The efficient signature in the smart card system

In this paper, we propose a new kind of efficient signature scheme that is the dual scheme of undeniable signatures. Also we construct a practical protocol that implements it using smart card. The new technique proposed in this paper achieves the following objectives: only the nominee can verify the nominator (signer)´s signature and if necessary, only nominee can prove to the third party that the signature is issued to him (her) and is valid. Contrary to the undeniable signature scheme, nominative signatures are confirmed via a protocol between the nominee and the third party, so the cooperation of the nominee is necessary. That is, not a signer (nominator) but verifier (nominee) can control the abuse of signatures. Undeniable signature cannot be verified without the cooperation of the signer, so the signer controls the abuse of signatures