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.