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@@ -100,7 +100,7 @@ The Caesar cypher is considered a weak encryption mechanism because it can easil
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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.
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-**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.
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+**Example 2.** Assume for the moment that both the message and the keyword are the same length. For example, 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. The final result will be "QIX" as shown in Figure 4.
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@@ -109,7 +109,7 @@ The main weakness of the Caesar cypher is that every letter in the clear text me
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| keyword | B | E | D |
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| ciphered text | Q | I | X |
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-**Figure 4.** Letter ‘P’ in the cleartext is shifted by 1 to ‘Q’ as indicated by the corresponding letter in the keyword (B). Letter ‘E’ in the cleartext is shifted by 4 to ‘I’ as indicated by the corresponding letter in the keyword (E). Letter ‘T’ in the cleartext is shifted by 3 to ‘X’ as indicated by the corresponding letter in the keyword (D).
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+**Figure 4.** Letter ‘P’ in the cleartext is shifted by 1 to ‘Q’ as indicated by the corresponding letter in the keyword (B). Letter ‘E’ in the cleartext is shifted by 4 to ‘I’ as indicated by the corresponding letter in the keyword (E). Letter ‘T’ in the cleartext is shifted by 3 to ‘X’ as indicated by the corresponding letter in the keyword (D).
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