parsifal
Colonel
Part III
The Codebooks
To apply the Kurzsignale, the Kriegsmarine used several different codebooks. The two most important codebooks were the Kurzsignalheft for all kinds of operational messages, and the Wetterkurzschlussel for weather reports. The Kurzsignalheft contained tables that converted sentences into four-letter groups. All kinds of expressions in many different topics were listed. Logistic matters such as refueling and rendez-vous with supply ships, positions and grid lists, names of harbors, countries, weapons, weather conditions, enemy positions and ships, date and time tables. All possible situations and topics were listed. Another codebook contained the Kenngruppen and Spruchschlussel, resp key identification and message key, that is the start position to the rotors of the Enigma. The codebooks were printed on special paper with red, water soluble, ink . If the codebooks could be captured, they were destroyed by throwing them into water.
Composition of the Kurzsignale
"It is best to try and explain the operation of Kurzsignale, using as an example a Short Message, encoded with the 1944 edition of the Kurzsignalheft. This edition was more complex than the previous alpha and beta versions. The Kurzsignalheft 44 consisted of two parts, Heft I and II. Heft I contained the Satzbuch or sentence book, to convert sentences into four-figure groups, and the Schlusselzahltafel or key number table. Heft II, called Buchgruppenheft, was used to convert four-number groups into four-letter words. In addition, to sign messages or identify other U-boats in a message, the Kriegsmarine used a codebook called Marinefunknamenliste or Naval Callsign List. This was a list with all existing U-boats and trigrams, three letter words, assigned to each U-boat. Unfortunately for the Kriegsmarine, the more complex 1944 edition didn't came into service on time to change the odds for the decimated U-boat fleet in the Atlantic."
The Kriegsmarine transmission procedures and message format were different from the Wehrmacht and Luftwaffe. The key sheets for the Enigma settings were also different. Importantly, Heer and Luftwaffe messages were largely solved by april 1942. With the introduction of the beta code methods, KM and uboats coding procedures remained a mystery for 10 months longer, and attempts to break this code had nothing to do with Dieppe.
The Wehrmacht used one table with rotors, ring settings, plugs for each day of a given month. The Kriegsmarine used various code sheets. The Kriegsmarine TRITON code sheets consisted of two parts.
The first sheet, called Schlusseltafel M Algemein - Innere Einstellung, contained the three rotors and their ring settings, the thin beta or gamma rotor and the reflector, and this for all odd days of a whole month. The second sheet, called Schlusseltafel M Algemein - Aussere Einstellung, contained the plugs and Grundstellung or start position for each day of the month.
The Kriegsmarine Sonderschlussel M, used for private conversations between the Commander of the U-Boat Fleet and a particular U-boat, had a special key sheet with only three inner settings, and three plugboard settings, each for a period of ten days, and a list of Spruchschlussel or message keys, designated by a code word. The Sonderschlussel M was similar to the Schlusseltafel M Offizier from TRITON. Examples of the Kriegsmarine keys on.
In order to prepare the message for transmission, the operator had to encipher the message with the Enigma cipher machine. The internal settings and plugboard of the Enigma would already be set. The operator selected a Kenngruppe and Spruchschlussel from his Kenngruppenheft codebook. A Spruchschlussel or message key was the initial start position of the Enigma rotors prior to enciphering. The Kenngruppe was a trigram to identify the Spruchschlussel. The kenngruppenheft was a fixed codebook, which was not regularly replaced. It had three parts: The first part is the Zuteilungsliste, a table where you could find sets with ranges of numbers, according to the day an radio net. Within a range that was derrived from the table, the operator selected a figure. The second part was Teil A, where you could look-up the figure and find the Kenngruppe and Spruchschlussel behind it. The Spruchschlussel was set as startposition on the Enigma and the Kenngruppe (in our example RDF) was added (not encrypted!) at the beginning of the message to identify the Spruchschlussel. The receiving operator would look-up the Kengruppe in the third part of his codebook, Teil B, and find the figure that was related to that Kenngruppe. With this figure, he could now find the appropriate Spruchschlussel (message key) to decipher his message.
