Code Atbash example

A simple replacement cipher used for the Hebrew alphabet and derived its name from there. Encryption occurs by replacing the first letter of the alphabet with the last one, the second with the last one. (Alef (first letter) is replaced by tau (last), bet (second) is replaced by tires (penultimate) of these combinations, the cipher gets its name)). Atbash code for the English alphabet:

Original alphabet: ABCDEFGHIJKLMNOPQRSTU VWXYZ

Replacement Alphabet: ZYXWVUTSRQPONMLKJIHGF EDCBA

Codeword cipher

The cipher using the code word is one of the simplest both in implementation and in decryption. The idea is that a code word is chosen that is written in front, then the other letters of the alphabet are written out in their order. A cipher using the WORD code word. Original alphabet: ABCDEFGHIJKLMNOPQRSTU VWXYZ

Replacement Alphabet: WORDABCEFGHIJKLMNPQST UVXYZ

As we see when using a short code word we get a very, very simple replacement. Also, we cannot use words with repeated letters as a code word, since this will lead to ambiguity in decoding, that is, the same letter of the ciphertext will correspond to two different letters of the original alphabet.