1. A method of creating a secure application environment in a computer system comprising at least one resource the access to which is governed by a user account, the method comprising: determining if the at least one resource is within the secure application environment; and, if the at least one resource is within the secure application environment, determining a transformation rule for the at least one resource based on the user account; and handling a request to access the at least one resource in accordance with the transformation rule for the at least one resource.