" ... 

.. REF ID:A67512 ~ 

WAR DEPARTMENT 

OFFICE OF THE CHIEF SIGNAL OFFICER 

WASHINGTON • 

1. In oonne9'l• with a •-l"UICI• 4at811 Augm\ 31, 19351 (1op7 

attuhed) aetting forth "11rta1n tan• la oomenloa with itae lnTat1on 

of •norul altel'lll.tlYe .... ot proridlag aa -.,.r:lodio diapla•--' of 

the ••'betltution 1lpber whoele ot a 1lpher ..ohin• •• graated 1n elaia 

17 of \he paten\ •PIOlflCll.tloa hariag ref11991 \o Co1r1ertw T:ne 

Mi-lit-Tl," \he followlq aclclit.ional fa.ta an mid• of reconb 

2• T'le prlnalple et •ploying a a8' ot JudapoBaJ rotat1ns IOllmatatot11 as a •-• of aoleding 1a an 1rnplar1 a119rloclia ._.r, the auoce1aiTe a1pba~8'• (for enaiphel"mellt er 4 .. iphe:rmeat) tram amoag 

a rl111"alit1 ot olpher alphalu"• 1.1 t!w oodrllldlon of rrut a. Rnle\\e 

s. The u101late4 prinoiple at O)a\rolU.ag the 1toppi111 poaUiona 

of • •lngle •11ll9tit11tlon o1pher Wheel '7 a 19' ot J11napo11Hl oontrol 

elpber wheel• i• tho 1ontri-.aH.on of 'l'Ult.aa r. rrl•dmlln• JI0\11 'fhua, 

ror _..ple, in friecl•n. lllll Graham u. a. FILtlB\ ••• 21 0281 '1'12 \h9 

•ipber key tran..ttter aad lt• .. aoolat .. --.n18a would '' replaoecl 1tJ a •et ot o on\rol a1phor 'ltleola, the • t.bal nntaot1 ot w!doh would 

be ••••tad to eh• which ....u •top tile eunltnloa o..nator in 

the en11pherlag (or 4eo1purina) J'D•itln. 

4• T'1e id• u to iu po•aibiUtr ot dlrMtl1 appl7iag th• rore101ng prJ.noipl• to the •tapp!ag at a nt&tlal pria\1a1 WhMl at ai•Glt ••»&em, the lat\tr ttelag auperSapoMt •Jllft , .. a\opPbg position 

de\trainecl by the kOJ depnaaed on the te,_,,.1 ll tile oqu.1 anti Joln\ 

••trlbution or llo\b Williall '· frl ..... alll1 Jftak •• Rowlett. la thie 

_.., in order to prnent •-la\1•• erron It le ••••ary to ntuna 

'11• printing wheel to an laltlal poaltlon after euh opera\:loa. The 

olphe_. atopplas poeltlon of tho pdntlag wheel i• ••t•l'llined after it 

ha• been stopped bJ the deproeaion of a tey of 'b• toJt»oar4. 

• A 

il1u... r. 1rloc1wa. 

lA\pproved for Release by NSA on 09-09-2013 pursuant to E. 0. 1352§ 

J 
DOCID: 67513 

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WAR DEPARTMENT 

OFFICE OF THE CHIEF SIGNAL OFFICER 

WASH I NG!TON 

August .31, 19.35 

1. This is to record certain tacts in connection with the 

invention of several alternative means of providing an aperiodic 

displacement of tne substitution cipher wheels of a cipher ma8 

chine as granted in claim 17 ot the patent specifications having 

reference to Converter Type M-1.34-T2. [ ~'2w*- ~ M~ (.,'°~c1~] 

2. It is desired to record here that the fundamental principle of using one or more eommutators in conjunction with a set 

ot selector magnets as a means £or e££ecting the aperiodic displacements discussed in par. 1 is the contribution or Frank B. 

Rowlett. 

3. The subsidiary principle (subsidiary to that set forth 

in par. 2) of producing aperiodic displacements (discussed in 

par. 1) of the substitution cipher wheels by means of an independent set of coJDlnuta.tors containing contacts equal in number 

to the number of substitution cipher wheels to be displaced, is 

the contribution of Frank B. Rowlett. 

4. The subsidiary principle (subsidiary to that set forth 

in par. 2) of producing aperiodic displacements (discussed in 

par. 1) of the substitution cipher wheels by means of an independent 

set of cipher wheels, hereina!'ter called the control cipher wheels, 

and having the latter cipher wheels identical in number or ce>ntacts 

and construction with the former so that all cipher wheels are 

interchangeable, is t.'ie contribution of William F. Friedman. 

s. The subsidiary principle (subsidiaI7 to that set :forth in 

par. 2) ot producing the aperiodic displacements (discussed in par. 

1) of the substitution cipher wheels by' means of a second set of 

control contacts on each face of es.ch ot the substitution cipher 

wheels themselves, and providing appropriate electrical circuits 

for the control contacts to govern the operation of the displacement mechanism, is the contribution of Frank B. Rowlett. 

6. The subsidiary principle (subsidiary to that set forth 

in par. 2) or producing the aperiodic displacements (discussed 

in par. 1) of the substitution cipher wheels b;y means of the same 

set of substitution contacts operating in connection nth a gang 

switch.which makes these contacts serve for snbstitution and 

control in alternate sequence, is the contribution of Frank B. 

Rowlett. 

JA'pproved for Release by NSA on 09-09-2013 pursuant to E.O. 1352EI 
oocrY, 67513 • 

REF ID:A67512 

REF ID: A67513 ' 

7• The application or the principle of aperiodic displacement or substitution cipher wheels to Cl'J'ptographs or the original 

Enigma type (in which the electrical circuit through the cipher 

wheels is reversed by means of a reversi:ag cipher wheel and again 

conducted through the other cipher wheels before reaching the 

signall.Jig element) is the contribution of William F. Friedman. 

8. The foregoing facts will be used as a basis £or evaluation 

and division of interest in all financial benefits which may accrue 

from the prosecution of the invention and its reduction to practice. 

CbJ~., 6·,J:-~oA. .. ,..v 

iiilliaI!l F. Friedman. 

Witnesses: