Viginere cipher is a much more complex form of a Caesar cipher. It is formed by taking the alphabet and a key to make an encrypted message. It uses each letter of the key as an index for the Caesar cipher to substitute the letter. In a Caesar cipher, each letter of the alphabet is shifted along some number of places. For example, in a Caesar cipher of shift 2, A would become C, B would become D, and so on. The Vigenere cipher has several Caesar ciphers in sequence with different shift values which are extracted from the key. Each letter of the key holds the value for the Caesar cipher. A = 0, B = 1, C = 2, and so on. We also have to extend or cut the key until it matches the length of the plain text.
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