Breaking a certificateless strong designated verifier signature scheme

As a special signature, certificateless strong designated verifier scheme is a combination of certificateless cryptography with designated verifier scheme. Recently, Xiao et al gave a certificateless strong designated verifier scheme. In the paper, we analyze Xiao et al signature scheme and show that the scheme is insecure. Then We give the corresponding attack based on your analysis above and the reason to produce such attack. Finally, the improved scheme is given, electronic document is a "live" template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document.