A New ID-Based Deniable Ring Authentication with Constant-Size Signature

Ring signatures allow a signer in an ad-hoc group to authenticate a message on behalf of the group without revealing which member actually produced the signature.Deniable ring authentication allows a member of an ad-hoc sunset of participants to authenticate a message without revealing which member has issued the signature, and the verifier cannot convince any third party that message m was indeed authenticated. The size of the signature of most of the proposed deniable ring authentication schemes is dependent on the size of the ring which causes inefficiency especially when the size of the ring is large. In this paper, we show that the scheme with constant-size signature proposed in has some security problems by using an insecure accumulator. Then we propose a new id-based deniable ring authentication scheme with constant size signature which uses an improved accumulators on bilinear pairings.