Unless completely unavoidable, data should never be analyzed using the same machine it is collected from. Instead, forensically sound copies of all data storage devices, primarily hard drives, must be made. To ensure that the machine can be analyzed as completely as possible, the following sequence of steps must be followed: Computer forensics - Examine the machine's surroundings. Look for notes, concealed or in plain view, that may contain passwords or security instructions. Secure any recordable m ...

See also:

Computer forensics, Computer forensics - Understand the suspects, Computer forensics - Electronic Evidence Considerations, Computer forensics - Secure the machine and the data, Computer forensics - Examine the machine's surroundings, Computer forensics - Record open applications, Computer forensics - Power down carefully, Computer forensics - Inspect for traps, Computer forensics - Fully document hardware configuration, Computer forensics - Duplicate the hard drives, Computer forensics - E-Mail Review

Read more here: » Computer forensics: Encyclopedia II - Computer forensics - Secure the machine and the data

See also:

Computer insecurity, Computer insecurity - Security and systems design, Computer insecurity - Financial cost, Computer insecurity - Reasons, Computer insecurity - Vulnerabilities, Computer insecurity - Code exploits, Computer insecurity - Eavesdropping, Computer insecurity - Social engineering and human error, Computer insecurity - Denial of service attacks, Computer insecurity - Indirect attacks, Computer insecurity - Backdoors, Computer insecurity - Direct access attacks, Computer insecurity - Reducing vulnerabilities, Computer insecurity - Security measures, Computer insecurity - Difficulty with response, Computer insecurity - Further reading

Read more here: » Computer insecurity: Encyclopedia II - Computer insecurity - Security and systems design

In cryptography, a Caesar cipher, also known as a Caesar's cipher or the shift cipher, is one of the simplest and most widely-known encryption techniques. It is a type of substitution cipher in which each letter in the plaintext is replaced by a letter some fixed number of positions further down the alphabet. For example, with a shift of 3, A would be replaced by D, B would become E, and so on. The method is named after Julius C ...

Including:

Caesar cipher - Example Caesar cipher - History and usage Caesar cipher - Breaking the cipher

Read more here: » Caesar cipher: Encyclopedia - Caesar cipher

The Colossus machines were early computing devices used by British codebreakers to read encrypted German messages during World War II. Colossus was an early electronic digital computer. Colossus was designed by engineer Tommy Flowers at the Post Office Research Station, Dollis Hill. The prototype, Colossus Mark I, was operational at Bletchley Park in February 1944. An improved Colossus Mark II was first installed in June 1944, and ...

Including:

Colossus computer - Purpose and origins Colossus computer - The construction of Colossus Colossus computer - Design and operation Colossus computer - Influence and fate Colossus computer - Reconstruction Colossus computer - Other meanings

Read more here: » Colossus computer: Encyclopedia - Colossus computer

SIGINT stands for SIGnals INTelligence, which is intelligence-gathering by interception of signals, whether by radio interception or other means. SIGINT - SIGINT. SIGINT is actually a broad discipline under which multiple sub-disciplines fall. There are three major sub-disciplines that fall under SIGINT which are COMmunications INTelligence (COMINT), ELectronic INTelligence (ELINT), and Foreign Instrumentation Signals INTelligence (FISINT ...

Including:

SIGINT - SIGINT SIGINT - Past and present SIGINT activities

Read more here: » SIGINT: Encyclopedia - SIGINT

In cryptanalysis, a brute force attack is a method of defeating a cryptographic scheme by trying a large number of possibilities; for example, exhaustively working through all possible keys in order to decrypt a message. In most schemes, the theoretical possibility of a brute force attack is recognised, but it is set up in such a way that it would be computationally infeasible to carry out. Accordingly, one definition of "breaking" a cryptographic sch ...

Including:

Brute force attack - Symmetric ciphers Brute force attack - Asymmetric algorithms Brute force attack - Theoretical limits

Read more here: » Brute force attack: Encyclopedia - Brute force attack

An analysis is a critical evaluation, usually made by breaking a subject (either material or intellectual) down into its constituent parts, then describing the parts and their relationship to the whole. See also analytic and synthesis and the Scientific Method. As such, it can be applied in many different fields of study: In philosophy: philosophical analysis In mathematics: mathematical analysis real analysis - real numbers complex analysis - holo ...

Read more here: » Analysis: Encyclopedia - Analysis

A computer is a machine capable of processing data according to a program — a list of instructions. The data to be processed may represent many types of information including numbers, text, pictures, or sound. Computers can be extremely versatile. In fact, they are universal information processing machines. According to the Church-Turing thesis, a computer with a certain minimum threshold capability is in principle capable of performing the tasks of any other computer, from those of a personal digital assistant ...

