arabic origins of cryptology vol. 2

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The Arabic Origins ofCryptology

Book Two

ibn Adlan's Treatise al-mu'allaf lil-malik al-'Asraf

Dr. M. MRAYATI

Dr. YAHYA MEER ALAM Dr. M. HASSAN at-TAYYAN


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The Arabic Origins of Cryptology


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Translated by

Said M. al-Asaad

Revised by

Prof. Mohammed I. AL-Suwaiyel

Prof. Ibrahim A. Kadi

Marwan al-Bawab

Composition and layout

Ousama Rajab


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Contents

Table of transliterating Arabic words ...................................... 7Preface ............................................................................................ 9

Chapter 1 : Analytical Study of ibn Adl n's treatise .................. 111.1 ibn Adl n's biography ........................................................... 131.2 Study and analysis of ibn Adl n's treatise

al-mu'allaf lil-malik al-'A raf ................................................ 141.3 Structure of the treatise .......................................................... 15

1.3.1 Preface ............................................................................ 151.3.2 Rules in cryptanalysis ..................................................... 171.3.3 Conclusion- Practice and exercise .................................. 23

1.4 ibn Adl n's originality .......................................................... 24

Chapter 2 : ibn Adl n's edited treatise ....................................... 252.1 Editing methodology .............................................................. 272.2 Description of the manuscript ................................................ 282.3 al-mu'allaf lil-malik al-'A raf on cryptanalysis ..................... 31

- Preface ................................................................................ 40- Rule 1: On the Order of Letter Frequency of Occurrence .. 48- Rule 2: On the Frequency of Two-Letter Words ................ 50- Rule 3: On the Length of Cryptanalysed Message .............. 52- Rule 4: On Spacers .............................................................. 58- Rule 5: On the Cryptanalysis of the Letters ( ) & ( ) ......... 60- Rule 6: On the Quantitative Identification of Every

Word with Definite Article ..................................... 64- Rule 7: On the Four Letters Preceding the Definite Article 66- Rule 8: On Introductory Expressions and Honorary Titles 66- Rule 9: On Letters Occurring Initially in Words ................. 68- Rule 10: On Letters Occurring Terminally in Words ...... 70


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Table of transliterating Arabic wordsFor transliterating Arabic words (names, titles, etc.) we have adopted the

International System for the Transliteration of Arabic characters, devised by theInternational Standards Organization (ISO). The system constitutes ISORecommendation R233 (December 1961). Given below is this system, with someadditional explanations found to be necessary.

Vowels:Arabic characters Transliteration Examples

ShortVowels

(fat a) a as u in c up.( amma) u as o in r ock,and u in p u t.

(kasra) i as e in r ed,and i in b ig.

LongVowels

As a in l a st.

(preceded by ) as oo in m oo n.

(preceded by ) as ee in sh ee t.

Consonants:Arabic

characters Transliteration Examples

' (e.g. 'amr, 'ibr h m, fu' d, kis ' , t ').

as a in add (e.g. ' dam, qur' n).

b as b in back.

t as t in tea.

as th in th in.

as g in lo gic.

(e.g. tim).

(e.g. lid).

d as d in day.

as th in th en.


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r as r in r ed.

z as z in zoo.

s as s in soon.

as sh in sh ow.

(e.g. mi r).

(e.g. ir r).

(e.g. riq).

(e.g. fir).

(e.g. Abb s).

(e.g. lib).

f as f in f ew.

q (e.g. qur' n).

k as k in key.

l as l in led.

m as m in su m .

n as n in su n .

h as h in hot.

w as w in wet (e.g. wahab, nawfal). y as ie in or ient (e.g. y q t, dunayn r).

Notes:(t ' marb a): In the absolute state, ignored in transliteration (e.g. mad na); in

the construct state, rendered by (t) (mad nat annab ).(suk n): Ignored in transliteration.

( adda): rendered by doubling the consonant.


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Preface

This is the second book of the The Arabic Origins of Cryptology series, which addresses the cryptological contributions of the Arabs,and translates the treatises of Arab cryptologists.

We dedicate an individual book for each treatise. The first book was devoted to the oldest treatise in cryptanalysis, which was written

by the well-known Arab philosopher al-Kind about 1200 years ago.The second book (this one) of the series tackles the treatise of ibnAdl n. The third deals with the treatise of ibn ad-Durayhim. For the

time being, nine books are envisaged, unless more manuscripts arediscovered.

The first three books of the series are the translated copy of Volume One of our Arabic book entitled " ilm at-ta miya wasti r al-mu amm inda al- Arab" (Origins of Arab Cryptography andCryptanalysis). This volume has been published in Damascus in 1987.

In Book One we have allotted a full chapter to study and analysecryptology among the Arabs. We hope this will prove useful for

understanding the whole series.

* * *

This book is divided into two chapters, devoting the first chapter to an analytical study of the edited treatise of ibn Adl n. It aims atelucidating difficult or vague points, spotting particular features and,more importantly, highlighting aspects of originality and innovation inthe treatie. It is divided into four sections , the first of which is onibn Adl n's biography.

The second section is a full study and analysis of ibn Adl n's

Treatise, while the third section delineates its structure. This sectioncontains a preface, rules in cryptanalysis, and a conclusion of apractical example of a real ciphered message, explaining the steps ibnAdl n follows in cryptanalysing it.


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In the fourth section we have concluded our analysis of the treatiseby a summary exposing the aspects of ibn Adl n's originality.

* * *The second chapter comprises the full text of the edited treatise of

ibn Adl n. It opens with a preamble to the editing methodologyadopted ( Section 1 ), which basically conforms to that commonly usedby scholars and the academic community. The treatise is precededwith a brief description of the manuscript, followed by samplephotocopies of pages from the original ( Section 2 ).

The treatise itself and its English translation represent ( Section 3) ,with the English translation on the left-hand pages, and the originalArabic text on the right-hand pages.

The task of editing the manuscript text was a challenge indeed. Noeffort has been spared correcting the mistakes and clearing theconfusion.

Special care has been taken to present the text of the treatise in dueform. This includes highlighting ibn Adl n's twenty rules concerningcryptanalysis, and providing appropriate headings for those which hedid not mark with titles.

Damascus, 2003

Dr. M. MrayatiDr. Y. Meer Alam Dr. M. H. Tayyan


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Chapter 1

Analytical Study of ibn Adlan'streatise

al-mu'allaf lil-malik al-'Asraf


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1.1 ibn Adlan's biography

He is Af f ad-D n Al ibn Adl n ibn amm d ibn Alal-Maw il an-Na w al-Mutar im. He was born in Mosul in AH 583/ AD 1187, received his education in Baghdad, and learnt syntax from anumber of teachers, foremost of whom was Ab al-Baq ' al- Ukbar .Then he taught the Arabic language for a while and had manystudents. He had his class in a - li Mosque in Cairo, where he diedin AH 666/ AD 1268. He was well-known for his intelligence and wasconsidered a leading figure in literature, besides being a great poet.Perhaps all of these traits qualified him to be expert at riddles andcryptanalysis, in which he excelled and for which he dedicated morethan one book.

His works

ibn Adl n's life spanned more than eight decades, during which hewas known for his scintillating wit, his eminence in syntax, andingenuity in cryptanalysis. Yet, he turned out very little writing;sources have cited no more than three books attributed to him. Thereare reasons to believe that these sources have certainly skipped someof his works. For example there was a reference by ibn Adl n in thetwentieth rule of his treatise al-Mu'allaf lil-malik al-'A raf to thetables included in his book al-Mu lam , regarding algorithms for thecryptanalysis of a cryptogram containing symbols which are greater orless in number than the letters of the alphabet.

ibn Adl n has left the following works:1. al-'inti b lika f al-'aby t al-mu kilat al-'i r b .2. uqlat al-mu t z f all al-'al z .3. al-Mu'allaf lil-malik al-'A raf .4. al-Mu lam .


