Privacy and security has been considered as the top criterion for the acceptance of e-service adoption. In this paper, we proposed a privacy aware identity protection design that improves the flaw in cheap pseudonym design under the limitation of ambient e-service environment. This design is being applied to a collaborative iTrust platform for ambient e-service, a new scope of mobile ad-hoc e-service. The collaborative iTrust platform highlights the collaborative power from nearby user groups to eliminate potential risk and provide appropriate estimation for trust decision in the ubiquitous environment.