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We provide bounds on the efficiency of secure one-sided output two-party computation of arbitrary finite functions from trusted distributed randomness in the statistical case. From these results, we derive bounds on the efficiency of protocols that use different variants of oblivious transfer (OT) as a black box. When applied to implementations of OT, these bounds generalize most known results to the statistical case. Our results hold in particular for transformations between a finite number of primitives and for any error. In the second part, we study the efficiency of quantum protocols implementing OT. While most classical lower bounds for perfectly secure reductions of OT to distributed randomness still hold in the quantum setting, we present a statistically secure protocol that violates these bounds by an arbitrarily large factor. We then prove a weaker lower bound that does hold in the statistical quantum setting and implies that even quantum protocols cannot extend OT. Finally, we present two lower bounds for reductions of OT to commitments and a protocol based on string commitments that is optimal with respect to both of these bounds. [ABSTRACT FROM PUBLISHER]

Abstract: Among security challenges raised by mobile Wireless Sensor Networks, clone attack is particularly dreadful since it makes an adversary able to subvert the behavior of a network just leveraging a few replicas of some previously compromised sensors. In this work, we provide several contributions: first, we introduce two novel realistic adversary models, the vanishing and the persistent adversary, characterized by different compromising capability. We then propose two distributed, efficient, and cooperative protocols to detect replicas: History Information-exchange Protocol (HIP) and its optimized version (HOP). Both HIP and HOP leverage just local (one-hop) communications and node mobility, and differ for the amount of computation required. We study their behavior against the introduced types of attacker, considering two different mobility models and comparing our solutions against the state of the art. Both analysis and simulation results show that our solutions are effective and efficient, providing high detection rate, while incurring limited overhead. [Copyright &y& Elsevier]

This work proposes a new direction in quantum cryptography called quantum authencryption. Quantum authencryption (QA), a new term to distinguish from authenticated quantum secure direct communications, is used to describe the technique of combining quantum encryption and quantum authentication into one process for off-line communicants. QA provides a new way of quantum communications without the presence of a receiver on line, and thus makes many applications depending on secure one-way quantum communications, such as quantum E-mail systems, possible. An example protocol using single photons and one-way hash functions is presented to realize the requirements on QA. [ABSTRACT FROM AUTHOR]

This study points out a man-in-the-middle (MIM) attack on many of quantum secure communication with authentication protocols. The MIM attack is due to a design carelessness on performing public discussions on a nonauthenticated classical channel. A possible solution is proposed to solve the problem. [ABSTRACT FROM AUTHOR]

Most Petri nets-based methods that have been developed to analyze cryptographic protocols provide the analysis of one attack trace only. Only a few of them offer the analysis of multiple attack traces, but they are rather inefficient. Analogously, the limitation of the analysis of one attack trace occurs in most model checking methods for cryptographic protocols. In this paper, we propose a very simple but practical Coloured Petri nets-based model checking method for the analysis of cryptographic protocols, which overcomes these limitations. Our method offers an efficient analysis of multiple attack traces. We apply our method to two case studies which are TMN authenticated key exchanged protocol and Micali's contract signing protocol. Surprisingly, our simple method is very efficient when the numbers of attack traces and states are large. Also, we find many new attacks in those protocols. [ABSTRACT FROM AUTHOR]

We motivate and present two designs for the composition of the authentication protocol, Kerberos, and the key transport protocol, Multimedia Internet KEYing (MIKEY) for authenticated transport of cryptographic keys for secure group-communication in enterprise and public-safety settings. A technical challenge, and our main contribution, is the analysis of the security of the composition. Towards this, we design our compositions to have intuitive appeal and thereby less prone to security vulnerabilities. We then employ protocol composition logic (PCL), a state-of-the-art approach for analyzing our composition. For this, we first articulate two properties that are of interest. Both properties are on the group key that is transported; we call them Group Key Confidentiality and Acquisition. Group Key Confidentiality is the property that if a principal possesses the key, then it is an authorized member of the group. Group Key Acquisition is the property that if a principal is a member of the group, then it is able to acquire the group key. In the course of our rigorous analysis, we discovered a flaw in our first design, which we point out, and which lead us to our second design. We have implemented both designs starting with the publicly available reference implementation of Kerberos, and an open-source implementation of MIKEY. Our implementations are available as open-source. We discuss our experience from the implementation, and present empirical results. [ABSTRACT FROM PUBLISHER]

This work proposes two quantum key distribution (QKD) protocols-each of which is robust under one kind of collective noises-collective-dephasing noise and collective-rotation noise. Due to the use of a new coding function which produces error-robust codewords allowing one-time transmission of quanta, the proposed QKD schemes are fault-tolerant and congenitally free from Trojan horse attacks without having to use any extra hardware. Moreover, by adopting two Bell state measurements instead of a 4-GHZ state joint measurement for decoding, the proposed protocols are practical in combating collective noises. [ABSTRACT FROM AUTHOR]

