Art of Writing Text or Data in a Secret Code

Hiding messages in other letters

The same epitome viewed by white, blue, green, and red lights reveals different hidden numbers.

Steganography ( STEG-ə-NOG-rə-fee) is the do of concealing a message within another message or a concrete object. In computing/electronic contexts, a computer file, bulletin, paradigm, or video is concealed within some other file, message, image, or video. The word steganography comes from Greek steganographia, which combines the words steganós ( στεγανός ), meaning "covered or concealed", and -graphia ( γραφή ) meaning "writing".^[1]

The start recorded use of the term was in 1499 by Johannes Trithemius in his Steganographia, a treatise on cryptography and steganography, disguised as a book on magic. Generally, the hidden messages appear to exist (or to be office of) something else: images, manufactures, shopping lists, or some other cover text. For example, the hidden bulletin may be in invisible ink between the visible lines of a private letter. Some implementations of steganography that lack a shared cloak-and-dagger are forms of security through obscurity, and cardinal-dependent steganographic schemes adhere to Kerckhoffs'southward principle.^[2]

The reward of steganography over cryptography solitary is that the intended secret message does not concenter attending to itself as an object of scrutiny. Obviously visible encrypted messages, no matter how unbreakable they are, arouse interest and may in themselves be incriminating in countries in which encryption is illegal.^[3]

Whereas cryptography is the do of protecting the contents of a message alone, steganography is concerned with concealing the fact that a undercover message is beingness sent and its contents.

Steganography includes the concealment of data within computer files. In digital steganography, electronic communications may include steganographic coding inside of a transport layer, such as a document file, image file, programme, or protocol. Media files are ideal for steganographic transmission because of their large size. For example, a sender might get-go with an innocuous image file and adjust the color of every hundredth pixel to correspond to a letter in the alphabet. The change is and then subtle that someone who is not specifically looking for it is unlikely to detect the modify.

History [edit]

The start recorded uses of steganography can be traced back to 440 BC in Greece, when Herodotus mentions two examples in his Histories.^[4] Histiaeus sent a message to his vassal, Aristagoras, by shaving the head of his about trusted retainer, "marker" the bulletin onto his scalp, then sending him on his style once his hair had regrown, with the instruction, "When chiliad art come to Miletus, bid Aristagoras shave thy head, and look thereon." Additionally, Demaratus sent a alert virtually a forthcoming attack to Greece by writing information technology straight on the wooden backing of a wax tablet before applying its beeswax surface. Wax tablets were in mutual apply and then as reusable writing surfaces, sometimes used for autograph.

In his work Polygraphiae, Johannes Trithemius adult his so-chosen "Ave-Maria-Cipher" that can hide data in a Latin praise of God. "Auctor Sapientissimus Conseruans Angelica Deferat Nobis Charitas Potentissimi Creatoris" for example contains the concealed word VICIPEDIA.^[5]

Techniques [edit]

Deciphering the code. Steganographia

Concrete [edit]

Steganography has been widely used for centuries. Some examples include:^[6]

