Cryptography, Information Theory, and Error-Correction. Aiden A. Bruen

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Cryptography, Information Theory, and Error-Correction - Aiden A. Bruen


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0 1 2 0 1 N O P Q R S T U V W X Y Z 0 0 5 0 0 0 1 1 4 0 0 0 0

      Since G is the most frequently occurring letter, we make the assumption that “e” enciphers to G. Thus the first key letter might be “C.” Similarly, for the second set of letters (i.e. the 2 Superscript n d Baseline comma 6 Superscript t h Baseline comma 1 0 Superscript t h Baseline comma ellipsis letters), we obtain the following table:

A B C D E F G H I J K L M
0 1 0 1 0 5 2 4 2 0 1 0 1
N O P Q R S T U V W X Y Z
0 1 0 1 0 4 0 1 2 1 0 0 1

      For the 3 Superscript r d Baseline comma 7 Superscript t h Baseline comma 1 1 Superscript t h Baseline comma ellipsis letters, we obtain the following frequency table:

A B C D E F G H I J K L M
1 1 0 1 1 2 2 8 0 0 2 2 0
N O P Q R S T U V W X Y Z
0 0 0 2 0 0 0 1 0 2 2 0 1

      For this set of letters, the most frequently occurring letter is H. Therefore, we make the assumption that “e” enciphers to “H.” This corresponds to a key letter of “D.”

      Finally, for the 4 Superscript t h Baseline comma 8 Superscript t h Baseline comma 1 2 Superscript t h Baseline comma ellipsis letters, we compute the frequencies to be

A B C D E F G H I J K L M
1 0 1 0
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