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Playfair cipher. The Playfair cipher uses a 5×5 grid of letters, and encrypts a message by breaking the text into pairs of letters and swapping them according to their positions in a rectangle within that grid: "HI" becomes "BM". The Playfair cipher or Playfair square or Wheatstone–Playfair cipher is a manual symmetric encryption technique ...
The Two-square cipher, also called double Playfair, is a manual symmetric encryption technique. [1] It was developed to ease the cumbersome nature of the large encryption/decryption matrix used in the four-square cipher while still being slightly stronger than the single-square Playfair cipher . The technique encrypts pairs of letters ...
Confusion in a symmetric cipher is obscuring the local correlation between the input ( plaintext ), and output ( ciphertext) by varying the application of the key to the data, while diffusion is hiding the plaintext statistics by spreading it over a larger area of ciphertext. [ 2] Although ciphers can be confusion-only ( substitution cipher ...
In cryptography, an S-box ( substitution-box) is a basic component of symmetric key algorithms which performs substitution. In block ciphers, they are typically used to obscure the relationship between the key and the ciphertext, thus ensuring Shannon's property of confusion. Mathematically, an S-box is a nonlinear [ 1] vectorial Boolean function.
List of free analog and digital electronic circuit simulators, available for Windows, macOS, Linux, and comparing against UC Berkeley SPICE. The following table is split into two groups based on whether it has a graphical visual interface or not. The later requires a separate program to provide that feature, such as Qucs-S, [ 1] Oregano, [ 2 ...
Index of coincidence. In cryptography, coincidence counting is the technique (invented by William F. Friedman [ 1]) of putting two texts side-by-side and counting the number of times that identical letters appear in the same position in both texts. This count, either as a ratio of the total or normalized by dividing by the expected count for a ...
John Playfair FRSE, FRS (10 [citation needed] March 1748 – 20 July 1819) was a Church of Scotland minister, remembered as a scientist and mathematician, and a professor of natural philosophy at the University of Edinburgh. He is best known for his book Illustrations of the Huttonian Theory of the Earth (1802), which summarised the work of ...
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 substituted is bigraphic . As a concept, polygraphic substitution contrasts with monoalphabetic (or simple ...