A non-interactive deniable authentication scheme based on designated verifier proofs

A deniable authentication protocol enables a receiver to identify the source of the given messages but unable to prove to a third party the identity of the sender. In recent years, several non-interactive deniable authentication schemes have been proposed in order to enhance efficiency. In this paper, we propose a security model for non-interactive deniable authentication schemes. Then a non-interactive deniable authentication scheme is presented based on designated verifier proofs. Furthermore, we prove the security of our scheme under the DDH assumption

A non-interactive deniable authentication scheme in the standard model

Deniable authentication protocols enable a sender to authenticate a message to a receiver such that the receiver is unable to prove the identity of the sender to a third party. In contrast to interactive schemes, non-interactive deniable authentication schemes improve communication efficiency. Currently, several non-interactive deniable authentication schemes have been proposed with provable security in the random oracle model. In this paper, we study the problem of constructing non-interactive deniable authentication scheme secure in the standard model without bilinear groups. An efficient non-interactive deniable authentication scheme is presented by combining the Diffie-Hellman key exchange protocol with authenticated encryption schemes. We prove the security of our scheme by sequences of games and show that the computational cost of our construction can be dramatically reduced by applying pre-computation technique

Pairing-Based Cryptographic Protocols : A Survey

The bilinear pairing such as Weil pairing or Tate pairing on elliptic and hyperelliptic curves have recently been found applications in design of cryptographic protocols. In this survey, we have tried to cover different cryptographic protocols based on bilinear pairings which possess, to the best of our knowledge, proper security proofs in the existing security models

A Provably Secure Certificate Based Ring Signature Without Pairing

Abstract In Eurocrypt 2003, Gentry introduced the notion of certificate-based encryption. The merit of certificatebased encryption lies in implicit certificate and no private key escrow. This feature is desirable especially for the efficiency and the real spontaneity of ring signature, which involve a large number of public keys in each execution. In this paper, we propose an efficient certificatebased ring signature scheme which does not require any pairing computation. Furthermore, this scheme is proven secure under the Discrete Logarithm assumption in the random oracle model. To the best of authors' knowledge, this is the first construction of certificate-based ring signature scheme in the literature that has such kind of feature

Anonymous Deniable Identification in Ephemeral Setup & Leakage Scenarios

In this paper we concern anonymous identification, where the verifier can check that the user belongs to a given group of users (just like in case of ring signatures), however a transcript of a session executed between a user and a verifier is deniable. That is, neither the verifier nor the prover can convice a third party that a given user has been involved in a session but also he cannot prove that any user has been interacting with the verifier. Thereby one can achieve high standards for protecting personal data according to the General Data Protection Regulation – the fact that an interaction took place might be a sensitive data from information security perspective. We show a simple realization of this idea based on Schnorr identification scheme arranged like for ring signatures. We show that with minor modifications one can create a version immune to leakage of ephemeral keys. We extend the above scenario to the case of k out of n, where the prover must use at least k private keys corresponding to the set of n public keys. With the most probable setting of k = 2 or 3, we are talking about the practical case of multifactor authentication that might be necessary for applications with higher security level

Reusable mesh signature scheme for protecting identity privacy of IoT devices

Peer reviewedPublisher PD

Constant Size Traceable Ring Signature Scheme without Random Oracles

Currently several traceable (or linkable) identity-based ring signature schemes have been proposed. However, most of them are constructed in the random oracle model. In this paper, we present a fully traceable ring signature (TRS) scheme without random oracles, which has the constant size signature and a security reduction to the computational Diffie-Hellman (CDH) assumption. Also, we give a formal security model for traceable ring signature and prove that the proposed scheme has the properties of traceability and anonymity

Cryptography in privacy-preserving applications.

