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The first letter of each ciphertext pair is the row, and the second ciphertext letter is the column, of the plaintext letter in the grid (e.g., "AF" means "row A, column F, in the grid"). Next, the fractionated message is subject to a columnar transposition. The message is written in rows under a transposition key (here "CARGO"):
DES has a key schedule in which the 56-bit key is divided into two 28-bit halves; each half is thereafter treated separately. In successive rounds, both halves are rotated left by one or two bits (specified for each round), and then 48 round key bits are selected by Permuted Choice 2 (PC-2) – 24 bits from the left half and 24 from the right ...
A good tutorial on reconstructing the key for a Playfair cipher can be found in chapter 7, "Solution to Polygraphic Substitution Systems," of Field Manual 34-40-2, produced by the United States Army. Another cryptanalysis of a Playfair cipher can be found in Chapter XXI of Helen Fouché Gaines' Cryptanalysis / a study of ciphers and their ...
Elliptic-curve cryptography (ECC) is an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields.ECC allows smaller keys to provide equivalent security, compared to cryptosystems based on modular exponentiation in Galois fields, such as the RSA cryptosystem and ElGamal cryptosystem.
Here, Alice initiates the communication to Bob . is a server trusted by both parties. In the communication: . and are identities of Alice and Bob respectively; is a symmetric key known only to and ; is a symmetric key known only to and ; and are nonces generated by and respectively; is a symmetric, generated key, which will be the session key of the session between and ; The protocol ...
Hill's cipher machine, from figure 4 of the patent. In classical cryptography, the Hill cipher is a polygraphic substitution cipher based on linear algebra.Invented by Lester S. Hill in 1929, it was the first polygraphic cipher in which it was practical (though barely) to operate on more than three symbols at once.
A Feistel network uses a round function, a function which takes two inputs – a data block and a subkey – and returns one output of the same size as the data block. [1] In each round, the round function is run on half of the data to be encrypted, and its output is XORed with the other half of the data.
Diffie–Hellman (DH) key exchange [nb 1] is a mathematical method of securely generating a symmetric cryptographic key over a public channel and was one of the first public-key protocols as conceived by Ralph Merkle and named after Whitfield Diffie and Martin Hellman.