ID-based Ring Signature and Proxy Ring Signature Schemes from Bilinear Pairings

In 2001, Rivest et al. firstly introduced the concept of ring signatures. A ring signature is a simplified group signature without any manager. It protects the anonymity of a signer. The first scheme proposed by Rivest et al. was based on RSA cryptosystem and certificate based public key setting. The first ring signature scheme based on DLP was proposed by Abe, Ohkubo, and Suzuki. Their scheme is also based on the general certificate-based public key setting too. In 2002, Zhang and Kim proposed a new ID-based ring signature scheme using pairings. Later Lin and Wu proposed a more efficient ID-based ring signature scheme. Both these schemes have some inconsistency in computational aspect. In this paper we propose a new ID-based ring signature scheme and a proxy ring signature scheme. Both the schemes are more efficient than existing one. These schemes also take care of the inconsistencies in above two schemes.Comment: Published with ePrint Archiv

Non-conventional digital signatures and their implementations – A review

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-19713-5_36The current technological scenario determines a profileration of trust domains, which are usually defined by validating the digital identity linked to each user. This validation entails critical assumptions about the way users’ privacy is handled, and this calls for new methods to construct and treat digital identities. Considering cryptography, identity management has been constructed and managed through conventional digital signatures. Nowadays, new types of digital signatures are required, and this transition should be guided by rigorous evaluation of the theoretical basis, but also by the selection of properly verified software means. This latter point is the core of this paper. We analyse the main non-conventional digital signatures that could endorse an adequate tradeoff betweeen security and privacy. This discussion is focused on practical software solutions that are already implemented and available online. The goal is to help security system designers to discern identity management functionalities through standard cryptographic software libraries.This work was supported by Comunidad de Madrid (Spain) under the project S2013/ICE-3095-CM (CIBERDINE) and the Spanish Government project TIN2010-19607

Identity-Based Blind Signature Scheme with Message Recovery

Blind signature allows a user to obtain a signature on a message without revealing anything about the message to the signer. Blind signatures play an important role in many real world applications such as e-voting, e-cash system where anonymity is of great concern. Due to the rapid growth in popularity of both wireless communications and mobile devices, the design of secure schemes with low-bandwidth capability is an important research issue. In this paper, we present a new blind signature scheme with message recovery in the ID-based setting using bilinear pairings over elliptic curves. The proposed scheme is unforgeable with the assumption that the Computational Diffie-Hellman problem is hard. We compare our scheme with the related schemes in terms of computational and communicational point of view

Insecurity of a Certificate-free Ad Hoc Anonymous Authentication

Abstract The ring signature scheme is a simplified group signature scheme for no manager while preserving unconditionally anonymous of the signer. Certificateless cryptography is introduced for eliminating the use of certificates in Public Key Infrastructure and solving the key-escrow problem in ID-based cryptogratography. Recently, Qin et al. proposed the first RSA-based certificateless ring signature scheme which was proved unforgeable in random oracle model. In this paper, we demonstrated that this scheme was not secure against the Type I adversary

A Biometric Identity Based Signature Scheme

We describe an identity based signature scheme that uses biometric information to construct the public key. Such a scheme would be beneficial in a legal dispute over whether a contract had been signed or not by a user. A biometric reading provided by the alleged signer would be enough to verify the signature. We make use of Fuzzy extractors to generate a key string from a biometric measurement. We use this biometric based key string and an elliptic curve point embedding technique to create the public key and corresponding private key. We then make use of a pairing based signature scheme to perform signing and verification with these keys. We describe a possible attack on this system and suggest ways to combat it. Finally we describe how such a biometric signature scheme can be developed by reusing existing components in our Java Identity Based Encryption implementation. The design allows traditional as well as biometric identity based signatures

Controlled secret leakage

How to leak authoritative secrets in an elegant way? The paper aims to solve this problem. The desired security properties i.e. Semantic-Security; Recipient-Designation; Verification-Dependence; Designated-Verifier Signature-Verifiability; Public Signature-Verifiability; Recipient-Ambiguity; Designated-Verifier Recipient-Verifiability; Public Recipient-Verifiability; Signer-Ambiguity; Signer- Verifiability are specified in secret leakage. Based on Chow-Yiu-Hui's ID-based ring signature scheme and techniques of zero-knowledge proof, an ID-based controlled secret leakage scheme is proposed. The proposed scheme satisfies all specified security properties and can be used in trust negotiation