Cryptographic History of Work on the German Naval Enigma



Q=Quadrant of Globe. LLLlll = Lat. and Long. GG = Time of observation to nearest hour. DLF = Wind direction and force. W W = Present weather. PPVTT = Pressure, Visibility and Temperature. CCCN = Amount and type of cloud. Td = Temperature difference between sea and air, KDk = Direction and type of swell. W = Past weather. a = Characteristic of pressure change in past 3 hours.

(3) W W messages as intercepted (i.e. encyphered)

 KeyI123456789SSPosition estimated from D.F.
(A)15.48.WPESTSJZUKTZ42 x 18
(C)03.17WNKBERSSRSON49 x 24

I = Indicator letter. 1, 2 = Lat. and Long. in degrees.

3 = Pressure change. 4, 3, 8 = Pressure, Temperature and Visibility.

6 = Wind direction and strength. 7 = Present weather and clouds.

9 = Direction and type of swell. 10, 11 = Signature.

(4) Cribs supplied by Archery converting from Met. international code into Wetterkurzsignalbuch code and re-arranging in the proper order

(a) SZ. Q.HA EP


(c) BL. AWN. .V

(5) Tieing up: we have to pair (a), (b) and (c) with (A), (B) and (C). (a) and (A) clearly go together. (a) has position 43.0 x 17.0 and time 16.00 and (A) has estimated position 42 x 18 and time 15.48. (B) and (b) cannot go together as this would give the R in YRJ encyphering as the R in LRS which is impossible (a "crash"). Also the estimated position 49 x 24 for (C) goes well with position in (b) which is ?9.0 x 25.0, so that the tie-up is (B) with (c) and (C) with (b).


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