It is well known (cf. Impagliazzo and Luby [in Proceedings of the 30th Annual IEEE Symposium on Foundations of Computer Science, 1989, pp. 230-235]) that the existence of almost all "interesting" cryptographic applications, i.e., ones that cannot hold information theoretically, implies one-way functions. An important exception where the above implication is not known, however, is the case of coin-flipping protocols. Such protocols allow honest parties to mutually flip an unbiased coin, while guaranteeing that even a cheating (efficient) party cannot bias the output of the protocol by much. Impagliazzo and Luby proved that coin-flipping protocols that are safe against negligible bias do imply one-way functions, and, very recently, Maji, Prabhakaran, and Sahai [in Proceedings of the 2001 51st Annual IEEE Symposium on Foundations of Computer Science, 2010, pp. 613-622] proved the same for constant-round protocols (with any nontrivial bias). For the general case, however, no such implication was known. We make progress towards answering the above fundamental question, showing that (strong) coin-flipping protocols safe against a constant bias (concretely, √2-1/2 - o(1)) imply one-way functions. [ABSTRACT FROM AUTHOR]

We take a model-theoretic viewpoint on security goals and how to establish them. The models are (possibly fragmentary) executions. Security goals such as authentication and confidentiality are geometric sequents, i.e. implications Φ→Ψ where Φ and Ψ are built from atomic formulas without negations, implications, or universal quantifiers.Security goals are then statements about homomorphisms, where the source is a minimal (fragmentary) model of the antecedent Φ. If every homomorphism to a non-fragmentary, complete execution factors through a model in which Ψ is satisfied, then the goal is achieved. One can validate security goals via a process of information enrichment. We call this approach enrich-by-need protocol analysis.This idea also clarifies protocol transformation. A protocol transformation preserves security goals when it preserves the form of the information enrichment process. We formalize this idea using simulation relations between labeled transition systems. These labeled transition systems formalize the analysis of the protocols, i.e. the information enrichment process, not the execution behavior of the protocols. [ABSTRACT FROM AUTHOR]

We present a new type system for verifying the security of reference implementations of cryptographic protocols written in a core functional programming language. The type system combines prior work on refinement types, with union, intersection, and polymorphic types, and with the novel ability to reason statically about the disjointness of types. The increased expressivity enables the analysis of important protocol classes that were previously out of scope for the type-based analyses of reference protocol implementations. In particular, our types can statically characterize: (i) more usages of asymmetric cryptography, such as signatures of private data and encryptions of authenticated data; (ii) authenticity and integrity properties achieved by showing knowledge of secret data; (iii) applications based on zero-knowledge proofs. The type system comes with a mechanized proof of correctness and an efficient type-checker. [ABSTRACT FROM AUTHOR]

Highlights: [•] There is a lack of end-to-end security mechanisms tailored to IP-enabled sensors. [•] Ladon is proposed as end-to-end authentication and authorization protocol. [•] We evaluate the time and energy cost of executing Ladon on the protected sensors. [•] Ladon is proved to be a suitable security protocol for resource-deprived devices. [ABSTRACT FROM AUTHOR]

The Shadow Semantics (Morgan, Math Prog Construction, vol 4014, pp 359-378, ; Morgan, Sci Comput Program 74(8):629-653, ) is a possibilistic (qualitative) model for noninterference security. Subsequent work (McIver et al., Proceedings of the 37th international colloquium conference on Automata, languages and programming: Part II, ) presents a similar but more general quantitative model that treats probabilistic information flow. Whilst the latter provides a framework to reason about quantitative security risks, that extra detail entails a significant overhead in the verification effort needed to achieve it. Our first contribution in this paper is to study the relationship between those two models (qualitative and quantitative) in order to understand when qualitative Shadow proofs can be 'promoted' to quantitative versions, i.e. in a probabilistic context. In particular we identify a subset of the Shadow's refinement theorems that, when interpreted in the quantitative model, still remain valid even in a context where a passive adversary may perform probabilistic analysis. To illustrate our technique we show how a semantic analysis together with a syntactic restriction on the protocol description, can be used so that purely qualitative reasoning can nevertheless verify probabilistic refinements for an important class of security protocols. We demonstrate the semantic analysis by implementing the Shadow semantics in Rodin, using its special-purpose refinement provers to generate (and discharge) the required proof obligations (Abrial et al., STTT 12(6):447-466, ). We apply the technique to some small examples based on secure multi-party computations. [ABSTRACT FROM AUTHOR]

Automated formal verification of security protocols has been mostly focused on analyzing high-level abstract models which, however, are significantly different from real protocol implementations written in programming languages. Recently, some researchers have started investigating techniques that bring automated formal proofs closer to real implementations. This paper surveys these attempts, focusing on approaches that target the application code that implements protocol logic, rather than the libraries that implement cryptography. According to these approaches, libraries are assumed to correctly implement some models. The aim is to derive formal proofs that, under this assumption, give assurance about the application code that implements the protocol logic. The two main approaches of model extraction and code generation are presented, along with the main techniques adopted for each approach. [ABSTRACT FROM AUTHOR]

