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Encryption
Caesar Cipher: A substitution cipher in which the cipher alphabet is merely the plain alphabet rotated left or right by some number of positions. For instance, here is a Caesar cipher using a right rotation of three places (three being the key). Base64: A data encoding scheme whereby binary-encoded data is converted to printable ASCII characters. The only characters used are the upper- and lower-case Roman alphabet characters (A-Z, a-z), the numerals (0-9), and the "+" and "/" symbols, with the "=" symbol as a special suffix code. Full specifications for base64 are contained in RFC 1421 and RFC 2440. The scheme is defined only for data whose original length is a multiple of 8 bits, a requirement met by most computer file formats. The resultant base64-encoded data has a length that is approximately 33% greater than the original data, and typically appears as seemingly random characters. RC4: In cryptography, RC4 is a symmetric key, secret key, stream cipher designed by Ron Rivest of RSA Security. Though RSA officially terms it "Rivest Cipher 4", the RC acronym is generally understood to stand for "Ron's Code". Also publicly known are his block ciphers RC2 and RC5, and the block cipher RC6 which he designed with others. RC4 was designed in 1987. RSA: The RSA algorithm is named after Ron Rivest, Adi Shamir and Len Adleman, who invented it in 1977 [RIVE78]. The basic technique was first discovered in 1973 by Clifford Cocks [COCK73] of CESG (part of the British GCHQ) but this was a secret until 1997.The RSA algorithm can be used for both public key encryption and digital signatures. Its security is based on the difficulty of factoring large integers. Vigenère Cipher: Vigenère is what cryptologists call a polyalphabetic substitution cipher system, meaning that multiple alphabets are used to encrypt a single message. It was designed in the 16th Century by a French cryptographer named Blaise de Vigenère. For a long time it was considered to be an unbreakable system, but with modern computers, Vigenère ciphers can usually be cracked quite rapidly as long as there is a large enough amount of ciphertext to work from. Morse Code: A system of representing letters, numbers and punctuation marks by means of a code signal sent intermittently. It was developed by Alfred Vail while he was helping Samuel Morse with Morse's invention of the telegraph (1835). Playfiar Cipher: A manual symmetric encryption technique invented in 1854 by Charles Wheatstone for telegraph secrecy and was the first literal digraph substitution cipher. It was used by British forces in the Boer War and World War I and also by the Australians during World War II. It is named after Wheatstone's friend Lord Lyon Playfair who popularized it. The technique encrypts pairs of letters (digraphs), instead of single letters as in the simple Substitution cipher and rather more complex Vigènere cipher systems then in use. The Playfair is thus significantly harder to break since straight frequency analysis doesn't work with it. Substitution Cipher: A substitution cipher is a cipher that replaces each plaintext symbol for another ciphertext symbol. The receiver decodes using the inverse substitution. A substitution alphabet is the extended list of ciphertext symbols. Examples are Caesar ciphers (such as ROT13) and the atbash cipher. Modular Transpose: (1) Start with a simple, small plaintext message, which will be encoded with modular transposition encoding.
Hashing MD4: MD4 is a message digest algorithm (the fourth in a series) designed by Professor Ronald Rivest of MIT. It implements a cryptographic hash function for use in message integrity checks. The digest length is 128 bits. The algorithm has influenced later designs, such as the MD5, SHA and RIPEMD algorithms. MD5: MD5 (Message-Digest Algorithm 5) is a message digest algorithm (and cryptographic hash function) with a 128-bit hash value. MD5 is one of a series of message digest algorithms designed by professor Ronald Rivest of MIT. It is an improvement upon its predecessor, MD4, made in response to some analytic work indicating that MD4 was likely to be insecure. MD4 was subsequently shown to be cryptographically insecure. DES: The NBS's popular, standard encryption algorithm. It is a product cipher that operates on 64-bit blocks of data, using a 56-bit key. It is defined in FIPS 46-1 (1988) (which supersedes FIPS 46 (1977)). DES is identical to the ANSI standard Data Encryption Algorithm (DEA) defined in ANSI X3.92-1981. RIPEMD-160: (RACE Integrity Primitives Evaluation Message Digest) is a 160-bit message digest algorithm (and cryptographic hash function) developed in Europe by Hans Dobbertin, Antoon Bosselaers and Bart Preneel, and first published in 1996. It is an improved version of RIPEMD, which in turn was based upon the design principles used in MD4, and is similar in both strength and performance to the more popular SHA-1. SHA-1: (Secure Hash Algorithm) is a message digest algorithm (and cryptographic hash function) designed by the National Security Agency (NSA) and published by the National Institute of Standards and Technology (NIST). It produces a 160-bit digest from a message with a maximum size of 264 bits, and is based on principles similar to those used by Professor Ronald L. Rivest of MIT in the design of the MD4 and MD5 message digest algorithms.
Misc. Brainfuck: Brainfuck is a minimalist computer programming language created by Urban Müller around 1993. The language is sometimes referred to as brainf*ck, brainf***, or just BF in polite company. |