An enhanced constant-size identity-based ring signature scheme

The ring signature can guarantee the signer´s anonymity. Most proposed ring signature schemes have the problem that the size of ring signature depends linearly on the ring size. Some authors have studied the constant-size ring signature. This paper shows that an identity-based ring signature scheme with constant size has some security problems by using an insecure accumulator and its verification process does not include the message m. A new constant-size id-based ring signature scheme is proposed based on bilinear pairings and improved accumulators.