Constant-size ID-based linkable and revocable-iff-linked ring signature

In this paper, we propose a new notion called Revocable-iff-Linked Ring Signature (R-iff-L Ring Signature). In R-iff-L ring signatures, a signer can sign on behalf of the whole group, just like ordinary ring signatures. However, if he signs twice or more, he can be linked and his identity can be revoked by everyone. We formally define a new security model for the new notion in identity-based (ID-based) setting and propose a constant-size ID-based construction, that is, the size of the signature is independent of the size of the group. In addition, we enhance the security model of ID-based linkable ring signature scheme and provide an implementation with constant size setting. Both schemes are provably secure in our new model.