Cryptology ePrint Archive: Report 2005/326

A Suite of ID-Based Threshold Ring Signature Schemes with Different Levels of Anonymity

Man Ho Au and Joseph K. Liu and Patrick P. Tsang and Duncan S. Wong

Abstract: Since the introduction of Identity-based (ID-based) cryptography by Shamir in 1984, numerous ID-based signature schemes have been proposed. In 2001, Rivest et al. introduced ring signature that provides irrevocable signer anonymity and spontaneous group formation. In recent years, ID-based ring signature schemes have been proposed and all of them are based on bilinear pairings. In this paper, we propose the first ID-based threshold ring signature scheme that is not based on bilinear pairings. We also propose the first ID-based threshold `linkable' ring signature scheme. We emphasize that the anonymity of the actual signers is maintained even against the private key generator (PKG) of the ID-based system. Finally we show how to add identity escrow to the two schemes. Due to the different levels of signer anonymity they support, the schemes proposed in this paper actually form a suite of ID-based threshold ring signature schemes which is applicable to many real-world applications with varied anonymity requirements.

Category / Keywords: public-key cryptography / ID-Based Cryptography, Ring Signature, Anonymity, Linkability

Date: received 14 Sep 2005, last revised 15 Nov 2005

Contact author: liu at cs bris ac uk

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Version: 20051115:175415 (All versions of this report)

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