensible Stylesheet Language Transformations). Formal specification of security policies together with location and mobility constraints within security policy rules are based on ambient calculus and ambient logic. Copyright © 2012 John Wiley & Sons, Ltd.

We propose a privacy-preserving authentication scheme for RFID systems with fast lookup time. Our solution is based on the use of Physically Unclonable Functions (PUFs). Although there are many proposals that addresses the security and privacy issues of RFID, the search efficiency still remains as a challenging issue. A first tree based mutual authentication scheme for RFID systems has been proposed by Molnar and Wagner to solve the search efficiency problem. The large communication overhead of this scheme has been reduced by Dimitriou performing the authentication with one message from the tag to the reader. However, tree-based schemes are vulnerable to tag compromising attack due to lack key-updating mechanism. Therefore, tree-based schemes are weak private in the Vaudenay-Model. In this paper, we present a tree-based authentication protocol for RFID systems that is destructive-private in the Vaudenay-Model. Our proposed scheme provides resistance against tag compromising attack by using PUFs as a secure storage to keep secrets of the tag.

In this paper, we analyze storage awareness RFID authentication protocol based on sparse tree structure (SAPA), which provides backward untraceability and reduces the space for storing key sequence. We discover that SAPA does not provide location and information privacy between successful authentication sessions and does not resist denial of service attacks, forward traceability, and server impersonation. We analyze the weaknesses of SAPA and propose a new RFID authentication protocol. The proposed protocol provides better protection against privacy and security threats than those before. Our proposed protocol provides tag information privacy and tag location privacy, and resists replay attacks, denial of service attacks, backward traceability, forward traceability (under an assumption), and server impersonation with an efficient keylookup. Furthermore, our protocol has the least computation and communication load on both the tag and the server side compared to other tree based protocols.

Security is one of the main issues to adopt RFID technology in daily use. Due to resource constraints of RFID systems, it is very restricted to design a private authentication protocol based on existing cryptographic functions. In this paper, we propose a new RFID authentication protocol. The proposed protocol provides better protection against privacy and security threats than those before. Our proposed protocol is resistant to server impersonation attack introduced in [17]. Former proposal assumes that the adversary should miss any reader-to-tag communication flows and claims that their protocol is secure against forward traceability only in such communication environment. We show that even under such an assumption, the former proposed protocol is not secure. Our proposed protocol is secure against forward traceability, if the adversary misses any reader-to-tag communication flows. Our protocol also has low computational load on both the tag and the server side.

We investigate trust relationships between and within a security policy and a security mechanism to assess system trust of software application. It has been recognized that trust assessment of security systems in dynamic environments with multiple entities, each with its own changing needs from the security mechanisms, is a complex task. In this paper, we propose a novel architectural approach to assess system trust of service oriented environments. The primary goal of this architecture is to show a way for constructing an automated system for trust assessment of web services. Particularly, we consider beliefs of an entity about a specific security mechanism of a service and the behavior of the service. In addition, we present new trust metrics for assessing system trust of a web service. Furthermore, trust and trust related issues in literature are reviewed to make clear the pros of our approach for trust assessment.

We consider query slipping and its prevention in wireless sensor networks. The problem happens when a query propagating along a subscribe trajectory moves through a publish trajectory without obtaining the desired information, even though the two trajectories intersect geometrically. There follows resubmission of the query or initiation of another subscribe trajectory. Thus, query slipping results in considerable time delay and, in the worst case, looping in the trajectory or query flooding the network. We address the problem formally and suggest a solution. First, the area where nodes are distributed is logically partitioned into smaller grids, and a grid-based next-hop selection algorithm is proposed. The algorithm not only attempts to make the trajectory straight but also considers the nodal density of recipient nodes and the seamless grid-by-grid multicast. We show that publishing and subscribing using the algorithm eventually eliminates the possibility of slipping. It turns out that our approach dissipates less power at neighbor nodes, compared to a non grid-based method, such as greedy forwarding.

