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README-en.md

 
 ###The Vigenere Cypher 
 
-A main weakness of the Caesar cypher is that every letter in the clear text message is shifted by the same number of positions. The Vigenere cypher is a somewhat stronger encryption method because the shift used on each letter is not constant. Whereas the Caesar cypher receives as an input a clear text message and a displacement, the Vigenere receives the clear text message and **keyword**. For now, let's assume that the keyword and the clear text message have the same length. The Vigenere cypher uses the keyword to determine the shift that will be applied to each letter of the cleartext message, i.e. the first letter of the keyword determines the shift number for the first letter of the message and so forth. 
+The main weakness of the Caesar cypher is that every letter in the clear text message is shifted by the same number of positions. The Vigenere cypher is a somewhat stronger encryption method because the shift used on each letter is not constant. The Caesar cypher receives as an input a clear text message and a displacement, while the Vigenere receives as a data entry the clear text message and **keyword** that determines the displacement that will have every letter in the clear text message. 
 
 **Example 2.** Suppose that the cleartext is “PET” and the keyword is “BED”. Each letter in the **keyword** determines the shift amount of the corresponding letter in the cleartext: letter ‘A’ specifies a shift of 0, ‘B’ is a shift of 1, and so on.  Thus, the ‘B’ in the keyword “BED” states that we shall shift the first letter of the cleartext by 1, the ‘E’ states that we will shift second the letter by 4 and the ‘D’ states that we will shift the last letter by 3.