to encrypt a secret message
21Enigma machine — Military Enigma machine …
22Internet security — is a branch of computer security[1] specifically related to the Internet. Its objective is to establish rules and measures to use against attacks over the Internet.[2] The Internet represents an insecure channel for exchanging information leading …
23Classical cipher — A cipher is a means of concealing a message, where letters of the message are substituted or transposed for other letters, letter pairs, and sometimes for many letters. In cryptography, a classical cipher is a type of cipher that was used… …
24Diffie–Hellman key exchange — (D–H)[nb 1] is a specific method of exchanging keys. It is one of the earliest practical examples of key exchange implemented within the field of cryptography. The Diffie–Hellman key exchange method allows two parties that have no prior knowledge …
25Symmetric-key algorithm — Symmetric key algorithms are a class of algorithms for cryptography that use trivially related, often identical, cryptographic keys for both decryption and encryption.The encryption key is trivially related to the decryption key, in that they may …
26Glossary of cryptographic key types — This glossary lists types of keys as the term is used in cryptography, as opposed to door locks. Terms that are primarily used by the U.S. National Security Agency are marked (NSA). For classification of keys according to their usage see… …
27Colossus computer — Colossus MkI/MkII A Colossus Mark 2 computer. The operator on the left is Dorothy Duboisson. The slanted control panel on the left was used to set the pin patterns on the Lorenz. The bedstead paper tape transport is on the right. Developer Tommy… …
28List of cryptographic key types — This glossary lists types of keys as the term is used in cryptography, as opposed to door locks. Terms that are primarily used by the U.S. National Security Agency are marked (NSA) . For classification of keys according to their usage see… …
29Coppersmith's Attack — describes a class of attacks on the public key cryptosystem RSA based on Coppersmith s theorem (see below). The public key in the RSA system is a tuple of integers (N,e), where N is the product of two primes p and q. The secret key is given by an …
30Steganography — is the art and science of writing hidden messages in such a way that no one apart from the sender and intended recipient even realizes there is a hidden message. By contrast, cryptography obscures the meaning of a message, but it does not conceal …
