... 

~ 

. •• . 

i> • .... . 

7 

--· 

.... tt7. 

:II I ;. 

.. 

Dear Friedman: 

REF ID :A9988'6 

THE UNIVERSITY OF 

PENNSYLVANIA CLUB 

OF NEW YORK CITY 

.JtaS./EMtt.150:.tiUi'lBEet:. 

~ 

37 East :10th 1:>t 

LA.ckawanna 5-3560 

Feb. 11th, 1936 

As I underst9.Ild it, you are not questioning the basic relationship of XX to 18470 - on this po•nt there can be no question - but the 

v.·ay in ;which this relationship was expressed in the printing of' the codebook. I hqve assumed a two-pa.rt code; you prefer the idea of d alphabetical arranp.;ement only, with ~ tables of one kind or another f'or enciphering ~his arrangement. 

when l was in na~hington for the Mix~d Claims ~omm.ission {1932?0 I showed~ you an arrangement of' this kind that .L had v.orked out. As I put it then, 

it v.ras1nn arrangement by ~hich a single printing might be me.de to serve for 

both e;icoding and decoding. l'.ou were not impressed - and I myself was not 

convinbed1 a possibility was all l ealled it. 

I' shall r~produce this arran~ement here. It is a bit awkward to use, 

and I am e..friad that its use might invite errors. On the other hand, because 

of the: random rearrangement of' the blocks - of - ten in going from .XX to 

18~70 there can be no simpler method. 

I do not believe thev did it this way. On tne other hand the idea may 

be ~o~th incorporating in my paper in the form of a foot-note. · 

dn the a.ccompanyini; sheet l am taking a hypothetical page, omitting 

the v9cabulary, and making a random a ·rang;ement of the blocks-of-ten. 

I 

If such an a.rr'l.llgament \•.as used it &'I'S f'or 18470 only - not for 80574:, 

1777, ;etc., ate. ihese are not co-ordinate in compilation ~ith 184:70, beC9.use :184:70 has, on page 18~, the ten grou •s assigned to 11Chif'fre Nummer 11 -

a positive sign that the original ~as of 184:70 only. All the brothers and siste~s arrived later and were used by means of page tables. Their blocksof-ten differ from those of' 18HO systematically (see my paper on Additional 

<;odes of the 18470 1''amily), and that is just the -difference between their re- latio~ship to 18~70 and the relationship of 184:70 to XX. 

it is nc>t impossible, but, in my opinion, e.J.l but impossible that a de- taile~ study might show that the different re-arrangements of the blocks-of-ten 

in go+ng from XX to 18470 are li~ited in number, and repeated with some system. 

In that case a table might be devised for these changes in connection with a 

formuia showing that pages •••••• will have rP-arran~ement A, pa~es ••••• re- arran~ement B, etc. This study could easily be combined with one to determine 

the P9sition of the stops and the numerals on the page. I'd be glad to make it, 

but should, nf course, have to have the 184.7') code-book.; I'd need l.~040 too as 

a check on blank blocks • 

It was nice to see you here. I hope that by this time r,oine; v.i thout tobacco has so improved your state of' health that you have a.gain begun to smoke. 

Cordi!illy 

l!\pproved for Release by NSA on 07-30-2014 pursuantto E.O. 1352a 

... ..... - !~ .:" 

·. 
ln encoding 

change penultimate :figure 

to 

8 

00 

01 

02 

'03 

.o~ 

:05 

06 

07 

'08 

1

09 

I 

---------------------

5 

·10 

:11 

12 

'13 

1

14 

'15 

1

16 

·17 

llJ:l 

:19 

---------------------- 20 

1~1 

123 

'2-4. 

·25 

;26 

27 

28 

:;9 

----------------------

6 

30 

31 

32 

33 

34-

'35 

1

36 

137 

1

38 

f-39 

' 

----------~----~------~ : 4:0 

'4:1 

-!2 

4:3 

44 ~ 4:5 

'46 

oi.7 

48 

149 

------------------------

-

50 

51 

52 

53 

54 

55 

56 

57 

58 

59 

In encoding 

change penultimate f'igure 

to 

1 

·. 

------------------------ Each pae;e will have its own arrangement. 

In addition there must be a page 

table :for decoding, to convert 18~70 

to XX. Instead of this table some o:f 

the printed volumes could be arranged 

in the order o:f the XX pages (alphabetical), and some in.the order o:f the 

60 

61 

62 

63 

64: 

65 

66 

67 

68 

69 

2 

18470 pages. Xhis last idea is not ----;~------------------

unattractive. 71 

72 

73 

74-

75 

·76 

11 

78 

79 

l 

------------------------ 80 

81 

82 

83 

84: 

85 

86 

87 

88 

89 

3 

------------------------ 90 

91 

92 

93 

94 

95 

96 

97 

98 

99· 

0 

------------------------- . In decoding, change penultllnate 0 1 ~ 3 ~ 5 6 7 8 9 

To 9 7 6 8 2 1 I 5 e o! 

(This v:ill, o:f course, dif:fer :for . each page.) 

81 (18470 page number)