A New Certificateless Electronic Cash Scheme with Multiple Banks Based on Group Signatures

Most of the proposed E-cash systems require that the shop and customer belong to the same bank, which becomes the bottle-neck of E-cashpsilas wide application. Fangguo Zhang et al. proposed a model of electronic cash using multi-banks, but a trusted third party is needed in their system. To solve this problem, we propose a new electronic cash scheme based on group signature from bilinear pairings. In the new scheme, the shop and customer need not belong to the same bank, and a trusted third party is not needed. The identity based public key cryptosystem is used, the KGC (key generator center, or central bank) can only control partial private key of the customer, the customer known all private key of himself, so the private key escrow problem in the identity based public key cryptosystem is solved in the system. As the scheme is certificateless, the management and maintenance of the public key is much simplified.