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In cryptography, a substitution cipher is a method of encrypting in which units of plaintext are replaced with the ciphertext, in a defined manner, with the help of a key; the "units" may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. The receiver deciphers the text by performing ...
Nyctography is a form of substitution cipher writing created by Lewis Carroll (Charles Lutwidge Dodgson) in 1891. It is written with a nyctograph (a device invented by Carroll) and uses a system of dots and strokes all based on a dot placed in the upper left corner. Using the Nyctograph, one could quickly jot down ideas or notes without the aid ...
Symmetric-key algorithms[ a] are algorithms for cryptography that use the same cryptographic keys for both the encryption of plaintext and the decryption of ciphertext. The keys may be identical, or there may be a simple transformation to go between the two keys. [ 1] The keys, in practice, represent a shared secret between two or more parties ...
A secret decoder ring (or secret decoder) is a device that allows one to decode a simple substitution cipher—or to encrypt a message by working in the opposite direction. [ 1 ] As inexpensive toys, secret decoders have often been used as promotional items by retailers, as well as radio and television programs, from the 1930s through to the ...
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 ...
ROT13 ( Rotate13, " rotate by 13 places ", sometimes hyphenated ROT-13) is a simple letter substitution cipher that replaces a letter with the 13th letter after it in the Latin alphabet. ROT13 is a special case of the Caesar cipher which was developed in ancient Rome. Because there are 26 letters (2×13) in the basic Latin alphabet, ROT13 is ...
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 (Rijndael), 3-Way, Kalyna, Kuznyechik, PRESENT, SAFER, SHARK, and Square . Such a network takes a block of the plaintext and the key as inputs, and applies several alternating ...
A cipher disk is an enciphering and deciphering tool developed in 1470 by the Italian architect and author Leon Battista Alberti. He constructed a device, (eponymously called the Alberti cipher disk) consisting of two concentric circular plates mounted one on top of the other. The larger plate is called the "stationary" and the smaller one the ...