Evening star., 1933-02-02
new KEYDECODES
Gang MESSAGES
E, 7, A and o Top Frequency
liable Compiled for:
Police Officials.
BY REX COLLIER.
..sNzz HZ CZMZ NcJMoGT."

''tNZZ HZ CZMZ NCJMOGT."
This cryptic tumble Of letters, con-
stftuting a typical code message used
in underworld grapevine" commun1ca-
tim. may be just meaningless puzzle
to the average person, but to c1pner
experts Of the United States Bureau OF
Investigation its hidden import Is
qlency key just furnished the Nations
police departments.
,Decoded with the aid Of an alpha
betical frequency table compiled by q
special tabulating machine from 220 900
lettars occurring in newspaper and
magazine articles. the message reads:
See me here shortly"
In this instance it was q simple mat
ter-for the expert to note that the let
ter"Z" occurred more frequently in the
message than any other letter, and to
assume, therefore, that the letter actu-
ally. represented e." the most fire.
quently used letter in the alphabet. BY
referring quickly to transposltion
table also supplied police, it was appar-
ent the message had been coded by re-
arranging the alphabet SO that 1t began
WITH the sequence W. w, x, =; 4, A.
B, c." ETC., and ended with ~ Un-
der this arrangement. the table showed,
"S" would become IN" "E" would be-
come q" m" would become H, :"
H, would become &C." and so on.
Methods Are Simple.
IN a bulletin sent yesterday to chiefs
of police and other law enforcement
officers the bureau pointed out that the
usual message Of this kind Is COM
paratively simple, as it Is impracticable
for those using such communications
to employ complicated methods"
."The reason for this" it was stated,
"is that the use of a cipher necessi-
tated the possession by the addressee
of q key or means by which the mes
sage is to be deciphered. Complicated
ciphers require complicated keys.
Because of the relative simplicity OF
solved without much difficulty. Cryp-
tographers utilize in this connection
frequency tables; that is, computations
showing the relative frequency with
which the various letters Of the Eng
lish alphabet appear normally in writ
iigS. These tables are prepared on the
basis of counts of various numbers OF
letters, and those offered by different
authors do not agree in detail. All
the general sequence is approximately
the-same."
TO arrive at more accurate stand
ard~of frequency the bureau made use
Ola tabulating machine in the Divi-
sion of Crime Statistics of the bureau.
Use of the machine, 1t was explained,
eliminates most of the human errors
usually found in such compilations.
The. study was made by Charles A.
Appel, In charge of statistical research.
at would appear" the bureau said,
that the difference in frequency tables
,sretofore available has probably been
ccasioned by the relatively small num-
ar of letters included and the likeli-
pQd of some clerical error in the
oant It is believed that the table
Tered, in the preparation of which
,sse factors largely were eliminated,
Nay be accepted as authoritative"
- "E" Leads Others.
N the compilation "E" led all other
Letters in popularity, occurring 2a,455
occurrences; "a" was third, with II, ,058;
1853; as" 1868; "R," 12,411; III"
1892; L." 8,81o; 3D." 1886; &C.
6,o6l; "U," 5,s2s; IN" $3.50; "F,"
5,rIb; wv" 4,574; "G," 4,317; "Y,'
4,i74: "P," 1856; "B," 1928; "v,''
2I14; *" 1,412; tx" 384; -" 3l5;
q. 176, and a." 146.
.aIn simple ciphers," the bulletin said,
"th6 proper letters Of the alphabet are
Mually replaced by other letters, num-
bers. or symbols. For instance, the
LETTERS of the alphabet may be trans
posed and substituted for the CORE
spending letters wherever they appear
ir~the message b could be used for
'Ayf~'C' for b. d for c. and so on.
In order to read such cipher message
it.,wpuld be necessary only in place of
each letter to substitute the letter which
immediately precedes that letter in the
alphabet.
"Of course, in practice the transpo-
siton may be anywhere from l to 26
letters before or after the proper letter
or the alphabet. In addition, one
transportation may be used for the first
letter, second one for the second let
tet,., and so on. The key to such a
message would be a number, such as