supported by the National Natural Science Foundation of China(Grants Nos.60225007 and 60572155);the National Research Fund for the Doctoral Program of Higher Education of China(Grant No.20020248024);the Science and Technology Research Project of Shanghai(Grant Nos.04JC14055 and 04DZ07067).
Threshold digital signature and blind signature are playing important roles in cryptography as well as in practical applications such as e-cash and e-voting systems. Over the past few years, many cryptographic researc...