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  2. Custom hardware attack - Wikipedia

    en.wikipedia.org/wiki/Custom_hardware_attack

    Their "Deep Crack" machine cost U.S. $250,000 to build and decrypted the DES Challenge II-2 test message after 56 hours of work. The only other confirmed DES cracker was the COPACOBANA machine (Cost-Optimized PArallel COde Breaker) built in 2006. Unlike Deep Crack, COPACOBANA consists of commercially available FPGAs (reconfigurable logic gates).

  3. Merkle's Puzzles - Wikipedia

    en.wikipedia.org/wiki/Merkle's_Puzzles

    In cryptography, Merkle's Puzzles is an early construction for a public-key cryptosystem, a protocol devised by Ralph Merkle in 1974 and published in 1978. It allows two parties to agree on a shared secret by exchanging messages, even if they have no secrets in common beforehand.

  4. Cipher - Wikipedia

    en.wikipedia.org/wiki/Cipher

    asymmetric key algorithms (Public-key cryptography), where two different keys are used for encryption and decryption. In a symmetric key algorithm (e.g., DES and AES), the sender and receiver must have a shared key set up in advance and kept secret from all other parties; the sender uses this key for encryption, and the receiver uses the same ...

  5. Playfair cipher - Wikipedia

    en.wikipedia.org/wiki/Playfair_cipher

    The keyword together with the conventions for filling in the 5 by 5 table constitute the cipher key. To encrypt a message, one would break the message into digrams (groups of 2 letters) such that, for example, "HelloWorld" becomes "HE LL OW OR LD". These digrams will be substituted using the key table.

  6. Running key cipher - Wikipedia

    en.wikipedia.org/wiki/Running_key_cipher

    In classical cryptography, the running key cipher is a type of polyalphabetic substitution cipher in which a text, typically from a book, is used to provide a very long keystream. The earliest description of such a cipher was given in 1892 by French mathematician Arthur Joseph Hermann (better known for founding Éditions Hermann ).

  7. Vigenère cipher - Wikipedia

    en.wikipedia.org/wiki/Vigenère_cipher

    Although there are 26 key rows shown, a code will use only as many keys (different alphabets) as there are unique letters in the key string, here just 5 keys: {L, E, M, O, N}. For successive letters of the message, successive letters of the key string will be taken and each message letter enciphered by using its corresponding key row.

  8. Caesar cipher - Wikipedia

    en.wikipedia.org/wiki/Caesar_cipher

    In cryptography, a Caesar cipher, also known as Caesar's cipher, the shift cipher, Caesar's code, or Caesar shift, is one of the simplest and most widely known encryption techniques. It is a type of substitution cipher in which each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet .

  9. Nihilist cipher - Wikipedia

    en.wikipedia.org/wiki/Nihilist_cipher

    The standard English straddling checkerboard has 28 characters and in this cipher these became "full stop" and "numbers shift". Numbers were sent by a numbers shift, followed by the actual plaintext digits in repeated pairs, followed by another shift. Then, similarly to the basic Nihilist, a digital additive was added in, which was called ...