Secure Anonymous Research Articles

Robust Anonymous Authentication Scheme for Telecare Medical Information Systems

Patient can obtain sorts of health-care delivery services via Telecare Medical Information Systems (TMIS). Authentication, security, patient's privacy protection and data confidentiality are important for patient or doctor accessing to Electronic Medical Records (EMR). In 2012, Chen et al. showed that Khan et al.'s dynamic ID-based authentication scheme has some weaknesses and proposed an improved scheme, and they claimed that their scheme is more suitable for TMIS. However, we show that Chen et al.'s scheme also has some weaknesses. In particular, Chen et al.'s scheme does not provide user's privacy protection and perfect forward secrecy, is vulnerable to off-line password guessing attack and impersonation attack once user's smart card is compromised. Further, we propose a secure anonymity authentication scheme to overcome their weaknesses even an adversary can know all information stored in smart card.

Using Distributed User Interfaces in Collaborative, Secure, and Privacy-Preserving Software Environments

In complex, ad hoc constituted situations, people with different intentions, experiences, and expertise need or want to cooperate to cope with the domain-specific challenges they face. These situations can occur in both a professional and a leisure-life context. Cooperative systems providing enhanced interaction facilities in the user interface (e.g., direct manipulation techniques) could substantially support cooperation especially for geographically distributed cooperating participants. In many cases, sensitive information has to be shared in a common workspace requiring different handling procedures according to the different types of participants involved in these ad hoc processes. This article proposes the use of a common, multilaterally secure distributed user interface to support collaboration for distributed groups of process participants. The system combines a collaborative multipointer system with an anonymous credential security system to provide users with an easy way to share and access information securely, ensuring the privacy of sensitive information communicated in the course of ad hoc processes. Various scenarios representing contrary use cases from three different projects are introduced to derive typical requirements and to show the generality of the proposed system and its core components.

Anonymous transactions in computer networks

We present schemes for providing anonymous transactions while privacy and anonymity are preserved, providing user's anonymous authentication in distributed networks such as the Internet. We first present a practical scheme for anonymous transactions while the transaction resolution is assisted by a Trusted Authority. This practical scheme is extended to a theoretical scheme where a Trusted Authority is not involved in the transaction resolution. Both schemes assume that all the players interact over anonymous secure channels. Given authority that generates for each player hard to produce evidence EVID (e.g., problem instance with or without a solution) to each player, the identity of a user U is defined by the ability to prove possession of aforementioned evidence. We use zero-knowledge proof techniques to repeatedly identify U by providing a proof that U has evidence EVID , without revealing EVID , therefore avoiding identity theft. In both schemes the authority provides each user with a unique random string. A player U may produce a unique user name and password for each other player S using a one-way function over the random string and the IP address of S . The player does not have to maintain any information in order to reproduce the user name and password used for accessing a player S . Moreover, the player U may execute transactions with a group of players S U in two phases; in the first phase the player interacts with each server without revealing information concerning its identity and without possibly identifying linkability among the servers in S U . In the second phase the player allows linkability and therefore transaction commitment with all servers in S U , while preserving anonymity (for future transactions).

A New Anonymous but Accountable Secure Proxy Signature Scheme

Privacy has become one of the most important human rights of the modern age. In order to verify the validity of the proxy signature, the verifier need get the original signers’ public key and the proxy signer’s public key. Obviously, the verification would leak the relationship between the proxy signer and the original signer. Using the technology of pseudonym, in this paper, we propose a simple secure anonymous but accountable method for proxy signer in a proxy signature scheme. Unless the corresponding evidence has been provided by the original signer, no one can find the proxy signer’s real identity or public key. In the scheme, the can reveal the identity of the proxy signer; moreover, the original signer can also demonstrate the identity of the proxy signer. Specially, we realize the property of anonymous but accountable without complex computation and trusted third party which is different to earlier method. The method can be used in any proxy signature scheme based on warrant to reach the target of proxy signer’s anonymity and accountability.

ACP BASED ANONYMOUS SECURE GROUP COMMUNICATION

Anonymous secure group communication is a new research and application paradigm. In this paper Anonymity between two-party communication, Access control polynomial to multi-part group communication, group key management for secure group communication and secure set concepts has been proposed. Newly extended scheme enforces Anonymous group membership, group size, Anonymous group communication and group message broadcasting. The experimental results and comparisons with existing system show that the ACP scheme is elegant, flexible, efficient and practical.

