We introduce SCENS, a secure content exchange negotiation system suitable for the exchange of private digital data that reside in distributed digital repositories. SCENS is an open negotiation system with flexibility, security and scalability. SCENS is currently being designed to support data sharing in scientific research, by providing incentives and goals specific to a research community. However, it can easily be extended to apply to other communities, such as government, commercial and other types of exchanges. It is a trusted third party software infrastructure enabling independent entities to interact and conduct multiple forms of negotiation.