When using formal methods, security protocols are usually modeled at a high level of abstraction. In particular, data encoding and decoding transformations are often abstracted away. However, if no assumptions at all are made on the behavior of such transformations, they could trivially lead to security faults, for example leaking secrets or breaking freshness by collapsing nonces into constants. In order to address this issue this paper formally states sufficient conditions, checkable on sequential code, such that if an abstract protocol model is secure under a Dolev-Yao adversary, then a refined model, which takes into account a wide class of possible implementations of the encoding/decoding operations, is implied to be secure too under the same adversary model. The paper also indicates possible exploitations of this result in the context of methods based on formal model extraction from implementation code and of methods based on automated code generation from formally verified models. [ABSTRACT FROM AUTHOR]

The Inductive Method is among the most established tools to analyse security protocols formally. It has successfully coped with large, deployed protocols, and its findings are widely published. However, perhaps due to its embedding in a theorem prover or to the lack of tutorial publications, it is at times criticised to require super-specialised skills and hence to be rather impractical. This paper aims at showing that criticism to be stereotypical. It pursues its aim by presenting the first tutorial-style paper to using the Inductive Method. This paper cannot cover every aspect of the method. It focuses on a key one, that is how the Inductive Method treats one of the main goals of security protocols: confidentiality against a threat model. The treatment of that goal, which may seem elegant in the Inductive Method, in fact forms a key aspect of all protocol analysis tools, hence the paper motivation rises still. With only standard skills as a requirement, the reader is guided step by step towards design and proof of significant confidentiality theorems. These are developed against two threat models, the standard Dolev-Yao and a more up-to-date one, the General Attacker, the latter turning out particularly useful also for didactic purposes. [ABSTRACT FROM AUTHOR]

Arbitrated quantum signature (AQS) is a cryptographic scenario in which the sender (signer), Alice, generates the signature of a message and then a receiver (verifier), Bob, can verify the signature with the help of a trusted arbitrator, Trent. In this paper, we point out there exist some security weaknesses in two AQS protocols. Our analysis shows Alice can successfully disavow any of her signatures by a simple attack in the first protocol. Furthermore, we study the security weaknesses of the second protocol from the aspects of forgery and disavowal. Some potential improvements of this kind of protocols are given. We also design a new method to authenticate a signature or a message, which makes AQS protocols immune to Alice's disavowal attack and Bob's forgery attack effectively. [ABSTRACT FROM AUTHOR]

Abstract: Although security of quantum cryptography is provable based on principles of quantum mechanics, it can be compromised by flaws in the design of quantum protocols. So, it is indispensable to develop techniques for verifying and debugging quantum cryptographic systems. Model-checking has proved to be effective in the verification of classical cryptographic protocols, but an essential difficulty arises when it is applied to quantum systems: the state space of a quantum system is always a continuum even when its dimension is finite. To overcome this difficulty, we introduce a novel notion of quantum Markov chain, especially suited for modelling quantum cryptographic protocols, in which quantum effects are encoded as super-operators labelling transitions, leaving the location information (nodes) being classical. Then we define a quantum extension of probabilistic computation tree logic (PCTL) and develop a model-checking algorithm for quantum Markov chains. [Copyright &y& Elsevier]

In the first part of this paper, I will present and explain the Singapore Personal Data Pro-tection Act ("PDPA") in the context of legislative developments in the Asian region and against the well-established international baseline privacy standards. In the course of the above evaluation, reference will be made to the national laws and policy on data privacy prior to the enactment of the PDPA as well as current social and market practices in relation to personal data. In the second part of this paper, I will decipher and assess the future trends in data privacy reform and the future development of the privacy regime in Singapore and beyond. In the course of this analysis, international standards, technological trends and recent legal developments in other jurisdictions will be considered. [ABSTRACT FROM AUTHOR]

This paper proposed a secure communication model for space delay-tolerant network. This model applied predicate logic, and built SDTN directed multi-path graph, security protocol service set, reliable path selection service set, and forwarding capacity set. It also gave out the model's security constraint rule and secure communication algorithm. It defined the state machine of space delay-tolerant network secure communication, and proved the model's security, reliability and delay-tolerant ability, which laid the foundation for space delay-tolerant network secure communication. [ABSTRACT FROM AUTHOR]

Detection efficiency of a quantum secure direct communication (QSDC) protocol is crucial. Therefore, it is necessary to improve the security of these protocols on the basis of new detection strategies. In this paper, a new strategy based on the five-particle cluster state is proposed, and applied to the two-step QSDC protocol. Moreover, information theoretical method and nu-merical analysis is applied to analyze the security of the improved protocol. If Eve intends to eavesdrop all of the information, the probability of being detected reaches up to 7/8, whereas the same is 0.5 in the original protocol. It is concluded that using the new detection strategy in the two-step QSDC protocol is more secure than using the original protocol when the quantum key distribution (QKD) protocol is considered. [ABSTRACT FROM AUTHOR]

