Hidden messages
Subliminal messages Shorthand is a writing method that can be done at speed because an abbreviated or symbolic form of language is used. ... Image File history File links This is a lossless scalable vector image. ... A hidden message is information that is not immediately noticeable, and that must be discovered or uncovered and interpreted before it can be known. ... A subliminal message is a signal or message embedded in another object, designed to pass below the normal limits of perception. ... Audio Backmasking Reverse speech Numeric Numerology Theomatics Bible code Cryptography Visual Fnord Pareidolia Psychorama Sacred geometry Steganography See also Apophenia Easter egg (virtual) Clustering illusion Observer-expectancy effect Pattern recognition Unconscious mind
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Steganography is the art and science of writing hidden messages in such a way that no one apart from the sender and intended recipient even realizes there is a hidden message. By contrast, cryptography obscures the meaning of a message, but it does not conceal the fact that there is a message. Today, the term steganography includes the concealment of digital information within computer files. For example, the sender might start with an ordinary-looking image file, then adjust the color of every 100th pixel to correspond to a letter in the alphabet -- a change so subtle that no one who isn't actively looking for it is likely to notice it. Backmasking (also known incorrectly as backward masking)[1] is a recording technique in which a sound or message is recorded backwards onto a track that is meant to be played forwards. ... This article is about the theory of reversed messages in normal speech. ... Numerology is any of many systems, traditions or beliefs in a mystical or esoteric relationship between numbers and physical objects or living things. ... Theomatics is a numerological study of the Greek and Hebrew text of the Christian Bible, based upon gematria and isopsephia, that its proponents assert demonstrates the direct intervention of God in the writing of Christian scripture. ... For the book that publicized the codes, see The Bible Code (book). ... The German Lorenz cipher machine, used in World War II for encryption of very high-level general staff messages Cryptography (or cryptology; derived from Greek κρυπτός kryptós hidden, and the verb γράφω gráfo write or λεγειν legein to speak) is the study of message secrecy. ... Look up Fnord in Wiktionary, the free dictionary. ... The term pareidolia (pronounced or ), referenced in 1994 by Steven Goldstein,[1] describes a psychological phenomenon involving a vague and random stimulus (often an image or sound) being perceived as significant. ... Psychorama (or The Precon Process) is the act of communicating subliminal information through film—flashing images on the screen so quickly that they cannot be perceived by the conscious mind, but nonetheless leaving an unconscious imprint on the viewer. ... The Parthenons facade showing an interpretation of golden rectangles in its proportions. ... Apophenia is the experience of seeing patterns or connections in random or meaningless data. ... A virtual Easter egg is a hidden message or feature in an object such as a movie, book, CD, DVD, computer program, or video game. ... The clustering illusion is the natural human tendency to see patterns where actually none exist. ... The observer-expectancy effect, in science, is a cognitive bias that occurs in science when a researcher expects a given result and therefore unconsciously manipulates an experiment or misinterprets data in order to find it. ... Pattern recognition is a field within the area of machine learning. ... This article does not adequately cite its references or sources. ... The German Lorenz cipher machine, used in World War II for encryption of very high-level general staff messages Cryptography (or cryptology; derived from Greek κρυπτός kryptós hidden, and the verb γράφω gráfo write or λεγειν legein to speak) is the study of message secrecy. ...

