International Journal of
Information and Education Technology

Abstract—Many identity-based public key cryptosystems from bilinear pairings use hash functions to construct their public keys. Most of these schemes only specify the need of applying cryptographic strong or collision free hash functions, without giving any detail of which or what hash functions should be used. Traditional understanding of a cryptographic strong hash function has three security properties, which are pre-image resistance, second pre-image resistance and collision resistance. However, with only these three properties, in this paper we show a potential security vulnerability of identity-based cryptographic cryptosystems if the hash functions used are not correctly constructed. To fix this vulnerability, this paper defines an additional desirable security property for the hash functions in these identity-based cryptosystems.

Index Terms—Public key cryptosystems, identity-based cryptosystems, cryptographic strong hash functions, bilinear pairings.

Jyh-Haw Yeh is with the Department of Computer Science, Boise State University, Boise, ID 83725, USA (e-mail: jhyeh@ boisestate.edu).

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Cite:Jyh-Haw Yeh, "Security Vulnerability in Identity-Based Public Key Cryptosystems from Pairings," International Journal of Information and Education Technology vol. 3, no. 4, pp. 466-470, 2013.