Delegatable proof of knowledge systems

In this paper, we propose the concept of delegatable proofs of knowledge (DPoK). A delegatable proof of knowledge enables a prover to delegate its proving work to another party instead of doing that itself. If the prover delegates the work to any party, the delegated party can prove the prover's statement to the verifier, however, it cannot compute the prover's secret. We present the concrete example of DPoK proven secure in the standard model.