With the development of wireless communication technology, the applications of Mobile ad hoc network (MANET) have been constantly expanded. However, MANET faces many security threats because of their own properties. Authentication is the fundamental service to protect the security of MANET, and in many applications users typically want personal information kept confidential, so that it required the anonymity in the process of authentication. In this paper, we present a distributed anonymous authentication scheme for MANET from the bilinear maps, based on the technique of secret share and zero-knowledge proof, solves the authentication and key management problems of MANET which is lack of fixed infrastructure, achieves the anonymity in the process of authentication and key transfer. Meanwhile the scheme shortens the signature length, thus reduces the computational cost of nodes that is important to the MANET which are often composed of weak or resource-limited devices.
A user centric approach to authentication for home networks is proposed. A zero-knowledge-proof (ZKP) authentication is used to leverage the emerging cloud infrastructure allowing users to temporarily transfer their service and content rights within a trusted environment such as a friend's home. This approach enables the sharing of personalized content and more sophisticated network-based services over a conventional TCP/IP infrastructure. Experimental results derived from a reference prototype are presented. These demonstrate the practicality of the underlying approach. The potential to develop new cloud services for "social" home networks is also discussed.
Ioannis Chatzigiannakis, Apostolos Pyrgelis, Paul G. Spirakis, Yannis C. Stamatiou
Elliptic Curve Cryptography (ECC) is an attractive alternative to\nconventional public key cryptography, such as RSA. ECC is an ideal candidate\nfor implementation on constrained devices where the major computational\nresources i.e. speed, memory are limited and low-power wireless communication\nprotocols are employed. That is because it attains the same security levels\nwith traditional cryptosystems using smaller parameter sizes. Moreover, in\nseveral application areas such as person identification and eVoting, it is\nfrequently required of entities to prove knowledge of some fact without\nrevealing this knowledge. Such proofs of knowledge are called Zero Knowledge\nInteractive Proofs (ZKIP) and involve interactions between two communicating\nparties, the Prover and the Verifier. In a ZKIP, the Prover demonstrates the\npossesion of some information (e.g. authentication information) to the Verifier\nwithout disclosing it. In this paper, we focus on the application of ZKIP\nprotocols on resource constrained devices. We study well-established ZKIP\nprotocols based on the discrete logarithm problem and we transform them under\nthe ECC setting. Then, we implement the proposed protocols on Wiselib, a\ngeneric and open source algorithmic library. Finally, we present a thorough\nevaluation of the protocols on two popular hardware platforms equipped with low\nend microcontrollers (Jennic JN5139, TI MSP430) and 802.15.4 RF transceivers,\nin terms of code size, execution time, message size and energy requirements. To\nthe best of our knowledge, this is the first attempt of implementing and\nevaluating ZKIP protocols with emphasis on low-end devices. This work's results\ncan be used from developers who wish to achieve certain levels of security and\nprivacy in their applications.\n
Ioannis Chatzigiannakis, Apostolos Pyrgelis, Paul G. Spirakis, Yannis C. Stamatiou
Elliptic Curve Cryptography (ECC) is an attractive alternative to conventional public key cryptography, such as RSA. ECC is an ideal candidate for implementation on constrained devices where the major computational resources i.e. speed, memory are limited and low-power wireless communication protocols are employed. That is because it attains the same security levels with traditional cryptosystems using smaller parameter sizes. Moreover, in several application areas such as person identification and eVoting, it is frequently required of entities to prove knowledge of some fact without revealing this knowledge. Such proofs of knowledge are called Zero Knowledge Interactive Proofs (ZKIP) and involve interactions between two communicating parties, the Prover and the Verifier. In a ZKIP, the Prover demonstrates the possesion of some information (e.g. authentication information) to the Verifier without disclosing it. In this paper, we focus on the application of ZKIP protocols on resource constrained devices. We study well-established ZKIP protocols based on the discrete logarithm problem and we transform them under the ECC setting. Then, we implement the proposed protocols on Wiselib, a generic and open source algorithmic library. Finally, we present a thorough evaluation of the protocols on two popular hardware platforms equipped with low end microcontrollers (Jennic JN5139, TI MSP430) and 802.15.4 RF transceivers, in terms of code size, execution time, message size and energy requirements. To the best of our knowledge, this is the first attempt of implementing and evaluating ZKIP protocols with emphasis on low-end devices. This work's results can be used from developers who wish to achieve certain levels of security and privacy in their applications.