Including:

Computer - History of computing Computer - How computers work: the stored program architecture Computer - Digital circuits
Computer - I/O devices Computer - Programs
Computer - Computer applications
Computer - Networking and the Internet
Computer - Computing professions and disciplines

Read more here: » Computer: Encyclopedia - Computer

It is absolutely vital for the forensics team to have a solid understanding of the level of sophistication of the suspect(s). If insufficient information is available to form this opinion, the suspects must be considered to be experts, and should be presumed to have installed countermeasures against forensic techniques. Because of this, it is critical that you appear to the equipment to be as indistinguishable as possible from its normal users until you have shut it down completely, either in a manner which provably prohibits the machin ...

See also:

Computer forensics, Computer forensics - Understand the suspects, Computer forensics - Electronic Evidence Considerations, Computer forensics - Secure the machine and the data, Computer forensics - Examine the machine's surroundings, Computer forensics - Record open applications, Computer forensics - Power down carefully, Computer forensics - Inspect for traps, Computer forensics - Fully document hardware configuration, Computer forensics - Duplicate the hard drives, Computer forensics - E-Mail Review

Read more here: » Computer forensics: Encyclopedia II - Computer forensics - Understand the suspects

In cryptography, a block cipher is a symmetric key cipher which operates on fixed-length groups of bits, termed blocks, with an unvarying transformation. When encrypting, a block cipher might take a (for example) 128-bit block of plaintext as input, and output a corresponding 128-bit block of ciphertext. The exact transformation is controlled using a second input — the secret key. Decryption is similar: the decryption algorithm takes a 128-bit block of ciphertext together with the secret key, and yields the original 128-bit block of plaintext. To encrypt messages longer than the block size (128 bits ...

Including:

Block cipher - Generalities
Block cipher - Iterated block ciphers
Block cipher - History Block cipher - Cryptanalysis

Read more here: » Block cipher: Encyclopedia - Block cipher

Information theory is the mathematical theory of data communication and storage, generally considered to have been founded in 1948 by Claude E. Shannon. The central paradigm of classic information theory is the engineering problem of the transmission of information over a noisy channel. The most fundamental results of this theory are Shannon's source coding theorem, which establishes that on average the number of bits needed to communicate the result of an uncertain event is given by the entropy of that uncertainty; and ...

Including:

Information theory - Mathematical preliminaries Information theory - Basic Concepts for Discrete Channels
Information theory - Self-information Information theory - Entropy Information theory - Joint Entropy Information theory - Conditional Entropy Equivocation Information theory - Mutual Information Transinformation
Information theory - Continuous Channels Information theory - Channel Capacity Information theory - Source Theory
Information theory - Rate
Information theory - Fundamental Theorem
Information theory - Statement Noisy-Channel Coding Theorem
Information theory - Channel capacity of particular model channels Information theory - Related Concepts
Information theory - Measure Theory Information theory - Kolmogorov Complexity
Information theory - Applications
Information theory - Coding Theory Information theory - Cryptography Cryptanalysis Information theory - Relation with thermodynamic entropy Information theory - Quantum Information Theory Information theory - Detection and Estimation Theory Information theory - Gambling Information theory - Intelligence Information theory - Music
Information theory - History

Read more here: » Information theory: Encyclopedia - Information theory

In cryptanalysis, a crib is a sample of known plaintext; the term originated at Bletchley Park, the British codebreaking operation during World War II (WWII). Their usage was adapted from the term meaning a bit of a cheat, for example, "I cribbed my answer from your test paper". The original sense of a "crib" was a literal or interlinear translation of a foreign language text — usually a Latin or Greek text — that st ...

Read more here: » Crib cryptanalysis: Encyclopedia - Crib cryptanalysis

An umbrella term is a word that provides a superset or grouping of related concepts. Thus cryptology is an umbrella term that encompasses cryptography and cryptanalysis. Similarly, an "umbrella group" can be an organisation which is a central and co-ordinating body representing a number of smaller, separate bodies. Umbrella term - Examples in archaeology/anthropology. Grave goods Venus figurines: (They extend over diverse time periods.) Votive deposit: (They are 'essentially' in ever ...

Including:

Umbrella term - Examples in archaeology/anthropology Umbrella term - Examples in earth sciences Umbrella term - Other examples

Read more here: » Umbrella term: Encyclopedia - Umbrella term

Ultra (sometimes capitalised ULTRA) was the name used by the British for intelligence resulting from decryption of German communications in World War II. The term eventually became the standard designation in both Britain and the United States for all intelligence from high-level cryptanalytic sources. The name arose because the code-breaking success was considered more important than the highest security classification available at the time (Most Secret) and so was regarded as being Ultra Secret. Much of t ...

