Malicious Adversaries Research Articles

An Efficient Protocol for Secure Two-Party Computation in the Presence of Malicious Adversaries

We show an efficient secure two-party protocol, based on Yao’s construction, which provides security against malicious adversaries. Yao’s original protocol is only secure in the presence of semi-honest adversaries, and can be transformed into a protocol that achieves security against malicious adversaries by applying the compiler of Goldreich, Micali, and Wigderson (the “GMW compiler”). However, this approach does not seem to be very practical as it requires using generic zero-knowledge proofs. Our construction is based on applying cut-and-choose techniques to the original circuit and inputs. Security is proved according to the ideal/real simulation paradigm, and the proof is in the standard model (with no random oracle model or common reference string assumptions). The resulting protocol is computationally efficient: the only usage of asymmetric cryptography is for running \(O(1)\) oblivious transfers for each input bit (or for each bit of a statistical security parameter, whichever is larger). Our protocol combines techniques from folklore (like cut-and-choose) along with new techniques for efficiently proving consistency of inputs. We remark that a naive implementation of the cut-and-choose technique with Yao’s protocol does not yield a secure protocol. This is the first paper to show how to properly implement these techniques, and to provide a full proof of security. Our protocol can also be interpreted as a constant-round black-box reduction of secure two-party computation to oblivious transfer and perfectly hiding commitments, or a black-box reduction of secure two-party computation to oblivious transfer alone, with a number of rounds which is linear in a statistical security parameter. These two reductions are comparable to Kilian’s (20th STOC, 1988) reduction, which uses OT alone but incurs a number of rounds which is linear in the depth of the circuit.

The Covering Canadian Traveller Problem

The Canadian Traveller Problem (CTP) is to find the shortest route from a source to a destination under uncertain conditions. Some roads may be blocked by accidents, and a traveller only discovers a blockage upon reaching an adjacent site of the road. More precisely, the objective of this problem is to design an adaptive strategy against a malicious adversary who sets up road blockages in order to maximize the gap between the distance cost resulting from the strategy and the distance cost of the static shortest path in which all blockages are known a priori. This study investigates a variation of the Travelling Salesman Problem that involves finding the shortest tour, visiting a set of locations, and returning to the origin under the same uncertainty as that of the CTP. This online routing problem, called the Covering Canadian Traveller Problem (CCTP), has real applications in dynamic navigation systems such as delivery routing in express logistics. We study this problem from a competitive analysis perspective, and present an efficient touring strategy within an O(k)-competitive ratio, where the number of blockages is up to k. We also demonstrate the tightness of the competitive analysis.

Certificateless Remote Anonymous Authentication Schemes for WirelessBody Area Networks

Wireless body area network (WBAN) has been recognized as one of the promising wireless sensor technologies for improving healthcare service, thanks to its capability of seamlessly and continuously exchanging medical information in real time. However, the lack of a clear in-depth defense line in such a new networking paradigm would make its potential users worry about the leakage of their private information, especially to those unauthenticated or even malicious adversaries. In this paper, we present a pair of efficient and light-weight authentication protocols to enable remote WBAN users to anonymously enjoy healthcare service. In particular, our authentication protocols are rooted with a novel certificateless signature (CLS) scheme, which is computational, efficient, and provably secure against existential forgery on adaptively chosen message attack in the random oracle model. Also, our designs ensure that application or service providers have no privilege to disclose the real identities of users. Even the network manager, which serves as private key generator in the authentication protocols, is prevented from impersonating legitimate users. The performance of our designs is evaluated through both theoretic analysis and experimental simulations, and the comparative studies demonstrate that they outperform the existing schemes in terms of better trade-off between desirable security properties and computational overhead, nicely meeting the needs of WBANs.

A Function Private Attribute-Based Encryption

The function privacy notion was proposed by Boneh, Raghunathan, and Segev in August 2013. It guarantees that the secret key reveals nothing to malicious adversary, beyond the unavoidable minimal information such as the length of ciphertext. They constructed a function private identity-based encryption that contains equality functionality. In this work we construct a new function private attribute-based encryption which supports more complex functionality. And we transform it to a searchable encryption. In searchable encryption, the trapdoor of searching keywords can be seen as the secret key. Hence, using this system can efficiently resist keyword guessing attack.

