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# chapter_09(pd) - Chapter 9 The Cipher Exchange and Cipher...

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30 Chapter 9 The Cipher Exchange and Cipher Guidelines The Cipher Exchange ( CE ) is that department of The Cryptogram that deals with ciphers which are NOT simple substitutions of the Aristocrat/Patristocrat variety. Here you will find the fruits of several hundred years of development of cryptography, as cryptanalysts discovered new ways to attack a cipher, and the encipherers then complicated the ciphers to compensate. Some of the ACA systems were used historically in precisely the form we use; some are simplified to highlight unique aspects of that cipher type; and some were invented by ACA members. ciphers given in are all solvable by pencil and paper methods, although computers and other mechanical aids are often used to assist. The ciphers are printed in approximate order of difficulty (as determined by experience) in The Cryptogram . They are listed in alphabetical order below, together with the length recommended for a suitable plaintext. AMSCO (period times 8-12 lines deep) The first entry may be either a digraph or a single letter. In both even and odd periods the first column and the first row always alternate. Solvers should be aware that a null is not required when the end of the text does not fill out the digraph-single letter or single letter-digraph pattern. Key : 41325 pt : Incomplete columnar with alternating single letters and digraphs. 4 1 3 2 5 in c om p le t ec o lu m na r wi t ha l te r na t in g si n gl e le t te r sa n dd i gr a ph s CT : CECRT EGLEN PHPLU TNANT EIOMO WIRSI TDDSI NTNAL INESA ALEMH ATGLR GR.

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31 AUTOKEY (40-55 letters) See: Vigenère This example is a Vigenère Autokey. Find Vigenère Table in Appendix 2 or use the insert. pt : The autokey can be used with Vigenère, Variant, Beaufort or Porta. Key : PRIMER K : P R I M E R T H E A U T O K E Y C A N B E U S E D W I T H pt : t h e a u t o k e y c a n b e u s e d w i t h v i g e n e CT : I Y M M Y K H R I Y W T B L I S U E Q X M N Z Z L C M G L K : V I G E N E R E V A R I A N T B E A U F O R T O pt : e r v a r i a n t b e a u f o r t o r p o r t a CT : M M B E E M R R O B V I U S H S X O L U C I M O CT : IYMMY KHRIY WTBLI SUEQX MNZZL CMGLM MBEEM RROBV IUSHS XOLUC IMO.
32 BACONIAN (25-letter plaintext maximum) A = aaaaa E = aabaa I/J= abaaa N = abbaa R = baaaa W = babaa B = aaaab F = aabab K = abaab O = abbab S = baaab X = babab C = aaaba G = aabba L = ababa P = abbba T = baaba Y = babba D = aaabb H = aabbb M = ababb Q = abbbb U/V= baabb Z = babbb Replace each plaintext letter with its Baconian equivalent. Example 1: pt : s u c c e s s baaab baabb aaaba aaaba aabaa baaab baaab The a-units and b-units are concealed; in this example the initial letter of each word indicates a or b: A-M = a, N-Z = b. CT : Now is a good time to attend college. School work is a good teacher and a good builder of character. Every man should be a student and learn all that there is about a subject.

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chapter_09(pd) - Chapter 9 The Cipher Exchange and Cipher...

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