A method for mediator identification using queued history of encrypted user information in an incentive attached peer to peer electronic coupon system

An incentive attached peer to peer (P2P) electronic coupon system is proposed in which users forward e-coupons to potential users by providing incentives to mediators. A service provider needs to acquire distribution history by recording it in the e-coupons, since this system is intended for pure P2P communication. This causes problems of dishonestly altering the distribution history. To solve such problems, distribution history is realized in a queue structure. Each element at the initial state consists of dummy UIDs, a secret key, and a digital signature. In recording one's UID, the encrypted UID is enqueued to the queue with a hash value of a dummy UID in the dequeued element, so that malicious users cannot impersonate it. Additionally, a public key queue is applied to generate digital signatures on mobile devices. The availability of the proposed method is evaluated by quantifying risk reduction effects using fault tree analysis (FTA).