An Anonymous Secure Payment Protocol in a Payment Gateway Centric Model

In the last few years, a significant number of mobile payment systems have been proposed. Most of them have been based on a scenario where all the entities are directly connected to each other (formally called Full connectivity scenario). Although these scenarios offer advantages to protocol designers in terms of design simplicity and the development of payment protocols without losing security capabilities, the full connectivity scenario does not consider those situations where the client cannot directly communicate with the merchant. We present the design of an anonymous secure Payment protocol based on the Payment Gateway Centric scenario for those scenarios in mobile environments where the Client cannot communicate directly with the Merchant to process the Payment Request. Our proposed protocol uses symmetric-key operations which require low computational power and can be processed faster than asymmetric ones.

LISISAP

For any communication (wired or wireless) such as control and data, the identity of source and destination is revealed in the header portion of the packet. Adversaries obtain sensitive in-formation such as the identity, location of a critical node, route, data, etc., during communication by using traffic analysis at-tacks, viz., similarity attack, data integrity attack, packet count-ing attack, latency attack, and clogging attack. Anonymous communication prevents adversaries from doing traffic analysis against the routing information embedded in the routing mes-sages and data packets. In order to thwart such traffic analysis, anonymous communication protocols were developed. In this paper, the existing anonymous communication protocols were analyzed in terms of techniques used, challenges, and applications. Anonymous Routing protocol with Multiple Routes (ARMR) is one of the existing protocols that achieves better route anonymity using fake routes and multiple paths. However, in ARMR, adversaries can modify the data with genuine user pseudonyms and send the modified data to the destination. In order to prevent data modification by adversary at link level, in this paper a Link level SIgnature based Secure Anonymous Protocol (LISISAP) protocol is proposed. In LISISAP, source node generates a signature for the data and sends the signature along with the encrypted data to the next node. Further, the next node verifies the signature. If signature matches, it generates its own signature and sends the encrypted data to its next node. Otherwise, it discards the packet. Verified data and signature are sent by each intermediate node until it reaches the destina-tion. In LISISAP, even if adversaries modify the data, every node in the route including the destination node verifies the data and discards the data if there is no match in the signature. Similarity attacks can be prevented by making the data look different on each hop which could be achieved by encrypting the data with link key. Proposed protocol, LISISAP is imple-mented and tested in Smart and Secure Network. From the ex-perimental results, it is evident that the data generated by source node is sent anonymously to the destination. Thus, in LISISAP protocol, communication is secure between nodes without revealing the node identities. Anonymous properties such as identity privacy, location privacy, route anonymity, and robustness against several attacks were achieved.

A Provably Secure Anonymous Buyer–Seller Watermarking Protocol

Buyer-seller watermarking (BSW) protocols allow copyright protection of digital content. The protocol is anonymous when the identity of buyers is not revealed if they do not release pirated copies. Existing BSW protocols are not provided with a formal analysis of their security properties. We employ the ideal-world/real-world paradigm to propose a formal security definition for copyright protection protocols, and we analyze an anonymous BSW protocol and prove that it fulfills our definition. Additionally, we implement the protocol and measure its efficiency.

Noninteractive, Anonymously Authenticated, and Traceable Message Transmission for VANETs

Unlike sensor and other ad-hoc wireless networks, vehicular ad-hoc networks (VANETs) are characterized by its high mobility which allows a very short communication interval among onboard units (OBUs) and between an OBU and road-side units (RSUs). This major characterization motivates the design of communication protocols that are noninteractive or at least require a very limited number of rounds between units. The challenging issue is that such protocols must satisfy a number of security services that could be complex by their nature. In secure VANETs protocols, anonymity and traceability are two important services, yet, achieving a satisfactory security level for both of them—with acceptable complexity—is not an easy task due to the contradicting requirements: anonymous transmission must not be traceable by any individual while if a transmission is traceable, then anonymity is threatened. Existing secure VANETs protocols for anonymous and traceable transmissions either, provide unconditional anonymity where traceability and revocation are impossible, or grant trust to a thirdparty not to reveal the identity of a unit unless there is a legal reason. In this paper, we propose the first secure VANET protocol that allows authenticated transmission among OBUs and RSUs and at the same time enjoys the following properties. (i) The transmission among OBUs and RSUs is noninteractive (i.e., a one-move transmission without any interactive setup requirements). (ii) The authenticated transmission between any pair of units is anonymous (i.e., no single authority knows any information about the identity of the communicating OBU). (iii) In serious road crimes (e.g., hit-and-run, road rage, etc.) and under court order, an OBU could be traced to its clear identity. We also show how our protocol could be used to setup a confidential session between any pair of units without relying on extensive number of interactive rounds.

