1. In an electronic document processing system for transferring information back and forth between an electronic domain and a hardcopy domain; said system including computer means for operating upon and storing electronic document files in a machine readable format in said electronic domain, input scanner means coupled to said computer means for transforming information from hardcopy documents in said hardcopy domain to said electronic domain, and printer means coupled to said computer means for printing human readable renderings of selected ones of said files on hardcopy documents; the improvement comprising an interface means between said computer means and said printer means for encoding at least one attribute of each of said selected electronic document files in a machine readable code that said printer means prints on said hardcopy documents along with the human readable renderings of the respective files; said attribute of each file being content of said file that is defined in said electronic domain but not explicitly defined by the human readable rendering of said file that is printed by said printer means, whereby said attribute of each of said selected electronic document files is recoverable from the code printed on a corresponding hardcopy document when information carried by said corresponding hardcopy document is transformed from said hardcopy domain to said electronic domain, even when such an attribute is irrecoverable from the human readable rendering.
13. The improvement of claim 1 wherein the attributes encoded in said code enables such a computer means to authenticate scanned-in electronic domain representations of said renderings.