Subconscious messages on a paper written in secret inks.
Hidden messages distributed, co-ordinate to a sure rule or key, as smaller parts (e.g. words or messages) among other words of a less suspicious cover text. This particular form of steganography is called a cipher zilch.
Letters written in Morse code on yarn and then knitted into a piece of clothing worn by a courier.
Letters written on envelopes in the surface area covered by postage stamp stamps.
In the early on days of the press printing, information technology was common to mix different typefaces on a printed page because the printer did not have enough copies of some letters in i typeface. Thus, a bulletin could be hidden by using two or more different typefaces, such as normal or italic.
During and after World War II, espionage agents used photographically-produced microdots to transport information back and forth. Microdots were typically minute (less than the size of the period produced past a typewriter). Globe War II microdots were embedded in the newspaper and covered with an agglutinative, such as collodion that was reflective and so was detectable by viewing against glancing low-cal. Alternative techniques included inserting microdots into slits cut into the edge of postcards.
During World War II, Velvalee Dickinson, a spy for Japan in New York City, sent information to accommodation addresses in neutral S America. She was a dealer in dolls, and her letters discussed the quantity and type of doll to ship. The stegotext was the doll orders, and the concealed "plaintext" was itself encoded and gave information about ship movements, etc. Her instance became somewhat famous and she became known as the Doll Adult female.
During World War 2, photosensitive glass was declared secret^{[ by whom? ]}, and used for transmitting information to Allied armies.
Jeremiah Denton repeatedly blinked his optics in Morse lawmaking during the 1966 televised press conference that he was forced into equally an American prisoner-of-war by his North Vietnamese captors, spelling out "T-O-R-T-U-R-Eastward". That confirmed for the showtime fourth dimension to the United states of america Naval Intelligence and other Americans that the North Vietnamese were torturing American prisoners-of-war.
In 1968, crew members of the USS Pueblo intelligence ship, held as prisoners by N Korea, communicated in sign linguistic communication during staged photo opportunities, to inform the U.s. that they were not defectors merely captives of the N Koreans. In other photos presented to the US, crew members gave "the finger" to the unsuspecting Northward Koreans, in an endeavor to discredit photos that showed them smiling and comfortable.

Digital messages [edit]

Epitome of a tree with a steganographically hidden image. The hidden image is revealed by removing all but the two least meaning $.25 of each colour component and a subsequent normalization. The hidden image is shown below.

Image of a true cat extracted from the tree prototype above.

Concealing messages within the lowest bits of noisy images or sound files. A survey and evaluation of relevant literature/techniques on the topic of digital image steganography tin can be plant here.^[7]
Concealing data inside encrypted data or inside random data. The bulletin to conceal is encrypted, then used to overwrite part of a much larger cake of encrypted data or a block of random data (an unbreakable cipher like the former pad generates ciphertexts that look perfectly random without the private central).
Chaffing and winnowing.
Mimic functions catechumen ane file to have the statistical profile of another. This can thwart statistical methods that aid brute-force attacks identify the right solution in a ciphertext-only attack.
Concealed messages in tampered executable files, exploiting redundancy in the targeted teaching set.
Pictures embedded in video cloth (optionally played at a slower or faster speed).
Injecting imperceptible delays to packets sent over the network from the keyboard. Delays in keypresses in some applications (telnet or remote desktop software) tin can mean a delay in packets, and the delays in the packets tin be used to encode information.
Changing the order of elements in a set up.
Content-Aware Steganography hides information in the semantics a homo user assigns to a datagram. These systems offer security against a nonhuman adversary/warden.
Blog-Steganography. Messages are fractionalized and the (encrypted) pieces are added equally comments of orphaned web-logs (or pin boards on social network platforms). In this instance, the pick of blogs is the symmetric key that sender and recipient are using; the carrier of the hidden message is the whole blogosphere.
Modifying the echo of a sound file (Echo Steganography).^[8]
Steganography for audio signals.^[9]
Prototype bit-plane complexity segmentation steganography
Including data in ignored sections of a file, such as after the logical finish of the carrier file.^[10]
Adaptive steganography: Pare tone based steganography using a underground embedding angle.^[11]
Embedding data within the command-flow diagram of a program subjected to command flow analysis^[12]

Digital text [edit]

Using not-printing Unicode characters Zero-Width Joiner (ZWJ) and Zero-Width Non-Joiner (ZWNJ).^[xiii] ^[14] These characters are used for joining and disjoining letters in Arabic and Persian, but can be used in Roman alphabets for hiding information because they have no meaning in Roman alphabets: considering they are "zero-width" they are not displayed. ZWJ and ZWNJ can stand for "1" and "0". This may besides be done with en infinite, effigy infinite and whitespace characters.^[fifteen]
Embedding a clandestine message in the blueprint of deliberate errors and marked corrections in a word processing document, using the word processor's change tracking feature.^[sixteen]
In 2020, Zhongliang Yang et al discovered that for text generative steganography, when the quality of the generated steganographic text is optimized to a certain extent, it may make the overall statistical distribution characteristics of the generated steganographic text more different from the normal text, making information technology easier to be recognized. They named this miracle Perceptual-Statistical Imperceptibility Conflict Result (Psic Effect).^[17]

