A short redactable signature scheme using pairing

Abstract

ABSTRACTRedactable signature schemes permit deletion of arbitrary substrings of a signed document while preserving the authenticity of the remaining document. Most of known redactable signatures based on pairing have large‐sized signatures and the sizes depend on the product of security parameter and the number of blocks of the redacted document. In this paper, we present a short redactable signature scheme based on pairing. We modify Waters signature scheme to obtain an underlying standard signature defined on composite‐order bilinear group. The modified scheme satisfies the unforgeability under the known message attack based on the Computational Diffie–Hellman assumption. Based on the modified Waters signature, we propose a short redactable signature that is existentially unforgeable under random message attack and weakly private. The size of the proposed scheme is 20% of known redactable signatures using aggregated pairing‐based signatures when half of the message blocks are deleted. Copyright © 2011 John Wiley & Sons, Ltd.