plaintext letter

См. также в других словарях:

• Known-plaintext attack — The known plaintext attack (KPA) is an attack model for cryptanalysis where the attacker has samples of both the plaintext (called a crib), and its encrypted version (ciphertext). These can be used to reveal further secret information such as… …   Wikipedia

• cryptology — cryptologist, n. cryptologic /krip tl oj ik/, cryptological, adj. /krip tol euh jee/, n. 1. cryptography. 2. the science and study of cryptanalysis and cryptography. [1635 45; < NL cryptologia. See CRYPTO , LOGY] * * * Introduction …   Universalium

• 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

• Vigenère cipher — The Vigenère cipher is a method of encrypting alphabetic text by using a series of different Caesar ciphers based on the letters of a keyword. It is a simple form of polyalphabetic substitution.The Vigenère (pronEng|ˌviːdʒɪˈnɛəɹ, veedj ih nair )… …   Wikipedia

• Frequency analysis — In cryptanalysis, frequency analysis is the study of the frequency of letters or groups of letters in a ciphertext. The method is used as an aid to breaking classical ciphers.this is wrong is based on the fact that, in any given stretch of… …   Wikipedia

• Four-square cipher — The Four square cipher is a manual symmetric encryption technique. It was invented by famous French cryptographer Felix Delastelle.The technique encrypts pairs of letters ( digraphs ), and thus falls into a category of ciphers known as… …   Wikipedia

• Japanese cryptology from the 1500s to Meiji — The cipher system that Uesugi used is basically a simple substitution usually known as a Polybius square or “checkerboard.” The i ro ha alphabet contains forty eight letters, so a seven by seven square is used, with one of the cells left blank.… …   Wikipedia

• Cryptography — Secret code redirects here. For the Aya Kamiki album, see Secret Code. Symmetric key cryptography, where the same key is used both for encryption and decryption …   Wikipedia

• Playfair cipher — The Playfair cipher or Playfair square is a manual symmetric encryption technique and was the first literal digraph substitution cipher. The scheme was invented in 1854 by Charles Wheatstone, but bears the name of Lord Playfair who promoted the… …   Wikipedia

• Jefferson disk — The Jefferson disk, or wheel cypher as Jefferson named it, is a cipher system using 26 wheels, each with the letters of the alphabet arranged randomly around them. First invented by Thomas Jefferson in 1795, it did not become well known and was… …   Wikipedia

• Caesar cipher — The action of a Caesar cipher is to replace each plaintext letter with one fixed number of places down the alphabet. This example is with a shift of three, so that a B in the p …   Wikipedia