A proxy blind signature scheme and an off-line electronic cash scheme

To support withdrawing and storing money from all levels of the bank for the customers in the real world, in this paper, we propose a proxy blind signature scheme and an off-line e-cash scheme based on the new proxy blind signature scheme. The proposed proxy blind signature is proven secure in the random oracle model under chosen-target computational Diffie-Hellman assumptions, and the e-cash scheme can satisfy the security requirements of unforgeability, anonymity, and traceability.