cap cryptographic analysis program

CAPCryptographic

Analysis Program

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Breaking a Column Transposition

Once you have a good estimate for the size of a column transposition you need to discover the correct arrangement of columns

One tool that may help in this process in the Anagram tool provided by CAP It allows you to try to arrange the columns to produce words The place to begin is to look for rows that have letters that

commonly belong together

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Letter Affinity

First, in all languages there are certain letters usually of medium or low frequency which combine with other letters to form diagrams of high frequency H (medium frequency) combines with T to form TH (highest frequency) H combines with C (medium frequency) to form CH V (low frequency) combines with E to form VE (medium frequency in

military text)

Some possible RULES: When there is an H, attempts should be made to combine it with a T or

a C A V should be combined first with an E A K should be combined first with a C

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Pilot Letters

Second, there is usually in every language at least one letter which can be followed by only certain other letters forming an obligatory sequence or invariable digraph Q is always followed by U J can only be followed by a vowel X can be preceded only by a vowel and except at the end of a

word can only be succeeded by a vowel or C, H, P, T

Letters such as these with limited affinity are called pilot letters

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Centiban Scores For other possible letter pairs the Centiban table could be helpful

The US government studied a set of 5,000 digrams and produced a table of what are called centiban weights

This table contains the logarithm of twice the frequency of each digram

A B C D E F G H I J K L M N O P Q R S T U V W X Y ZA 33 45 61 73 13 38 45 25 64 13 25 76 61 89 25 58 00 82 80 83 59 48 33 00 58 00 B 38 00 00 00 66 00 00 00 25 13 00 45 13 00 38 00 00 25 13 13 25 00 00 00 48 00C 67 00 33 13 76 13 00 61 48 00 38 42 13 13 80 00 00 38 13 61 38 00 13 00 13 00D 76 38 38 51 77 51 25 25 73 13 00 33 42 38 63 42 25 58 59 62 42 33 38 00 13 00E 78 38 76 88 81 66 38 48 73 13 00 74 61 99 58 67 58 94 86 79 33 67 48 48 38 13F 42 00 25 13 55 56 13 00 80 00 00 25 13 00 80 13 00 53 33 56 33 00 13 00 13 00G 48 00 25 13 61 25 13 67 42 13 00 25 13 33 45 25 00 42 33 38 25 00 13 00 00 00H 67 13 33 25 67 42 00 00 77 00 00 13 25 33 67 13 13 64 38 74 51 00 13 00 13 00I 51 25 69 45 59 55 67 00 00 00 25 70 53 92 80 48 00 73 78 73 00 72 00 62 00 25J 18 00 00 00 25 00 00 00 00 00 00 00 00 00 25 00 00 00 00 00 25 00 00 00 00 00K 13 00 13 00 45 00 00 00 25 00 00 13 00 13 00 00 00 00 13 00 00 00 00 00 00 00L 74 33 33 53 79 33 13 13 67 00 00 73 25 13 59 33 00 25 45 51 25 25 25 00 55 00M 78 45 33 13 72 13 00 13 53 00 00 00 59 00 55 51 00 25 38 25 25 00 00 00 25 00N 72 25 67 85 87 53 73 38 75 13 25 42 42 51 66 33 13 38 71 93 48 33 33 00 42 00O 48 38 51 58 33 72 25 33 42 13 25 67 72 92 45 72 00 89 61 67 79 48 51 13 25 00P 61 13 13 13 70 25 00 33 45 00 00 59 38 13 64 56 00 66 45 51 33 13 13 00 13 00Q 00 00 00 00 00 00 00 00 00 00 00 00 13 00 00 00 00 13 00 00 62 00 00 00 00 00R 80 25 53 64 96 45 48 33 75 13 13 42 53 48 74 59 00 56 75 81 42 42 38 00 53 00S 71 33 59 42 84 58 25 72 77 00 13 25 33 38 62 55 00 42 67 88 56 13 38 00 13 00T 74 33 45 45 91 48 13 92 82 00 00 42 45 48 84 25 13 64 67 67 42 00 78 00 80 13U 42 33 33 33 56 13 51 00 42 00 00 45 42 68 13 25 00 75 58 58 00 13 00 00 00 00V 45 00 00 00 87 00 00 00 58 00 00 00 00 00 13 00 00 00 00 13 00 00 00 00 00 00W 58 00 00 00 69 00 00 38 59 00 00 13 00 25 67 00 00 13 13 00 00 00 00 00 13 00 X 25 00 25 13 13 13 00 13 25 00 00 00 00 13 13 25 00 13 13 48 00 00 00 00 00 00Y 45 25 38 38 53 56 13 13 33 00 00 25 25 45 55 33 00 38 56 62 13 00 13 00 00 00Z 13 00 00 00 25 00 00 00 13 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Second LetterFirst Letter

The higher the scorethe more likely the two letter should bepaired

cap cryptographic analysis program

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