Analysis of bilinear pairing-based accumulator for identity escrowing

An accumulator based on bilinear pairings was proposed at CT-RSA’05. In this paper, we first demonstrate that the security model proposed by Lan Nguyen does lead to a cryptographic accumulator which is not collision resistant. Second we show that we can provide collision-resistance by updating the adversary model appropriately. Finally, we propose an improvement on Nguyen’s identity escrow scheme with membership revocation based on the accumulator by removing the trusted third party.