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1.2 Study and analysis of ibn Adlan's treatise

al-mu'allaf lil-malik al-'Asraf

The author, Al ibn Adl n an-Na w , had a wealth of practicalexperience in cryptanalysis which he called " all al-mutar am". Hisexperience was due to his contacts with the kings and princes of histime. His major two books in this field are: al-mu lam and al-mu'allaf lil-malik al-'A raf , the subject of our present study.

al-mu'allaf is entirely concerned with cryptanalysis. The authormade no attempt to approach the various types and methods of cryptography, as was the case with al-Kind before, and ibnad-Durayhim after him. The work is more of a manual or handbook than a theoretical book. This is indicated by its designational-muqaddima 1 (Introduction), and its division into preface, rules andconclusion, besides its omission in covering methods of cryptography,as declared by the author: " I enclose in this treatise some of mysecrets It contains only laconical words and choice meanings" 2.This idea is manifested after the conclusion of his treatise, in thecourse of addressing his reader as whence practice and exercise areattained: "Study that downright, use it in similar cases, and practise allthat I have made known to you; for this glimpse , I tell you, is of utmost advantage in this field" 3. ibn Adl n wrote his treatise as aresponse to a request from King al-'A raf, then king of Damascus.

1See his treatise, p. 40.

2Ibid., pp. 38-40.

3Ibid., p. 112.


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1.3 Structure of the treatise ibn Adl n divides his treatise into a preface, twenty rules, and a

conclusion. In the interest of facilitating analysis, and clustering topicsof a kind together, we shall break it up into three sections, each of which is composed of several related topics:1: Preface , which consists of the following three topics:

1) Cryptanalyst's tools.2) Examples of encipherment by simple substitution.3) A study in letter combination for building the Arabic word.

2: Rules in cryptanalysis , which consists of 20 rules that can begrouped into nine topics, namely:1) Analytical method for cryptanalysis (Rules 1, 2 and 3).2) Extracting the "space" (Rule 4).3) Cryptanalysing the definite article (al and adjacent letters (

(Rules 5, 6, and 7).4) The probable word (Rule 8).5) The utilization of initial and final letters of words (Rules 9

and 10).6) The use of double letters or double bigrams (Rules 11, 13,

14, and 15).

7) Cryptanalysing no- word-spacer cryptograms (Rule 12).8) Cryptanalysing enciphered poetry (Rules 16 and 17).9) Summary and helpful tips (Rules 18, 19, and 20).

3: Conclusion , which revolves around a single topic, namely practiseand exercise through a practical model example.

1.3.1 PrefaceIn his preface, ibn Adl n addressed the following three significant

topics:1. Cryptanalyst's tools:

These are the essential tools considered to be indispensable to thecryptanalysis, and are mentioned by ibn Adl n in the following detail:a) Intelligence and perspicacity.b) Dynamism.c) Thorough knowledge of language, syntax, morphology, and

structures used.


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d) Prosody and rhyme.e) Frequency of letter occurrence, association and dissociation.f) Frequency of two-letter and three-letter words in particular.g) Word spacers.h) Honorary titles and opening statements (Probable words).i) Practice and exercise.j) Familiarity with the numerous methods of encipherment.

2. Examples of encipherment by simple substitution:ibn Adl n reported, in broad outline, some of the methods of

encipherment, describing simple substitution as: "You inscribe theplain letters of any language, under which you draw agreed signs.Using these signs, you then write" 4. At this point he elaborated anissue more fully than al-Kind before him; namely, "space" (al-fa l).Moreover, he set the term "no- word-spacer" (al-mudma ) to meanencipherment without the use of space, i.e. absence of symbolsfunctioning as indicators of spaces between words.

ibn Adl n proceeds to consider the method of simple substitution(monoalphabetic), citing in each of the following two verses theArabic alphabet in such a way as to avoid the repetition of any letter:

1

2

The one represents the alphabet as being made up of 29 letters(including ); the other of 28 (excluding ). These verses he named"the regulators" (a aw be ) 5, or "key" (al-mift ) in today'sterminology, so called because knowing it leads to easily interpretingciphertexts. This point has not particularly been mentioned by al-Kind .ibn Adl n then stated two methods for utilizing these regulators. Thefirst is by exercising substitution between every couple of letters ineach of the two verses; thus d) is substituted for) (q), for ( )

( ), and so forth. The other is by substituting for each letter of theverse one letter of the alphabet respectively in order. It follows, taking


5Ibid., p. 42.


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the first verse, that ( ) would replace (q), (b) would replace ,(d) (t) instead of ( ), and so on till the end of the alphabet. Likewise,taking the other verse, ( ) would take the place of ( ), (b) theplace of ( ), etc.

ibn Adl n indicated the existence of other encipherment methods,and referred his reader to other works, preferring brevity here, as thiscompendium would not abide lengthy details. He said: "Examples of that are available in sources other than this glimpse" 6.

3. A study in letter combination for the conformation of theArabic word

This is the third topic of the Preface, termed by ibn Adl n"at-tar k b" (Structures) in which he treated combination of letters in aword, referring the reader to such principal Arabic dictionaries astah b al-'Azhar and Mu kam ibn S da . He did, however, mention thestructure of bigrams and their association and dissociation in anterioror posterior positions, and he offered worthy examples for no-word-spacer cryptanalysis that al-Kind had not given before him.

1.3.2 Rules in cryptanalysisThis section includes the twenty rules, which the author gradually

elaborated. The core of these rules may be summed up in nine topics;specifically we are more interested here in those distinguishing ibnAdl n from his predecessor al-Kind , such as the division into three

categories of letters as far as their frequency of occurrence isconcerned, cryptanalysing no-word-spacer cryptograms, the use of initial and final letters of words, and the emphasis on the use of theprobable word.

However, the predominant characteristic of this chapter is theprofound and clear development of each rule an indication of ibnAdl n's expertise and absolute command of cryptography as well as

his long experience in cryptanalysis. This point he frequentlyproclaimed: "I have broken what had been interpreted" 7, and again,


7Ibid., p. 54.


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in the context of mentioning the case of encipherment in whichseveral symbols are used for the "space": "Some of those pursuing thismethod of cryptography -with several symbols for the space- allegethat their ciphers can defy detection and analysis. I managed to solveseveral messages of this type that I was challenged to solve, and alsotwo other messages intercepted by some kings" 8. Under thenineteenth rule he also said: "When you are at a loss in solving theletter ( ), you have wrongly solved it as (y), upon which case Ihave happened more times than one" 9.

In the following paragraphs we shall review the nine topics that

constitute ibn Adl n's twenty rules:1) Analytical method for cryptanalysis:Here ibn Adl n explains the utilization of letter frequency of

occurrence in language, and also the frequency of bigrams andtrigrams, as a method for cryptanalysis. This notion has been coveredin three rules. It seems that in respect of stating the order of letteroccurrence he patterned himself upon al-Kind , so that the numbers heused for letter frequencies were identical with those determined byal-Kind , although he never makes the slightest allusion to al-Kind .But what is really original in his treatment of the subject is the

division of letters, as far as their frequency is concerned, intoabundant, common, and scarce letters as follows:

Order of letters Number LettersAbundant 7

Common 11

Scarce 10

Total 28

Another original aspect in his presentation is offering a table of thecommonest two- and three- letter words. Far more important is hisreference to the consequence of the length of the cryptogram when


9Ibid., p. 102.


