Designated-verifier chameleon proxy signature

We construct a new chameleon hash scheme. In our hash function the owner of a public key doesn't need to retrieve the associated secret key. We prove that our new chameleon hash scheme satisfies all the attributes defined in [1] and our chameleon hash scheme is secure assuming Weak Computational Diffie-Hellman(WCDH) assumption is difficult. Moreover, we use the proposed chameleon hash function to design a designated-verifier ID-based chameleon proxy signature(DVICPS) scheme. In our signature scheme, only the receiver who owns the corresponding secret key can verify the validity of the signature which efficiently protects the benefit of the verifier We also prove our signature scheme is secure in random oracle model. The difficulty of forging our DVICPS scheme is equivalent. to solving Computational Diffie-Hellman Problem(CDHP).