Abstract:This paper proposes an efficient verifiably encrypted signature scheme without random oracles. The scheme is constructed from the recent Gentry signature and can be rigorously proven to be secure in the standardmodel. The scheme has several advantages over previous systems such as, shorter public keys, lower computationoverhead, and a tighter security reduction, therefore, it is a truly practical verifiably encrypted signature withoutrandom oracles, which can be used in online contract signing protocols. Additionally, the proof of our scheme,which depends on the Strong Diffie-Hellman assumption, may be of independent interest.