The paper introduces the concept of designated verifier proofs, which allow only the specified verifier to be convinced of the correctness of a proof. This is particularly useful in scenarios where authentication and privacy must coexist, such as in undeniable signatures. The authors demonstrate how trap-door commitments can be used to construct designated verifier proofs, both interactive and non-interactive. They provide examples of how this can be applied to the confirmation protocol for undeniable signatures and show that it can also be extended to multiple designated verifiers. The paper discusses practical issues and concludes by highlighting the importance of ensuring that only the designated verifier can simulate identically distributed transcripts.The paper introduces the concept of designated verifier proofs, which allow only the specified verifier to be convinced of the correctness of a proof. This is particularly useful in scenarios where authentication and privacy must coexist, such as in undeniable signatures. The authors demonstrate how trap-door commitments can be used to construct designated verifier proofs, both interactive and non-interactive. They provide examples of how this can be applied to the confirmation protocol for undeniable signatures and show that it can also be extended to multiple designated verifiers. The paper discusses practical issues and concludes by highlighting the importance of ensuring that only the designated verifier can simulate identically distributed transcripts.