Yong Li 0002 Non-interactive Designated Confirmer Signature with Specific Verifier. 635-640 2007 SNPD (3) http://doi.ieeecomputersociety.org/10.1109/SNPD.2007.387 conf/snpd/2007 db/conf/snpd/snpd2007-3.html#Li07d