Even in this age of the Internet, the fax machine has remained an indispensable means of
communication because of its speed, simplicity and reliability. Faxes are also virtually
unequalled when it comes to sending documents in a manner which is legally binding or
which preserves their legal character. However, phone and fax communication is easy to
tap. If one has sensitive information to fax, you must encrypt it to protect it from the
interfering eyes of others.
This paper describes a system of exchanging encrypted documents (text or images)
through fax machines based on the highest cryptographic standards. It was found that the
encrypted images were affected by electronic and computation noise rather than text
documents, when they were exchanged through fax machines by 27%. However, this
percentage was decreased to 3% when the restored images passed on an average weighted
filter of size 3x3 elements.
The presented system was tested experimentally and its performance was found to
be in average about 95%. The 5% off was attributed to the effect of electronic and
computation noise and the capability of the Optical Character Recognitions (OCR). Thus
this technology enhances the security of documents that have been printed and makes
possible new services and solutions for preventing information from being leaked from
printed material.