Hiding an prototype within a soundfile [edit]

An paradigm or a text tin can be converted into a soundfile, which is then analysed with a spectrogram to reveal the image. Diverse artists have used this method to conceal subconscious pictures in their songs, such every bit Aphex Twin in "Windowlicker" or Nine Inch Nails in their album Year Aught.^[18]

1. The discussion "Wikipedia" is fatigued using calculator software

two. The paradigm is converted into an audio file

3. Finally, the audio is analysed through a spectrogram, revealing the initial image

[edit]

In communities with social or government taboos or censorship, people use cultural steganography—hiding messages in idiom, pop culture references, and other messages they share publicly and assume are monitored. This relies on social context to make the underlying messages visible only to certain readers.^[xix] ^[20] Examples include:

Hiding a bulletin in the championship and context of a shared video or prototype.
Misspelling names or words that are pop in the media in a given calendar week, to propose an alternate meaning.
Hiding a picture that can be traced by using Pigment or any other drawing tool.^{[ citation needed ]}

Steganography in streaming media [edit]

Since the era of evolving network applications, steganography research has shifted from image steganography to steganography in streaming media such as Voice over Internet Protocol (VoIP).

In 2003, Giannoula et al. developed a data hiding technique leading to compressed forms of source video signals on a frame-past-frame ground.^[21]

In 2005, Dittmann et al. studied steganography and watermarking of multimedia contents such every bit VoIP.^[22]

In 2008, Yongfeng Huang and Shanyu Tang presented a novel approach to data hiding in low chip-charge per unit VoIP speech stream, and their published work on steganography is the first-ever effort to amend the codebook segmentation by using Graph theory along with Quantization Alphabetize Modulation in low bit-rate streaming media.^[23]

In 2011 and 2012, Yongfeng Huang and Shanyu Tang devised new steganographic algorithms that utilise codec parameters as embrace object to realise existent-time covert VoIP steganography. Their findings were published in IEEE Transactions on Information Forensics and Security.^[24] ^[25] ^[26]

Cyber-physical systems/Internet of Things [edit]

Academic work since 2012 demonstrated the feasibility of steganography for cyber-physical systems (CPS)/the Cyberspace of Things (IoT). Some techniques of CPS/IoT steganography overlap with network steganography, i.e. hiding data in advice protocols used in CPS/the IoT. Yet, specific techniques hide data in CPS components. For case, information tin be stored in unused registers of IoT/CPS components and in the states of IoT/CPS actuators.^[27] ^[28]

Printed [edit]

Digital steganography output may be in the grade of printed documents. A message, the plaintext, may be starting time encrypted by traditional ways, producing a ciphertext. Then, an innocuous cover text is modified in some manner and so every bit to comprise the ciphertext, resulting in the stegotext. For instance, the letter size, spacing, typeface, or other characteristics of a cover text can be manipulated to behave the hidden bulletin. Only a recipient who knows the technique used tin recover the message and then decrypt it. Francis Salary developed Salary'south aught every bit such a technique.

The ciphertext produced by most digital steganography methods, notwithstanding, is not printable. Traditional digital methods rely on perturbing racket in the channel file to hide the message, and equally such, the channel file must be transmitted to the recipient with no additional noise from the transmission. Printing introduces much noise in the ciphertext, by and large rendering the message unrecoverable. At that place are techniques that address this limitation, ane notable example being ASCII Art Steganography.^[29]

Yellow dots from a light amplification by stimulated emission of radiation printer

Although not archetype steganography, some types of modern colour laser printers integrate the model, serial number, and timestamps on each printout for traceability reasons using a dot-matrix code made of small, yellow dots not recognizable to the naked eye — see printer steganography for details.

Using puzzles [edit]

The art of concealing information in a puzzle can have reward of the degrees of liberty in stating the puzzle, using the starting data to encode a key within the puzzle/puzzle paradigm.

