Linkability analysis of some blind signature schemes

Blind signature allows a user to obtain signatures from an authority on any document, in such a way that the authority learns nothing about the message that is being signed. The blindness is an important property which distinguishes the blind signature from other signature schemes. In this work, we analyze security of two ID-based blind signature schemes [4, 7] and a blind signature scheme. [5] based on witness indistinguishable signature, and show that the they don't satisfy blindness. It means that the three blind signature schemes are insecure.