Secure ID-based linkable and revocable-iff-linked ring signature with constant-size construction

In this paper, we propose a new ID-based event-oriented linkable ring signature scheme, with an option as revocable-iff-linked. With this option, if a user generates two linkable ring signatures in the same event, everyone can compute his identity from these two signatures. We are the first in the literature to propose such a secure construction in an ID-based setting. Even compared with other existing non ID-based schemes, we enjoy significant efficiency improvement, including constant signature size and linking complexity. Our scheme can be also regarded as a normal ID-based ring signature. We are also the first to propose such a scheme with constant signature size and enhanced privacy, namely the signer is anonymous even to the PKG who has the master secret key. We prove the security