Quantum steganography is the art of hiding the fact that communications, which transmit the secret message in an insecure quantum channel, are occurring. This paper presents a novel quantum steganography protocol based on probability measurements for transmitting n qubits secret message in an insecure quantum channel. In the protocol, senders embed the secret message into the cover data by POVM measurements. Then, receivers can correctly extract the secret message and recover the cover data with a certain probability by selecting two sets of appropriate protective measurement operators to act projective measurements, respectively. More importantly, the existence of the secret message has no influence on the cover data. In addition, the security of our protocol does not rely on other protocols. The paper analyzes the secrecy and the security in detail. [ABSTRACT FROM AUTHOR]

Three-party key exchange protocol is one of the most essential cryptographic technique in the secure communication areas. In this protocol, two clients, each shares a human-memorable password, working with a trusted server, can agree a secure session key. Recently, Lu and Cao proposed a new simple three-party key exchange (S-3PAKE) protocol and claimed that it is not only very simple and efficient, but also can survive against various known attacks. However, Nam et al. pointed out that S-3PAKE is vulnerable to both off-line password guessing attack and undetectable on-line password guessing attack. Based on their finding, Nam et al. proposed an improved method to resolve this weakness. They further claimed that so far no off-line password guessing attack has been successful against their proposed protocol. In this paper, we demonstrate that Nam et al.'s improved protocol, unfortunately, is still vulnerable to an undetectable on-line password guessing attack. We therefore propose a simple and powerful method to address this issue. Which results in an improved three-party key exchange protocol that can protect against an undetectable on-line password guessing attack. [ABSTRACT FROM AUTHOR]

Abstract: Security for the Internet of Things (IoT) presents the challenge of offering suitable security primitives to enable IP-based security protocols such as IPSec and DTLS. This challenge is here because host-based implementations and solutions are not providing a proper performance over the devices used in the IoT. This is mainly because of the use of highly constraint devices in terms of computational capabilities. Therefore, it is necessary to implement new optimized and scalable cryptographic primitives which can use existing protocols to provide security, authentication, privacy and integrity to the communications. Our research focus on the mathematical optimization of cryptographic primitives for Public Key Cryptography (PKC) based on Elliptic Curve Cryptography (ECC). PKC has been considered, since the IoT requires high scalability, multi-domain interoperability, self-commissioning, and self-identification. Specifically, this contribution presents a set of optimizations for ECC over constrained devices, and a brief tutorial of its implementation in the microprocessor Texas Instrument MSP430 (Briel, 2000) [1] (commonly used in IoT devices such as 6LoWPAN, active RFID and DASH7). Our main contribution is the proof that these special pseudo-Mersenne primes, which we have denominated ‘shifting primes’ can be used for ECC primitives with 160-bit keys in a highly optimal way. This paper presents an ECC scalar multiplication with 160-bit keys within 5.4 million clock cycles over MSP430 devices without hardware multiplier. Shifting primes provide a set of features, which make them more compliant with the set of instructions available with tiny CPUs such as the MSP430 and other 8 and 16-bit CPUs. [Copyright &y& Elsevier]

Recently, an enhanced multiparty quantum secret sharing of classical message by using entanglement swapping was presented. In this protocol, a code table was used to improve the efficiency. However, as we show, this protocol is insecure in the sense that an outside attacker or two special dishonest agents can eavesdrop part or all information about the secret. Hence, this high efficiency may be unrealistic because it results in the decrease of security. [ABSTRACT FROM AUTHOR]

A quantum dialogue protocol is proposed based on triple particle W states. Each particle is transferred only once in the entire communication, which reduces the risk of eavesdropping and improves the security of the protocol. The protocol can resist various attacks. The efficiency of this protocol can be up to 80 % without information leakage. [ABSTRACT FROM AUTHOR]

Abstract: Electronic auctions (e-auction) enable bidders to bid for diverse sold objects under an electronic platform via the Internet. Relevant literature has presented numerous online bidding auction schemes considering different security issues. However, none of them can satisfy all essential properties simultaneously and some of them possess security vulnerabilities. For example, the winner cannot hold the properties of anonymity and unlinkability without re-registration for the auction of another product. In order to cope with the above problems, this study presents an e-auction scheme which owns the following features: every bidder’s anonymity during the entire auction, unlinkability among plural auctions of different selling topics, unforgeability, no framing (tamper resistance of bidding tickets), non-repudiation, public verifiability of all bidding tickets, and easy revocation for illegal activities. In our e-bidding protocol, all participants can take part in a sequence of different auctions for various products unlimitedly after performing one time of registration, where the winner does not need to re-register again, either. We formally prove the security of the proposed scheme and also provide comparisons to show that it is the most efficient one as compared with previous works. [Copyright &y& Elsevier]

