The Art and Science of Steganography - Research Paper Example

? Steganography This research examines the art and science of steganography. The history, modern applications, and enhancements are examined. The research establishes that while the term steganography dates to 16th century, the process of concealing messages has been in practice since at least Greek antiquity. World War II is demonstrated as marking a period of significant development for steganography as all major powers implemented these techniques. Vietnam again contained a number of seminal uses of steganography, with a prisoner even spelling out messages in Morse code with his eyes. The modern era of steganography is witnessed with the development of digital techniques in the late 20th century. Finally, the digital era of steganography is demonstrated to have greatly expanded the reach and complexity of these practices through visual, audio, and programming techniques. Table of Contents Introduction……………………………………………………………………………....4 Background…………………………………………………………………………...….4 Modern Incarnations………………………………………………………………………………9 Concerns with Terrorist………………………………………………………………………………....10 Miscellaneous Uses………………………………………………………………………………………12 Conclusion………………………………………………………………………………13 References……………………………………………………………………………….14 Introduction Steganography is the art and science of constructing hidden messages in a way that nobody but the sender and receiver can sense its existence. While steganography was implemented to crucial importance in the 20th century, particularly in World War II, the process itself has been in practice since antiquity. Still, it wasn’t until the Renaissance period when steganography became a recognized term. In 1499 Johannes Trithemius wrote ‘Stegnographia: the art through which writing is hidden requiring recovery by the minds of men,’ a treatise on cryptography and steganography that was disguised as a book on magic (Sing, p. 10). Stenography takes on a variety of forms. Most prominently perhaps are forms of steganography that transfer one form of text to a cover-text. Still, steganography also includes messages that are transferred to images, articles, or even invisible ink. Steganography has often been confused with cryptography. The difference between these two forms, however, is that steganography is the concealment of a message, whereas cryptography is the writing of a message into code (Murphy, p. iv). The obvious advantage of steganography over cryptography is that the latter, because of its eccentric style, draws attention to its existence; conversely steganography is a more subtle form of communication. Steganography is an expansive discipline that throughout history has made a considerable impact on the world. This research essay examines the history of steganography, its various uses and dimensions, and a variety of ways that it has been enhanced over the years. Background As noted the earliest use of the term steganography was implemented by Johannes Trithemius. Trithemius was a German Abbot who lived between 1462 and 1516. His text ‘Stegnographia: the art through which writing is hidden requiring recovery by the minds of men’ was a three part tome. The first two parts are today recognized as some of the earliest books written on cryptography. The third part is ostensibly a book written on occult astrology. This third book contains a number of obscure tables containing numbers. In the late 20th century two researchers at the University of Pittsburgh – Thomas Ernst and Jim Reeds – became convinced that these tables of numbers were actually secret code. They began researching the text and uncovered a number of hidden phrases. Among these phrases include, “The quick brown fox jumps over the porch,” and “The bearer of this letter is honorable. Guard yourself against him. He wants to do something to you” (Singh, p. 10) While the messages were frivolous in nature, Trithemius’ text was highly significant as from it the term steganography develops. While Trithemius’ text provided the moniker steganography, the practice itself had been in existence long before he wrote his book. In the United Kingdom there is the recognition that Mary Queen of Scots implemented both cryptography and steganography to write her letters. Notably she concealed her letters in the bunghole of a beer barrel, allowing her to successfully pass letters in and out of prison. While Mary Queen of Scots constitutes an early use of steganography in writing there are early uses in other forms. One considers the geoglyphs in Nazca Peru. These are seen in Fig. 1 below. While these geoglyphs are open to public view, it was not until many years later that the messages they contain were detected through air. Fig. 1. Nazca Peru Geoglyphs Another early implementation of steganography can be witnessed in Greek antiquity. During the 5th century BC Histaiacus implemented steganography with actual humans. Specifically, messages were shaved into the head of a messenger that encouraged Aristagoras of Miletus to revolt against the king of Persia. The process occurred as after the message was shaved, the person waited until their hair grew back to allow its concealment. They were then dispatched with the message. Another frequent occurrence of steganography in Greek antiquity occurred with silk. The message would be written on silk, it would then be covered with wax, and swallowed by the messenger. The individual would then vomit or defecate the wax ball and uncover the message. Still another form of steganography used in Greek antiquity occurred in 480 BC when Demaratus sent a message to the Spartans. The message specifically warned again the upcoming invasion by Xerxes. The process of concealing this message was described by Demaratus, As the danger of discovery was great, there was only one way in which he could contrive to get the message through: this was by scraping the wax off a pair of wooden folding tables, writing on the wood underneath what Xerxes intended to do, and then covering the message over with the wax again. In this way the tablets, being apparently blank, would cause no trouble with the guards along the road (Singh, p. 19). Ultimately, it’s clear that steganography has been a major part of society for thousands of years. The modern world demonstrates a number of prominent uses of steganography. Some of the most prominent such uses occurred throughout World War II. During World War II the French Resistance wrote messages on the backs of couriers in invisible ink. A famous incident occurred in New York with a Japanese woman. Specifically, the woman was involved in shipping dolls to South America. While she would write