CONSTANT-ROUND PRIVACY PRESERVING MULTISET UNION

Privacy preserving multiset union (PPMU) protocol allows a set of parties, each with a multiset, to collaboratively compute a multiset union secretly, meaning that any information other than union is not revealed. We propose efficient PPMU protocols, using multiplicative homomorphic cryptosystem. The novelty of our protocol is to directly encrypt a polynomial by representing it by an element of an extension field. The resulting protocols consist of constant rounds and improve communication cost. We also prove the security of our protocol against malicious adversaries, in the random oracle model.

Anonymous Spatial Query on Non-Uniform Data

Location and local service is one of the hottest bunches of applications in recent years, due to the proliferation of Global Position System (GPS) and mobile web search technology. Spatial queries retrieving neighboring Point-Of-Interests (POI) require actual user locations for services. However, exposing the physical location of querier to service system may pose privacy threat to users, if malicious adversary has access to the system. To hinder the service system from obtaining the “true” location of querier, current obfuscation-based approach requires a trusted third party anonymizer. As for the data-encryption-based and cPIR-based approaches, they incur costly computation overheads. Although the secure hardware-aided PIR-based technique has been shown to be superior to formers, it did not consider the characteristics of data distribution of searching domain. To deal with the problem of non-uniform data distribution and efficient retrieval, we propose four schemes: MSQL, NSQL, MNSQL, MHBL, based on flexible multi-layer grids, non-empty lookup table and Hilbert space-filling curve for efficient storage and retrieval of POI data, so that improved performance of PIR-based techniques could be achieved. Numerical experiments demonstrate that the proposed techniques indeed deliver better efficiency under various criteria.

Constant-round adaptive zero-knowledge proofs for NP

Secure two-party computation allows two parties with private inputs to securely compute some function of their inputs, even in the presence of a malicious adversary. In this work, we revisit zero-knowledge proofs and focus on adaptive adversaries, which could corrupt an arbitrary number of parties and adaptively determine who and when to corrupt during the computation phase.Previous constructions could realize adaptive zero-knowledge proofs for all languages in NP (Lindell and Zarosim TCC’09) at the cost of a high round-complexity, i.e., super-constant number of rounds. In this work, assuming the existence of constant-round statistically hiding commitment schemes, we build efficient adaptive zero-knowledge proofs for all languages in NP, which only require constant number of communication rounds. The system is also a proof of knowledge. The construction relies on an adaptive instance-dependent commitment scheme, and the proof of security requires only the use of black-box techniques and is presented according to the real/ideal simulation paradigm.

Mitigating Event Confidentiality Violations in Smart Grids: An Information Flow Security-Based Approach

Modern smart grids, by and large, merge physical interconnections and cyber controllers. Invariably, this tight coupling results in cyber commands manifesting in the physical layer as observable changes, leading to possible disclosure of sensitive system settings. Thus, cyber event confidentiality of the smart grid is violated. Attacks on confidentiality can ultimately lead to integrity and availability attacks; with adequate knowledge of the system topology, internal settings, and how the physical layer responds to cyber commands, a malicious adversary gains knowledge to attack the system. This work shows how to develop self-obfuscating systems based on information flow security properties that can mitigate event confidentiality violations in smart grids.

Secure Hamming distance based record linkage with malicious adversaries

Record linkage aims at finding the matching records from two or multiple different databases. Many approximate string matching methods in privacy-preserving record linkage have been presented. In this paper, we study the problem of secure record linkage between two data files in the two-party computation setting. We note that two records are linked when all the Hamming distances between their attributes are smaller than some fixed thresholds. We firstly construct two efficient secure protocols for computing the powers of an encrypted value and implementing zero test on an encrypted value, then present an efficient protocol within constant rounds for computing the Hamming distance based record linkage in the presence of malicious adversaries by transferring these two protocols. We also discuss the extension of our protocol for settling the Levenshtein distance based record linkage problem.

Secure similarity coefficients computation for binary data and its extensions

SUMMARYSimilarity measures play an important role in classification problems, cluster analysis, and identification issues. This paper studies the secure similarity coefficients computation in the two‐party setting. Recently, a privacy‐preserving similarity coefficients protocol for binary data was proposed by Wong and Kim (Computers and Mathematics with Application 2012). We point out that their protocol is not secure, even in the semi‐honest model. In their protocol, the client can retrieve the inputs of the server without deviating from the protocol. Next, we propose a secure similarity coefficients computation protocol in the presence of malicious adversaries, which solves the same similarity coefficients functionality as that proposed by Wong and Kim. Meanwhile, we prove the protocol secure against the malicious adversaries by using the standard simulation‐based security definitions for secure two‐party computation. Also several extensions of our protocol for settling other specific problems are discussed. At last, we present a protocol computing the similarity coefficients with better privacy by using the secure integer division on ciphertexts. Copyright © 2013 John Wiley & Sons, Ltd.