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using the analytical method. As ibn Adl n puts it: "The length of thetext to be cryptanalysed should be at least in the neighborhood of ninety letters as a rule of thumb, because the letters thus would havehad three rotations. Yet the number of letters may be less than that incertain cases" 10. He reiterates this idea under the twelfth rule: "I saidthe cryptogram should be long enough, since in a short one the orderof letter frequency would no longer be applicable" 11 .

2) Cryptanalysing the "space":A "space" or "word-spacer" is the symbol used to denote the end of

a word and the beginning of another. ibn Adl n divides theencipherment of space into two kinds:(a) The unified space; i.e. , enciphering it by one and the same

symbol; and(b) The variable space; i.e. , enciphering it by more than one

symbol. He illustrates the symbols later under the fifth rule bythe following calligraphs:

He restricts himself here -in the fourth rule- to offering algorithms forcryptanalysing both kinds, emphasizing that this is the first step in

cryptanalysis.

3) Cryptanalysing the definite article ( :and adjacent letters (ibn Adl n devotes three rules (the fifth, the sixth and the seventh)

for cryptanalysing ( = al) and contiguous letters of commonoccurrence. He handles the cryptanalysing method in such a way thatexhibits his full mastery and practical experience in this art. Hementioned ciphering the definite article, first using two symbols, thenusing one symbol only, which, he notes, "are even more problematicto cryptanalyse". 12 He then shifts to discuss the length of a word and


11Ibid., p. 80.

12Ibid., p. 62.


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how this ties in with " when prefixed to it. This, indeed, is another "original aspect in his treatise.

4) The probable word:To ibn Adl n, this topic is of paramount importance. Over all other

topics, he believes, this one must take priority: "Honorary titles-probable words- should have been the first rule to mention. Since Iforgot to do that in due course, I am herein mentioning them" 13. Heexplains their meaning, giving examples of such various kinds of honorary titles as: In the name of God, the Compassionate, the

Merciful; in Your name, my gracious God (Bismika all humm); etc..Probable words are used in the same manner, whether they occur inthe opening or closing statements.

He was so keen as to invite the reader's attention to anothersignificant issue bearing upon the "probable word" concept, namely,that the cryptanalyst should take pains in fathoming the encipherer'sdegree of expertise. Should the latter be found an expert, thecryptanalyst would have to assume the most intricate possibilities. Hewould also have to make an earnest effort in what was designated byibn Adl n "surmising the occasion and attending circumstances of writing the ciphered message, and developing the context" 14. He

emphasizes that the cryptanalyst would have to relate the context of the ciphertext to occasion of writing it, since this may quite wellconduce towards cryptanalysing the message.

The importance of this argument can best be substantiated by thefact that alal l ibn 'A mad al-Far h dy had counted on it incryptanalysing a cryptogram, and in writing the first book incryptography attributed to him. In his abaq t an-Na wiyy n wal-lu awiyy n (Strata of syntax and language scientists), az-Zubaydyrelates: "It is said that the king of Greece wrote a message to alal lin Greek. The latter immured himself for about a month, working oncryptanalysing it until he succeeded in solving it. alal l latercommented: 'I presumed the message would of necessity open with


14Ibid., p. 102.


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the name of God or similar phrases. Accordingly I discovered the firstfew letters of the message, which finally yielded to interpretation'.That was the groundwork of alal l's book: al-mu amm "15.

5) The utilization of initial and final letters of words:This topic is covered by the ninth and tenth rules. ibn Adl n draws

attention to such letters often occurring initially in words, as theconjunction (w), meaning "and" in Arabic, and the preposition (k)denoting resemblance. Likewise, he also noted letters often occurringterminally such as ( ) and (h). He gives examples for all these

cases.It should be pointed out that ibn Adl n's special concentration onterms like word-spacer, the definite article ( and the initial and ,(terminal letters in words, implies that the use of no-word-spacercryptograms was a common practice in his days, contrary to the caseduring al-Kind 's period.

6) The use of double letters or double bigrams:In the eleventh, thirteenth, fourteenth and fifteenth rules, ibn Adl n

puts forward a good group of words which contain a repeated letter inpositions varying from one word to another. Once again, this serves as

an example of his extensive knowledge in the Arabic language, bydelving into myriads of books and dictionaries in order to extract rulesuseful in cryptanalysis. It is to be noted that he was the first to writeabout the importance of repetitive letters, and their use incryptanalysis, linking them with the order of letters (abundant,common and scarce).

7) Cryptanalysing no-word-spacer cryptograms:This may be the most original of all the ideas of his treatise. It

appears in Rule 12. Of those who worked on cryptology, none, as faras we know, had ever paid attention to this topic as ibn Adl n did.This fact highlights the popularity of no-word-spacer in his time.

He displays the possibilities for each of the Arabic letters to occurconsecutively several times in a text. He reviewed the Arabic alphabet

15See abaq t an-Na wiyy n wal-Lugawiyy n , p. 51.


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carefully, stating the possible times for each character to occur thisway and exemplifying his argument as often as necessary.

8) Cryptanalysing enciphered poetry:Having covered the rules of cryptanalysing prosaic (i.e. non-

metrical) cryptograms, ibn Adl n devotes the sixteenth andseventeenth rules to cryptanalyse ciphered poetry. The followingprinciples he considers sine qua non for cryptanalysing poeticalcryptograms:

a. acquaintance with prosody.

b. familiarity with rhyme.c. knowledge in hemistiches (ta r), and rhyme letter (raw ).d. the number of letters for each meter.There is generally nothing in these principles more than what had

already been propounded by al-Kind . Nevertheless, ibn Adl n'sdescription of their usage is precise, detailed and illustrated.

9) Summary and helpful tips:The last three rules (18, 19 and 20) include further views that

evince the author's experience in cryptanalysis.In the eighteenth rule, which he calls "preliminaries to

cryptanalysis" 16, he deals with the methodology of cryptanalysis byconsidering bigrams in the first place, trigrams secondly, andtetragrams lastly. He argues for systematic approach to cryptanalysisby adopting the following sequence of steps towards solution, passingfrom the completely unknown to the actual plaintext:

a. the unknown.b. the wildly guessed.c. the uncertain.d. the expected.e. the known (cryptanalysed plaintext).

Thus, ibn Adl n has specified the levels and stages for breaking a

ciphertext -- the so-called "algorithm" in today's terminology, inwhich the "answer" is reached through this measured transition froman utterly unknown cipher to a known clear text. In his treatise he

16 See his treatise, p. 100.


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frequently illustrates this algorithm and the progress of its stages byseveral examples.

In the nineteenth rule, he offers a practical method fordistinguishing the letter ( ) from the letter (y) in case of confusion.

ibn Adl n concludes his rules with a general account, callingattention to tables included in his al-mu lam . He reiterates his adviceto cryptanalysts, regarding the assumption of the most intricatepossibilities in the process of cryptanalysing a cryptogram, andeliciting the appropriate meaning for both the occasion and thecontext; namely, the use of the probable-word concept. He then moves

to talk about a type of steganography, asserting that he would allocatea special study to this kind of encipherment. Steganography was latertreated at length by al-Qalqa andy in his book ub al- A 17.

1.3.3 Conclusion- Practice and exercise

ibn Adl n brings his book to a close by presenting a practicalexample, in which he breaks a couple of lines of verse encipheredusing the method of "conceptual relationship and diffusion", where therelationship is bird species.

In cryptanalysing this example he observes the followingalgorithm:

1. Finding number of symbols.2. Extracting the word-spacer.3. Utilizing word lengths.4. Cryptanalysing the letter ( ), then the letter (l).5. Using bigrams.6. Cryptanalysing the cryptogram.

