Crypto Transmission from KPH!

KPH will transmit ENIGMA encrypted messages on 22 July 2023. This will be the second event of its type. The first was so well received that we hope to make it a repeating event.

ATTENTION ALL INTERCEPT OPERATORS!

Crypto Transmission from KPH!

Background

The MRHS in cooperation with our good friends at the Cipher History Museum will send a coded message in 5-letter groups via the facilities of coast stations KPH on Saturday July 22, 2023 Pacific time. The message will be encrypted using the famous Enigma code machine and is an authentic message sent by a U-boat in the North Atlantic in 1942.

All KPH listeners are invited to try their hand at receiving and decrypting the message. Certificates will be awarded for proof of successful decode, first to decode and use of original or replica hardware.

You say your Enigma macine is a bit rusty? Perhaps it has slipped a cog? No problem, MRHS has you covered! Software simulations exist for the Enigma code machine. Click Here for an easy-to-use Enigma simulator. It is web-based, no download necessary.

Enigma

The Enigma was the Germans' most sophisticated coding machine for securely transmitting command and control messages via radio communications in WWII. It was considered so secure that it was used to encipher the most top-secret of messages.

The arrangement of Enigma's rotors and plugboard connections provided a unique series of letter substitutions which changed with each keystroke. The daily rotor order and the ring and plugboard settings to be used were specified in a codebook distributed monthly to all users of a network.

Crypto broadcast date, time and formats

The crypto broadcast will commence at 2000Z (1300 Pacific) on 22 July on all KPH CW frequencies. The broadcast will begin with a 'callup' (in plain text) announcing the broadcast, followed by the cipher message. The callup and cipher messages will be sent at 15 WPM. The cipher message will be sent in 5 letter groups and the message will be sent twice to ensure proper reception.

The usual KPH channel marker or 'wheel' running at 20 WPM will precede the announcement for the crypto broadcast to give listeners a chance to tune to the strongest signal in their area.

The KPH CW frequencies are (in kc):

426 (after an announcement on 500)

6477.5

8642.0

12808.5

17016.8

22477.5

Upon completion of the CW transmissions, the broadcast will be repeated at 2015Z (1315 PST) on all KPH RTTY frequencies. The RTTY transmission will be 170cps shift Baudot, 45 baud.

The KPH RTTY frequencies are (in kc):

6324.5, 8427.0 and 12585.5

Code Machine Key Settings - IMPORTANT!

Decoding an Enigma message requires the use of two keys: a Daily Key (valid for particular day), and a Message Key (unique to each individual message sent that day).

The Daily Key

Prior to decoding a message, the daily key must be set into your Enigma code machine. The daily key settings were specified in secret codebooks and distributed monthly. Please consult the following codebook to obtain the daily key setting for the GMT date in the message header plaintext (NOTE: not the date of the broadcast!).

Here is the software enigma decoder for the KPH Enigma transmission.

http://ciphermachinesandcryptology.com/en/enigmasim.htm

Needed instructions - scroll down to see the settings for "before 1940"

https://swling.com/blog/2022/07/decode-the-enigma-crypto-transmission-from-kph-on-saturday-july-23-2022/

Decode the Enigma: Crypto Transmission from KPH on Saturday, July 23, 2022 | The SWLing Post

This page contains the code settings but just as importantly how the settings are used - scroll down on the page to see it.

https://www.ciphermachinesandcryptology.com/en/enigmaproc.htm

From the code settings:

Date

Roller Position

V II III

Ring Positions

11 21 08

Plug Connections

EY DT KF MO XP HN WG ZL IV JA

Characteristic Groups

lsd nuo vcr vcx

MESSAGE FROM SANFRANCISCORADIO/KPH TO DECODE:

HQ FR FOCH 1914Z 100 BRV LTV

VCXTY JRVHA NNKMO FGKIG

OIPLM KVHVZ WDMIP XWRBX

JKDWT KGZZA IWJVN QUTJF

HPPWG KEDDQ QFEMT UKMQU

IDIGF YUAJB RPPWS IBJCV

I believe the entire message has to be entered to decode it because after I found the decoded initial rotor settings (see the decoding process) BRV has to be initially entered to decode the second tri-letter group of LTV, to obtain the decode of LTV which I then set my enigma machine to use but my first decode was garbage, so it must be that the entire message including what I call the "check group" which is VCXTY (which I did NOT include) resulted in garbage output.