In a history-based trust-management system, users and service providers use information about past transactions to make trust-based decisions concerning current transactions. One category of such systems is represented by the reputation systems. However, despite the growing body of experience in building reputation systems, there are several limitations on how they are typically implemented. They often rely on scores that are evaluated by service providers and are often not reliable or well understood. We believe that reputation has to be based on objective and reliable information. In such context, transaction histories play an important role. In this paper, we present the VeryIDX system that implements an electronic receipt infrastructure and supports protocols to build and manage online transaction history of users. The receipt protocols are shown to have several essential security and privacy properties. We present a basic yet reasonably expressive language which provides service ...