For each of the above stages the partial results are comparedthroughout the entire text.

* * *

17See ub al-'A a , 9/229 on.


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1.4 ibn Adlan's Originality

The originality of ibn Adl n, and his distinctive attribute incryptanalysis have been basically manifested in the followingunprecedented contributions:

1. He presented the treatise in the form of a practical manual ratherthan a theoretical book on cryptanalysis; thus advancing the firstcryptanalysis manual in history.

2. He offered the concept of cryptographic "Keys" or what hecalled "regulators" (a - aw bi ) in a line of verse functioning asa "key".

3. He expanded upon manipulating the "space" by publishing adetailed description of how to solve a monoalphabetic cipherwith no space or word divisions, there centuries beforeG.B.Porta (A.D. 1563). In the West Porta has been considered asthe first to write on cryptanalysing the no-word-spacercryptograms 18. ibn Adl n also treated cryptanalysingcryptograms using several symbols for the space, or what hecalled "the variable space".

4. He divided letters into abundant, common and scarce accordingto their frequency of occurrence.

5. He used word lengths and frequencies of letters in the initial andfinal positions of words for cryptanalysis. He also emphasizedthe use of two-, three-, and four-letter words respectively, givingdata on each of them.

6. He accorded special care to the "probable word" concept.7. He made good use of double and triple letters, double bigrams,

and their frequencies.In short, the information contained in this treatise is in every sense

worthy of consideration. In fact, his manual remains, even after morethan seven centuries, a useful practical guide to any cryptanalysttoday.

18See David Kahn's The Codebreakers , p. 138.


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Chapter 2

ibn 'Adlan's edited treatiseal-mu'allaf lil-malik al-'Asraf


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2.1 Editing methodology

The main purpose of editing is the reproduction of a text as close tothe author's original as possible. In line with this objective we haveopted for conserving the statement of the original whenever possible.

No effort has been spared in the interpretation of citations(Koranic verses, Prophetic traditions, lines of poetry,sayings, etc.) contained in the treatises. We have given brief biographical identification of personalities, relegating theinterested reader to such authorities as al-A l m by ayr al-D n al-Zirkily or Mu am al-mu'allif n by Omar RiKa ala, for further and more detailed biographicalreference. Those citations and personalities that our effortsfell short of their interpretation or identification have alsobeen properly recorded.

In explaining the linguistic terms included in the treatise wehave made use of various dictionaries, old and modern,foremost of which are: Lis n al- Arab and Matn al-lu a .Unless otherwise helpful, no reference has been made toany dictionary.

We have adopted the same symbols and signs commonlyemployed by editors of Arabic manuscripts. We conformedto the modern spelling norms, and we enclosed requisitecontextual additions -i.e. explanatory insertions andcomments other than the writer's own words- within squarebrackets [ ]; examples illustrating rules of enciphermenthave been set off by round brackets (parentheses) ( ); book titles in italics, quoted material and Prophetic traditionshave appeared within quotation marks " ", while floralbrackets have been used to enclose Koranic verses. 19

19Translator's explanatory additions are placed between pairs of hyphens: - -.


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2.2 Description of the manuscriptIbn 'Adl n's treatise, as stated earlier, is one of several treatises

constituting a large assemblage of papers. The aggregate is made up of (191) medium-sized sheets covering various topics, among which aretreatises on cryptology found between sheet No.(48) to No.(133)representing all that is in our possession. Ibn Adl n's treatise occupiesthe pages 89/A to 107/B, the handwriting of which varies in size, qualityand number of lines. The average number of lines in each page issomething like 14-15 lines. The assemblage copy is in the stock of theF ti Library, preserved in as-Sulaym niyya Library in Istanbul under

the number 5359. In the summer of 1980, we had the opportunity to viewthis manuscript on the premises. It was not our aim to get a photocopy of it, because we have already had one courteously presented to us byMr. 'A mad Ratib al-Naff , who had theretofore received it from hisgood friend Dr. Fu' d Sezgin in Germany as a gift. It should be pointedout that sheet No.74 of the manuscript in our possession, and perhaps inthe original manuscript, is missing.

The following is a list of the titles of treatises included in theassemblage, arranged in the order of their appearance, with the number of the first page of each beside the title:

* treatise of Ab al- asan ibn ab ab : f isti r

al-mu amm - On cryptanalysis - 48/A* Zubad fus l ibn Dunayn r f all at-tar im - Gist of ibn Dunayn r's chapters on cryptanalysis - 54/A

* Maq id al-fu l al-mutar ima an all at-tar ama - Designs of expressive chapters on cryptanalysis - 55/A

* From al- urhum 's book 80/A* From Al-bay n wattaby n by Ab al- usayn Is q

ibn 'Ibr h m ibn Sulaym n ibn Wahab al-K tib 82/A* From al- urhum 's treatise 83/A* From al- A book 87/A* al-Mu'allaf lil-malik al-'A raf on cryptanalysis 89/A

* The first essay on the summary of cryptanalysis 109/A* The second essay on cryptanalysing abstruse and

ambiguous ciphers 115/A* A treatise on the cryptanalysis of poetry, extracted

from the book: Adab a u ar ' 119/B


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A photocopy of the first page of ibn Adln's treatise

A photocopy of the title-page of ibn Adl

n's treatise

(Document No. 5359, as-Sulaym niyya Ottoman Archives, Turkey)


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A photocopy of the last page of ibn Adln's treatise

A photocopy of the second last page of ibn A

dln's treatise

(Document No. 5359, as-Sulaym niyya Ottoman Archives, Turkey)


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2.3 al-mu'allaf lil-malik al-'Asraf on cryptanalysis

(Original Arabic Text and English Translation)


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al-mu'allaf lil-malik al-'A raf on cryptanalysis

Made by

The individual nonpareil authority of knowledgeSheik Af f ad-D n Al ibn Adl n an-Na w


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In the name of God,

The Compassionate the Merciful

Praised be the Lord of grace and favour, granter of eloquence, giver

of intellect and acumen; who is able to conceal the manifest and to

manifest the concealed. Praise be to Him secretly and publicly; and

therefrom I take the safest shelter and protection against deceit and

delusion, like a goodly tree: its root set firm, its branches reaching into

sky.

And God's blessing and peace be upon His Prophet whom He hath

chosen, and upon whom He conferred His divine bestowal; who

stayed steadfast and patient in the face of affliction and misfortune;

who extinguished the fire of hostility and disbelief, and who declared

war on disbelievers and heretics. May God be pleased with the

Prophet's noble house and his courteous, faithful companions, who

positively chose the way unto their Lord.


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This addressed to our sultan King al-'A raf Mu affar ad-D n M s ,

may God prosper him and guide his steps and guard him from his

enemies; he who has always been characterized by even-handed

justice, prudence, magnanimity and omnifarious knowledge; who

typifies the statement of our Prophet, blessing and peace be upon him,

that "a sovereign is the shadow of God and His lance on earth". The

shadow is the haven for the afflicted; the lance the means for charging

the enemy and defending the homeland. With benefaction and

munificence his hand is so open beyond measure; at the same time he

is always on the look-out, holding himself in readiness to repulse the

enemy.


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Verse:

Of a verity is he on foes so hard;

And yet in leniency is unsurpassed.

Damascus was indeed blessed with becoming under his wing,

under his care and guidance. It is by him that it thrived, and through

his introduction in it of the fascinating everlasting splendours that it

came to be the delight of the eye and taste, the center of attraction, and

the destination of men of light and leading. Thus it merited the

description of being 'a thing of beauty' and a place for every grace.

