Proxy signature is a special signature, it allows an original signer to delegate her signing capability to a proxy signer and
the proxy signer can produce a signature on behalf of the original signer. At present, most of proxy signature in essence
consists of two signatures. To overcome the problem, we propose a short efficient proxy signature scheme based on a
certificateless signature scheme. And we show that the proposed scheme is secure in the random oracle model. The
security of the scheme is related to Inverse Computational Diffie-Hellman Problem and the k-CCA problem. Comparison
with Huang et.al scheme, our scheme has an advantage over Huang et.al's scheme in terms of the size of proxy signature.
Since the length of proxy signature in our scheme is 160bit, it is very suitable for mobile devices.