The completed message contained the following information:
a. The introduction signal (beta beta)
b. The Kenngruppe trigram, non enciphered
c. All signal groups, enciphered
d. The signature, enciphered
e. The repeated non enciphered Kenngruppe
An experienced radio operator could easily transmit this little message in morse in about 20 seconds.
At the end, the operator used 7 tables or key sheets to encipher his message! The Kurzsignalheft Heft I with its Satzbuch to convert sentences into four-figure groups and the Schlusselzahltafel to add the key number, Heft II with the Buchgruppenheft to convert the four-figure groups into four-letter groups, the Marinefunknamenliste to identify the U-boats, the two key sheets Schlusseltafel M for inner an outer settings of the Enigma machine and finally the Kenngruppenheft to select the message key. No wonder they were confident their communications were secure. Nonetheless, Allied codebreakers succeeded in breaking into the U-boats communications as you can read in Enigma and the U-boat War.
The Wetterkurzschlussel
Weather reports were vital tactical information for the Kriegsmarine, and it was through intercepts of the weather reports beginning in june 1942 that the system was eventually and initially cracked (ther was no definitive point where KM codes were finally and completely cracked….it was a never ending battle right to th end of the war). Every few hours, the U-boats had to send detailed weather reports by radio. However, each broadcast from a submarine increased the risk of detection by Allied direction finding systems. Therefore, it was important to put as much as possible information into a message that was as small as possible. The Wetterkurzschlussel or WKS did just that. Each Wetterkurzsignal consisted of 23 or 24 letters, representing a certain weather condition. Thirteen tables determined which letter or letter combination was used for a particular weather condition. These included barometric pressure, clouds, winds, visibility, rain fall and so on. Thanks to the Wetterkurzschlussel a large amount of weather variables was compressed in only a few letters.
The Codebooks
To apply the Kurzsignale, the Kriegsmarine used several different codebooks. The two most important codebooks were the Kurzsignalheft for all kinds of operational messages, and the Wetterkurzschlussel for weather reports. The Kurzsignalheft contained tables that converted sentences into four-letter groups. All kinds of expressions in many different topics were listed. Logistic matters such as refueling and rendez-vous with supply ships, positions and grid lists, names of harbors, countries, weapons, weather conditions, enemy positions and ships, date and time tables. All possible situations and topics were listed. Another codebook contained the Kenngruppen and Spruchschlussel, resp key identification and message key, that is the start position to the rotors of the Enigma. The codebooks were printed on special paper with red, water soluble, ink . If the codebooks could be captured, they were destroyed by throwing them into water.
Composition of the Kurzsignale
"It is best to try and explain the operation of Kurzsignale, using as an example a Short Message, encoded with the 1944 edition of the Kurzsignalheft. This edition was more complex than the previous alpha and beta versions. The Kurzsignalheft 44 consisted of two parts, Heft I and II. Heft I contained the Satzbuch or sentence book, to convert sentences into four-figure groups, and the Schlusselzahltafel or key number table. Heft II, called Buchgruppenheft, was used to convert four-number groups into four-letter words. In addition, to sign messages or identify other U-boats in a message, the Kriegsmarine used a codebook called Marinefunknamenliste or Naval Callsign List. This was a list with all existing U-boats and trigrams, three letter words, assigned to each U-boat. Unfortunately for the Kriegsmarine, the more complex 1944 edition didn't came into service on time to change the odds for the decimated U-boat fleet in the Atlantic."
The Kriegsmarine transmission procedures and message format were different from the Wehrmacht and Luftwaffe. The key sheets for the Enigma settings were also different. Importantly, Heer and Luftwaffe messages were largely solved by april 1942. With the introduction of the beta code methods, KM and uboats coding procedures remained a mystery for 10 months longer, and attempts to break this code had nothing to do with Dieppe.