The word steganography is of Greek origin and means "covered, or hidden writing". Its ancient origins can be traced back to 440 BC. Herodotus mentions two examples of steganography in The Histories of Herodotus [1]. Demeratus sent a warning about a forthcoming attack to Greece by writing it on a wooden panel and covering it in wax. Wax tablets were in common use then as re-usable writing surfaces, sometimes used for shorthand. Another ancient example is that of Histiaeus, who shaved the head of his most trusted slave and tattooed a message on it. After his hair had grown the message was hidden. The purpose was to instigate a revolt against the Persians. Later, Johannes Trithemius's book Steganographia is a treatise on cryptography and steganography disguised as a grimoire. Herodotus of Halicarnassus (Greek: Hērodotos Halikarnāsseus) was a Greek historian from Ionia who lived in the 5th century BC (ca. ... The Histories of Herodotus by Herodotus is considered the first work of history in Western literature. ... This page is a candidate for speedy deletion. ... Shorthand is a writing method that can be done at speed because an abbreviated or symbolic form of language is used. ... Histiaeus (died 494 BC), the son of Lysagoras, was the tyrant of Miletus in the late 6th century BC. Histiaeus owed his status as tyrant to Darius I, king of Persia, who had subjugated Miletus and the other Ionian states in Asia Minor. ... The Persians of Iran (officially named Persia by West until 1935 while still referred to as Persia by some) are an Iranian people who speak Persian (locally named Fârsi by native speakers) and often refer to themselves as ethnic Iranians as well. ... Polygraphia (1518) — the first printed book on cryptography. ... This design for an amulet comes from the Black Pullet grimoire. ...

Generally, a steganographic message will appear to be something else: a picture, an article, a shopping list, or some other message. This apparent message is the covertext. For instance, a message may be hidden by using invisible ink between the visible lines of innocuous documents. Invisible ink is a substance used for writing, which is either invisible on application, or soon thereafter, and which later on can be made visible by some means. ...

The advantage of steganography over cryptography alone is that messages do not attract attention to themselves, to messengers, or to recipients. An unhidden coded message, no matter how unbreakable it is, will arouse suspicion and may in itself be incriminating, as in countries where encryption is illegal.[2] Often, steganography and cryptography are used together to ensure security of the covert message.

Steganography used in electronic communication include steganographic coding inside of a transport layer, such as an MP3 file, or a protocol, such as UDP. For other uses, see MP3 (disambiguation). ... User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. ...

A steganographic message (the plaintext) is often first encrypted by some traditional means, producing a ciphertext. Then, a covertext is modified in some way to contain the ciphertext, resulting in stegotext. For example, the letter size, spacing, typeface, or other characteristics of a covertext can be manipulated to carry the hidden message; only the recipient (who must know the technique used) can recover the message and then decrypt it. Francis Bacon is known to have suggested such a technique to hide messages (see Bacon's cipher). This article is about cryptography. ... This article is about algorithms for encryption and decryption. ... “Font” redirects here. ... For other persons named Francis Bacon, see Francis Bacon (disambiguation). ... Bacons cipher or the Baconian cipher is a method of steganography (a method of hiding a secret message as opposed to a true cipher) devised by Francis Bacon. ...

Steganographic techniques

Modern steganographic techniques

Modern Steganography entered the world in 1985 with the advent of the Personal Computer applied to classical steganography problems. [3] Development following that was slow, but has since taken off, based upon the number of 'stego' programs available.

• Concealing messages within the lowest bits of noisy images or sound files.
• Concealing data within encrypted data. The data to be concealed is first encrypted before being used to overwrite part of a much larger block of encrypted data. This technique works most effectively where the decrypted version of data being overwritten has no special meaning or use: some cryptosystems, especially those designed for filesystems, add random looking padding bytes at the end of a ciphertext so that its size cannot be used to figure out the size of the original plaintext. Examples of software that use this technique include FreeOTFE and TrueCrypt.
• Chaffing and winnowing
• Invisible ink
• Null ciphers
• Concealed messages in tampered executable files, exploiting redundancy in the i386 instruction set [4].
• Embedded pictures in video material (optionally played at slower or faster speed).
• A new steganographic technique involves injecting imperceptible delays to packets sent over the network from the keyboard. Delays in keypresses in some applications (telnet or remote desktop software) can mean a delay in packets, and the delays in the packets can be used to encode data. There is no extra processor or network activity, so the steganographic technique is "invisible" to the user. This kind of steganography could be included in the firmware of keyboards, thus making it invisible to the system. The firmware could then be included in all keyboards, allowing someone to distribute a keylogger program to thousands without their knowledge.[5]
• Content-Aware Steganography hides information in the semantics a human user assigns a datagram; these systems offer security against a non-human adversary/warden.[6]
• BPCS-Steganography - a very large embedding capacity steganography.

