Price negotiation is an important aspect of supply chain transactions. This paper considers a specific scenario wherein a supplier negotiates with a group of buyers. We present two privacy preserving price negotiation protocols integrating the concepts of secure multi-party computation and supply chain management. The first protocol is useful for discriminatory pricing based supply chain transactions; different buyers pay different prices to a supplier. The scheme does not use any mediator. The second protocol is useful for non-discriminatory pricing based transactions; the buyers pay the same unit price to the supplier. Both the protocols preserve the privacy of the buyers and the supplier regarding their inputs i.e. demand and capacity allocation model respectively. The concept given by Atallah et al. (2003) forms the basis of our work. The design of such type of protocols is useful for several applications - supply chain interaction and price negotiation in electronic market (e.g. auction, reverse auction and exchange).

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