out doll orders, she included information to accommodation addresses in South America. This encoded information was ultimately uncovered and resulted in large-scale publicity. The Nazis developed Microdots. These are microfilm chips that were created at very high magnification levels. An equivalent of the size of these microdots would be the period on a keyboard. The Nazis were highly successful in this process, as they were able to fit documents, drawings, and even pages of information at these magnification levels. Correspondents could then uncover these microdots and the message conveyed. Other methods implemented by the Nazis include inks and null ciphers, as a means of concealing messages. It’s recorded that among the major messages recorded in this way include the message, “Apparently neutral’s protest is thoroughly discounted and ignored. Isman hard hit. Blockade issue affects pretext for embargo on by-products, ejecting suets and vegetable oils. Pershing sails from NY June 1st” (Wayner, p. 56). In additions to these methods the Nazis are recognized as implementing dials on wristwatches to even chess games. The United States has also prominently implemented steganography in wartime situations. During World War II the United States used Navajo ‘codetalkers’ that sent simple messages in clear text. Another methods implemented by the United States incorporated the Cardano grill. Girolama Cardano invented this device. It is a simple piece of paper with holes cut at specific points. When this grill is placed over another piece of paper it reveals specifically encoded messages. This method has been further enhanced through the use of pin punctures at specific points. There is the recognition that this approach is very similar to cryptographic techniques. Research notes that slaves prior to the Civil War used steganography to convey messages. Most prominently these processes occurred in stitched quilts. Various patterns were sewn into quilts, such as Bear Paw claws. These quilts were then hung from strategic locations, such as windowsills, under the auspices that they were drying. In reality the quilts were conveying messages that coordinated escape plans. In recent years a captured crew spelled the words ‘snowjob’ with their hands when a picture was taken of them. Hand gestures were also implemented by United States soldiers in the Vietnam War. Captured United States soldiers used various types of hand gestures during photographs. These gestures would be recorded by the United States military and then airbrushed out by the media. The soldiers would also implement eye codes by blinking out words such as ‘torture’ in Morse code. One seminal event occurred in 1966 with prisoner of war (POW) Jeremiah Denton. During a televised interview Denton repeatedly blinked his eyes in Morse code to spell out T-O-R-T-U-R-E. This was a highly significant event as it confirmed for the first time to United States Naval intelligence that torture was in fact occurring in the region. Prisoners that were captured and kept in the Vietnamese Hanoi Hilton used tapping methods to communicate with each other. There was a specific code that they established. The code involved a five by five matrix. Each letter on this matrix then corresponded to a specific type of tapping. Spaces also constituted a specific letter based on the length of the pause between taps. Fig. 2 below demonstrates this matrix. Fig. 2 Vietnam Steganography Matrix Modern Incarnations The modern world has considerably shifted the nature of steganography. The main turning point in these regards occurred in 1985 with the development of digital techniques. Digital steganography is recognized as an expansive discipline encompassing a nearly endless array of techniques. Some of the most prominent techniques include text files, images, audio, and movie images. As one would expect there are considerable potentials for this process of steganography. In audio methods techniques have been implemented that mirror the Nazis 20th century use of Microdots. Specifically, messages in this way are recorded with the lowest bits of frequency and then reconstituted by an end-point receiver. Audio has also been implemented through altering the echo of a sound file. Another method has been a hybrid process of steganography and cryptography. In this way the message to be concealed is first encrypted with cryptographic processes. This data is then used to overwrite a much larger portion of previously encrypted data, or a random block of data. This way the text appears entirely random unless one knows what they are looking for. Two of the most prominent tools are image domains tools and transform domain tools. It’s noted that, “Image Domain tools encompass bit-wise methods that apply least significant bit (LSB) insertion and noise manipulation... The transform domain group of tools include those that involve manipulation of algorithms and image transforms such as discrete cosine transformation (DCT) [CKSL96], [KRZ94] and wavelet transformation [XBA97]” (Fridrich, p. 112). Within these processes there are increasingly complex forms of steganography. Mimic functions have been implemented that make one file have the same statistical formulations of another; this method is most prominently used as a means of concealing information for cyber attacks. Within this area of consideration, tampered files oftentimes have been used to conceal messages. The recognition in these regards is that the redundancy in these files makes them considerably go spots to conceal messages. Images have also been correspondingly implemented in these processes. A frequent way images are implemented in modern steganography practices is through embedding them in video material. When the video is played at a specific speed – exceptionally fast or exceptionally slow – the image then becomes visible. In terms of computer programming processes, steganography has been frequently established in changing the order of elements in a set. Additionally, there is content-aware steganography. This form of steganography hides information in semantics when an end-user assigns them to a datagram. Concerns with Terrorists One of the most relevant uses of steganography in recent years has been witnessed in terms of its use by terrorist. The September 11th attacks on the World Trade Center towers ushered in a new era of vigilance, with precautions regarding steganography one of the key areas of focus. Reports argued that al Queda had used steganography to plan the attacks. In planning the attacks it was reported that al Queda encoded messages into images. These images were then transported to email and communicated