substitution key

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• Substitution cipher — In cryptography, a substitution cipher is a method of encryption by which units of plaintext are replaced with ciphertext according to a regular system; the units may be single letters (the most common), pairs of letters, triplets of letters,… …   Wikipedia

• Substitution box — In cryptography, a substitution box (or S box) is a basic component of symmetric key algorithms. In block ciphers, they are typically used to obscure the relationship between the plaintext and the ciphertext mdash; Shannon s property of confusion …   Wikipedia

• Substitution instance — In propositional logic, a substitution instance of a propositional formula is a second formula obtained by replacing symbols of the original formula by other formulas. A key fact is that any substitution of a tautology is again a tautology.… …   Wikipedia

• substitution — 1. In chemistry, the replacement of an atom or group in a compound by another atom or group ( e.g., s. of H by Cl in CH4 to give CH3Cl). 2. In psychoanalysis, an unconscious defense …   Medical dictionary

• Substitution-permutation network — In cryptography, an SP network, or substitution permutation network (SPN), is a series of linked mathematical operations used in block cipher algorithms such as AES.These networks consist of S boxes and P boxes that transform blocks of input bits …   Wikipedia

• substitution code —   n.    a code whose individual characters are converted to individual key cuts or combination numbers by means of a reference table …   Locksmith dictionary

• Chord substitution — Tritone substitution: F♯7 may substitute for C7, and vice versa, because they both share E♮ and B♭/A …   Wikipedia

• Finger substitution — is a playing technique used on many different instruments, ranging from stringed instruments such as the violin and cello to keyboard instruments such as the piano and pipe organ. It involves replacing one finger which is depressing a string or… …   Wikipedia

• Running key cipher — In classical cryptography, the running key cipher is a type of polyalphabetic substitution cipher in which a text, typically from a book, is used to provide a very long keystream. Usually, the book to be used would be agreed ahead of time, while… …   Wikipedia

• Polygraphic substitution — A polygraphic substitution is a cipher in which a uniform substitution is performed on blocks of letters. When the length of the block is specifically known, more precise terms are used: for instance, a cipher in which pairs of letters are… …   Wikipedia

• Reseau de substitution-permutation — Réseau de substitution permutation En cryptographie, un réseau de permutation substitution (SPN en anglais) est une architecture utilisée dans les chiffrements par bloc comme AES. Elle consiste en une série de transformations mathématiques sur le …   Wikipédia en Français