This article is about noise as in sound. ... FreeOTFE v2. ... TrueCrypt is a free open source on-the-fly encryption (OTFE) program for Microsoft Windows XP/2000/2003 and Linux. ... Chaffing and winnowing is a cryptographic technique to achieve confidentiality without using encryption when sending data over an insecure channel; it was conceived by Ron Rivest. ... Invisible ink is a substance used for writing, which is either invisible on application, or soon thereafter, and which later on can be made visible by some means. ... A null cipher is an ancient form of encryption where the plaintext is mixed with a large amount of non-cipher material. ... For the packet switched network, see Telenet. ... In computing, remote desktop software is remote access and remote administration software that allows GUI applications to be run remotely on a server, while being displayed locally. ... BPCS-Steganography (Bit-Plane Complexity Segmentation Steganography) is a type of digital steganography. ...

Historical steganographic techniques

Steganography has been widely used in historical times, especially before cryptographic systems were developed. Examples of historical usage include:

• Hidden messages in wax tablets: in ancient Greece, people wrote messages on the wood, then covered it with wax so that it looked like an ordinary, unused tablet.
• Hidden messages on messenger's body: also in ancient Greece. Herodotus tells the story of a message tattooed on a slave's shaved head, hidden by the growth of his hair, and exposed by shaving his head again. The message allegedly carried a warning to Greece about Persian invasion plans. This method has obvious drawbacks:

1. It is impossible to send a message as quickly as the slave can travel, because it takes months to grow hair.
2. A slave can only be used once for this purpose. (This is why slaves were used: they were considered expendable.)

• Hidden messages on paper written in secret inks under other messages or on the blank parts of other messages.
• During and after World War II, espionage agents used photographically produced microdots to send information back and forth. Since the dots were typically extremely small—the size of a period produced by a typewriter or even smaller—the stegotext was whatever the dot was hidden within. If a letter or an address, it was some alphabetic characters. If under a postage stamp, it was the presence of the stamp. The problem with the WWII microdots was that they needed to be embedded in the paper, and covered with an adhesive (such as collodion), which could be detected by holding a suspected paper up to a light and viewing it almost edge on. The embedded microdot would reflect light differently than the paper.
• More obscurely, during World War II, a spy for the Japanese in New York City, Velvalee Dickinson, sent information to accommodation addresses in neutral South America. She was a dealer in dolls, and her letters discussed how many of this or that doll to ship. The stegotext in this case was the doll orders; the 'plaintext' being concealed was itself a codetext giving information about ship movements, etc. Her case became somewhat famous and she became known as the Doll Woman.
• Counter-propaganda: During the Pueblo Incident, US crew members of the USS Pueblo (AGER-2) research ship held as prisoners by North Korea communicated in sign language during staged photo ops to inform the United States that they had not defected, but had instead been captured by North Korea and were still loyal to the U.S. In other photos presented to the US, the crew members gave "the finger" to the unsuspecting North Koreans, in an attempt to discredit the pictures that showed them smiling and comfortable. [7]
• The one-time pad is a theoretically unbreakable cipher that produces ciphertexts indistinguishable from random texts: only those who have the private key can distinguish these ciphertexts from any other perfectly random texts. Thus, any perfectly random data can be used as a covertext for a theoretically unbreakable steganography. A modern example of OTP: in most cryptosystems, private symmetric session keys are supposed to be perfectly random (that is, generated by a good Random Number Generator), even very weak ones (for example, shorter than 128 bits). This means that users of weak crypto (in countries where strong crypto is forbidden) can safely hide OTP messages in their session keys.

