Multi-policy threshold signature with distinguished signing authorities

Threshold signature plays an important role to distribute the power of a single authority in modern electronic society. In order to add functions and improve efficiency of threshold signatures, a multi-policy threshold signature scheme with distinguished signing authorities is proposed. In the scheme two groups can sign and verify each other, so the scheme is two-way signing and verifying. Moreover, the threshold values of the two groups can change with the security classification of the signing document, every discretionary signatory only signs a small part of the document instead of the whole one, so the bandwidth of data transmission for group signature construction can be reduced and the size of group signature is equivalent to that of any individual signature.