Alexandra Boldyreva Threshold Signatures, Multisignatures and Blind Signatures Based on the Gap-Diffie-Hellman-Group Signature Scheme. 31-46 2003 conf/pkc/2003 Public Key Cryptography http://link.springer.de/link/service/series/0558/bibs/2567/25670031.htm db/conf/pkc/pkc2003.html#Boldyreva03