For instance, steganography using sudoku puzzles has equally many keys as there are possible solutions of a Sudoku puzzle, which is six.71×x²¹ .^[30]

Network [edit]

In 1977, Kent concisely described the potential for covert channel signaling in general network advice protocols, even if the traffic is encrypted (in a footnote) in "Encryption-Based Protection for Interactive User/Figurer Communication," Proceedings of the 5th Data Communications Symposium, September 1977.

In 1987, Girling first studied covert channels on a local surface area network (LAN), identified and realised three obvious covert channels (2 storage channels and one timing channel), and his enquiry paper entitled "Covert channels in LAN's" published in IEEE Transactions on Software Engineering science, vol. SE-13 of two, in Feb 1987.^[31]

In 1989, Wolf implemented covert channels in LAN protocols, eastward.g. using the reserved fields, pad fields, and undefined fields in the TCP/IP protocol.^[32]

In 1997, Rowland used the IP identification field, the TCP initial sequence number and acknowledge sequence number fields in TCP/IP headers to build covert channels.^[33]

In 2002, Kamran Ahsan made an first-class summary of research on network steganography.^[34]

In 2005, Steven J. Murdoch and Stephen Lewis contributed a chapter entitled "Embedding Covert Channels into TCP/IP" in the "Information Hiding" book published past Springer.^[35]

All information hiding techniques that may be used to substitution steganograms in telecommunication networks tin can be classified under the general term of network steganography. This nomenclature was originally introduced past Krzysztof Szczypiorski in 2003.^[36] Contrary to typical steganographic methods that utilize digital media (images, sound and video files) to hibernate data, network steganography uses communication protocols' control elements and their intrinsic functionality. As a result, such methods can be harder to detect and eliminate.^[37]

Typical network steganography methods involve modification of the properties of a single network protocol. Such modification tin can be applied to the PDU (Protocol Data Unit),^[38] ^[39] ^[forty] to the fourth dimension relations between the exchanged PDUs,^[41] or both (hybrid methods).^[42]

Moreover, it is feasible to utilize the relation betwixt two or more than unlike network protocols to enable clandestine communication. These applications fall under the term inter-protocol steganography.^[43] Alternatively, multiple network protocols can be used simultaneously to transfer hidden information and so-called command protocols tin can be embedded into steganographic communications to extend their capabilities, e.k. to let dynamic overlay routing or the switching of utilized hiding methods and network protocols.^[44] ^[45]

Network steganography covers a broad spectrum of techniques, which include, among others:

Steganophony – the darkening of messages in Phonation-over-IP conversations, eastward.g. the employment of delayed or corrupted packets that would normally exist ignored by the receiver (this method is called LACK – Lost Sound Packets Steganography), or, alternatively, hiding information in unused header fields.^[46]
WLAN Steganography – transmission of steganograms in Wireless Local Surface area Networks. A practical instance of WLAN Steganography is the HICCUPS organization (Hidden Advice System for Corrupted Networks)^[47]

Terminology and Taxonomy [edit]

In 2015, a taxonomy of 109 network hiding methods was presented by Steffen Wendzel, Sebastian Zander et al. that summarized core concepts used in network steganography inquiry.^[48] The taxonomy was developed further in recent years by several publications and authors and adjusted to new domains, such as CPS steganography.^[49] ^[50] ^[51]

Boosted terminology [edit]

Discussions of steganography generally use terminology analogous to and consistent with conventional radio and communications technology. However, some terms appear specifically in software and are easily confused. These are the most relevant ones to digital steganographic systems:

The payload is the data covertly communicated. The carrier is the bespeak, stream, or information file that hides the payload, which differs from the channel, which typically means the type of input, such equally a JPEG epitome. The resulting betoken, stream, or data file with the encoded payload is sometimes called the packet, stego file, or covert message. The proportion of bytes, samples, or other signal elements modified to encode the payload is called the encoding density and is typically expressed as a number betwixt 0 and 1.

In a ready of files, the files that are considered probable to comprise a payload are suspects. A doubtable identified through some type of statistical analysis can be referred to as a candidate.