This page is a candidate for speedy deletion. ... candle wax This page is about the substance. ... Herodotus of Halicarnassus (Greek: Hērodotos Halikarnāsseus) was a Greek historian from Ionia who lived in the 5th century BC (ca. ... For other uses, see Tattoo (disambiguation). ... Slave redirects here. ... A razor shaving some stubble off the underside of a chin. ... Persia redirects here. ... An invasion is a military action consisting of armed forces of one geopolitical entity entering territory controlled by another such entity, generally with the objective of conquering territory, or altering the established government. ... For other meanings of this term, see plan (disambiguation) Informal or ad-hoc plans are created by individual humans in all of their pursuits. ... Invisible ink is a substance used for writing, which is either invisible on application, or soon thereafter, and which later on can be made visible by some means. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... Spy and Secret agent redirect here. ... HI Mark IV microdot camera A microdot is a text or image shrunk to prevent viewing by unintended recipients. ... A full stop or period (sometimes stop, full point or dot), is the punctuation mark commonly placed at the end of several different types of sentences in English and many other languages. ... Mechanical desktop typewriters, such as this Underwood Five, were long time standards of government agencies, newsrooms, and sales offices. ... // Collodion is a solution of nitrocellulose in ether or acetone, sometimes with the addition of alcohols. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... Midtown Manhattan, looking north from the Empire State Building, 2005 New York City (officially named the City of New York) is the most populous city in the state of New York and the entire United States. ... Velvalee Dickinson (October 12, 1893 - ca. ... Accommodation address is a term used mostly in the United Kingdom to denote a location where mail can be delivered in the name of a person or business for retrieval. ... South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ... For other uses, see Doll (disambiguation). ... In the context of cryptography, a code is a method used to transform a message into an obscured form, preventing those not in on the secret from understanding what is actually transmitted. ... USS Pueblo (AGER-2) USS Pueblo, AGER-2 is a United States ship, famous for being boarded and captured by soldiers of North Korea in 1968 in what is known as the Pueblo incident. ... For other uses of terms redirecting here, see US (disambiguation), USA (disambiguation), and United States (disambiguation) Motto In God We Trust(since 1956) (From Many, One; Latin, traditional) Anthem The Star-Spangled Banner Capital Washington, D.C. Largest city New York City National language English (de facto)1 Demonym American... USS Pueblo (AGER-2) is a Banner-class technical research ship which was boarded and captured by the Democratic Peoples Republic of Korea on 23 January 1968 in what is known as the Pueblo incident or alternatively as the Pueblo crisis. ... This article is about the gesture. ... Excerpt from a one-time pad. ... There are two different meanings of the word cryptosystem. ... Symmetric-key algorithms are a class of algorithms for cryptography that use trivially related cryptographic keys for both decryption and encryption. ... A random number generator is a computational or physical device designed to generate a sequence of elements (usually numbers), such that the sequence can be used as a random one. ...

Additional terminology

In general, terminology analogous to (and consistent with) more conventional radio and communications technology is used; however, a brief description of some terms which show up in software specifically, and are easily confused, is appropriate. These are most relevant to digital steganographic systems.

The payload is the data it is desirable to transport (and, therefore, to hide). The carrier is the signal, stream, or data file into which the payload is hidden; contrast "channel" (typically used to refer to the type of input, such as "a JPEG image"). The resulting signal, stream, or data file which has the payload encoded into it is sometimes referred to as the package, stego file, or covert message. The percentage of bytes, samples, or other signal elements which are modified to encode the payload is referred to as the encoding density and is typically expressed as a floating-point number between 0 and 1.

In a set of files, those files considered likely to contain a payload are called suspects. If the suspect was identified through some type of statistical analysis, it may be referred to as a candidate.

Countermeasures

The detection of steganographically encoded packages is called steganalysis. The simplest method to detect modified files, however, is to compare them to the originals. To detect information being moved through the graphics on a website, for example, an analyst can maintain known-clean copies of these materials and compare them against the current contents of the site. The differences (assuming the carrier is the same) will compose the payload. Steganalysis is the art and science of detecting messages hidden using steganography; this is analogous to cryptanalysis applied to cryptography. ...

In general, using an extremely high compression rate makes steganography difficult, but not impossible; while compression errors provide a good place to hide data, high compression reduces the amount of data available to hide the payload in, raising the encoding density and facilitating easier detection (in the extreme case, even by casual observation).