Including:

Ultra - Sources and history
Ultra - Encrypted messages Ultra - Breaking the cipher
Ultra - Use of Ultra Ultra - Magic and Purple in Europe Ultra - Postwar public disclosure of Ultra
Ultra - Difficulties with some disclosures
Ultra - Ultra's strategic consequences
Ultra - Wartime consequences Ultra - Postwar consequences
Ultra - Notes

Read more here: » Ultra: Encyclopedia - Ultra

The Data Encryption Standard (DES) is a cipher (a method for encrypting information) selected as an official Federal Information Processing Standard (FIPS) for the United States in 1976, and which has subsequently enjoyed widespread use internationally. The algorithm was initially controversial, with classified design elements, a relatively short key length, and suspicions about a National Security Agency (NSA) backdoor. DES consequently came under intense academic scrutiny, and motivated the ...

Including:

Data Encryption Standard - History of DES
Data Encryption Standard - NSA's involvement in the design Data Encryption Standard - The algorithm as a standard Data Encryption Standard - Chronology
Data Encryption Standard - Replacement algorithms Data Encryption Standard - Description
Data Encryption Standard - Overall structure Data Encryption Standard - The Feistel F function Data Encryption Standard - Key schedule
Data Encryption Standard - Security and cryptanalysis
Data Encryption Standard - Brute force attack Data Encryption Standard - Attacks faster than brute-force Data Encryption Standard - Minor cryptanalytic properties

Read more here: » Data Encryption Standard: Encyclopedia - Data Encryption Standard

Unicity distance is a term used in cryptography referring to the length of an original ciphertext needed to break the cipher by reducing the number of possible spurious keys to zero in a brute force attack. That is, after trying every possible key, there should be just one decipherment that makes sense. Consider an attack on the ciphertext string "WNAIW" encrypted using a Vigenere cipher with a five letter key. Conceivably, this string could be deciphered into any other string — RIVER and WATER are both possibilities f ...

Read more here: » Unicity distance: Encyclopedia - Unicity distance

Cryptography is the field concerned with linguistic and mathematical techniques for securing information, particularly in communications. Historically, cryptography was concerned solely with encryption; that is, means of converting information from its normal, comprehensible form into an incomprehensible format, rendering it unreadable without secret knowledge. Encryption was used primarily to ensure secrecy in important communications, such as those of spies, military leaders, and diplomats. In recent decades, however, the fie ...

Including:

Cryptography - Terminology Cryptography - Cryptanalysis Cryptography - History of cryptography Cryptography - Secure communications Cryptography - Symmetric key cryptography Cryptography - Public key cryptography Cryptography - Other topics

Read more here: » Cryptography: Encyclopedia - Cryptography

The VENONA project was a long-running and highly secret collaboration between United States intelligence agencies and the United Kingdom's MI5 and GCHQ that involved the cryptanalysis of messages sent by several Soviet intelligence agencies. There were known to be at least 13 code words for this effort used by the US and UK. VENONA was the last code word for the project. In the early years of the Cold War, VENONA would be an important source on Soviet intelligence activity for the Western powers. Although unknown to the public, ...

Including:

VENONA project - Background VENONA project - The break-in VENONA project - Results VENONA project - Public disclosure VENONA project - Significance VENONA project - Document release issues VENONA project - Notes VENONA project - Additional background material

Read more here: » VENONA project: Encyclopedia - VENONA project

In statistics, the term cross-correlation is sometimes used to refer to the covariance cov(X, Y) between two random vectors X and Y, in order to distinguish that concept from the "covariance" of a random vector X, which is understood to be the matrix of covariances between the scalar components of X. In signal processing, the cross-correlation (or sometimes "cross-covariance") is a measure of similarity of two signals, commonly used to find features in an unknown signal by c ...

Including:

Cross-correlation - Properties

Read more here: » Cross-correlation: Encyclopedia - Cross-correlation

Cryptography List of cryptographers - Pre-computer. Charles Babbage, UK, 19th century mathematician who, about the time of the Crimean War, secretly developed an effective attack against polyalphabetic substitution ciphers. His development was published independently a few years later by Friedrich Kasiski, a Prussian officer. Babbage also designed, and had partially built, the first programmable digital computer, the Analytical Engine. He first designed and had partially bui ...

Including:

List of cryptographers - Pre-19th century List of cryptographers - Pre-computer List of cryptographers - Modern List of cryptographers - External link

Read more here: » List of cryptographers: Encyclopedia - List of cryptographers