Based on the assumption that the customer is time and price sensitive and price is a piecewise function of the delivery time, a service delivery time guarantee decision model is proposed, and the existence of the optimal service delivery time guarantee L^＊ is proved. Furthermore, the impact of the correlation parameters on the optimal L^＊ is analyzed. It is revealed that if the optimal L^＊ is smaller than the industry level L0, the service provider with low cost should quote a shorter delivery time, and the service provider should increase the delivery time guarantee under the conditions of the decrease in customer time sensitivity or the increase in the difference of the customer reservation payment. When L^＊ 〉 L0, the service provider should quote a longer delivery time guarantee and should increase the delivery time guarantee and reduce the price under the conditions of the increase in the customer price sensitivity or the decrease in the mean customer reservation payment.
The development and deployment of privary preserving supply chain quantity discount contract design can allow supply chain collaborations to take place without revealing any participant＇s data to others, reaping the benefits of collaborations wbile avoiding the drawbacks of privacy information disclosure. First, secure multi-party computation protocols are applied in the joint-ordering policy between a single supplier and a single retailer, the joint-ordering policy can be conducted without disclosing private cost information of any of the other supply chain partners. Secondly, secure multi-party computation protocols are applied in the privacy preserving supply chain quantity discount contract design between a single supplier and a single retailer. The information disclosure analyses of the algorithm show that： the optimal quantity discount of the jointordering policy can be conducted without disclosing private cost information of any of the other supply chain partners; the above protocol can be implemented without mediators; the privacy preserving quantity discount algorithm can be mutually verifiable and has solved the problem of asymmetric information.