My wish is to become a member of the retinue of our King. I

have therefore composed this "muqaddima" (Introduction) on

cryptanalysing the interpretation, and called it Al-Mu'allaf lil-malik

al-'A raf , according to my lights. I enclose in this treatise some of my

secrets, and thereby hoping to guard against the vicissitudes of time,

and trying to seek a resort of peace, prestige and opulence with you.


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Verse:

When earnest pain hit me in heart and face,

And life got so barren as death;

A gaunt and bleak blossom of scentless breath,

To thee I turned for help and grace!

The book contains laconical words and choice meanings, which I

made to sound like current sayings, and which would redeem any

prolixity in this concern. I pray God, the All-Hearing and Responsive,

that the king may take pleasure in it and find it suitable to his

purposes.

* * *

My Introduction is based on a preface, rules and a conclusion.

[Preface]Several factors are needed in cryptanalysing an interpreted text

[cryptogram], such as intelligence, lucidity, alertness, linguistics,

syntax, morphology, idioms, knowledge of prosody and rhymes,

frequency of letter occurrence, combination and non-combination of

letters, knowledge of the most frequently used words and those less

used: two- and three-letter words, familiarity with word spacers and

opening honorary expressions, plenty of practice and exercise thatmake perfection, and acquaintance with other numerous methods of

interpretation [ciphering].


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To encipher, you inscribe the plain letters of any language, under

which you draw agreed signs. Using these signs, you then write

-simple substitution-, adding at the end of each word the sign

indicating a space, when the interpreted text is free from no-word-

spacers. You may encipher without the use of space- i.e. without

utilizing symbols functioning as indicators of spaces between words-.

For example:

Analogous to these symbols are those cipher alphabets

(CA's = calligraphs) currently used in writing. However, what is

expressed by CA's is not Arabic. Ancient CA's may have carried

Arabic, Hindi, etc. signification. They are plaintext, and so are the

regulators [cryptographic keys], as in these two verses:


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You may exercise substitution between every pair of letters in each

of the above verses; [thus the letters d) may be substituted for the)

letter (q); the letter for ( ) ( ), and so on]. You may also

substitute for each letter of the verse one letter of the alphabet

respectively in order, and consequently, taking the second verse, [the

letter ( ) would replace ( ); the letter (b) would replace ( );

(t) in place of ( ), etc., etc.]

You may also wish to make the number of symbols the same as

that of letters, or less, in which case you would have to make up for

the insufficiency by re-starting right from the beginning. Examples of

this are available in sources other than this glimpse. Various spaces

may be used; and that is more problematic.

The lexical structures are plentiful in the lengthy books of

language, such as: Tah b al-lu a by al-Azhar , al-mu kam by ibn

S da al-Ma rib , An-nasab li a r kal m al- Arab , ibn al- abb n's A -

mil , and others. In the following paragraph we are going to touch on

these structures:


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The First Rule

On the Order of Letter Frequency of Occurrence

As far as frequency of occurrence is concerned, some Arabic lettersare ABUNDANT, and these are seven in number, i.e.: ( ( ), (l),

(m), (h), (w), (y), and (n)) [in descending rank]. If the letter ( ) occurred in a piece of writing as many times as, say, 600 times, ithas been found as a corollary, that the letter (l) would occur about400 times, add or take few, the letter (m) 320 times, the letter (h)270 times, (w) 260 times, (y) 250 times, and the letter (n) 220times. This is so in all likelihood, but there may be some variation inthis order.

Some other letters are COMMON in their frequency of occurrence.These are eleven letters, viz. (r), ( ), (f), (t), (b), (k), ,(d)

(s), (q), ( ), and also in descending order-. In the piece - ( )of writing assumed above, the letter (r) would occur 155 times orthereabouts, the letter ( ) 138 times, (f) 122 times, (t) 118, (b)and (k) 112 times each, ,d) 92) (s) 86, (q) 63, ( ) 57 and ( ) 46 times.

SCARCE letters are ten in number; [they are: ( ), ( ), ( ),,(z) ,( ) ( ), ( ), ( ), ( ), and in ascending order - ( )of frequency-]. The letters are brought together in a line of verse, andrepresented by the initial letters of its words:

Again, according to the above, the letter ( ) would occur 8 times,the letter ( ) 12 times, ( ) 15, (z) 16, ( ) 17, ( ) 20, ( ) 23,

( ) 28, ( ) 32, and .times 35 ( )The letters (t) and (k), however, may on occasion turn to be

abundant in their frequency of occurrence when they are used with the

second person a phenomenon of no small use in the Glorious

Koran. Moreover, the letter (s) may, though infrequently, go withverbs to indicate futurity.


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The Third Rule

[On the Length of Cryptanalysed Message]

The length of the text to be cryptanalysed should be at least in theneighborhood of ninety letters as a rule of thumb, because the lettersthus would have had three rotations. Yet, the number of letters may beless than that in certain cases.

I have broken, among many ciphers, the following cryptogram,enciphered by T ad-D n al- anaf :

Verses:With you, wine has a special taste, and the

meeting marvelous glamour.You promised to come alone; why did you

turn up with a tattler?!I have also broken the cipher of Ab al- asan Al ibn Abd

al- abb r al-T nis al-Mans :

Verse:Our time denied us relief in ourselves, but it

relieved us of those whom it loves and honours.Likewise I have made out the following -anonymous- verse,interpreted by Mu ammad Mu y ad-D n ibn Af f al- und , aliasAf f al-Aw n :

Verse:arb's grave is in a wasteland,

with no graves near arb's grave.I have as well contrived this verse enciphered by Abd al- af r

al-K tib in his presence:

Verse:It so happens that a man may become wealthy and solvent,

after a time of desperate straits.


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I have also cryptanalysed, on the spot, the poetical interpretation of

ibn al-Bi r q al-W si al- ill :

Verses:

ibn Adl n is well-informed in syntax and

cryptanalysis. He's a universal scholar.

These two verses, though of the brachycatalectic light metre

- ma z ' al- af f -, may be looked at as one verse of the long metre

- al- aw l -, seeing that their sum total of letters adds up to forty-seven.

To be noted is that a verse of the long metre may consist of as many as

fifty-nine letters. An example of this is the following verse of my

own:

Verse:

A virtuous man spends his life seeking

an honest living. He's righteous in weal and woe.

Furthermore, I have broken what had been interpreted specially forme, with no-word-spacer by Al ibn Muwaffaq ad-D n ibn Ya

al-Na w :

Verses:

Look into what I wrote,

for you are skilled in cryptanalysis.

Show it to me, and uncover its secrets,as you are a man of insight.


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In general, if you wish to cryptanalyse an interpreted[enciphered] text , set down each type of letter symbols; then count allthe types, specifying the number precisely. Arrange types in clustersof three orders according to their being abundant ( ( ), (l), (m), etc.

respectively), common ( (r), ( ), etc.), or scarce letters ( ( ), ( ),( ), etc.). Next, look for two-letter words and three-letter words, and

consider their frequency order, relating each one to its respectiveorder, such as: , , , , trying to approach their signification ,now by checking up on orders, now through their suitability to theexpected meaning, until the message makes sense, or else you try overagain, substituting for what you first guessed to be ( ) the letter (l)and for what you guessed to be (m) the letter (l), and so with therest until all seven abundant letters are exhausted. Then you move tothe common letters, of which you start looking, first of all, for theletters: (t) and (k), since their frequency of occurrence exceedsthat of other common letters, especially when used with the secondperson, such that they often tend to go with the abundant letters. Thenyou consider the letter (r), etc. to the last of common letters. You do

the same with the scarce letters, exercising exchange among letters, asyou did with the abundant letters, seeking to obtain intelligibility. If,in one word, two or more letters remain intractable they are tracedback individually to the scarce letters, and thus forming meaningfulwords. You do this over and over again, changing letters, until theword comes right.


