Abstract: A revocable anonymous ecash scheme from group signature added a one time tag was presented in this paper. In the scheme the bank acts as the group manager but just issues certificates, i.e. coins, to customers who become the group members when they withdraw coins from bank, and there is a trustee whose duty is revoking the anonymity of the coins. Ateniese et al's group signature scheme was used in the proposed scheme. Owing to the properties of the group signature scheme, the scheme can meet most demands of ecash schemes and have a high efficiency.

Key words: Ecash, revocable anonymity, group signature, against bank stealing coins