A trust evaluation framework exposes a common interface that may be used by file transfer clients in the process of retrieving or downloading a file. Using the common interface, each file transfer client can take advantage of multiple trust providers to evaluate the incoming file. In this way, disparate file transfer clients can present a common user experience for downloading or retrieving files. In addition, trust providers may be updated or added to the system without modifying the installed file transfer clients. This enables the user experience to be incrementally improved without updating the installed programs.