Browse Prior Art Database

Distributed Steganography

IP.com Disclosure Number: IPCOM000204600D
Publication Date: 2011-Mar-05
Document File: 8 page(s) / 275K

Publishing Venue

The IP.com Prior Art Database

Abstract

Hiding messages is a key element in clandestine communications. However steganography has become more widely known and it is not uncommon for people to use forensics tools to scan images (and other media) for hidden messages. By breaking up the message and hiding it in several, diverse locations, it makes discovering the message much more difficult for third parties. The primary novelty in this process lies not only in the distribution of the steganographically hidden message/file, but in providing multiple alternative methods for locating and retrieving the various fragments/blocks that constitute the hidden message/file. This is ideal for clandestine communications such as those used by intelligence agencies and even undercover law enforcement agents. Messages could be spread across videos, music files, an innocuous images stored in various places around the internet until retrieved.

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Distributed Steganography

Background

Steganography refers to any methodology used to hide a message (including text, sound, or picture) in a separate file. Most commonly text or an image is inserted into another image. However there are permutations where video is hidden in another video, or sound in sound or even sound in video. The image/sound/video that the underlying message is hidden in is referred to as a carrier or cover file or signal.

The most common method is to use the least significant bits of an image to store data. For example in a high resolution graphics file, each pixel is represented by 24 bits. By using the least significant (i.e. the last 1 or 2 bits) to store other data, the image is not compromised and data is hidden in the image.

Specialized tools exist, including free software available on the internet, to insert a text or image into a carrier image.

There have been modifications to the underlying technique, such as these:

Patent 6,557,103 B1 Spread Spectrum Steganography. This patent is primarily concerned with hiding an image/text within another image so that errors are minimal and detection of the image is more difficult.

Patent 7,242,790 Video Steganography. The purpose of this invention is to hide some signal in a video transmission.

Patent 6,266,430 B1Audio or Video Steganography. In this invention two signals (the message and the carrier) are combined to form a new signal. This invention also includes calibration data to facilitate adding and retrieving the hidden signal.

Patent 6,211,849 Encryption Based Selection System for Steganography. The purpose of this invention is to integrate encryption with steganography.

Discussion

The purpose of steganography, regardless of the implementation, is to hide some underlying message so that an observer is not even aware the message is present. This is very useful in covert communications, particularly in the intelligence community.

Most permutations of steganography deal with how to embed the message (text, image, video, or audio) into the carrier file. Some permutations, such as SNOW, even use blanks at the end of text files in order to hide messages. However this process is concerned with


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how to fragment the message and hide it in various carrier/cover files making the detection of the entire message extremely difficult, approaching impossibility.

In this process the message is distributed across multiple carrier signals/sources in order to further hide the message. For example a single text message would be broken into blocks, each block hidden in a different image. Another aspect if this process is that the block size can vary and the blocks are not necessarily stored in order. This means that the first carrier file will not necessarily hold the first segment of the hidden message/file. This is applying permutation to the blocks. It should be noted that many cryptographic algorithms employee permutation along with substitution in order to en...