Countermeasures and detection [edit]

Detecting physical steganography requires a careful physical examination, including the use of magnification, programmer chemicals, and ultraviolet light. It is a time-consuming procedure with obvious resources implications, even in countries that employ many people to spy on their fellow nationals. Withal, it is feasible to screen mail of certain suspected individuals or institutions, such as prisons or prisoner-of-state of war (POW) camps.

During Globe War 2, pw camps gave prisoners specially-treated paper that would reveal invisible ink. An article in the 24 June 1948 event of Paper Trade Journal by the Technical Director of the United States Government Press Office had Morris South. Kantrowitz describe in general terms the development of this paper. Three prototype papers (Sensicoat, Anilith, and Coatalith) were used to manufacture postcards and stationery provided to German prisoners of war in the US and Canada. If POWs tried to write a hidden message, the special newspaper rendered information technology visible. The US granted at to the lowest degree two patents related to the engineering science, 1 to Kantrowitz, U.S. Patent 2,515,232, "Water-Detecting paper and Water-Detecting Blanket Limerick Therefor," patented 18 July 1950, and an earlier one, "Moisture-Sensitive Paper and the Industry Thereof," U.South. Patent ii,445,586, patented xx July 1948. A similar strategy issues prisoners with writing paper ruled with a water-soluble ink that runs in contact with water-based invisible ink.

In calculating, steganographically encoded package detection is called steganalysis. The simplest method to discover modified files, however, is to compare them to known originals. For example, to detect information being moved through the graphics on a website, an analyst can maintain known clean copies of the materials and then compare them confronting the current contents of the site. The differences, if the carrier is the same, comprise the payload. In general, using extremely loftier compression rates makes steganography difficult merely not impossible. Compression errors provide a hiding place for information, simply high pinch reduces the amount of information bachelor to hold the payload, raising the encoding density, which facilitates easier detection (in extreme cases, even by casual observation).

At that place are a variety of basic tests that can be washed to place whether or not a secret message exists. This process is not concerned with the extraction of the bulletin, which is a unlike process and a separate step. The nearly bones approaches of steganalysis are visual or aural attacks, structural attacks, and statistical attacks. These approaches effort to detect the steganographic algorithms that were used.^[52] These algorithms range from unsophisticated to very sophisticated, with early on algorithms beingness much easier to observe due to statistical anomalies that were nowadays. The size of the message that is being hidden is a factor in how hard it is to detect. The overall size of the cover object besides plays a factor likewise. If the comprehend object is small and the message is large, this tin distort the statistics and make it easier to notice. A larger encompass object with a small bulletin decreases the statistics and gives information technology a better chance of going unnoticed.

Steganalysis that targets a particular algorithm has much better success equally it is able to key in on the anomalies that are left backside. This is because the analysis tin perform a targeted search to discover known tendencies since information technology is aware of the behaviors that information technology commonly exhibits. When analyzing an image the least meaning bits of many images are really not random. The camera sensor, especially lower-end sensors are non the best quality and tin can introduce some random $.25. This tin can also be affected by the file compression done on the paradigm. Secret letters can exist introduced into the to the lowest degree significant bits in an prototype and then subconscious. A steganography tool tin can be used to cover-up the undercover message in the least meaning bits but it tin introduce a random surface area that is too perfect. This surface area of perfect randomization stands out and can exist detected by comparing the least pregnant bits to the adjacent-to-to the lowest degree significant bits on an image that hasn't been compressed.^[52]

Generally, though, in that location are many techniques known to be able to hibernate messages in data using steganographic techniques. None are, by definition, obvious when users apply standard applications, but some tin can be detected past specialist tools. Others, however, are resistant to detection—or rather it is not possible to reliably distinguish data containing a hidden message from data containing just noise—fifty-fifty when the well-nigh sophisticated analysis is performed. Steganography is being used to muffle and evangelize more constructive cyber attacks, referred to as Stegware. The term Stegware was start introduced in 2017^[53] to depict any malicious functioning involving steganography as a vehicle to conceal an attack. Detection of steganography is challenging, and because of that, not an acceptable defence force. Therefore, the only way of defeating the threat is to transform data in a way that destroys any hidden messages,^[54] a process called Content Threat Removal.