A new group of end-to-end reliable event transfer schemes is introduced for sensor networks. In these schemes, reliable event delivery is considered rather than reliable delivery of data packets, since the ultimate goal is the detection of events in sensor networks. Reliable event transfer is critical in many applications. Therefore, the need for transferring the events in a reliable way coerced us to introduce a new group of end-to-end event transfer schemes, in sensor networks end-to-end reliable event transfer schemes can be categorized into two broad classes, as acknowledgement based and non-acknowledgement based. Our new schemes introduced in this paper are in acknowledgement based class. The performance of the proposed schemes is also evaluated for various application areas by simulation.

Certification is a common mechanism for authentic public key distribution. In order to obtain a public key, verifiers need to extract a certificate path from a network of certificates, which is called public key infrastructure (PKI), and verify the certificates on this path recursively. This is classical methodology. Nested certification is a novel methodology for efficient certificate path verification. Basic idea is to issue special certificates (called nested certificates) for other certificates. Nested certificates can be used together with classical certificates in PKIs. Such a PKI, which is called nested certificate-based PKI (NPKI), is proposed in this paper as an alternative to classical PKI. The concept of "certificates for other certificates" results in nested certificate paths in which the first certificate is verified cryptographically while others are verified by just fast hash computations. Thus, we can employ efficiently verifiable nested certificate paths instead of classical certificate paths. NPKI is a dynamic system and involves several authorities in order to add a new user to the system. This uses the authorities' idle time to the benefit of the verifiers. We formulate the trade-off between the nested certification overhead and the time improvement on certificate path verification. This trade-off is numerically analyzed for a 4-level 20-ary balanced tree-shaped PKI and it has been shown that the extra cost of nested certification is in acceptable limits in order to generate quickly verifiable certificate paths for certain applications. Moreover, PKI-to-NPKI transition preserves the existing hierarchy and trust relationships in the PKI, so that it can be used for PKIs with fixed topology. Although there are many certificates in NPKI, certificate revocation is no more of a problem than with classical PKIs. NPKI even has an advantage on the number of certificate revocation controls: at most two certificate revocation controls are sufficient independent of the path length. Nested certificates can be easily adopted into X.509 standard certificate structure. Both verification efficiency and revocation advantage of NPKI and nested certificates make them suitable for hierarchical PKIs of wireless applications where wireless end users have limited processing power.

Location area (LA) planning plays an important role in cellular networks because of the tradeoff caused by paging and registration signalling. The upper boundary for the size of an LA is the service area of a mobile services switching center (MSC). In that extreme case, the cost of paging is at its maximum but no registration is needed. On the other hand, if each cell is an LA, the paging cost is minimal but the cost of registration is the largest. Between these extremes lie one or more partitions of the MSC service area that minimize the total cost of paging and registration. In this paper, we seek to determine the location areas in an optimum fashion. Cell to switch assignments are also determined to achieve the minimization of the network cost. For that purpose, we use the available network information to formulate a realistic optimization problem, and propose an algorithm based on simulated annealing (SA) for its solution. Then, we investigate the quality of the SA-based technique by comparing it to greedy search, random generation methods, and a heuristic algorithm.

During the optimization of the Global System for Mobile Communications (GSM) network, the operations and maintenance center (OMC) measurements are of significant importance. Because of false predictions, the capacity planning of a cell may be done inaccurately. If the capacity of the cell is not adequate to handle all of the busy-hour requests, the requests are not granted a channel and users are blocked. Thus, when the blocking ratio is high, the cellular capacity should be replanned. However, the capacity planning should not rely on the raw OMC measurements since these are inflated by the redials and retrials of fresh calls, as well as the retrials of the hand-off call attempts. In this paper, we provide a simple-to-implement analytical model that computes the average number of retrials and redials per original call attempt using only the OMC statistics. The effective load is then determined through appropriate scaling. That way, unnecessary waste of channels to sustain the retrials and redials is avoided during the cellular capacity replanning phase.

