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| The problem has been ] and is available either as part of ] or as a book in itself. Both are published by ]. | The problem has been ] and is available either as part of ] or as a book in itself. Both are published by ]. | ||
| ==External links== | |||
| {{spoiler-blank|(partial solutions)}} | |||
| * for the Zendian problem | |||
| ] | ] | ||
Revision as of 12:23, 11 June 2007
The Zendian Problem was a series of problems in traffic analysis and cryptanalysis devised by Lambros D. Callimahos as part of a course taught to National Security Agency cryptanalysts, whose graduates became members of the Dundee Society.
The scenario involves 375 radio messages intercepted on December 23 by the US Army contingent of a United Nations force landed on the fictional island of Zendia in the Pacific Ocean. A typical intercept looks like this:
XYR DE OWN 4235KCS 230620T USM-99/00091 9516 8123 0605 7932 8423 5095 8444 6831 JAAAJ EUEBD OETDN GXAWR SUTEU EIWEN YUENN ODEUH RROMM EELGE AEGID TESRR RASEB ENORS RNOMM EAYTU NEONT ESFRS NTCRO QCEET OCORE IITLP OHSRG SSELY TCCSV SOTIU GNTIV EVOMN TMPAA CIRCS ENREN OTSOI ENREI EKEIO PFRNT CDOGE NYFPE TESNI EACEA ISTEM SOFEA TROSE EQOAO OSCER HTTAA LUOUY LSAIE TSERR ESEPA PHVDN HNNTI IARTX LASLD URATT OPPLO AITMW OTIAS TNHIR DCOUT NMFCA SREEE USSDS DHOAH REEXI PROUT NTTHD JAAAJ EUEBD
where the first line is provided by the intercept operator, giving call signs, frequency, time, and reference number. The rest of the message is a transcript of the Morse code transmission. The numeric "header" originally has unknown meaning; the meanings of various components of this header (such as a serial number assigned by the transmitting organization's message center) can be puzzled out through traffic analysis. The rest of the message is ciphertext; the first group indicates the cryptosystem used, and often the second group contains a message-specific keying element such as initial rotor settings.
Cryptosystems employed include a one-part code and transposition, dinome, and rotor-based machine ciphers; these can be solved without use of a computer. However, solution is not easy, and the practical exercise reinforces many basic principles.
A certain amount of cleartext inter-operator "chatter" is provided, and may help with the analysis.
Headers and initial ciphertext groups are also given for intercepts from the next three days; these may be helpful in traffic analysis and in determining certain daily operating procedures.
The problem has been declassified and is available either as part of Military Cryptanalytics or as a book in itself. Both are published by Aegean Park Press.
External links
- Solutions for the Zendian problem