Applications [edit]

Use in modern printers [edit]

Some modernistic figurer printers utilize steganography, including Hewlett-Packard and Xerox brand colour laser printers. The printers add tiny yellow dots to each page. The barely-visible dots contain encoded printer series numbers and date and time stamps.^[55]

Example from mod practice [edit]

The larger the cover bulletin (in binary information, the number of bits) relative to the hidden message, the easier it is to hide the hidden bulletin (equally an analogy, the larger the "haystack", the easier information technology is to hide a "needle"). And so digital pictures, which contain much data, are sometimes used to hide messages on the Net and on other digital advice media. It is not clear how mutual this practice actually is.

For example, a 24-bit bitmap uses 8 bits to stand for each of the three colour values (ruby, light-green, and blue) of each pixel. The bluish lonely has 2⁸ dissimilar levels of bluish intensity. The difference between 11111111 and 11111110 in the value for blue intensity is probable to be undetectable by the man eye. Therefore, the least pregnant chip can be used more or less undetectably for something else other than color data. If that is repeated for the light-green and the red elements of each pixel besides, information technology is possible to encode ane alphabetic character of ASCII text for every three pixels.

Stated somewhat more than formally, the objective for making steganographic encoding difficult to find is to ensure that the changes to the carrier (the original signal) because of the injection of the payload (the point to covertly embed) are visually (and ideally, statistically) negligible. The changes are duplicate from the dissonance floor of the carrier. All media can be a carrier, simply media with a big amount of redundant or compressible data is improve suited.

From an information theoretical indicate of view, that means that the channel must have more chapters than the "surface" point requires. There must be redundancy. For a digital image, information technology may be noise from the imaging chemical element; for digital sound, it may be noise from recording techniques or amplification equipment. In general, electronics that digitize an analog signal suffer from several noise sources, such every bit thermal noise, flicker noise, and shot dissonance. The noise provides plenty variation in the captured digital information that information technology can be exploited as a racket embrace for hidden data. In add-on, lossy compression schemes (such as JPEG) always introduce some error to the decompressed information, and it is possible to exploit that for steganographic utilise, every bit well.

Although steganography and digital watermarking seem similar, they are non. In steganography, the subconscious bulletin should remain intact until it reaches its destination. Steganography can be used for digital watermarking in which a message (being just an identifier) is hidden in an prototype then that its source can be tracked or verified (for case, Coded Anti-Piracy) or even just to identify an prototype (as in the EURion constellation). In such a example, the technique of hiding the bulletin (here, the watermark) must be robust to prevent tampering. Nonetheless, digital watermarking sometimes requires a brittle watermark, which tin exist modified easily, to check whether the image has been tampered with. That is the key difference between steganography and digital watermarking.

Alleged employ by intelligence services [edit]

In 2010, the Federal Agency of Investigation alleged that the Russian strange intelligence service uses customized steganography software for embedding encrypted text messages inside image files for sure communications with "illegal agents" (agents without diplomatic cover) stationed abroad.^[56]

On April 23, 2019 the U.S. Department of Justice unsealed an indictment charging Xiaoqing Zheng, a Chinese man of affairs and former Principal Engineer at Full general Electrical, with fourteen counts of conspiring to steal intellectual property and trade secrets from Full general Electrical. Zheng had allegedly used steganography to exfiltrate xx,000 documents from General Electric to Tianyi Aviation Engineering science Co. in Nanjing, Prc, a visitor the FBI accused him of starting with backing from the Chinese government.^[57]

Distributed steganography [edit]

In that location are distributed steganography methods,^[58] including methodologies that distribute the payload through multiple carrier files in diverse locations to make detection more difficult. For instance, U.Due south. Patent eight,527,779 by cryptographer William Easttom (Chuck Easttom).

Online challenge [edit]

The puzzles that are presented by Cicada 3301 comprise steganography with cryptography and other solving techniques since 2012.^[59] Puzzles involving steganography have also been featured in other alternate reality games.