Dynamic group signatures (DGS) enable a user to generate a signature on behalf of a group of users, allowing a prospective user to join via an appropriate join protocol. A natural security requirement in the dynamic setting is to permit an adversary to concurrently perform join protocol executions. To date, most of DGS schemes do not provide the efficient concurrent join protocols in their security analysis, because of the need to use knowledge extractors. Also, DGS schemes have to provide efficient batch verifications for practical applications such as Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) communication, where a large number of group signatures should be verified in a very short time. In this paper, we propose a new practical DGS scheme that supports not only efficient concurrent joins but also batch verifications. The concurrent security is proven by showing that our join protocols are simulated without any knowledge extractor in security analysis. To do this, we introduce a modified Pointcheval–Sanders (PS) problem that can guarantee efficiently checking equality of discrete logarithms. In terms of efficiency, when considering a type-3 pairing, our DGS scheme has the advantages that the signature generation and verification are faster and especially our batch verification is at least 7 times faster in case of verifying 100 signatures, compared to other comparable pairing-based DGS schemes in the literature. • Construct a dynamic group signature scheme based on the sign–randomize–prove paradigm. • Prove concurrent security of our join protocol under a variant of Pointcheval–Sanders assumption. • Achieve the fastest signing and (batch) verification, compared with all of the existing pairing-based schemes. [ABSTRACT FROM AUTHOR]

Abstract: Formal methods have proved their usefulness for analyzing the security of protocols. Most existing results focus on trace properties like secrecy or authentication. There are however several security properties, which cannot be defined (or cannot be naturally defined) as trace properties and require a notion of behavioral equivalence. Typical examples are anonymity, privacy related properties or statements closer to security properties used in cryptography. In this paper, we consider three notions of equivalence defined in the applied pi calculus: observational equivalence, may-testing equivalence, and trace equivalence. First, we study the relationship between these three notions. We show that for determinate processes, observational equivalence actually coincides with trace equivalence, a notion simpler to reason with. We exhibit a large class of determinate processes, called simple processes, that capture most existing protocols and cryptographic primitives. While trace equivalence and may-testing equivalence seem very similar, we show that may-testing equivalence is actually strictly stronger than trace equivalence. We prove that the two notions coincide for image-finite processes, such as processes without replication. Second, we reduce the decidability of trace equivalence (for finite processes) to deciding symbolic equivalence between sets of constraint systems. For simple processes without replication and with trivial else branches, it turns out that it is actually sufficient to decide symbolic equivalence between pairs of positive constraint systems. Thanks to this reduction and relying on a result first proved by M. Baudet, this yields the first decidability result of observational equivalence for a general class of equational theories (for processes without else branch nor replication). Moreover, based on another decidability result for deciding equivalence between sets of constraint systems, we get decidability of trace equivalence for processes with else branch for standard primitives. [Copyright &y& Elsevier]

Abstract: Nowadays, the secure flash disk is the most common secure mobile storage device. Two conventional schemes, flash encryption and identity authentication, are used to ensure the security of the information stored in it, but there is no comprehensive security model. We summarize three shortcomings of it: the USB cable is very easy to be monitored; the disk is not applicable to a big group and does not resist the corruption attack. In this paper, a new attack named USB cable monitor attack is proposed and implemented. In order to overcome the existing shortcomings, we give a notion of “secure group flash disk” and its security model. Accordingly, a set of universal cryptographic strategies and a concrete authenticated key exchange protocol are devised, whose security can be proved via the universally composable security model. Based on the strategies, the system architecture of this USB flash disk is designed. An IP core of the USB device controller is implemented and verified on a FPGA, so that the performance superiority can be given. Our experiment shows that our strategies can perfectly solve the problems of USB cable monitor, group application, and resistance to corruption. [Copyright &y& Elsevier]

This paper is motivated by the observation that existing security models for direct anonymous attestation (DAA) have problems to the extent that insecure protocols may be deemed secure when analysed under these models. This is particularly disturbing as DAA is one of the few complex cryptographic protocols resulting from recent theoretical advances actually deployed in real life. Moreover, standardization bodies are currently looking into designing the next generation of such protocols. Our first contribution is to identify issues in existing models for DAA and explain how these errors allow for proving security of insecure protocols. These issues are exhibited in all deployed and proposed DAA protocols (although they can often be easily fixed). Our second contribution is a new security model for a class of 'pre-DAA scheme', that is, DAA schemes where the computation on the user side takes place entirely on the trusted platform. Our model captures more accurately than any previous model the security properties demanded from DAA by the trusted computing group (TCG), the group that maintains the DAA standard. Extending the model from pre-DAA to full DAA is only a matter of refining the trust models on the parties involved. Finally, we present a generic construction of a DAA protocol from new building blocks tailored for anonymous attestation. Some of them are new variations on established ideas and may be of independent interest. We give instantiations for these building blocks that yield a DAA scheme more efficient than the one currently deployed, and as efficient as the one about to be standardized by the TCG which has no valid security proof. [ABSTRACT FROM AUTHOR]

