A method of securely transferring files from an un-trusted to a trusted network is disclosed. A file that is an archive file of many component files is separated into constituent files. Each file is stored on a server connected to an un-trusted network, and a series of initial checks, such as virus, file size, and file extension are performed. If the files pass, additional, file format specific security rules are applied. An open format transform is performed on proprietary format type files, and embedded file components are separated out. A user-definable security rule set is performed on each open format transform component. If all security tests pass, the file is reassembled and saved as a trusted file in the same format as the original file.