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The Fourth Rule

[On Spacers]

This rule should have more rightly been marked the first. It treatsof the word-spacer the symbol used to denote a blank between everytwo words.

If the interpretation is "spaced" out using a unified space i.e.

enciphering it by one symbol only-, cryptanalysis will be easier, andcan be accomplished in two ways: (a) through observing in thecryptogram the symbol that is most recurring; and (b) through itsrecurrence at intervals that are believed to bound words. Notice thatsome words may be long, some others are short but of frequentoccurrence. (This point will be elaborated later on.) Take all that intoconsideration. Then look into what you expect are the beginnings andends of words. Having arranged the ( 's), you are now fairly sure thatwhat you supposed to be a space is most likely so. Remember,however, that a space is sometimes intentionally meant to beconcealed beside a letter that may be mistaken for a space. You had

rather give heed to that possibility. Examine the proximity of (beforeand after) the space carefully and you will detect the word-spacer,God willing.

On the other hand, if the variable space is used in the interpretation[i.e. the space enciphered by several symbols], cryptanalysis gets veryproblematical indeed. Some of those pursuing this method of cryptography allege that their ciphers can defy detection and analysis.I managed to solve several messages of this type that I was challengedto solve, and also two other [encrypted] messages intercepted by somekings. The first cryptogram I cryptanalysed was intercepted by HisMajesty King s , son of King Ab Bakr ibn Ayy b; the other for hisson, King an- i , who got hold of it from some frontiers.


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The algorithm is to look for the symbol that you believe all-likely

to be ( ). The following letter you assume to be (l). If the expected

( ) is regarded as the first letter of a word, the preceding letter would

most probably be a space. Consider the feasibility of that in several

other places of the cryptogram. If not proved feasible consider the

letter following the assumed word-spacer, since the definite article ( (

is liable to be preceded by one of four letters (to be tackled later). You

rely on word-beginnings, considering the ( s) especially at front or'

end positions of words, and assuming word-spacers anterior to the

first, and posterior to the last letters of words.

The Fifth Rule

On the Cryptanalysis of the Letters ( ) & ( (

[i.e. the definite article]

This rule is a staple aid in cryptanalysis. The algorithm is to definethe word-spacer and then to look into initial letters of words. If yousee two frequent forms which you tend to believe are the first twoletters of a word (provided the cryptogram is of a fairly reasonablelength), you then have good reason to assume that those two letters are ( ) and (l). Consider identical forms elsewhere in the cipher untilyou make it out all of it; otherwise you try another access. Now tocryptanalyse a cryptogram with no-word-spacers, you consider everycouple of combinable letters right through, according to the above

condition, attempting flexibly to guess the words themselves.Determine that the two combinable letters are ( ) and (l).Remember that in no-word-spacer cryptograms, the definite article ( (is not infrequently confused with: (min), ( an), (f ), ( al ),and suchlike. Watch that out!


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The letters ( ) and (l) [i.e. the definite article], when enciphered

both using one form [i.e. one symbol], are even more problematic to

cryptanalyse. The algorithm (for cryptanalysis) is to look for one form

recurring at the beginning of words, and which you tend to think is

( Then you look elsewhere in the cryptogram for the letter .( ( ) and

for the letter (l) individually, and cryptanalyse them, assigning a

distinctive mark to the form representing either letter. Try then to

cryptanalyse the next, and guess its meaning through the way you

articulate the word in the light of the preceding and the following

context. Otherwise you look into the symbol itself. If the word

represented is a two-letter word, you try to hit it by analogy, matching

against similar instances in several places of the cryptogram until it

gets out.

You must also consider the letter (l) elsewhere in the cryptogram.

If a form is guessed to be (l), look into the form you have alreadytaken as ( ). Any augmentation to the (l) form should be expected

as (l) of the definite article, as this would be more precise. I have

seen several forms such as this one, for example ( ) for the letter

(l) and ( ) for the letter ( ). Indeed I have seen this in many

ciphers. In addition, the variable space can be enciphered by several

symbols, such as the following calligraphs: ( ), ( ), ( ), and ( ).

Observe this carefully and you will find it out, Deo volente.


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The Sixth Rule

On the Quantitative Identification of

Every Word with Definite Article

I tell you that any such word consists of at least two letters

[exclusive of the definite article], e.g. , , , , , , ,

provided that they are not suffixed by the letter , (y). Themajority of these words are [seven] and eight-letter words, e.g.

, , , A little less frequent are words .

that do not admit the definite article, e.g. , which is a

ten-letter word. The rest may be either fourteen-letter words, such as:

:or eleven-letter words, which are really ample, such as ,

, . These words will be found of great use in

educing word-spacers, such as in the case of the existence of numerous forms that could mislead you as to believe it is not a word,

or the case of a space that you may have wrongly guessed. So keep

mindful, and do not neglect this rule; it is very rewarding in this

science; and the failure to master it is adverse to accurate

cryptanalysis.


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The Seventh Rule

[On the Four Letters Preceding the Definite Article]

The letters preceding the definite article al) may be one of four)letters, viz., in descending order of occurrence: (w), (b), (k), and

(f). Thus a letter prior to the definite article must perforce be one of them. You should think flexibly and look for identical elementselsewhere in the cipher, seeking to acquire intelligibility andcoherence of meaning. Indeed, some cryptograms are unveiled this

way. On the other hand, two of the above letters may possibly precedethe definite article; for example the letter (w) and (b) as in: ( );or (w) and (k) as in: ( ); or (f) and (w) as in: ( or ;(

(f) and (b) as in: ( .which is the rarest ,(

The Eighth Rule

On Introductory Expressions and Honorary Titles

Honorary titles [probable words] should have been the first rule tomention. Since I forgot to do that in due course, I am hereinmentioning them. Examples of honorary titles include: In the name of God, the Compassionate, the Merciful; in your name, my graciousGod (this was a common pre-Islamic opening); that which Allahwilleth will come to pass; all power appertaineth wholly to God; fromGod I take my help; praise be to Him who deserveth praise; all favourbelongeth to God; God preserveth /helpth; my trust is in God; etc.

Such expressions, if used as openings of messages and identified ashonorary titles, will facilitate cryptanalysis beyond measure.

Similarly, there are such closing honorary statements as: God'sblessing and peace be upon our prophet Mu ammad and his folk, Godbeing willing, and Peace be upon you.


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The Tenth Rule

On Letter Occurring Terminally [in Words]

Know that if the final letters of words were ( s), the preceding'

letters would most likely be ( 's), e.g. , and, from the ,

Glorious Koran: -= By the sun and

his brightness, and the moon when she followeth-. So consider that.

Less likely, they could be ( 's) such as: , , and the following

Koranic verse:

-= Our Lord! Condemn us not if we forget or miss the mark-. Be

heedful enough: use common sense and approximation, and match

against similar forms elsewhere in the cryptogram, and you are in line

for cryptanalysis, God willing.


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For the case when the two repeated orders were 's (b's), followed

by other letters, here are a few examples: , , , , , , ,

, , , , etc. I have dilated much upon this point in my book ,

al-mu lam , which I wrote for al-Im m al-Mustan ir, peace be on his

soul.

Other examples of letters repeated in one word include: (A) without

another letter in between i.e. the letter doubled- : , , , , ,

in a formal context, with the exception of ( which is frequent and in (

common use. Also: , , , , , , 20, (derived from

"to obtain"), (from "to sleep"), (from "to prevent"), , 21.