Social rational secure multi‐party computation

SUMMARYRational party is a new kind of parties who behave neither like honest parties nor like malicious adversaries. The crux point of rational party is the definition of the utility function, as rational parties only care about how to maximize their utility. In other words, rational parties choose the strategies, which can bring them the highest utilities. In rational secure two‐party computation protocol, the main task is how to boost mutual cooperation to complete the protocol. Social rational secure multi‐party computation (SRSMPC) means that in a social network, some distributed and rational parties with reputation properties want to jointly compute a functionality. The seemingly simple task becomes tough under three conditions. The first condition is that the network composed by parties may not be complete. That is, two parties may not be neighbors and they are connected through other parties. The second is that the network may be not secure. That is, messages may be tempered by malicious parties. The third condition is that parties may run the protocol under incomplete information scenario. That is, parties may have types and each type has a corresponding utility function. Under the first and second conditions, parties need to consider how to securely transmit messages between two parties who are not neighbors. Under the third condition, we propose the Tit‐for‐Tat strategy and prove that mutual cooperation is a sequential equilibrium between two parties. In this paper, we construct an SRSMPC protocol by using mechanism design under incomplete information to facilitate the implementation of the SRSMPC protocol within constant rounds. Meanwhile, newcomers are allowed to participate in the protocol. To the best of our knowledge, this is the first social rational secure computation protocol for multi‐party under an incomplete information scenario and an incomplete network. Copyright © 2013 John Wiley & Sons, Ltd.

A Decentralized Privacy Preserving Reputation Protocol for the Malicious Adversarial Model

Users hesitate to submit negative feedback in reputation systems due to the fear of retaliation from the recipient user. A privacy preserving reputation protocol protects users by hiding their individual feedback and revealing only the reputation score. We present a privacy preserving reputation protocol for the malicious adversarial model. The malicious users in this model actively attempt to learn the private feedback values of honest users as well as to disrupt the protocol. Our protocol does not require centralized entities, trusted third parties, or specialized platforms, such as anonymous networks and trusted hardware. Moreover, our protocol is efficient. It requires an exchange of messages, where and are the number of users in the protocol and the environment, respectively.

Multi-party trust computation in decentralized environments in the presence of malicious adversaries

In this paper, we describe a decentralized privacy-preserving protocol for securely casting trust ratings in distributed reputation systems. Our protocol allows n participants to cast their votes in a way that preserves the privacy of individual values against both internal and external attacks. The protocol is coupled with an extensive theoretical analysis in which we formally prove that our protocol is resistant to collusion against as many as n−1 corrupted nodes in both the semi-honest and malicious adversarial models.The behavior of our protocol is tested in a real P2P network by measuring its communication delay and processing overhead. The experimental results uncover the advantages of our protocol over previous works in the area; without sacrificing security, our decentralized protocol is shown to be almost one order of magnitude faster than the previous best protocol for providing anonymous feedback.

A Novel Secure Cosine Similarity Computation Scheme with Malicious Adversaries

Similarity coefficients play an important role in many aspects.Recently,several schemes were proposed,but these schemes aimed to compute the si milarity coefficients of binary data. In this paper, a novel scheme which can compute the coefficients of integer is proposed. To the best knowledge of us,this is the first scheme which canesist malicious adversaries attack.

Computationally Secure Pattern Matching in the Presence of Malicious Adversaries

We propose a protocol for the problem of secure two-party pattern matching, where Alice holds a text t?{0,1}? of length n, while Bob has a pattern p?{0,1}? of length m. The goal is for Bob to (only) learn where his pattern occurs in Alice's text, while Alice learns nothing. Private pattern matching is an important problem that has many applications in the area of DNA search, computational biology and more. Our construction guarantees full simulation in the presence of malicious, polynomial-time adversaries (assuming the hardness of DDH assumption) and exhibits computation and communication costs of O(n+m) group elements in a constant round complexity. This improves over previous work by Gennaro et al. (Public Key Cryptography, pp. 145---160, 2010) whose solution requires overhead of O(nm) group elements and exponentiations in O(m) rounds. In addition to the above, we propose a collection of protocols for important variations of the secure pattern matching problem that are significantly more efficient than the current state of art solutions: First, we deal with secure pattern matching with wildcards. In this variant the pattern may contain wildcards that match both 0 and 1. Our protocol requires O(n+m) communication and O(1) rounds using O(nm) computation. Then we treat secure approximate pattern matching. In this variant the matches may be approximated, i.e., have Hamming distance less than some threshold, ?. Our protocol requires O(n?) communication in O(1) rounds using O(nm) computation. Third, we have secure pattern matching with hidden pattern length. Here, the length, m, of Bob's pattern remains a secret. Our protocol requires O(n+M) communication in O(1) rounds using O(n+M) computation, where M is an upper bound on m. Finally, we have secure pattern matching with hidden text length. Finally, in this variant the length, n, of Alice's text remains a secret. Our protocol requires O(N+m) communication in O(1) rounds using O(N+m) computation, where N is an upper bound on n.

