An Improved Threshold Ring Signature Scheme Based on Error Correcting Codes

The concept of threshold ring signature in code-based cryptography was introduced by Aguilar et al. in [1]. Their proposal uses Stern’s identification scheme as basis. In this paper we construct a novel threshold ring signature scheme built on the q-SD identification scheme recently proposed by Cayrel et al. in [14]. Our proposed scheme benefits of a performance gain as a result of the reduction in the soundness error from 2/3 for Stern’s scheme to 1/2 per round for the q-SD scheme. Our threshold ring signature scheme uses random linear codes over the field Fq, secure in the random oracle model and its security relies on the hardness of an error-correcting codes problem (namely the q-ary syndrome decoding problem). In this paper we also provide implementation results of the Aguilar et al. scheme and our proposal, this is the first efficient implementation of this type of code-based schemes.