In practice, collaborative processes using web services present complex information security requirements, as a domain security model needs to conditionally control access to data and services by both internal and external collaboration participants. One embodiment presents an automated process for defining required trust relationships between collaboration participants that can be used for materializing domain IT policies. A BPMN choreography process model of a business process is parsed to extract participant and task lists. An initiating participant is identified for each task in the task list. A trust graph (can be represented in a matrix format) is generated to represent trust relationships implicit in the business process model by indicating in the trust graph that all other participants in a given task are to trust the initiating participant of that task. A registry can be used to gather data used to materialize security policies based on the trust relationships.