Efficient fair digital-signature exchange based on misbehaviour penalisation

A protocol is presented for the fair digital-signature exchange commonly seen in e-commerce systems. The protocol incorporates a novel approach for the recovery of a signature with the assistance of an offline trusted third party that can impose a penalty on a misbehaving party. This new approach enables the protocol to achieve fairness in a simpler and more efficient manner than other relevant fair exchange protocols, while being able to deter a dishonest party from misbehaving.