Concurrent signature protocol on conic curve over ring Zn

The proposing of concurrent signatures makes it the truly fairness to both participants. Compared with the finite field, conic curves have advantages of embedding plaintext ´conveniently, easy points operating, and fast in speed etc. Based on these superiorities of the conic curves, a new concurrent signature protocol on conic curve over ring Z_n is proposed in this paper. It has higher efficiency than the one proposed by Chen L. Furthermore, the scheme is also based on the large number factorization and discrete logarithm in conic curves, so it has the same security.