CAP Cryptographic Analysis Program

1. CAPCryptographic Analysis Program Anagram Help Presentation Press Enter or click on your mouse button to continue

2. 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

3. 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

4. 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

5. 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 The higher the scorethe more likely the two letter should be paired Second Letter F i r s t L e t t e r 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 Z A 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 00 C 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 00 D 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 00 E 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 13 F 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 00 G 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 00 H 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 00 I 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 25 J 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 00 K 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 00 L 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 00 M 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 00 N 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 00 O 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 00 P 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 00 Q 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 00 R 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 00 S 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 00 T 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 13 U 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 00 V 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 00 W 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 00 Y 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 00 Z 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