The Wehrmacht used one table with rotors, ring settings, plugs for each day of a given month. The Kriegsmarine used various code sheets. The Kriegsmarine TRITON code sheets consisted of two parts.
The first sheet, called Schlusseltafel M Algemein - Innere Einstellung, contained the three rotors and their ring settings, the thin beta or gamma rotor and the reflector, and this for all odd days of a whole month. The second sheet, called Schlusseltafel M Algemein - Aussere Einstellung, contained the plugs and Grundstellung or start position for each day of the month.
The Kriegsmarine Sonderschlussel M, used for private conversations between the Commander of the U-Boat Fleet and a particular U-boat, had a special key sheet with only three inner settings, and three plugboard settings, each for a period of ten days, and a list of Spruchschlussel or message keys, designated by a code word. The Sonderschlussel M was similar to the Schlusseltafel M Offizier from TRITON. Examples of the Kriegsmarine keys on.
In order to prepare the message for transmission, the operator had to encipher the message with the Enigma cipher machine. The internal settings and plugboard of the Enigma would already be set. The operator selected a Kenngruppe and Spruchschlussel from his Kenngruppenheft codebook. A Spruchschlussel or message key was the initial start position of the Enigma rotors prior to enciphering. The Kenngruppe was a trigram to identify the Spruchschlussel. The kenngruppenheft was a fixed codebook, which was not regularly replaced. It had three parts: The first part is the Zuteilungsliste, a table where you could find sets with ranges of numbers, according to the day an radio net. Within a range that was derrived from the table, the operator selected a figure. The second part was Teil A, where you could look-up the figure and find the Kenngruppe and Spruchschlussel behind it. The Spruchschlussel was set as startposition on the Enigma and the Kenngruppe (in our example RDF) was added (not encrypted!) at the beginning of the message to identify the Spruchschlussel. The receiving operator would look-up the Kengruppe in the third part of his codebook, Teil B, and find the figure that was related to that Kenngruppe. With this figure, he could now find the appropriate Spruchschlussel (message key) to decipher his message.
The completed message contained the following information:
a. The introduction signal (beta beta)
b. The Kenngruppe trigram, non enciphered
c. All signal groups, enciphered
d. The signature, enciphered
e. The repeated non enciphered Kenngruppe
An experienced radio operator could easily transmit this little message in morse in about 20 seconds.
At the end, the operator used 7 tables or key sheets to encipher his message! The Kurzsignalheft Heft I with its Satzbuch to convert sentences into four-figure groups and the Schlusselzahltafel to add the key number, Heft II with the Buchgruppenheft to convert the four-figure groups into four-letter groups, the Marinefunknamenliste to identify the U-boats, the two key sheets Schlusseltafel M for inner an outer settings of the Enigma machine and finally the Kenngruppenheft to select the message key. No wonder they were confident their communications were secure. Nonetheless, Allied codebreakers succeeded in breaking into the U-boats communications as you can read in Enigma and the U-boat War.
The Wetterkurzschlussel
Weather reports were vital tactical information for the Kriegsmarine, and it was through intercepts of the weather reports beginning in june 1942 that the system was eventually and initially cracked (ther was no definitive point where KM codes were finally and completely cracked….it was a never ending battle right to th end of the war). Every few hours, the U-boats had to send detailed weather reports by radio. However, each broadcast from a submarine increased the risk of detection by Allied direction finding systems. Therefore, it was important to put as much as possible information into a message that was as small as possible. The Wetterkurzschlussel or WKS did just that. Each Wetterkurzsignal consisted of 23 or 24 letters, representing a certain weather condition. Thirteen tables determined which letter or letter combination was used for a particular weather condition. These included barometric pressure, clouds, winds, visibility, rain fall and so on. Thanks to the Wetterkurzschlussel a large amount of weather variables was compressed in only a few letters.
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