Abstract: A new ID-based threshold signature scheme is proposed from bilinear pairings, based on our improved ID-based signautre scheme. In our ID-based threshold signature scheme, the dishonest Private Key Generator (PKG) can not impersonate any user at any time. We show that it is secure against existential forgeable on adaptively chosen message and ID attack under the random oracle. Compared with the previous scheme, it is shorter and more efficient with the same security.

Key words: ID-based signature, ID-based threshold signature, computation Diffie-Hellman problem, bilinear parings