Fair offline digital content transaction system

More and more customers are purchasing digital content through the Internet because it is both popular and convenient. However, there are lots of pirated editions of digital products and they have become more available and easier to obtain. Hence, proving who the legal owner of digital content has become an important issue. In this study, the authors want to preserve customer ownership; they propose an intact arbitration mechanism to solve the fairness transaction between the customer and the shop. The arbiter can make correct judgements without the customer´s and the shop´s private keys in the arbitration phase. In order to achieve the above objectives, the security of this protocol is based on three cryptographic techniques: the subliminal channel, one-way hash function and RSA cryptosystem. Our scheme not only protects a customer´s legal ownership of digital content, but also achieves fair transaction, customer anonymity, owner tracing of E-cash and payment security.