Location area (LA) planning plays an important role in cellular networks because of the trade-off caused by paging and registration signaling. The upper bound on the size of an LA is the service area of a mobile switching center (MSC). In that extreme case, the cost of paging is at its maximum, but no registration is needed. On the other hand, if each cell is an LA, the paging cost is minimal, but the registration cost is the largest. In general, the most important component of these costs is the load on the signaling resources. Between the extremes lie one or more partitions of the MSC service area that minimize the total cost of paging and registration. In this paper, we try to find an optimal method for determining the location areas. For that purpose, we use the available network information to formulate a realistic optimization problem. We propose an algorithm based on simulated annealing (SA) for the solution of the resulting problem. Then, we investigate the quality of the SA technique by comparing its results to greedy search and random generation methods.

Nested certification is a methodology for efficient certificate path verification. Nested certificates can be used together with classical certificates in the Public Key Infrastructures (PKIs). Such a PKI, which is called nested certificate based PKI (NPKI), is proposed as an alternative to classical PKI. The NPKI formation model is a transition from an existing PKI by issuing nested certificates. Thus, we can extract efficiently verifiable nested certificate paths instead of classical certificate paths. NPKI is a dynamic system and involves several authorities in order to add a new user to the system. This uses the authorities' idle time to the benefit of the verifiers. We analyze the trade-off between the nested certification overhead and the time improvement on the certificate path verification. This trade-off is acceptable in order to generate quickly verifiable certificate paths. Moreover, PKI-to-NPKI transition preserves the existing hierarchy and trust relationships in the PKI, so that it can be used for strictly hierarchical PKIs.

GSM operators work with call data that include retrials and redials as well. Based on these inflated, virtual call attempt statistics, it appears that enormous demands are put on the available spectrum. In this paper, we develop simple models to estimate the expected number of retrials and redials per original call attempt, which is used to determine the effective load and the number of traffic channels required to meet the grade of service. It is shown that significantly fewer channels are capable of handling high traffic loads.

Nested certificates are used to certify their subject certificates. In this way, the subject certificates can be verified via their nested certificates without using signature verification methods based on public key cryptosystems. Such a verification method is called subject certificate verification. In this paper, a subject certificate verification method will be introduced. It will be shown that subject certificate verification has the same confidence as the cryptographic certificate verification. Moreover, subject certificate verification is faster than cryptographic certificate verification. It will also be shown that a classical certificate can be verified via a sequence of nested certificates-called nested certificate path-and such verification has the same confidence as the cryptographic verification of the same certificate. Nested certificate path verification is faster than the classical certificate path verification also. Moreover in this paper, simulation results will be presented for efficiency improvement in the nested certificate path verification method over the cryptographic classical certificate path verification method.

This paper presents a new self-routing packet network called the plane interconnected parallel network (PIPN). In the proposed design, the traffic arriving at the network is shaped and routed through two banyan network based interconnected planes. The interconnections between the planes distribute the incoming load more homogeneously over the network. The throughput of the network under uniform and heterogeneous traffic requirements is studied analytically and by simulation. The results are compared with the results of the baseline network and another banyan network based parallel interconnection network. It is shown that, for the proposed design, a higher degree of heterogeneity results in better performance.

A model for representing and analyzing the design of a distributed software system is presented. The model is based on a modified form of Petri net, and enables one to represent both the structure and the behavior of a distributed software system at a desired level of design. Behavioral properties of the design representation can be verified by translating the modified Petri net into an equivalent ordinary Petri net and then analyzing that resulting Petri net. The model emphasizes the unified representation of control and data flows, partially ordered software components, hierarchical component structure, abstract data types, data objects, local control, and distributed system state. At any design level, the distributed software system is viewed as a collection of software components. Software components are externally described in terms of their input and output control states, abstract data types, data objects, and a set of control and data transfer specifications. They are interconnected through the shared control states and through the shared data objects. A system component can be viewed internally as a collection of subcomponents, local control states, local abstract data types, and local data objects.