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19~ 

pp roved for Release by NSA on 10-09-2013 

ursuantto E.O. 13526 
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LECTURE NOTE 'I 1~1 

How I came to be a cryptanalyst. Riverbank - the 

unofficial Black Chamber. The School of Cryptography. 


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LECTURE NOTE 

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FOR SLIDE 33, ~ 

One of the ciphers used by the Hindu conspirators - 1916-17 
LECTURE NOTE 

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FOR SLIDE 34 

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LECTURE NOTE 

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FOR SLIDE 82 

One of the classes of student officers at the 

Ri.verbank School of Cryptography, 1917-18. 

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FOR SLIDE 11 

Cipher system used b,y the Russians in World War I 

(from a book b,y the Austrian cryptologist, Andreas 

Figl) 

/jidsuse of this cryptographic system (or failure to 

use) cost the Russians the defeat at Tannenbergj] 

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13 
LECTURE 

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FOR. SLIDE l4 

The German ADFGVX cipher system, used by the German 

High Command during World War I. 

~rst new system used by them._ Invented by putting 

together two well-known steps,,/ 
LECTURE 

The Playfair Cipher -

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FOR SLIDE 23 

/.This cipher was used by the BritiSh and Americans, 

and was thought to be 0 hot stuff" in 1914. Solution 

was described in Mauborgne 1s ~An advanced problem 

in cryptographylf. 

Cipher allegedly invented by Playfair, but he d:Ld 

not do it -- rather Wheatstone. Wheatstone is 

credited with hav'ng invented the electrical bridge, 

but he did not do it --rather Christy.:J 

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FOR SLIDE 16 

An example of a commerical code 

LGaJ.l attention to 2-letter difference. All kinds, 

suited and specially constructed for general or 

specific businesses and industries, such as leather, 

steel, automotive, shipping, etc;J 
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LECTURE FOR SLIDE 18 

A highly specialized Rcommerical code~ 

LOall attention to 3-letter difference: 

YGATA - 00?.f.A 

YGKRO - DELIRIUM TREMENS 

YGCIB • CONSTIPATION 

YGMAN - DIARRHEA 
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11 
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LECTURE NOTE 

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FOR SLIDES 19-22 

Prior to World War I and, in fact, for the first two 

years of World War I code was thought to be impractical 

for JDJ.litary field or tactical use. But the Germans 

began to use code late in 1916, and the Allies followed 

suit. Question of reproduction then as it is today. 

Field Codes in WW I - will show only one example in 

slides -- the German type of KRUSA code. Exhibits 

can be examined later. 
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LECTURE 

FOR SLIDE 20 

One ot the German. Army Field Codes, World War I 

KRU 

KRUS 

KR USA 

676 x 3 1928 (1) 

..!tl.2 

2604 (2) 

676 

3280 (3) 
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LECTURE 

An early AEF Code in World War I 

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FOR SLIDE 21 

~ indication of how poorly prepared we were for 

COUSEY 

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LECTURE NOTE -- Cryptanaltyic work in World War- I 

-'American successes in cryptanaltyic work in the AEF, 

World War I, were not remarkable because of circumstances. We were working on traffic from Rquiet 

sectors•t -hence had little but practice, and that 

was largely in 2-part codes. Fair success with ciphe~ 

because traffic from all sources and collaboration 

with French and British. Best results were in connection with lower echelon 3-number codes 1 often 

tactically useful information was obtained after the 

introduction of the 3-number code. 
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FOR SLIDE 14.1 

11Speaial Code Section Report" by G-2, A-6, GHQ,.AEF 

20 Nov 1918. 

/j. c:cypt "bulletin• from the ADFGVX cipher. This 

forms a good_example of Special Intel11gence in 

World War IJ ' 
LECTURE NOTE 

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FOR SLIDE 15 

One of the earliest examples of traffic analysis and 

traffic intelligence - based on study of traffic in 

ADFGVX messages. 
LEOTURE NOTE 

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On trafi'ic analysis 

~The problem of the extent to which traffic analysis 

can be regarded as a reliable source of intelligence 

is an extremely triclq one. I feel that it will 

always have its limitations, that the 'i'irst impressions' which it gives may often be wrong, that it 

mu.st rely heavily on later confirmation from cryptanlysis or collateral, and that in particular it is 

regrettably vulnerable to deception activity by an 

enem;y.n 

-Travis in letter to Wenger 5 Jan 51 

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LECTURE NOTE 

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U.S. COMINT activities in 1920 -29 

1. Navy had RPS but small. OOMINT JUSt in infan· 

cy. All work under Naval Communications. No official 

relations between A:r!nry' and Navy. 

2. Array -- cryptologic work under much divided 

authority: 

Signal Corps, G-2, and AG with MI having over 

all responsibility for security. 

Y\P':t 3. m' came to OCSigO on 1 Jan 1920. - ~ \ ~.-.-P~---4--. ""'H!i"Ollfi! in-New Yorlf. No relations AifOwit'boCSig 

r O, AB. AB solved J messages in 1922 Disarmament Oonf. 

5·5-3 ratio. 

5. Albright st.udies situation. 

6. Closing of ABO - STD!.SON -~? [oVER.J 
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7. SIS formally established on paper in April 1929 by transfer of solution aotiVJ.ty to OCSigO and 

little later transfer of AG duties to OCSigO also - thus integrating all work under one head. But B-2 

retained overall responsibility. 

8. Publication of Yardley book and effects. 

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Ov.l'l- S. I 61 

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