SUMMARY In this paper, we first showed that Lou and Huang's three-party password-based key exchange protocol is still vulnerable to offline dictionary attacks. Thereafter, we proposed an enhanced protocol that can defeat the attack described and yet is efficient. Finally, we provided the rigorous proof of the security for it. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Security of wireless computer networks was initially secured with the WEP security protocol, which relies on the RC4 encryption algorithm and the CRC algorithm to check the integrity. The basic problems of the WEP are a short initialization vector, unsafe data integrity checking, using a common key, the lack of mechanisms for management and exchange of keys, the lack of protection from the endless insertion of the same package into the network, the lack of authentication of access points and the like. The consequences of these failures are easy attacks against the WEP network, namely their complete insecurity. Therefore, the work began on the IEEE 802.11i protocol, which should radically improve the security of wireless networks. Since the development of a protocol lasted, the WPA standard was released to offset the security gap caused by the WEP. The WPA also relies on RC4 and CRC algorithms, but brings temporary keys and the MIC algorithm for data integrity. The 802.1X authentication was introduced and common keys are no longer needed, since it is possible to use an authentication server. The length of the initialization vector was increased and the vector is obtained based on the packet serial number, in order to prevent the insertion of the same packet into the network. The weakness of the WPA security mechanism is the use of a common key. WPA2 (802.11i) later appeared. Unlike the WPA mechanism that worked on old devices with the replacement of software, WPA2 requires new network devices that can perform AES encryption. AES replaces the RC4 algorithm and delivers much greater security. Data integrity is protected by encryption. Despite progress, there are still weaknesses in wireless networks. Attacks for denial of service are possible as well as spoofing package headers attacks. For now, it is not advisable to use wireless networks in environments where unreliability and unavailability are not tolerated. [ABSTRACT FROM AUTHOR]

SUMMARY Password-authenticated group key exchange protocols enable communication parties to establish a common secret key (a session key) by only using short secret passwords. Such protocols have been receiving significant attention. This paper shows some security weaknesses in some recently proposed password-authenticated group key exchange protocols. Furthermore, a secure and efficient password-authenticated group key exchange protocol in mobile ad hoc networks is proposed. It only requires constant round to generate a group session key under the dynamic scenario. In other words, the overhead of key generation is independent of the size of a total group. Further, the security properties of our protocol are formally validated by a model checking tool called AVISPA. Security and performance analyses show that, compared with other related group key exchange schemes, the proposed protocol is also efficient for real-world applications in enhancing the security over wireless communications. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper presents a secure protocol for spontaneous wireless ad hoc networks which uses an hybrid symmetric/asymmetric scheme and the trust between users in order to exchange the initial data and to exchange the secret keys that will be used to encrypt the data. Trust is based on the first visual contact between users. Our proposal is a complete self-configured secure protocol that is able to create the network and share secure services without any infrastructure. The network allows sharing resources and offering new services among users in a secure environment. The protocol includes all functions needed to operate without any external support. We have designed and developed it in devices with limited resources. Network creation stages are detailed and the communication, protocol messages, and network management are explained. Our proposal has been implemented in order to test the protocol procedure and performance. Finally, we compare the protocol with other spontaneous ad hoc network protocols in order to highlight its features and we provide a security analysis of the system. [ABSTRACT FROM PUBLISHER]

Abstract: In this paper, we analyze the communication of trusted platform modules and their interface to the hosting platforms. While trusted platform modules are considered to be tamper resistant, the communication channel between these modules and the rest of the trusted platform turns out to be comparatively insecure. It has been shown that passive attacks can be mounted against TPMs and their bus communication with fairly inexpensive equipment, however, similar active attacks have not been reported, yet. We pursue the idea of an active attack and show how the communication protocol of the LPC bus can be actively manipulated with basic and inexpensive equipment. Moreover, we show how our manipulations can be used to circumvent the security mechanisms, e.g. the chain of trust, provided by modern trusted platforms. In addition, we demonstrate how the proposed attack can be extended to manipulate communication buses on embedded systems. [Copyright &y& Elsevier]

Abstract: Secret handshake (SH) schemes enable two members who belong to the same group to authenticate each other in a way that hides their affiliation to that group from all others. In previous work on SH, the group authority (GA) of the group G has been shown to have the ability to reveal the identity (ID) of a handshake player who belongs to G. The capability to reveal a malicious player is important in SH systems. In this paper, we focus first on the classification of traceability of GA. We classify this feature as follows: (i) GA of G is able to reveal IDs of members belonging to G by using a transcript of a handshake protocol; and (ii) GA of G is able to confirm whether handshake players belong to G or not by using a transcript of a handshake protocol. Previous research in this field only considers the former capability. In some situations, only the latter capability is needed. Next, we consider a SH system that GA has only an ability to confirm whether a handshake player belongs to his own group without revealing his ID. The most naive method is that member IDs are eliminated and members have a common group ID. However, if member ID does not exist, one cannot reveal the handshake player’s ID in the event of disputes. Thus, we introduce a SH with request-based-revealing (SHRBR). In SHRBR schemes, GA can check whether handshake players belong to their own group, but cannot reveal member IDs alone. After a handshake player executes a handshake protocol with , if wants to reveal a handshake partner (in this case ), requests GA to reveal a handshake partner’s ID by bringing forth his own ID and secret information of . We define the security requirements for SHRBR schemes and propose two concrete SHRBR schemes, SHRBR-1 and SHRBR-2. We prove that the proposed SHRBR schemes satisfy security requirements in the random oracle model. [Copyright &y& Elsevier]