MET𝔸P: revisiting Privacy-Preserving Data Publishing using secure devices

The goal of Privacy-Preserving Data Publishing (PPDP) is to generate a sanitized (i.e. harmless) view of sensitive personal data (e.g. a health survey), to be released to some agencies or simply the public. However, traditional PPDP practices all make the assumption that the process is run on a trusted central server. In this article, we argue that the trust assumption on the central server is far too strong. We propose Met 𝔸P, a generic fully distributed protocol, to execute various forms of PPDP algorithms on an asymmetric architecture composed of low power secure devices and a powerful but untrusted infrastructure. We show that this protocol is both correct and secure against honest-but-curious or malicious adversaries. Finally, we provide an experimental validation showing that this protocol can support PPDP processes scaling up to nation-wide surveys.

Comments on an Improved RFID Security Protocol for ISO/IEC WD 29167-6

With the rapid progress of RFID security technologies, the international standard group ISO/IEC JTC 1/SC 31 is developing a few security technologies for RFID systems. One of the initial proposals is ISO/IEC working draft (WD) 29167-6. Recently, Song and others stated that Protocol 1 of ISO/IEC WD 29167-6 is vulnerable to a malicious adversary. However, their analysis comes from a misunderstanding regarding a communication parameter called Handle. In this letter, we point out that an adversary cannot obtain any sensitive information from intervening in Protocol 1.

Communication security for smart grid distribution networks

The operation and control of the next generation electrical grids will depend on a complex network of computers, software, and communication technologies. Being compromised by a malicious adversary would cause significant damage, including extended power outages and destruction of electrical equipment. Moreover, the implementation of the smart grid will include the deployment of many new enabling technologies such as advanced sensors and metering, and the integration of distributed generation resources. Such technologies and various others will require the addition and utilization of multiple communication mechanisms and infrastructures that may suffer from serious cyber vulnerabilities. These need to be addressed in order to increase the security and thus the greatest adoption and success of the smart grid. In this article, we focus on the communication security aspect, which deals with the distribution component of the smart grid. Consequently, we target the network security of the advanced metering infrastructure coupled with the data communication toward the transmission infrastructure. We discuss the security and feasibility aspects of possible communication mechanisms that could be adopted on that subpart of the grid. By accomplishing this, the correlated vulnerabilities in these systems could be remediated, and associated risks may be mitigated for the purpose of enhancing the cyber security of the future electric grid.

Secure computation of functionalities based on Hamming distance and its application to computing document similarity

This paper examines secure two-party computation of functions, which depend only on the Hamming distance of the inputs of the two parties. We present efficient protocols for computing these functions. In particular, we present protocols which are secure in the sense of full simulatability against malicious adversaries. We then show applications of HDOT. These include protocols for checking similarity between documents without disclosing additional information about them these protocols are based on algorithms of Broder et al. for computing document similarity based on the Jaccard measure. Another application is a variant of symmetric private information retrieval SPIR, which can be used if the server's database contains N entries, at most N / logN of which have individual values, and the rest are set to some default value. The receiver does not learn whether it receives an individual value or the default value. This variant of PIR is unique since it can be based on the existence of OT alone.

A Secure Scalar Product Protocol Against Malicious Adversaries

A secure scalar product protocol is a type of specific secure multi-party computation problem. Using this kind of protocol, two involved parties are able to jointly compute the scalar product of their private vectors, but no party will reveal any information about his/her private vector to another one. The secure scalar product protocol is of great importance in many privacy-preserving applications such as privacy-preserving data mining, privacy-preserving cooperative statistical analysis, and privacy-preserving geometry computation. In this paper, we give an efficient and secure scalar product protocol in the presence of malicious adversaries based on two important tools: the proof of knowledge of a discrete logarithm and the verifiable encryption. The security of the new protocol is proved under the standard simulation-based definitions. Compared with the existing schemes, our scheme offers higher efficiency because of avoiding inefficient cut-and-choose proofs.