PURPLE cipher machine challenge


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The PURPLE cipher machine was put into service by japoneses in 1939. It was used by japonese embassies. PURPLE is the codename given by American's cryptanalists. In fact it genuine name is 97-shiki ohbun-injiki (System 97 Printing Machine) or Angoki Taipu-B (Type-B Cipher Machine). The PURPLE cipher replaced the RED Purple machine.

The RED system is not very secure, neither is the PURPLE machine. The main flaw of the two machine is the separate encryption of six letters (the SIXES). The PÜRPLE system was broken successfully by the American Army (SIS) in 1940.

Problems (notes)

1st Problem
(very easy)
Rafael Pascual
01/09/20
Garcia Larragan
05/06/21
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2nd Problem
(easy)
Rafael Pascual
22/09/20
Garcia Larragan
05/06/21
G. Lasry
22/06/22
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3rd Problem
(medium)
Rafael Pascual
22/09/20
G. Lasry
23/06/22
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4th Problem
(medium)
Rafael Pascual
22/09/20
G. Lasry
23/06/22
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5th Problem
(medium)
Rafael Pascual
24/09/20
G. Lasry
23/06/22
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6th Problem
(difficult)
Rafael Pascual
26/09/20
G. Lasry
23/06/22
. . . . . . . . . .
7th Problem
(difficult)
G. Lasry
27/06/22
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8th Problem
(difficult)
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9th Problem
(difficult)
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