Headstega: e-mail-headers-based steganography methodology

Abstract

The frequent exchange of e-mails is widely popular and generates a high volume of traffic that allows communicating parties to establish a covert channel without a suspicious pattern rendering e-mails an attractive steganographic carrier to transmit hidden messages. This was the motive of developing e-mail-headers-based steganography methodology (Headstega). Headstega encodes a message then assigns it to steganographic carriers (e-mail-headers), e.g. recipient's e-mail addresses, names, subject fields, etc., in order to camouflage data by following Nostega paradigm. Thus, Headstega neither hides data in a noise (errors) nor produces noise while a message is concealed in the textual e-mail headers and the e-mail contents (the body of e-mails) are completely legitimate and do not conceal data. The presented implementation, validation and steganalysis of Headstega demonstrate: the robust capabilities of achieving the steganographic goal, the adequate room for concealing data and the superior bitrate to all contemporary text steganography approaches, which is roughly 3.38 7.67%.