Tsang Pak Kong.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.Includes bibliographical references (leaves 95-107).Abstracts in English and Chinese.Abstract --- p.iiAcknowledgement --- p.ivChapter 1 --- Introduction --- p.1Chapter 1.1 --- Privacy --- p.1Chapter 1.2 --- Cryptography --- p.5Chapter 1.2.1 --- History of Cryptography --- p.5Chapter 1.2.2 --- Cryptography Today --- p.6Chapter 1.2.3 --- Cryptography For Privacy --- p.7Chapter 1.3 --- Thesis Organization --- p.8Chapter 2 --- Background --- p.10Chapter 2.1 --- Notations --- p.10Chapter 2.2 --- Complexity Theory --- p.11Chapter 2.2.1 --- Order Notation --- p.11Chapter 2.2.2 --- Algorithms and Protocols --- p.11Chapter 2.2.3 --- Relations and Languages --- p.13Chapter 2.3 --- Algebra and Number Theory --- p.14Chapter 2.3.1 --- Groups --- p.14Chapter 2.3.2 --- Intractable Problems --- p.16Chapter 2.4 --- Cryptographic Primitives --- p.18Chapter 2.4.1 --- Public-Key Encryption --- p.18Chapter 2.4.2 --- Identification Protocols --- p.21Chapter 2.4.3 --- Digital Signatures --- p.22Chapter 2.4.4 --- Hash Functions --- p.24Chapter 2.4.5 --- Zero-Knowledge Proof of Knowledge --- p.26Chapter 2.4.6 --- Accumulators --- p.32Chapter 2.4.7 --- Public Key Infrastructure --- p.34Chapter 2.5 --- Zero Knowledge Proof of Knowledge Protocols in Groups of Unknown Order --- p.36Chapter 2.5.1 --- The Algebraic Setting --- p.36Chapter 2.5.2 --- Proving the Knowledge of Several Discrete Logarithms . --- p.37Chapter 2.5.3 --- Proving the Knowledge of a Representation --- p.38Chapter 2.5.4 --- Proving the Knowledge of d Out of n Equalities of Discrete Logarithms --- p.39Chapter 2.6 --- Conclusion --- p.42Chapter 3 --- Related Works --- p.43Chapter 3.1 --- Introduction --- p.43Chapter 3.2 --- Group-Oriented Signatures without Spontaneity and/or Anonymity --- p.44Chapter 3.3 --- SAG Signatures --- p.46Chapter 3.4 --- Conclusion --- p.49Chapter 4 --- Linkable Ring Signatures --- p.50Chapter 4.1 --- Introduction --- p.50Chapter 4.2 --- New Notions --- p.52Chapter 4.2.1 --- Accusatory Linking --- p.52Chapter 4.2.2 --- Non-slanderability --- p.53Chapter 4.2.3 --- Linkability in Threshold Ring Signatures --- p.54Chapter 4.2.4 --- Event-Oriented Linking --- p.55Chapter 4.3 --- Security Model --- p.56Chapter 4.3.1 --- Syntax --- p.56Chapter 4.3.2 --- Notions of Security --- p.58Chapter 4.4 --- Conclusion --- p.63Chapter 5 --- Short Linkable Ring Signatures --- p.64Chapter 5.1 --- Introduction --- p.64Chapter 5.2 --- The Construction --- p.65Chapter 5.3 --- Security Analysis --- p.68Chapter 5.3.1 --- Security Theorems --- p.68Chapter 5.3.2 --- Proofs --- p.68Chapter 5.4 --- Discussion --- p.70Chapter 5.5 --- Conclusion --- p.71Chapter 6 --- Separable Linkable Threshold Ring Signatures --- p.72Chapter 6.1 --- Introduction --- p.72Chapter 6.2 --- The Construction --- p.74Chapter 6.3 --- Security Analysis --- p.76Chapter 6.3.1 --- Security Theorems --- p.76Chapter 6.3.2 --- Proofs --- p.77Chapter 6.4 --- Discussion --- p.79Chapter 6.5 --- Conclusion --- p.80Chapter 7 --- Applications --- p.82Chapter 7.1 --- Offline Anonymous Electronic Cash --- p.83Chapter 7.1.1 --- Introduction --- p.83Chapter 7.1.2 --- Construction --- p.84Chapter 7.2 --- Electronic Voting --- p.85Chapter 7.2.1 --- Introduction --- p.85Chapter 7.2.2 --- Construction . --- p.87Chapter 7.2.3 --- Discussions --- p.88Chapter 7.3 --- Anonymous Attestation --- p.89Chapter 7.3.1 --- Introduction --- p.89Chapter 7.3.2 --- Construction --- p.90Chapter 7.4 --- Conclusion --- p.91Chapter 8 --- Conclusion --- p.92A Paper Derivation --- p.94Bibliography --- p.9