Code-based Ring Signature Scheme

McEliece is one of the oldest known public key cryptosystems, however it was not quite as successful as RSA. One main reason is that it is widely believed that code-based cryptosystems like McEliece do not allow practical digital signatures. Although X.M. Wang presented a code-based signature scheme in 1990, some authors find that it is not secure. Recently, T.Courtois et al. show a new way to build a practical signature scheme based on coding theory (simply, Courtois et al.s scheme). The security is reduced to the well-known syndrome decoding problem and the distinguishability of permuted binary Goppa codes from a random code. This shows that error correct codes can be used to construct some other cryptosystems. In this paper, we present, for the first time, a code-based ring signature scheme with signature length of 144+ 126l bits (l is the number of ring members), which is one of the most short ring signature among all the presented ring signature schemes up to now.