Applications

Usage in modern printers

Main article: Printer steganography

Steganography is used by some modern printers, including HP and Xerox brand color laser printers. Tiny yellow dots are added to each page. The dots are barely visible and contain encoded printer serial numbers, as well as date and time stamps.^{[citation needed]} Printer steganography is a type of steganography produced by color printers, including HP and Xerox brand printers, where tiny yellow dots are added to each page. ...

An example from modern practice

The larger the cover message is (in data content terms—number of bits) relative to the hidden message, the easier it is to hide the latter. For this reason, digital pictures (which contain large amounts of data) are used to hide messages on the Internet and on other communication media. It is not clear how commonly this is actually done. For example: a 24-bit bitmap will have 8 bits representing each of the three color values (red, green, and blue) at each pixel. If we consider just the blue there will be 2⁸ different values of blue. The difference between 11111111 and 11111110 in the value for blue intensity is likely to be undetectable by the human eye. Therefore, the least significant bit can be used (more or less undetectably) for something else other than color information. If we do it with the green and the red as well we can get one letter of ASCII text for every three pixels. Image File history File links StenographyOriginal. ... This article is about the unit of information. ... Image which was extracted from Image:StenographyOriginal. ... This article is about the unit of information. ... A digital image is a representation of a two-dimensional image as a finite set of digital values, called picture elements or pixels. ... This article is about the storage organization of raster images. ... This article is about the picture element. ... The binary representation of decimal 149, with the lsb highlighted. ... Image:ASCII fullsvg There are 95 printable ASCII characters, numbered 32 to 126. ... This article is about the picture element. ...

Stated somewhat more formally, the objective for making steganographic encoding difficult to detect is to ensure that the changes to the carrier (the original signal) due to the injection of the payload (the signal to covertly embed) are visually (and ideally, statistically) negligible; that is to say, the changes are indistinguishable from the noise floor of the carrier.

From an information theoretical point of view, this means that the channel must have more capacity than the 'surface' signal requires, that is, there must be redundancy. For a digital image, this may be noise from the imaging element; for digital audio, it may be noise from recording techniques or amplification equipment. In general, electronics that digitize an analog signal suffer from several noise sources such as thermal noise, flicker noise, and shot noise. This noise provides enough variation in the captured digital information that it can be exploited as a noise cover for hidden data. In addition, lossy compression schemes (such as JPEG) always introduce some error into the decompressed data; it is possible to exploit this for steganographic use as well. Not to be confused with information technology, information science, or informatics. ... Channel, in communications (sometimes called communications channel), refers to the medium used to convey information from a sender (or transmitter) to a receiver. ... This article does not cite any references or sources. ... In information theory, a signal is the sequence of states of a communications channel that encodes a message. ... Redundancy in information theory is the number of bits used to transmit a message minus the number of bits of actual information in the message. ... This article is about noise as in sound. ... Digital audio comprises audio signals stored in a digital format. ... For the British rock band of the same name, see Amplifier (band). ... An analog or analogue signal is any continuously variable signal. ... Johnson-Nyquist noise, thermal noise, Johnson noise, or Nyquist noise) is the noise generated by the equilibrium fluctuations of the electric current inside an electrical conductor, which happens regardless of any applied voltage, due to the random thermal motion of the charge carriers (the electrons). ... 1/f noise is a signal or process with a frequency spectrum such that the spectral energy density is proportional to the reciprocal of the frequency. ... Photon noise simulation. ... Original Image (lossless PNG, 60. ... JPG redirects here. ...

Steganography can be used for digital watermarking, where a message (being simply an identifier) is hidden in an image so that its source can be tracked or verified. Digital watermarking is a technique which allows to add hidden copyright or other verification messages to digital audio, video, or image signals and documents. ...