20 Name of a valley. This is the sole example in Arabic of a three-letter word, the

first and second letters of which being ( ). (See Mu am al-Buld n 5/454). 21 Nun : from na (verb) = (a) to stretch out (rope, etc.). (b) to keep silent. The verb

na is a variant of = to give.


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(B) with another letter in between: , , , , , , , , ,

, , , , , , (from "to be lenient"), (from "to be low"),

, , , , , , , , , , , , , (from "to

favor").

In some other instances you get a word in which the repeated letter

does not occur in succession with its fellow letter, but separated form

it by another intervening letter doubled in succession, e.g. -"alifs"

repeated but separated, with the letter "lam" repeated in between-,

, , .

Another possibility is to have a letter closely repeated thrice, and

enclosed on each side by another letter separately repeated. Examples:

, , (diminutive of "night"), (diminutive of (m)). 22

22 These examples, as a matter of fact, are not really illustrative of this case, but

rather of the one immediately preceding.


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As for 23

And (, , , , , ) and the like. Familiarity with these

tools is indeed helpful in cryptanalysis, so that if one or two abundant

letters of a three-letter word were cryptanalysed, the cryptogram

would come out all at once, and cryptanalysis would be much

accelerated. The same applies in the case where a scarce on common

letter is enclosed, in a three-letter word, by an abundant letter

repeated; examples: , , , , , , . Conversely, an

abundant letter may occur in between the two identical parts of a

common or scarce letter repeated, as in the examples: , ; ,

.Such is common in the language, and is worthy of note .

23 Text interrupted at this point, and a blank line follows in the original.


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The Twelfth Rule

On Cryptanalysing No-Word-Spacer Cryptograms

This requires you to find the order of frequency of letters. In casethe message is long enough, you can determine that it is a no-word-spacer cryptogram if the number of characters is found equal to that of

letters. I said the cryptogram should be long enough, since in a shortone the order of letter frequency would no longer be applicable. Alsoif, in a long cipher, the character between each two words is notfrequently recurring, you sample groups of letters. Finding twocharacters which you guess as s ( 's), you assume the first is at'terminal position of a word and the other is at initial position of thenext word. This is because, in Arabic, more than two s ( 's) do not'normally go together this way, such as: another came) and) (Adam wished) 24, although some linguists did write such

sentences using four s ( 's). Regarding the letter' (b), it can possiblyoccur four consecutive times at the most, as in: and so can ,the letter (t), as in: Three times of consecutive .occurrence is even commoner. The letters (y), ,( ) ( ), ( ) caneach occur consecutively three times, but twice is commoner. Theletter d) may also occur consecutively as many as four times; an)example: .Yet three times of repetition is more frequent. Al-Bula a linguist, poet and historian-, peace be on his soul, affected aline of poetry in which he used nine consecutive ,s (d's), namely'

24 By the two alifs is meant the terminal "hamza" of and and the initial ,

"hamza" of and .


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The word dad) is used in this verse with different senses: once)

as a proper name of person in the vocative case, with the vocative

particle ( omitted, and once as a name of particular place. Needless (

to say, this is affectation.

This last-mentioned sense of the word (dad) appears in a verse

written by arafa ibn al- Abd -a first-rate pre-Islamic poet-:

The word (dad) may also mean: trifling or frivolity, as in the

following " ad " of the tradition of Prophet Mu ammad, God's

blessing and peace be upon him: "I do not appertain to (dad), nor doth

(dad) appertain to me".

As concerns the letters ,( ) (r), ,(z) (s), ( ), ( ), ( )

and ( ), three times of consecutive occurrence is possible, but twice

is by far more frequent. The letter ( ) has greater possibility of

occurring twice consecutively, and thrice is much less common. The

letters ( ) and ( ) may well occur twice each of them, whereas the

letter (f) four successive times, e.g. ; the letter (q) three

times, e.g. . Five consecutive 's (k's) are possible, as in:

, yet four times successive occurrence is still

commoner. Al-Bula , again affected two verses, in the second of

which he massed nine 's (k's) continuously:


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.aral) = sailor in Egyptian dialect )

.kukaka) = (plural the same) type of ships)To move to other letters of the Arabic alphabet, we mention that

the letters (l), (m) and (n) may each occur four consecutive timesat most, the letter (h) three times; while five times for the letter (w), as in: , , though its succession four times iscommoner in Arabic. As for (l ), it can occur four timessuccessively, e.g. and The letter . (y) has amaximum possibility of four times, e.g. ; commoner, threetimes.

Now when you define the s ( 's) in a cipher, you see whether they'

are in front or end position of words. If found ample at end position,the characters immediately preceding, being also ample, will mostprobably be either the letter (h) or the letter (n). You then look forsimilar cases as you proceed with cryptanalysis.

You are also required to fix the number of times each character isrepeated and see to the order of letter frequency in the cryptogram.Try also to gather letters that make sense together, and review timeand again what you have had so far, in line with the instructions givenin the rule prior to this one; examples such as , etc. Pay special ,attention to the couple of letters: ( ) and (l), with their twopossibilities of collocation in relation to each other. Fully comprehend

that I have told you and ponder on it until it works out, Deo volente.


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The Thirteenth Rule

[On a Word's Initial Letter Repeated Twice]

This rule treats of the case in which individual words are obtainedby cryptanalysis, with a letter repeated twice at initial position of eachword. Except for a word like the letter repeated must necessarily ,be one of the following letters: ( ), (b), (t), (f), (k), (l), (m), (n), (l ) 25, or (y) no doubt. Awareness of this is reallyuseful and time-saving as it spares the cryptanalyst quite a lot of brainwork. Thereupon you attend to the order of these double letters,i.e. whether they are abundant, common or scarce, and work accordingly. This applies when the characters of the cryptogram areon a par with its letters.

The Fourteenth Rule

[On a Word's Terminal Letter Repeated Twice]

This is about a word cryptanalysed and identified from thepreceding and following words, with a letter repeated twice atterminal position. The repeated letter may be any one of the alphabet,with less likelihood for some, such as the letters: ( ) and ( ); andmore likelihood for some others, foremost of which are: (l), (m),

(n), (h), (w) (less likely than (h)), (b), (t), ,( ) (f) and (r). You can turn this rule to full advantage if you attend to itproperly. It is also applicable when the characters of the cryptogramare equal in number to its letters.

25 Just so in the original; but considering that two consecutive ( 's) never occur

initially in an Arabic word, the double letter may correctly be ( ).


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It should be pointed out that knowing the number of letters for each

metre makes access easier. Each of the two metres: a - aw l and

al-bas has a number of characters ranging between forty and fifty.

Should the characters be found forty, more or less, the metre would

probably be one of the following metres: a - aw l, al-mad d, al-bas ,

al-k mil, al-w fir, perfect ra az, perfect ramal, perfect sar ,

al-munsari , al- af f, perfect mutaq rib 26 . Thirty characters or

thereabouts suggest brachycatalectic mad d, al-bas , square k mil,

al-w fir, al-haza , ar-ra az, ar-ramal, as-sar , al- af f, al-mu ra ,

al-mu ta and al- mutaq rib. If the number is found a little upwards of

ten characters, this indicates certain varieties of poetical metres, such

as the curtailed munsari and ra az. No less than two-unit lines are

ever heard to have been said by Arab poets. An example from

al-munsari :

Verse:

Was there a sense of amiability,when they met in Solaf.

And from ar-ra az:

Verse:

If only I were a youth,to jump and disport myself.

