A convertible limited verifier signature scheme

In some cases, it is not necessary for anyone to be convinced a justification of signer's signature. Motivated by the above case, in this work we propose a provably secure convertible limited verifier signature scheme which based on the CDH assumption and the difficulty of solving inverse of hash function, and a prominent property of the scheme is that only the limited verifier can independently convert the limited verifier signature into the ordinary signature in the conversion phase, the original signer cannot convert signature instead of the limited verifier. The limited verifier signature schemes available have not this property. To the best of my knowledge, it seems to be first provably secure convertible limited verifier signature scheme without using random oracle model.