In the era of digital video recorders and devices like TiVo, TV commercials authors have figured out how to make use of such devices as well—by putting a hidden message which becomes visible when played at frame-by-frame speed (see KFC Unveils 'TiVo-proof' Ad). Foxtel IQ, a digital video recorder and a satellite cable set-top box. ... TiVo (pronounced tee-voh, IPA: ) is a popular brand of digital video recorder (DVR) in the United States (and coming to Canada in December 7, 2007) and is a consumer video device which allows users to capture television programming to internal hard disk storage for later viewing (time shifting), provides...

Rumored usage in terrorism

When one considers that messages could be encrypted steganographically in e-mail messages, particularly e-mail spam, the notion of junk e-mail takes on a whole new light. Coupled with the "chaffing and winnowing" technique, a sender could get messages out and cover their tracks all at once. Wikipedia does not yet have an article with this exact name. ... E-mail spam, also known as bulk e-mail or junk e-mail is a subset of spam that involves sending nearly identical messages to numerous recipients by e-mail. ...

Rumors about terrorists using steganography started first in the daily newspaper USA Today on February 5, 2001 in two articles titled "Terrorist instructions hidden online" and "Terror groups hide behind Web encryption". In July of the same year, the information looked even more precise: "Militants wire Web with links to jihad". USA Today is a national American daily newspaper published by the Gannett Company. ... is the 36th day of the year in the Gregorian calendar. ... Year 2001 (MMI) was a common year starting on Monday (link displays the 2001 Gregorian calendar). ...

A citation from the USA Today article: "Lately, al-Qaeda operatives have been sending hundreds of encrypted messages that have been hidden in files on digital photographs on the auction site eBay.com". These rumors were cited many times—without ever showing any actual proof—by other media worldwide, especially after the terrorist attack of 9/11. A sequential look at United Flight 175 crashing into the south tower of the World Trade Center The September 11, 2001 attacks (often referred to as 9/11—pronounced nine eleven or nine one one) consisted of a series of coordinated terrorist[1] suicide attacks upon the United States, predominantly...

For example, the Italian newspaper Corriere della Sera reported that an Al Qaeda cell which had been captured at the Via Quaranta mosque in Milan had pornographic images on their computers, and that these images had been used to hide secret messages (although no other Italian paper ever covered the story). The headquarters in Milan. ...

The USA Today articles were written by veteran foreign correspondent Jack Kelley, who in 2004 was fired after allegations emerged that he had fabricated stories and invented sources. Jack Kelley was a longtime USA Today reporter and nominee for the Pulitzer Prize. ...

In October 2001, the New York Times published an article claiming that al-Qaeda had used steganographic techniques to encode messages into images, and then transported these via e-mail and possibly via USENET to prepare and execute the September 11, 2001 Terrorist Attack. 2001 : January - February - March - April - May - June - July - August - September - October - November - December Events: October 2 - Bankruptcy of Swissair. ... The New York Times is an internationally known daily newspaper published in New York City and distributed in the United States and many other nations worldwide. ... Al-Qaeda (Arabic: القاعدة, the foundation or the base) is the name given to a worldwide network of militant Islamist organizations under the leadership of Osama bin Laden. ... Usenet (USEr NETwork) is a global, decentralized, distributed Internet discussion system that evolved from a general purpose UUCP architecture of the same name. ... The World Trade Center on fire The September 11, 2001 attacks were a series of coordinated terrorist attacks against the United States on September 11, 2001. ...

The Federal Plan for Cyber Security and Information Assurance Research and Development [8], published in April 2006 makes the following statements:

• "…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…" (p 9–10)

• "International interest in R&D for steganography technologies and their commercialization and application has exploded in recent years. These technologies pose a potential threat to national security. Because steganography secretly embeds additional, and nearly undetectable, information content in digital products, the potential for covert dissemination of malicious software, mobile code, or information is great." (p 41–42)

• "The threat posed by steganography has been documented in numerous intelligence reports." (p 42)

Moreover, a captured terrorist training manual, the "Technical Mujahid, a Training Manual for Jihadis" contains a section entitled "Covert Communications and Hiding Secrets Inside Images." A brief summary is provided by the Jamestown Foundation [9].

