1. A file transfer system configured to transfer files from an un-trusted computer system to a trusted computer system, the file transfer system comprising: volatile memory; and a processing system configured to: load a file from the un-trusted computer system into the volatile memory; if the file is a text file, convert the text file to a converted file comprising a marked-up version of the text file using a markup language; apply information-invariant data transformation (IIDT) operations to the converted file in the volatile memory, the IIDT operations comprising redacting metadata from the converted file and applying a random steganography operation to the converted file, the random steganography operation comprising: generating entropy for seeding a random data generator, the entropy generated by recording environmental noise associated with the un-trusted computer; generating random data for one or more comments based on the generated entropy, the random data comprising random characters, the one or more comments having a random length; formatting the one or more comments in the markup language of the converted file; and inserting the one or more comments at random locations within the converted file; and make the transformed file available in a persistent storage that is accessible by the trusted computer system.