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  2. Ciphertext - Wikipedia

    en.wikipedia.org/wiki/Ciphertext

    Polygraphic substitution cipher: the unit of substitution is a sequence of two or more letters rather than just one (e.g., Playfair cipher) Transposition cipher: the ciphertext is a permutation of the plaintext (e.g., rail fence cipher) Historical ciphers are not generally used as a standalone encryption technique because they are quite easy to ...

  3. Cipher - Wikipedia

    en.wikipedia.org/wiki/Cipher

    In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption—a series of well-defined steps that can be followed as a procedure. An alternative, less common term is encipherment. To encipher or encode is to convert information into cipher or code.

  4. Transposition cipher - Wikipedia

    en.wikipedia.org/wiki/Transposition_cipher

    The Rail Fence cipher is a form of transposition cipher that gets its name from the way in which it is encoded. In the rail fence cipher, the plaintext is written downward and diagonally on successive "rails" of an imaginary fence, then moves up when it gets to the bottom. The message is then read off in rows.

  5. One-time pad - Wikipedia

    en.wikipedia.org/wiki/One-time_pad

    A format of one-time pad used by the U.S. National Security Agency, code named DIANA.The table on the right is an aid for converting between plaintext and ciphertext using the characters at left as the key.

  6. Encryption - Wikipedia

    en.wikipedia.org/wiki/Encryption

    Around 1790, Thomas Jefferson theorized a cipher to encode and decode messages to provide a more secure way of military correspondence. The cipher, known today as the Wheel Cipher or the Jefferson Disk, although never actually built, was theorized as a spool that could jumble an English message up to 36 characters. The message could be ...

  7. 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 .

  8. Substitution cipher - Wikipedia

    en.wikipedia.org/wiki/Substitution_cipher

    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.

  9. Stream cipher - Wikipedia

    en.wikipedia.org/wiki/Stream_cipher

    A stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream . In a stream cipher, each plaintext digit is encrypted one at a time with the corresponding digit of the keystream, to give a digit of the ciphertext stream.