The cipher text messages below are believed to have been enciphered on the Enigma T (TIRPITZ) machine that was used for Japanese-German intercommunications.
UPDATE: The four messages below have now been broken. The first two messages from 6 March 1944 were broken by Dan Girard on 15/16 June 2009 using a novel cryptanalytical attack specially adapted for this problem. The third message from 10 March 1944 was broken by Dan three, four days later. To our knowledge this is the first time these messages have been broken and read. The US Navy's signal intelligence and cryptanalytical group, OP-20-G, tried to break these messages in 1945 but failed.
On 29 July 2009 Dan Girard also succeeded in breaking the last message; a very short sample of JN-18 traffic from 5 August 1944. The strength of his attack is proved by the plain text which turns out to be a mixture of English and German. A most impressive performance.
Further information about the Enigma T machine and the Japanese-German communication agreement is available here:
German Enigma T message A:
DAN C" C" 6 March 1944 1814/6/27 51 HCHFZ JIISW NXFZQ JOHCG TSWYI FBHKD TJLJH XLHQT NZEXR YLIAE XHQHW LAYXW KGDRX FLDPC PYLSE XEBDP HPQTY YEKHN RGZVX XNZHP XGQPL ACDKI VUPGV NUSUZ HALMB ACBHI LVYVC HNOYU XIACT IVVKG UJEPJ BOJHX KHTFQ ZVVTZ VBDDA MLVPS ZMJCU AZMWU WSAXF ZVPUF LULIF EZATT ASOLY JRDVP HYVRE GSBBV OQJMN YPUMA IQWQJ 12725 KHz
German Enigma T message B:
DAN C" C" 6 March 1944 1947/6/28 51 DJYQT FKCHD JEBKM QZDFY QLHCP TLKUL RYIAA BDGEJ XWDBY BABMH LSVLF NCSUA BNBKW BRNRP XZOKE UJDLO QYYGV ZGHXG IGJLO ODTRC SQQOO GTBET RNGUP IVWGF JNGBW MISQY KVYJI GCTYO YLWWC CXFPM IKVHQ RRBJA ZLZAE SAMPF BJXOT QOYGQ TYQEI NHZYQ ZCWOP XBOUJ AOEIV GGJKG MKHNB PQKBI ZNVEH GENJU MNGEI FGJXU UMWRC 12725 KHz
German Enigma T message C:
(1) DAN C" C" 10 March 1944 (2)(3)(4) (5) 0251/10/29 27 IHXLP RWUIK IRCYP XNVSF ERKMK MNJZZ ZTDBF GMFBO JGADL KJSVG JKSGB JQFKU FXWVS MWGKO CPKMQ KFDDR MRDSQ OAOIU GAIRM ZZCBQ MEFMG ZVAOQ QWJXN JENOF DBHVK 1907 KHz (6) Message format: 1) Call sign 2) Time of Origin 3) Date 4) Serial Number 5) Group Count 6) Frequency Note: The group count it off by two. The reason is that in these three messages the two last numerical groups have been removed. The correct format is shown below.
DAN 5 August 1944 C" C" DAN DAN 63 W12 5/8 1507 BT KLDSS ANGWY XWMID CRXFC CLQZS UJNRD VJYLG OPFME TIGPJ DQWIW 01305 01305 AR Digit groups: Two five digit groups at the end, first repeating second. First three digits message number, last two day of month.
The exact crypto procedure for the TIRPITZ (JN-18) traffic is not known. It is only known that it used the Enigma T (TIRPITZ) machine code named OPAL by the Americans.
Enigma T was also used by the Japanese naval attachés at the end of the war and even diplomatic traffic passed over these machines after the Japanese had destroyed their PURPLE machines. This traffic first appeared in April 1945 between the stations in Tokyo, Berlin, Stockholm and Bern.
The setup of the machines was a complicated issue using an existing code book to find the wheel order, Ringstellung and Grundstellung. The selected message key was enciphered twice but in mirrored order. The enciphered result was expanded to two five letter groups and placed as the first and last group of the message. To illustrate this, if the first and last groups are TXGGP and AWOBF, eliminate the third letter in the first group and the fourth letter of the second group. Write the new groups TXGP AWOF and decipher it on the Enigma T on the given Grundstellung. This would in this case result in the deciphered letters SPII IIPS, giving the message key SPII. Enigma T wheel would be adjusted to SPII and the message deciphered.
However, another important complication was introduced during ciphering and deciphering. After each group (every five letters) was enciphered or deciphered the left-most wheel (the reflector wheel which does not move by itself) was advanced one step by hand in the increasing alphabet. In our case after deciphering the first group of five letters the reflector would be moved by hand from ‘S’ to ‘T’. Hopefully this procedure is unique to the naval attaché and diplomatic traffic and the normal TIRPITZ traffic used the machine without moving the reflector during enciphering.
Copyright: Frode Weierud © 2006
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