Anonymity Authentication and Measure in Ubiquitous Computing

Authentication and anonymity usually are inconsistent. To obtain services, a user must be authenticated. Much of the sensitive information of the user will be exposed to service providers. In order to protect privacy, users must communicate with service providers in an anonymous way. But if the user does not show his true identity, how can the service provider believe that the user is true. This paper presents a secure anonymity authentication protocol for ubiquitous computing which allows service providers to authenticate anonymous users. Anonymity is achieved by separating the linkability of the user's identity information and the action of the user. By finding out objects linkability relationship, we also address an anonymity measure to analyze anonymity and detect the concealing security exposure. 1. Anonymity Authentication There exist three principals in the anonymity authentication protocol: the user, the service discoverer, and the service provider. The anonymity authentication protocol contains two authentication stages. First, the authentication between the user and the service discoverer which determines the user whether he has the right to access the requested resource. And then the service discoverer makes use of blind signature on the user's public key as a ticket. Second, the service provider authenticates the user, in which the service provider judges the user whether is the genuine user. 2. Anonymity Measure Linkability is the relation between objects (such as subjects, events, actions etc.) in a system before and after an action occurs. Unlinkability is the sufficient condition of anonymity. Definition 1 (function decision) Let R denote the object set, X and Y be subsets of R, and X≠ Y. If Y can be known from X with probability p, then say X function decision Y, recorded as: X→ Y( p). Definition 2 (function decision set) To the object set R, the function decision set is the set F of function decisions among the objects known by attackers. Definition 3 (function decision implication) If F is the function decision set known by attackers, let R denote the object set, X and Y be subsets of R, and X≠ Y. If X→ Y( p) can be deduced from F, then say F implication X→ Y( p). Definition 4 (function decision closure) All the function decision sets implicated by F are called the closure of F, written as F+. Whether user anonymity is protected can be judged by seeing if there are relations between users' location/actions and users' identity in F+.

Efficient anonymous secure auction schema (ASAS) without fully trustworthy auctioneer

PurposeIn traditional commerce, an auction is known as a mechanism of determining the value of a commodity that does not have a fixed price. Auctions are exciting and an increasing number of transactions are performed through e‐auctions. But most current auctions cannot address all the important security requirements. Usually, auction systems force bidders and sellers to trust the auctioneer and, on the other hand, do not provide anonymity for bidders and sellers. This paper aims to solve these problems by presenting an efficient anonymous secure auction schema (ASAS) without a fully trustworthy auctioneer.Design/methodology/approachThe paper analyzes security properties and the complexity of previous works in auction security and then proposes a new ASAS that is more secure and efficient than previous works. Finally, security properties and the complexity of the new schema and previous works are compared with one another.FindingsThe proposed auction protocol does not force bidders and sellers to trust the auctioneer. In addition, it provides anonymity for both of them. Owing to these newly added features and high degree of security of ASAS, it is suggested that its use in high‐value auctions should require tighter security.Originality/valueThe paper proposes a new schema for electronic auctions that is secure and efficient and, in addition, does not force bidders and sellers to trust the auctioneer.

Strategic Embodiment in Virtual Spaces: Exploring an on-line discussion about sexualities equality in schools

This paper analyses patterns of participation on a voluntary anonymous Web-based discussion forum, open to students and faculty in one UK university, concerning sexualities equality in schools. Analysis revealed that participants often rejected the security of anonymity and strategically embodied themselves and others (as gay, straight, parents, etc.) to provide authority and ethical grounding for certain arguments. These embodied arguments invited engagement and promoted dialogue. We found that while personal embodiments were crucial for meaningful interaction, they also brought the risk of personalizing systematic inequality and fostering a victimization discourse. In the light of this, we argue that both individual and collective perspectives are crucial for promoting sexualities equality in school.

Design on PKI-based anonymous mobile agent security in E-commerce

The security of mobile agent directly decides its usage width in e-commerce. Especially, to protect users' private information is becoming more important now and future. So an anonymous mobile agent security mechanism with the secure authentication infrastructure based on PKI (public key infrastructure) is proposed in the paper. The multi-agent system is programmed by java language and every agent must register itself in CA (certificate authority) before working in the net and express his legit identity which is temptly produced and used only once. The CA ensures the legal of all agents' identity which take part in communication or trade. And every user agent identity only is used once which makes other agents cannot decipher users' private information. The security mechanism of the multi-agent system implements anonymity, integrity, data confidentiality of mobile agent based on the MH(multiple hop) integrity protection regard to PKI limit.