The communications^[threescore] ^[61] of The May Day mystery incorporate steganography and other solving techniques since 1981.^[62]

Stegoanalysis [edit]

Stegoanalytical algorithms [edit]

Stegoanalytical algorithms can be cataloged in different ways, highlighting: according to the bachelor information and according to the purpose sought.

According to the data available [edit]

There is the possibility of cataloging these algorithms based on the data held by the stegoanalyst in terms of articulate and encrypted messages. It is a technique similar to cryptography, however, they have several differences:

Chosen stego assail: the stegoanalyst perceives the concluding target stego and the stenographic algorithm used.
Known embrace attack: the stegoanalyst comprises the initial conductive target and the last target stego.
Known stego attack: the stegoanalyst knows the initial carrier target and the final target stego, in addition to the algorithm used.
Stego just attack: the stegoanalist perceives exclusively the stego target.
Chosen bulletin assail: the stegoanalyst, post-obit a message selected by him, originates a stego target.
Known message attack: the stegoanalyst owns the stego target and the subconscious message, which is known to him.

Co-ordinate to the purpose sought [edit]

The principal purpose of steganography is to transfer information unnoticed, however, it is possible for an attacker to have two different pretensions:

Passive stegoanalysis: does not modify the target stego, therefore, it examines the target stego in order to found whether it carries hidden information and recovers the hidden message, the key used or both.
Agile stegoanalysis: changes the initial stego target, therefore, it seeks to suppress the transfer of data, if information technology exists.

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Sources [edit]

Wayner, Peter (2002). Disappearing cryptography: information hiding: steganography & watermarking. Amsterdam: MK/Morgan Kaufmann Publishers. ISBN978-1-558-60769-nine.
Wayner, Peter (2009). Disappearing cryptography 3rd Edition: information hiding: steganography & watermarking. Amsterdam: MK/Morgan Kaufmann Publishers. ISBN978-0-123-74479-ane.
Petitcolas, Fabien A.P.; Katzenbeisser, Stefan (2000). Information Hiding Techniques for Steganography and Digital Watermarking. Artech House Publishers. ISBN978-1-580-53035-4.
Johnson, Neil; Duric, Zoran; Jajodia, Sushil (2001). Information hiding: steganography and watermarking: attacks and countermeasures. Springer. ISBN978-0-792-37204-2.
Petitcolas, Fabien A.P.; Katzenbeisser, Stefan (2016). Data Hiding. Artech House Publishers. ISBN978-1608079285.

External links [edit]

An overview of digital steganography, particularly within images, for the computationally curious by Chris League, Long Island University, 2015
Steganography at Curlie
Examples showing images hidden in other images
Information Hiding: Steganography & Digital Watermarking. Papers and information about steganography and steganalysis enquiry from 1995 to the nowadays. Includes Steganography Software Wiki list. Dr. Neil F. Johnson.
Detecting Steganographic Content on the Net. 2002 paper past Niels Provos and Peter Honeyman published in Proceedings of the Network and Distributed Arrangement Security Symposium (San Diego, CA, February 6–eight, 2002). NDSS 2002. Net Social club, Washington, D.C.
Covert Channels in the TCP/IP Suite – 1996 paper by Craig Rowland detailing the hiding of data in TCP/IP packets.
Network Steganography Eye Tutorials. How-to manufactures on the subject area of network steganography (Wireless LANs, VoIP – Steganophony, TCP/IP protocols and mechanisms, Steganographic Router, Inter-protocol steganography). By Krzysztof Szczypiorski and Wojciech Mazurczyk from Network Security Grouping.
Invitation to BPCS-Steganography.
Steganography past Michael T. Raggo, DefCon 12 (1 August 2004)
File Format Extension Through Steganography by Blake W. Ford and Khosrow Kaikhah
Reckoner steganography. Theory and practice with Mathcad (Rus) 2006 paper by Konakhovich G. F., Puzyrenko A. Yu. published in MK-Press Kyiv, Ukraine

boantaknottem.blogspot.com

Source: https://en.wikipedia.org/wiki/Steganography