SUMMARY A fault-tolerant group key agreement is an essential infrastructure for Internet communication among all involved participants; it can establish a secure session key no matter how many malicious participants exit simultaneously in an effort to disrupt the key agreement process. Recently, Zhao et al. proposed an efficient fault-tolerant group key agreement protocol named efficient group key agreement that can resist denial-of-service attacks, reply attacks, man-in-middle attacks, and common modulus attacks; it can also preserve forward secrecy with lower computational cost than previous protocols. We show that it is still vulnerable to active attacks by malicious participants and modify the corresponding security weakness adaptively. Furthermore, we propose an efficient fault-tolerant group key agreement based on a binary tree structure and enhance it to a dynamic setting where participants can leave or join the group arbitrarily according to their preferences with instant session key refreshment. Additionally, our session key refreshment is based on secure key updating to protect forward/backward confidentiality and is resistant to active/passive attacks. The performance analysis shows that our proposed protocol has lower computational cost and little additional communication cost exploiting dynamic setting. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Cloud computing offers scalable on-demand services to consumers with greater flexibility and lesser infrastructure investment. Since Cloud services are delivered using classical network protocols and formats over the Internet, implicit vulnerabilities existing in these protocols as well as threats introduced by newer architectures raise many security and privacy concerns. In this paper, we survey the factors affecting Cloud computing adoption, vulnerabilities and attacks, and identify relevant solution directives to strengthen security and privacy in the Cloud environment. [ABSTRACT FROM AUTHOR]

Abstract: The main goal of this paper is to analyze the security of a multiple-key agreement protocol and to show that this protocol is vulnerable to forgery attack. In order to address the security weakness, a new efficient multiple-key agreement protocol is proposed. The proposed protocol is based on bilinear pairings and utilizes a novel signature scheme without one-way hash functions. In contrast to related protocols which are based on bilinear pairings, in the proposed protocol, these pairings are not utilized for the included signature scheme, but they are only used for session keys. As a result, the computational complexity of the proposed protocol is decreased by 50% compared to that of the existing protocols. Another contribution of the proposed protocol is an increase of the number of the session keys up to (n 2(n +1)2/4), for n ⩾2 random numbers, regarding the bilinear property of the pairings. Finally, the simulation results from AVISPA tools confirm the security analysis of the proposed protocol. [Copyright &y& Elsevier]

The key for cooperative collision avoidance (CCA) systems is the real-time and reliable delivery of safety-related messages among vehicles, which include periodical beacons and risk-triggered warning messages. In this paper, we first design a risk-aware dynamic medium-access control (R-MAC) protocol tailored for vehicular CCA applications. In this protocol, each frame is divided into two parts: TDMA segment for transferring beacons and CSMA segment for delivering warning messages. Then, we propose a stochastic model to predict the average total number of potential collisions in a platoon of vehicles, which determines the size of CSMA segment in the R-MAC protocol meticulously. Monte Carlo simulations validate that our model is reliable and practical. The performance of the R-MAC protocol is verified through theoretical analysis and extensive simulations under different traffic scenes. Simulation results show that R-MAC outperforms the traditional IEEE 802.11p protocol in terms of packets delivery rate and transmission delay, as well as the Jain's fairness index of the medium access between beacons and warning messages. [ABSTRACT FROM AUTHOR]

Energy efficiency is the main concern of research community while designing routing protocols for wireless sensor networks (WSNs). This concern can be addressed by using energy-harvesting scheme in routing protocols. In this paper, we propose a secure routing protocol that is based on cross layer design and energy-harvesting mechanism. It uses a distributed cluster-based security mechanism. In the cross-layer design, parameters are exchanged between different layers to ensure efficient use of energy. Energy-harvesting system is used to extract and store energy, which is used to take decisions for the node state and thus for the routing issues. Simulation results show that our routing protocol can perform better in many scenarios and in hostile attack-prone environment. [ABSTRACT FROM AUTHOR]

In this paper we propose an extended version of the ping-pong protocol and study its security. The proposed protocol incorporates the usage of mutually unbiased bases in the control mode. We show that, by increasing the number of bases, it is possible to improve the security of this protocol. We also provide the upper bounds on eavesdropping average non-detection probability and propose a control mode modification that increases the attack detection probability. [ABSTRACT FROM AUTHOR]

Security and anonymity are essential to E-payment systems. However, with the increasing computing power, existing E-payment systems will gradually become insecure. In this paper, we propose an inter-bank E-payment system which is based on quantum proxy blind signature. Adopting the techniques of quantum key distribution, one-time pad and quantum proxy blind signature, our quantum E-payment system could protect user's anonymity as the traditional E-payment systems do, and also have unconditional security which the classical E-payment systems cannot provide. Furthermore, compared with the existing quantum E-payment systems, the proposed system could support inter-bank transactions. [ABSTRACT FROM AUTHOR]

In this paper, a quantum private comparison protocol with Bell states is proposed. In the protocol, two participants can determine the relationship between their secret inputs in size, with the assistance of a semi-trusted third party. The presented protocol can ensure fairness, correctness, and security. Meanwhile, all the particles undergo only a one-way trip, which improves the efficiency and security of the communication. Furthermore, only Bell states are exploited in the implementation of the protocol, and two participants are just required having the ability to perform single particle operations, which make the presented protocol more feasible in technique. [ABSTRACT FROM AUTHOR]