26 A space occupied by an illegible word in the original Arabic manuscript.


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The relief letter -ridf-, can lend further guidance to cryptanalysis.This is the letter immediately prior to the rhyme letter, provided that itis one of the three letter: ( ( ), (w), or (y)). Examples: ( , , You realize the letter .( ( ) when enciphered

independently of any other letters, but it may assume differentrepresentation when it occur in connection with another letter. Forexample, the - i.e. + - in the word ( ) may sometimes berepresented by a single character. The letter (w) and (y) may beused either deliberately or haphazardly. Other letters may occur of necessity. That is why you should take particular heed when in doubt,

and check up on similar instances as the case may be.As for the other "ridf" letters, i.e. ( (w) and (y)), the target lettermay be either of them, or other letters like ( + ) as in ,( , .(The benefit of this distinction is obvious in this art, as it limits therange of choices exclusively to these two letters, ruling out otherpossibilities. Such being the case, you consider similar instances in thepoetical cryptogram, and thereof seek articulation according tocontext.

The so-called basal ( alif at-ta's s- is another parameter actively- (promotive of cryptanalysing poetry. In the word of thefollowing second hemistich:

the letter ( ) is basal, the letter (b) is the rhyme letter -raw -, andthe letter (l) extraneous. Examples of the kind show the letter ( )being mostly basal, whether deliberately or haphazardly. Thefollowing verse, written by ibn al- u ayn in Damascus, Godsafeguard it, is a case in point:


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Here the letter (q) in the words , may be misconstrued

as basal, the letter ( ) extraneous, and (h) the rhyme letter; but not

so. Actually the letter ( ) is the basal letter, ( ) the rhyme letter,

(q) extraneous, and (h) linkage. You act in the light of the

mainstream of the so-far cryptanalysed part of the cryptogram, and

single out the letter ( ) therefrom. This is very useful in the

cryptanalysis of poetry.

You should also be aware of the fact that several forms with

common features may be found at the end of a verse. For instance:

Here we have four letters in one word - , etc.-. The first ,

will most likely be ( ), and so will the last form, of necessity. You

also expect that the letter immediately preceding the last ( ) will

probably be either (h) or (n), as you have already known. Youthen work on the rhyme letter "raw ", trying to elicit it by means of

matching up with identical forms. There may be minor differences

concerning the first letter, as you have seen with ( ) above. Try to

understand that! It is really worthwhile, and remember that it is the

first that you have to work on.


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The Nineteenth Rule[On the Letter ( [y" at the End of Words" (

The letter (y) is copiously used in Arabic with verbs in thepresent tense, e.g. (to honor me), . (to inform me). Whenyou are at a loss in solving the letter ( ), you have wrongly solved itas (y), upon which case I have happened more times than one. Inaddition, when you have cryptanalysed a terminal (y) in a no-word-spacer cryptogram, the letter immediately preceding will most likelybe (n).

The Twentieth RuleGeneral

It should be well known to you that the forms used in a ciphermessage may be greater or less in number than the letters represented.Algorithms for cryptanalysing such cryptograms are elaborated intables included in my book al-mu lam , as they are such that cannot becovered in a resum the size of this. We have recourse to the firstseven letters since these are combinable with every letter [of thealphabet]; also we have recourse to the first six letters. All in all, it isvery problematic indeed.

You [as a cryptanalyst] would have to fathom the encipherer'sdegree of expertise. Should he be found an expert, you would have toassume the most intricate possibilities, for he is certainly conscious of that. You would also have to make an earnest effort in surmising theoccasion and the attending circumstances of writing the cipheredmessage, and developing the context. You then enter upon educing theconnotations appropriate for both occasion and context, until it is laidopen, God willing.

Furthermore, encipherment can be performed on a white sheet, thatlooks to nonexperts like blank; or, in the interest of still moreconcealment, the sheet may be loaded up with a cryptanalysable pieceof writing that is irrelevant to the substance of the message intended,for the real secret is in fact hidden there in the blank [using a type of steganography]. To this kind of encipherment I shall allocate a specialstudy, as it is a really quaint secret.


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I then moved on to the word ( of which only the letter ,( (b)

was left unsolved. I checked it against the alphabet, and the word

( "came out. I studied it so as to see whether the figure "magpie (

stood for the letter (b). To do that I considered its identical figure in

the words ( ) and ( and reflected on that for quite a while, but ,(

to no avail as yet. I left it over to the word ( of which all letters ,(

were then known except the letter (h). I came away with it

meaningfully right away; the letter ( ), being in terminal position,

warranted my belief a fortiori that (h) should have been the choice

as the preceding letter. Moving on to the word ( of which only ,(

"grackle" was still unsolved, I matched "grackle" against the letters of

the alphabet, and thereby the word ( got out. All this I did without (

as yet hitting a well-organized context after the word ) I considered .(

the counterpart of "grackle" and found it prior to "dove" in the word

( which I did cryptanalyse, obtaining the coherency required except ,(

for ( ) and ( ).


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Now I looked into the remainder of the other line. My failure at

first to solve the word ( ) in it induced me to switch over to ( ).

Upon identifying "ringdove" against the alphabet I got ( ). I made

another attempt at the word ( again unsuccessfully. I turned ,(

over to the word ( .of which only "crane" was still hidden, i.e ,(

the letter (s). I matched it against the letters of the alphabet, and the

word ( ) manifested itself. I did the same with the word ( ), of

which "bat" being the sole unknown figure. Afterwards I turned to the

word ( with the figure "blackbird" being still unsolved, and set ,(

it to the touchstone in order to bear out the authenticity of my

cryptanalysis of ( ) above. I matched "blackbird" against the

alphabet, and the letter (r) appeared. Again, in the interest of

verification, I considered the beginning of the other line, of which the

figure "nightingale" was still close, matching it against the alphabet.

The word ( got out, and rightly so, for it comports with the (general purport, in view of the conceptual relationship between the

two verses. Now that all the words of the cryptogram were practically

out, the word ( ) developed in the light of the context as well as

from the dual-form usage necessitated by it.

Study that downright, use it in similar cases, and practise all that I

have made known to you; for this glimpse, I tell you, is of utmost

advantage in this field. May God favour your intentions, and maygood luck attend your steps at all times. Praise be to God, the Lord of

the worlds, and His blessing and peace be on our Prophet Mu ammad

and his noble household.


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1

23

4

5

6

7

(1)

(2) (3) (4) (5) (6)

(7)


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1

23

4

4

5

(1) 6271230

644

6621263

53117319 (2) (3) (4) (5)

105106

1213


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1

2

34

(1)

(2) (3) 28822154 (4)


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1

23

4

5

(1) 5231129

5966001204

8141 (2) (3) 360970

7167168 (4) (5)

6431245

820613256


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1

2

3

(1)

(2) (3)


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1

2

34

(1) (2) 57611806241227

5107108 (3)

5401145

6151218 (4) 6031206

6561258

2334


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1

2

3

(1) (2) (3)


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1

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3

4

(1) (2) (3) 1128 (4)


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1

2

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(1) (2) (3)


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1

2

34

(1)

324

285

3369

(2) 9113 (3) (4)


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1

2

3

4

(1) (2) (3) (4) 5241130

5991202

12141167213513642126167


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1

2

3

(1)

(2) (3) 111


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1

(1)


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1

2

3

(1) (2)

152 (3)

116117

373


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1

2

3

4

802186 (1)

3110111 (2) 22631160 (3) 300912 (4) 2263

1160


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1

23

4

(1) (2) (3) (4)


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(1)


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12

345

6

7

(1) (2) (3) (4)

(5)

(6) (7)


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1

(1)


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arabic origins of cryptology vol. 2

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