through USENET. Specific focuses after these attacks considered the potential of al Queda implementing steganography. The Federal Plan for Cyber Security and Information Assurance Research and Development noted, …immediate concerns also include the use of cyberspace for covert communications, particularly by terrorists but also by foreign intelligence services; espionage against sensitive but poorly defended data in government and industry systems; subversion by insiders, including vendors and contractors; criminal activity, primarily involving fraud and theft of financial or identity information, by hackers and organized crime groups (Wayner, p. 232). Following these measures a number of discoveries were made by anti-terrorist organizations. The United States government located a terrorist training manual referred to as the Technical Mujahid, a Training Manual for Jihadis. This manual is noted to have contained a specific section devoted to developing covert communications. One sensational account even considered the al Queda was placing steganographic messages on XXX adult-rated porn sites. Other reports considered the potential of terrorist messages being implemented through the eBay auction site. This led a group at the University of Michigan to conduct a mass scanning of images. Despite scanning over two million images no secret messages were ever uncovered. Another major concern related to terrorist messages concerned Osama Bin Laden’s video broadcasts. Before his ultimate assassination by the United States Special Forces, Bin Laden intermittently released videos that taunted the United States and encouraged his followers. Considerable focus was given to the potential that messages were concealed in these videos. Despite investigation no messages were ever uncovered. Currently, the United States government has developed a Counter Terrorist Steganography Search Engine that attempts to detect the most likely sources for terrorist steganography messages. Miscellaneous Uses Another major contemporary use of steganographic techniques has been in digital watermarking. While generally the intention of steganography is to conceal messages, digital watermarking has frequently been implemented to prevent the replication of a file or document. Digital watermarking techniques have been implemented on a large variety of media, including movies, music, images, and even computer software programs. There are a number of divisions among specific digital watermarks. The most prominent divisions are between “fragile and robust, private vs. public, and visible vs. invisible” (Petitcolas, p. 98). Fragile watermarks are those that are the easiest to manipulate through digital photography editing; these are predominantly implemented in image authentication systems. Generally commercial software applications are used in the creation of fragile digital watermarking. While digital media methods are the predominant forms of watermarking, printing has also been implemented in this process. Notably, Xerox developed a digital watermarking process for printed images. The Xerox process implements a half-tone screen that is then combined with a key image. The watermark is then superimposed over the original image. When viewed from a slight angle the image then appears. Of course a similar process to this is used in much currency watermarking. This process ensures that easy forgeries are not possible. Another digital watermarking technique is witnessed in stochastic screen. This process is similar to the process Xerox implements, however dot methods are implemented in the image. Generally algorithms are implemented to create unique spacing that uniquely marks the image or document. Textual steganography is also frequently implemented in contemporary contexts. Much develop of this approach occurred in the United Kingdom during the administration of British Prime Minister Margaret Thatcher. Thatcher recognized that there were press leaks of cabinet documents. Thatcher reportedly had the word processors programmed so that the documents would have unique spacing. Thatcher was then able to link the specific cabinet document to the minister that leaked it. This is uniquely a modern technique because of the precision with which text can be constructed on documents. Textual steganography is now available in a number of software applications. Sound and still image steganography also have a number of readily used applications. In terms of sound steganography, there are many applications that will conceal .mp3 files. It’s noted that this occurs as the, “hiding process takes place at the heart of the Layer III encoding process name in the inner_loop” (Fridrich, p. 54) Additionally, there are many applications in use that hide information in .avi, .au, .mpeg, or .wav formats. Still image steganography is another prominent occurrence. To a large extent individuals skilled with the Adobe application Photoshop have developed steganographic techniques. Additionally, there are a number of applications that specifically alter images for specific purposes. Conclusion In conclusion, this essay has examined steganography. Within this context of understanding the history, modern applications, and enhancements have been examined. It’s established that while the term steganography dates to 16th century, the process of concealing messages has been in practice since at least Greek antiquity. World War II marked a period of significant development for steganography as all major powers implemented these techniques. Vietnam again contained a number of seminal uses of steganography, with a prisoner even spelling out messages in Morse code with his eyes. The modern era of steganography is witnessed with the development of digital techniques in the late 20th century. The digital era of steganography has greatly expanded the reach and complexity of these practices through visual, audio, and programming techniques. Ultimately, it’s clear that the future of steganography will be firmly entrenched in these digital processes. References Fridrich, Jessica. Steganography in Digital Media: Principles, Algorithms, and Applications . Massachusetts : Cambridge University Press, 1999. Print. Murphy, Sean. Cryptography: A Very Short Introduction . London: Oxford Paperbacks, 2002. Print. Petitcolas, Fabien (2000). Information Hiding Techniques for Steganography and Digital Watermarking. Artech House Publishers. Singh, Simon. The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography. New York: Anchor, 2010. Print. Wayner, Peter. Disappearing Cryptography: Information Hiding: Steganography & Watermarking. New York: Morgan Kaufmann, 2008. Print. Read More