Automated trust negotiation is an approach to establishing trust across security domains in a dynamic coalition in real time. This is accomplished through the use of access control policies that specify what combinations of digital credentials a stranger must disclose to gain access to a coalition resource. TrustBuilder, a system for negotiating trust in dynamic coalitions, is being designed and implemented in the Internet Security Research Lab at Brigham Young University. The TrustBuilder architecture incorporates trust negotiation into standard network technologies. This paper describes the technology in the current TrustBuilder prototype.