Abstract: A conditionally anonymous ring signature is an exception since the anonymity is conditional. Specifically, it allows an entity to confirm/refute the signature that he generated before. A group signature also shares the same property since a group manager can revoke a signer’s anonymity using the trapdoor information. However, the special node (i.e., group manager) does not exist in the group in order to satisfy the ad hoc fashion. In this paper, we construct a new conditionally anonymous ring signature, in which the actual signer can be traced without the help of the group manager. The big advantage of the confirmation and disavowal protocols designed by us are non-interactive with constant costs while the known schemes suffer from the linear cost in terms of the ring size or security parameter . [Copyright &y& Elsevier]

SUMMARY Three-party password-authenticated key exchange (3PAKE) protocols allow entities to negotiate a secret session key with the aid of a trusted server with whom they share a human-memorable password. Recently, Lou and Huang proposed a simple 3PAKE protocol based on elliptic curve cryptography, which is claimed to be secure and to provide superior efficiency when compared with similar-purpose solutions. In this paper, however, we show that the solution is vulnerable to key-compromise impersonation and offline password guessing attacks from system insiders or outsiders, which indicates that the empirical approach used to evaluate the scheme's security is flawed. These results highlight the need of employing provable security approaches when designing and analyzing PAKE schemes. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Decentralized attribute-based encryption (ABE) is a variant of a multiauthority ABE scheme where each authority can issue secret keys to the user independently without any cooperation and a central authority. This is in contrast to the previous constructions, where multiple authorities must be online and setup the system interactively, which is impractical. Hence, it is clear that a decentralized ABE scheme eliminates the heavy communication cost and the need for collaborative computation in the setup stage. Furthermore, every authority can join or leave the system freely without the necessity of reinitializing the system. In contemporary multiauthority ABE schemes, a user's secret keys from different authorities must be tied to his global identifier (GID) to resist the collusion attack. However, this will compromise the user's privacy. Multiple authorities can collaborate to trace the user by his GID, collect his attributes, then impersonate him. Therefore, constructing a decentralized ABE scheme with privacy-preserving remains a challenging research problem. In this paper, we propose a privacy-preserving decentralized key-policy ABE scheme where each authority can issue secret keys to a user independently without knowing anything about his GID. Therefore, even if multiple authorities are corrupted, they cannot collect the user's attributes by tracing his GID. Notably, our scheme only requires standard complexity assumptions (e.g., decisional bilinear Diffie-Hellman) and does not require any cooperation between the multiple authorities, in contrast to the previous comparable scheme that requires nonstandard complexity assumptions (e.g., q-decisional Diffie-Hellman inversion) and interactions among multiple authorities. To the best of our knowledge, it is the first decentralized ABE scheme with privacy-preserving based on standard complexity assumptions. [ABSTRACT FROM AUTHOR]

Abstract: We present two quantum cryptography protocols. The first one generalizes the concept of the two-way deterministic protocol to work with qudits in prime d-dimensional system where d is odd. The second protocol makes use of the tomographically complete set construction for odd d-dimensional systems where d = p 1 p 2 to modify the BB84 protocol to work with qudits of such systems. The securities of the two protocols are analyzed according to the intercept and resend attack. [Copyright &y& Elsevier]

Zhou et al. proposed a quantum encryption scheme based on quantum computation in 2006 [N. Zhou et al., Physica A 362 (2006) 305]. Each qubit of the ciphertext is constrained to two pairs of conjugate states. So, its implementation is feasible with the existing technology. But it is inefficient since it entails six key bits to encrypt one message bit, and the resulting ciphertext for one message bit consists of three qubits. In addition, its security cannot be directly reduced to the well-known BB84 protocol. In this paper, we improve it using the technique developed in BB84 protocol. The new scheme entails only two key bits to encrypt one message bit. The resulting ciphertext is just composed of two qubits. It saves about a half cost without the loss of security. Moreover, the new scheme is probabilistic instead of deterministic. [ABSTRACT FROM AUTHOR]

We introduce the concept of Affiliation-Hiding Authenticated Asymmetric Group Key Agreement (AH-AAGKA) and construct a concrete one-round AH-AAGKA protocol. An AH-AAGKA protocol allows the participants of a group to establish a common encryption key associated with several decryption keys; each of which can only be computed by the corresponding legitimate group member. An AH-AAGKA protocol has the following privacy feature. For a member i of a group G, if i participates in an AH-AAGKA protocol, any protocol participant j cannot learn whether i is a member of G, unless j himself is a member of group G. Our scheme demonstrates new features in comparison with other existing AH-AGKA protocols. If non-group members participate in our protocol, honest parties can identify these non-group members. Our scheme also captures Unlinkability and Perfect Forward Secrecy (PFS), which are missing in other existing schemes. We propose a novel security model to prove that our protocol holds PFS and present a new privacy model to prove that our scheme meets Affiliation-Hiding property. [ABSTRACT FROM AUTHOR]