Nan Guo, Tianhan Gao, Bin Zhang, Ruchith Fernando · 5 authors
An aggregated privacy-preserving identity verification scheme is proposed for composite Web services. It aggregates multiple component providers' interactions of identity verification to a single one involving the user. Besides, it protects users from privacy disclosure through the adoption of zero-knowledge of proof of knowledge. This approach can dramatically reduce the computation time, independently on the number of identity attributes and component providers.
We introduce WORM-ORAM, a first mechanism that combines Oblivious RAM (ORAM) access privacy and data confidentiality with Write-Once Read-Many (WORM) regulatory data retention guarantees. Clients can outsource their database to a server with full confidentiality and data access privacy, and, for data retention, the server ensures client access WORM semantics. In general simple confidentiality and WORM assurances are easily achievable, e.g., via an encrypted outsourced data repository with server-enforced read-only access to existing records (albeit encrypted). However, this becomes hard when also access privacy is to be ensured-when client access patterns are necessarily hidden and the server cannot enforce access control directly. WORM-ORAM overcomes this by deploying a set of zero-knowledge proofs to convince the server that all stages of the protocol are WORM-compliant.
As radio frequency identification (RFID) applications become ubiquitous, security and privacy issues have been addressed with universal acceptances. This paper proposes a lightweight Zero-Knowledge Authentication Protocol (ZKAP) based on alternative mode to address such severe problems. In ZKAP, dual zero-knowledge proofs are randomly chosen to provide anonymity and mutual authentication without revealing any sensitive identifiers. Pseudo-random flags and access lists employed for quick search and check ensure high efficiency and scalability. Meanwhile, formal proof model based on reasonable mathematical assumptions is established to prove the adaptive completeness, soundness and zero-knowledgeness, and the attack models are adopted to analyze the resilience and resistance for malicious attacks. It indicates that ZKAP owns no obvious design defects theoretically and is robust enough to resist major attacks (e.g., forgery, replay, Man-in-the-Middle, and tracking). The protocol is attractive and appropriate for low-cost and resource-restricted RFID systems.
We present a cryptographic framework to achieve access control, privacy of social relations, secrecy of resources, and anonymity of users in social networks. The main idea is to use pseudonyms to hide user identities, signatures on pseudonyms to establish social relations, and zero-knowledge proofs on these signatures to demonstrate the existence of the corresponding social relations without sacrificing user anonymity. Our framework is generally applicable and, in particular, constitutes an ideal plug-in for decentralized social networks.
This paper presents a distributed anonymous authentication scheme for MANET based on the technique of group signature, secret share and zero-knowledge proof. The scheme takes advantage of the distributed certificate management to solve the authentication and key management problems of MANET which is lack of fixed infrastructure. Meanwhile, the scheme adopts the efficient group signature presented by Camenisch and Stadler, achieved the anonymity in the process of authentication and public key transmission. In the case of a later dispute, the group manager can reveal the identity of node by opening its signature. Besides anonymity and traceability, the scheme also has the property of unforgeability and robustness.
A public watermark detection scheme based on secure multiparty computation is proposed. It removes the expensive zero-knowledge interactive proofs and replaces the traditional trusted third party with a group of proxies. Then, the proposed scheme is robust against "single point failure", and efficient in terms of computation cost, the number of rounds and bandwidth required in the communications. Because of using integer comparison technique, the scheme achieves the provable security against sensitivity attacks without leaking any information about the secret watermark.
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
Market research surveys report that 75% of hacks occur at the application layer. Of the multiple vulnerabilities that exist in Web application software, proper authentication of the client and the server to each other is fundamental to the security of the system. In the current scenario, we manage this with the adoption of password-based client authentication and PKI-based server authentication. There exist unresolved vulnerabilities in this system due to the misuse of the client's passwords (impersonation) by those managing the servers. The clients' trust of the server based on the certificates issued by an increasing number of certification authorities is questionable in terms of validity and freshness. For proper authentication in Web applications, we need to verify two conditions: 1) the binding of the identity of the entity with the publicly known name or key and 2) the entity does possess the corresponding private key for the identified public key. In this paper, we use the elliptic curve discrete log problem-based version of classical zero knowledge protocol for proving number 2 and modifications of the existing schemes for proving number 1. We have done a prototype implementation of the solution and security analysis required to satisfy the security objectives.
A public watermark detection scheme using verifiable secret sharing is proposed. It removes the expensive zero-knowledge interactive proofs and replaces the traditional trusted third party with a group of proxies. Moreover, the scheme is secure against sensitivity attacks and very efficient in terms of computation cost, the number of rounds and bandwidth required in the communications.
