"The Zendian Problem, presenting an operational communication intelligence situation in miniature, affords opportunity to apply the techniques of traffic analysis and cryptanalysis, to derive intelligence, and to prepare reports. This problem deals with the enemy communication during a (fictitious) operation against Zendia, a totalitarian island state."
(Lambros D. Callimahos, 1959) Traffic Analysis And The Zendian Problem. By Lambros D. Callimahos
Aegean Park Press, P.O.Box 2837, Laguna Hills, CA 92654
By the morning of 23 December, radio intelligence units were operative and began an all-out effort to intercept and solve the encrypted Zendian traffic. The traffic intercepted on 23 December totalled 375 messages.
The top line of the message heading is the intercept line, consisting of the receiving and transmitting call signs, the frequency, the intercept date/time, and the intercept station designation; also included is a teleprinter serial number (which can serve as a worksheet number in subsequent processing) used in forwarding the traffic by teleprinter.
The second line of the heading is the message preamble which consists of eight 4-digit groups; this is followed by the message text, invariably transmitted in groups of five characters. In all messages, the first two groups are repeated at the end.
The tasks are:
Results of an intial analysis of the messages:
It can easily been seen that there are three different types of discriminants: "ab c ab", ab c ba" and "aa b cc".
ab c ab
ab c ba
aa b cc
|A diagram shows the radio station net together with call signs and discriminants used on the various radio connections. This net is identical to the ordre-de-bataille of the Zendian army.|
|The system of call signs (except the call signs of battalion level) is given an analysis.|
|Further cryptanalysis is done according to the discriminant, the first cipher text group.|
You can read the up to now decrypted messages, sorted according to the originator:
|Originator 000 - 202|
|Originator 212 - 399|
|Originator 400 - 499|
|Originator 500 - 599|
|Originator 600 - 699|
|Originator 700 - 799|
|Originator 800 - 999|
© Karlheinz Everts