ID-based blind signature and proxy blind signature without trusted PKG

Abstract

Private key escrow is an inherent disadvantage for ID-based cryptosystem, i.e., the PKG knows each signer's private key and can forge the signature of any signer. Blind signature plays a central role in electronic cash system. Private key escrow is more severe in electronic cash system since money is directly involved. To avoid the key escrow problem, we propose an ID-based blind signature and proxy blind signature without trusted PKG. If the dishonest PKG impersonates an honest signer to sign a document, the signer can provide a proof to convince that the PKG is dishonest. © 2008 Springer-Verlag.