Unconditionally Secure Anonymous Encryption and Group Authentication

Anonymous channels or similar techniques that achieve sender's anonymity play important roles in many applications, e.g. electronic voting. However, they will be meaningless if cryptographic primitives containing sender's identity are carelessly used during the transmission. In computationally secure settings, this problem may be easily overcome by using public key encryption and group signatures. However, in an unconditionally secure setting, in which no computational difficulty is assumed, this is not an easy case as such. As the increasing computational power approaches the point where security policy can no longer assume the difficulty of solving factoring or discrete logarithm problems, it must shift its focus to assuring the solvency of unconditionally secure schemes that provide long-term security. The main contribution of this paper is to study the security primitives for the above problem. In this paper, we first define the unconditionally secure asymmetric encryption scheme, which is an encryption scheme with unconditional security and where it is impossible for a receiver to deduce the identity of a sender from the encrypted message. We also investigate tight lower bounds on required memory sizes from an information theoretic viewpoint and show an optimal construction based on polynomials. It is remarkable to see that these bounds are considerably different from those in Shannon's model of the conventional unconditionally secure symmetric encryption. Other than the polynomial-based scheme, we also show a construction based on combinatorial theory, a non-malleable scheme and a multi-receiver scheme. Then, we define and formalize the group authentication code (GA-code), which is an unconditionally secure authentication code with anonymity like group signatures. In this scheme, any authenticated user will be able to generate and send an authenticated message while the receiver can verify the legitimacy of the message---that it has been sent from a legitimate user but at the same time retains his anonymity. However, by cooperating with the group authority, such as in the case of disputes, the receiver is able to obtain information of the user's identity. For GA-code, we show two concrete constructions.

Cryptanalysis of Security Enhancement for Anonymous Secure E-voting over a Network

Cryptanalysis of Security Enhancement for Anonymous Secure E-voting over a Network

On the security enhancement for anonymous secure e-voting over computer network

On the security enhancement for anonymous secure e-voting over computer network

On the security enhancement for anonymous secure e-voting over computer network

Mu and Varadharajan proposed an electronic voting system which can be utilized in large-scale elections in 1998. Recently, Lin et al. showed that Mu and Varadharajan's scheme has a weakness. That is, voters can successfully vote more than once without being detected. To avoid this weakness, Lin et al. proposed a modified scheme. However, this paper shows that the Lin et al.'s modification allows the Authentication Server to identify the voters of published tickets so that voters will lose their privacy. An improved scheme is further proposed to solve this problem and thus enhance the security.

Is Partition Really the Only Hope? Reconciling Contradictory Findings About Ethnic Civil Wars

Click to increase image sizeClick to decrease image size Acknowledgments The original version of this article was written in 1997. An initially revised version was presented at the 96th annual meeting of the American Political Science Association, Washington, D.C. August 31–September 3, 2000. That version has been further substantially revised for publication in the current special issue of the journal Security Studies on “Living Together After Ethnic Killing.” The author gratefully acknowledges past financial support from the mit Department of Political Science, the U.S. Institute of Peace, Harvard University's Belfer Center for Science and International Affairs, the Institute for the Study of World Politics, the Harvard-mit MacArthur Transnational Security Fellowship, the Brookings Institution, and the Federation of American Scientists. The author also would like to thank Jim Alt and Chaim Kaufmann, and two anonymous Security Studies reviewers for their comments on earlier versions of this article.

Improved Anonymous Secure e-Voting over a Network

In a democratic country voting is one of the most important activities. However, many eligible voters do not exercise their right simply because they do not want to visit a public booth where they can vote. In 1981, David Chaum first introduced the concept of electronic voting and attempted to overcome the prob- lems associated with the traditional voting environment. Hereafter, Mu and Varadharajan proposed in 1998 an anonymous secure e-voting scheme over a net- work. They claimed that the proposed scheme is not only capable of preventing double voting but it can also protect the privacy of voters. However, many re- searchers afterwards have discovered that Mu and Varadharajan's scheme is not se- cure. Attackers can easily forge a valid ballot and can vote more than once. In this paper, an e-voting scheme based on Mu and Varadharajan's scheme is proposed that meets the following e-voting requirements: democracy, accuracy, anonymity, mobility and efficiency.

AVOIDING TRAGEDY IN POWER POLITICS:

Click to increase image sizeClick to decrease image size Acknowledgments Earlier versions of this article were presented at the Program on International Politics, Economics, and Security (PIPES), University of Chicago, in December 1999, and at the annual convention of the American Political Science Association in August 2002. I am grateful for the helpful comments of Clifford Bob, Daniel Drezner, Charles Kupchan, Charles Lipson, Tony Messina, David Nickles, Duncan Snidal, Al Tillery, Alexander Wendt, and several anonymous Security Studies reviewers.