Open access
Advanced Steganography and Watermarking Techniques
Zero-knowledge proof is an important part of the field of cryptography. In this paper, we obtain two zero-knowledge proof schemes based on the conic curve group being studied. The two schemes are interactive proof systems that one party claims to have some kind of information to the other who yields nothing beyond the validity of the assertion.
In this paper, we study methods for improving the utility and privacy of reputation scores for online auctions, such as used in eBay, so as to reduce the effectiveness of feedback extortion. The main ideas behind our techniques are to use randomization and various schemes to escrow reputations scores until appropriate external events occur. Depending on the degree of utility and privacy needed, these external techniques could depend on the number and type of reputation scores collected. Moreover, if additional privacy protection is needed, then random sampling can be used with respect reputation scores in such a way that reputation aggregates remain useful, but individual reputation scores are probabilistically hidden from users. Finally, we show that if privacy is also desired with respect to the the reputation aggregator, then we can use zero-knowledge proofs for reputation comparisons.
We present a cryptographic framework to achieve access control, privacy of social relations, secrecy of resources, and anonymity of users in social networks. We illustrate our technique on a core API for social networking, which includes methods for establishing social relations and for sharing resources. The cryptographic protocols implementing these methods use pseudonyms to hide user identities, signatures on these pseudonyms to establish social relations, and zero-knowledge proofs of knowledge of such signatures to demonstrate the existence of social relations without sacrificing user anonymity. As we do not put any constraints on the underlying social network, our framework is generally applicable and, in particular, constitutes an ideal plug-in for decentralized social networks. We analyzed the security of our protocols by developing formal definitions of the aforementioned security properties and by verifying them using ProVerif, an automated theorem prover for cryptographic protocols. Finally, we built a prototypical implementation and conducted an experimental evaluation to demonstrate the efficiency and the scalability of our framework.
Abstract : Zero-knowledge proof systems have many characteristics that are desirable for determining trustworthy parties in an airborne networking environment. One approach is to base zero-knowledge proof systems on the instances and solutions of NP-complete problem. This report investigates this approach with a focus on the graph theory problems within the NP-complete and NP-hard classes.
In this thesis, we provide contributions to signature schemes and identi cation schemes in four di erent ways.\nFirst, we make contributions to universal designated veri er signatures. We propose the notion of a one-time universal designated veri er signature such that the number of veri ers verifying the signature is controlled by the signer. We also propose the notion of a universal designated veri er signature with threshold-signers such that the privacy and anonymity of the signer can be achieved.\nSecond, we propose a new notion called "policy-controlled signatures". In this notion, a policy-controlled signature can be veri ed by a veri er that satis es a policy assigned by a signer. We provide two extensions to this notion, which are "universal policy-controlled signatures" and "multi-level controlled signatures". Universal policy-controlled signatures allow a party called "a policy signer" to apply a policy on a signature on a particular message such that only a veri er that satis es this policy can verify this policy-controlled signature. In practice, some policies can be simply represented by a level of the security, for example, "POLICY= more than the fth level of security". From the above idea, a de nition of multi-level controlled signatures is introduced. It allows a signer to eliminate the unnecessary chain of attributes in the policy and simply assign the level of security as a policy instead. Hence, the size of the policy remains constant.\nNext, a new notion called "fair multi-signatures" is proposed. A multi-signature allows a group of parties to engage in an interactive protocol in order to generate a joint signature on an agreement. If all the signers follow the protocol honestly, then a multi-signature is generated and distributed fairly. However, if a dishonest signer refuses to complete his part in the protocol, but he has already obtained the other parties' contributions, then the honest signers cannot obtain a multi-signature and yet the dishonest signer can generate a multi-signature. Our notion of fair multisignatures ensures that if the protocol is completed, then every signer involved in the signing protocol can output a multi-signature. Meanwhile, if the protocol is not completed, then none of the signers involved in the signing protocol can output a multi-signature.\nFinally, in modern communications, the public becomes aware of privacy issues. Some identi cation systems provide privacy for users, especially those that are based on zero knowledge proof. However, a malicious user may take advantage of privacy to deny his malicious acts. Hence, we propose a new notion called "escrowed deniable identi cation schemes". In this notion, a trusted party is introduced to act as a transaction opener such that it can generate evidence of the conversation from the deniable transcript generated during the interaction between a prover and a veri er. In an identi cation scheme, the major concern about security is impersonation. The strongest type of attack against identi cation schemes is the reset attack. In this thesis, we provide an identity-based identi cation scheme secure against reset attack. We also provide proof of our scheme which is secure against reset attack in the standard model.