To date, over 625 digital steganography applications have been identified by the Steganography Analysis and Research Center [10]

See also

• Canary trap
• Covert channel
• Steganographic file system
• Deniable encryption
• Encryption
• Polybius square
• Security engineering
• Camera/Shy Stand-alone browser that automatically scans for and delivers decrypted content straight from the Web.

A canary trap is a method for exposing an information leak, that involves giving different versions of sensitive information to each of a group of suspects and seeing which version gets leaked. ... In information theory, a covert channel is a communications channel that does a writing-between-the-lines form of communication. ... Steganographic file system are a kind of file system first proposed by Ross Anderson, Roger Needham, and Adi Shamir. ... In cryptography, deniable encryption allows an encrypted message to be decrypted to different sensible plaintexts, depending on the key used, or otherwise makes it impossible to prove the existence of the real message without the proper encryption key. ... Encrypt redirects here. ... In cryptography, the Polybius square, also known as the Polybius checkerboard, is a device invented by the Ancient Greek historian and scholar Polybius, described in Hist. ... Security engineering is the field of engineering dealing with the security and integrity of real-world systems. ... Hacktivismo logo Hacktivismo is an offshoot of CULT OF THE DEAD COW (cDc), whose beliefs include access to information as a basic human right. ...

External links

• Watermarking and Steganography Search Engine - search engine customized for best search steganography and digital watermarking documents and web pages.

Books

• [11] Disappearing Cryptography by Peter Wayner
• [12] Information Hiding—Techniques for Steganography and Digital Watermarking edited by Stefan Katzenbeisser and Fabien, A.P. Petitcolas
• [13] Information Hiding: Steganography and Watermarking—Attacks and Countermeasures by Neil F. Johnson, Zoran Duric, and Sushil Jajodia
• All published books about Steganography

Steganography articles

• QuickStudy:Steganography: Hidden Data at computerworld.com
• Steganography Articles, Links, and Whitepapers at Forensics.nl
• Examples showing images hidden in other images
• FBI Article: An Overview of Steganography for the Computer Forensics Examiner
• Cryptography and Steganography (web version of PowerPoint slides), 2002. Elonka Dunin's presentation of an overview of steganography, as well as a discussion of whether or not Al Qaeda might have been using steganography to plan the September 11th, 2001 attacks
• Steganography & Digital Watermarking—papers and information related to steganography and steganalysis research by Neil F. Johnson from 1995 to the present.
• Detecting Steganographic Content on the Internet, 2001. Paper by Niels Provos and Peter Honeyman, Center for Information Technology Integration, University of Michigan
• Rights Protection for Natural Language Text, includes several articles on this topic
• Network Steganography, includes articles on network steganography (Wireless LANs and VoIP).
• Steganography, Steganalysis, and Cryptanalysis BlackHat and DefCon presentations by Michael T. Raggo (aka SpyHunter)
• Invitation to BPCS-Steganography introduces you to a very large capacity steganography.
• Principle and applications of BPCS-Steganography—Original paper on BPCS-Steganography.

Elonka Dunin (born December, 1958) is an American game developer, writer, and amateur cryptographer who maintains a website dedicated to the Kryptos sculpture/cipher located at the CIAs headquarters. ... Map of major attacks attributed to al-Qaeda Al-Qaeda (also al-Qaida or al-Qaida or al-Qaidah) (Arabic: ‎ , translation: The Base) is an international alliance of terrorist organizations founded in 1988[4] by Osama bin Laden and other veteran Afghan Arabs after the Soviet War in...

Steganalysis

• Steganography Analysis and Research Center (SARC) A Backbone Security Center of Excellence providing tools for steganography detection and extraction as well as steganography examiner training.
• StegAlyzerSS An automated tool to detect and extract steganography embedded within various carrier files by numerous steganography applications.
• Steganalysis papers on attacks against Steganography, Watermarking and Countermeasures to these attacks.
• Cyber warfare: steganography vs. steganalysis For every clever method and tool being developed to hide information in multimedia data, an equal number of clever methods and tools are being developed to detect and reveal its secrets.
• "Detecting Steganographic Content on the Internet", PDF file, 813 KB.
• Some sample pages of Gaspar Schott's Schola steganographica
• Research Group An example of ongoing research on Steganography.
• StegDetect A tool to automatically find hidden messages in images embedded by seven steganography applications.
• StegSpy A tool that will detect hidden messages embedded by five steganography applications
• Analyzing steganography applications: Practical examples on how some steganography software works, and how many of them are crackable.

