From Selective-ID to Full-ID IBS without Random Oracles

Chatterjee, Sanjit and Kamath, Chethan (2013) From Selective-ID to Full-ID IBS without Random Oracles. In: 3rd International Conference on Security, Privacy, and Applied Cryptography Engineering (SPACE), OCT 19-23, 2013, Indian Inst Technol Kharagpur, Kharagpur, INDIA, pp. 172-190.

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Abstract

Since its induction, the selective-identity (sID) model for identity-based cryptosystems and its relationship with various other notions of security has been extensively studied. As a result, it is a general consensus that the sID model is much weaker than the full-identity (ID) model. In this paper, we study the sID model for the particular case of identity-based signatures (IBS). The main focus is on the problem of constructing an ID-secure IBS given an sID-secure IBS without using random oracles-the so-called standard model-and with reasonable security degradation. We accomplish this by devising a generic construction which uses as black-box: i) a chameleon hash function and ii) a weakly-secure public-key signature. We argue that the resulting IBS is ID-secure but with a tightness gap of O(q(s)), where q(s) is the upper bound on the number of signature queries that the adversary is allowed to make. To the best of our knowledge, this is the first attempt at such a generic construction.

Item Type:	Conference Proceedings
Series.:	Lecture Notes in Computer Science
Additional Information:	Copy right for this article belongs to the SPRINGER-VERLAG BERLIN, HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY
Department/Centre:	Division of Electrical Sciences > Computer Science & Automation
Date Deposited:	18 Sep 2014 09:12
Last Modified:	18 Sep 2014 09:12
URI:	http://eprints.iisc.ac.in/id/eprint/49912

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