1 

r'\PFE:NDIX 2 

14 July 1954 

GEE 

Narrative Account ot a Broken One-Time Pad System 

PL 86-36/50 USC 3605 

by H. Campaigne Eo 3 . 3 ( h) ( 2 ) 

It is generally conceded ~bata one,..'l;me pad cipher system 1s 

immune to cJ:-yptanal7a1s. 1'ut a careful, study shows that there are 

some tr1clQr concepts ~nvolved, and 1;ba1; a ceyptographer \must be 

yerv :arefnl 'Vdf!~d not to mis·l···eac.t himself". The Genna··· D8\ ..... 1n the I Jdur1ng World War II did mislead themselves with a 

one-t me s7i:1tem and we were able to exploit this weakness .• 

It may be ot 1ntel"est to quickly recount what happened.., and 

estimate what it would have taken to make a more immediate\. and 

thorough exploitation~ 

.. 't 

A :=11" ot German comun1cat1ons .showed that tor! .. high l· .. evel !_messages a s7stem which resembled one-time•pad was 

being u • This s7stem was designated GEE tor short.. It had 

apparently been in use since prior to 1934, and in 1943 was $till 

being used hea.v117 • perhaps a hundred thousand messagEts a 7ea.r. 

llmong the other German systems was another! I system called GEO. These two were used among the same correspondents and employed the same code book. 

In 1940 a passenger Dr. Emil Wolf"t. aboard a Japanese ship passing through the Panama Canal was f'ound to have 3600 pages o\t additive. 1

l'hese were photographed and studied. The study established that the pages were intended ~or GEE. and that the additive 

was essentially random. 

\ 

19P SL6RET CONTROL NllMBER .30 1.:t.s;f , CnPY 11 Uf ,,- COPfES 

PAliE .Ji~ -· .. n~~}~3, ,PAGES 

Declassified and approved for release by NSA on 01-02-2014 pursuantto E.O. 1352a 

'"""DENO IX 2 

TOP SECRET FROTH 
PL 86-36/50 USC 3605 

EO 3.3(h) (2) 

As more was learned about GEE hope revived that something eou.ld be accomplished. It was now kn.Ollt1 .that an occa.ss!ot18.l 

exception to strict one-time use bad been allowed. So a renewed 

attack was begun. An account of this has been excellentl::rl"elated b7 T. A. Waggoner in the A.SA document "The Solution and 

Exploitation ot the German one-Time Pad System, GEE" (TEO #TS290). 

' restudy ot the 3600 photostatted pages or additive taken 

from Dr. &nil Woltt showed that there were so e non-ran4om rod. 

-2-

TOP SECRET FROTII 
. , 

~L 86-36/50 USC 3605 

EO 3.3(h) (2) 

The success described here d1c1/not occur until l'ebruary, 1945, 

when the war 1'aS annroacbinq: ff;s/end. By May· about 5000 page .. s had 

been read on the! _circuit alone. The intorma.tion in 

this trattic con 1nued to be valuable even atter hostilities 

ceased. In all 118aOOO pages trom this one link were read. 

The question ot interest now 1s, what equipment, procedure, establishment,, or organization would have insured that this analysis succeeded, and would have expedited it? 

tic 

n 9 hey 11ere done much more easily. In 195 they can be done 

more easily yet. But there is still room tor improvement. 

Evidently the diagnosis {which was correct) of one-time usage deterred any strong action at the time. The cryptanalyst must 

always be ale1•t to exploit any mistake ma.de by the communicator and 

must never be discouraged by the apparent unsolvability ot a pro- blem~ This platitude must be considered basic. 

Once the 1n1t1al break had been made the exploitation was 

carried forward well enough. and today it could be done even more 

expeditiously. with more flexible and taster machineryo 'l'he critical stage is diagnosis. To get the traffic, get it eorted into 

homogeneous bundles, and make the counts in all the ways the 

analyst can think or. and get all this done tast is the preliminary goal to reading everything currently. 

-3-

TOP SEeRET FR0TII