Implementations

Online (Hiding text)

• mozaiq Has a large library of stock photos it provides if you can't supply a photo of your own. A good starting point for creating simple steganographic examples.
• spammimic.com will take a sentence that you provide and turn it into text that looks to all the world like spam.
• Hide text in a PNG or BMP image and its corresponding decoder.

Online (Hiding files)

• Stegger, PHP Steganography—PHPClasses Repository—An open source, feature rich, secure implementation of image steganography written in PHP.

The PHPClasses Repository is a site located at http://www. ...

Downloadable (Hiding text)

• Concealar ...coz a picture speaks a thousand words! The software "Concealar" hides text into images & pictures by a password using cryptographic and steganographic techniques. Encryption algorithm used for text is AES (Rijndael) and the password is hashed with SHA512. The software don't create any noise in the resultant image so pattern-finding & pixel-mapping techniques of steganalysis don't work on this software.
• Bapuli Online—implementing steganography using Visual Basic.
• BitCrypt BitCrypt is one of the easiest to use encryption tools which at the same time provide ultra-strong encryption. It uses up to 8192 long bit key ciphers to encrypt the text, and then stores the encrypted text within bitmap images.

Downloadable (Hiding files)

• Hiding Glyph: Bytewise Image Steganography: Hides any file (or folder) into any losslessly compressed image (BMP, PNG, etc…). (freeware)
• BestCrypt Commercial Windows/Linux disk encryption software that supports hiding one encrypted volume inside another
• Crypto-Stego Utility for the Zillions of Games program.
• Digital Invisible Ink Toolkit An open-source cross-platform image steganography suite that includes both steganography and steganalysis implementations.
• FreeOTFE Free, open-source Windows/PocketPC/Linux disk encryption software that supports hiding one encrypted volume inside another, without leaving any evidence that the second encrypted volume exists. This probably resists any statistical analysis (as opposed to tools that conceal data within images or sound files, which is relatively easy to detect).
• MP3 Steganographic File System, a description of an approach to create a file system which is implemeted over MP3 files.
• OutGuess A steganography application to find data in Jpeg images.
• PCopy A steganography commandline tool with a userfriendly wizard which can produce lossless images like PNG and BMP. Special features are RLE, Huffman compression, strong XOR encryption and the Hive archiving format which enables the injection of entire directories.
• Phonebook FS protects your disks with Deniable Encryption
• RevelationA platform independent tool created in Java that can hide any data file within a 24-bit bitmap image. Features a unique wizard style interface in the encoding and decoding process.
• stego and winstego Steganography by justified plain text.
• Stego-0.5, a GNOME/GTK+ based GUI for LSB algorithm. License (GPL)
• Stego Archive Source for a large variety of steganography software.
• Steghide Free .jpeg and .wav encryption for Linux and other operating systems.
• SteGUI Free GUI for Steghide for Linux.
• TrueCrypt Free, open-source Windows/Linux disk encryption software that supports hiding one encrypted volume inside another, without leaving any evidence that the second encrypted volume exists. This probably resists any statistical analysis (as opposed to tools that conceal data within images or sound files, which is relatively easy to detect).
• Peter Wayner's website—sample implementations of steganographic techniques, by the author of Disappearing Cryptography.
• NetTools Steganography by hiding data in pictures, archives, sounds, text files, html, and lists.
• Qtech Hide & View v.01 is the newest BPCS-Steganography program for Windows. This is an image steganography. (Free to use)
• ZebDisk ZebDisk is a free software, and you can store, and share your files on the internet with it using Google’s Picasa service.
• SteganoG a simple program to hide a text file in a .bmp file.