Cryptography Reference
In-Depth Information
cryptologist for the Treasury Department. Her picture now sits along with her
husband's in the N.S.A. Hall of Fame for her cryptological contributions.
By 1938, Joseph Mauborgne, now a two-star general, was heading a group
at SIS to look at Japanese cipher systems, since it was beginning to look
like a new war was brewing. He asked Friedman to head up the new divi-
sion at SIS, and Friedman agreed. The Japanese cipher machine was called
Purple
, given its name from the Japanese cipher of the same name in which
their correspondence was written. It proved to be incredibly diQcult, but
by August of 1940, Friedman's team had constructed an exact replica of the
Purple machine,
2.13
(see Figure 2.16) allowing them to decipher an increas-
ing amount of Japanese traQc. (Copies of the machine were also given to
the British to decrypt correspondence between the Japanese and the Ger-
mans.) However, Friedman suffered a nervous breakdown and was hospital-
ized on January 4, 1941, after which his work schedule was severely cut back.
The information that
was obtained from break-
ing Purple, the Ameri-
cans called
MAGIC
. This
name was given by Rear
Admiral Walter S. Ander-
son, probably for reasons
surrounding the associa-
tions with the occult that
we discussed in Section
1.3. MAGIC has come
to be known as the code
name for the joint Army
and Navy operation, first
set up in 1939 to break
Japanese codes.
Figure 2.16: Purple machine replica.
Pearl Harbour, Midway, and Post-World War II
On December 7, 1941, a message to the Japanese Embassy in Washington
was intercepted. The decryption showed that the Embassy was being ordered to
end all negotiations with the United States. The implication of impending war
was crystal clear, and this message was to have been delivered to the American
State Department only hours before the attack on Pearl Harbour. However,
the ruse — to come as close to the attack before giving formal notice — failed
since the embassy's first secretary Katzuso Okumura, was still typing the formal
notification for the State Department when the bombs began raining down on
Pearl Harbour. They had started a war without formal declaration, a failure
that would be part of the charges against Japanese war criminals on trial after
2.13
Figure 2.16 is a representation of the 1941 Purple Machine Replica, courtesy of the CIA
website
http://www.cia.gov/cia/publications/facttell/intel overview.html
.
Search WWH ::
Custom Search