ATTENTION ALL AGENTS!

                     KPH Crypto Transmission After Action Report!

Here’s the report on the KPH crypto transmission from event organizer Kevin McGrath:

According to the reports received, the MRHS Numbers Station event was an enormous success.

On January 20, 2024, shortwave listeners, ham radio operators, cryptographic enthusiasts and (we must assume) secret agents
across the globe huddled over their HF radios and listened at the appointed time and frequencies as KPH sent a coded message
in 5-digit groups. The message was encrypted using typical Cold War "Numbers Station" cryptographic procedures.
All KPH listeners were invited to try their hand at receiving and decrypting the message. Certificates were
awarded to all who successfully decoded the message and a special certificate was awarded to
the first successful decode.
 
MRHS received 161 entries and sent out 156 "Certificates of Cryptographic Excellence".

Entries came in from US, Japan, Canada, Brazil, Argentina, Puerto Rico, Spain, France, Italy, Germany, Finland, Netherlands, England, Australia, New Zealand, Czech Republic and Poland. About 1/3 of the participants had participated in previous KPH crypto challenges.

Decoding the Numbers Message involved 130 modulo-10 additions (one for each digit in the message), converting the resulting digits
back to letters using the supplied conversion chart and the use of a codebook to look up useful words and phrases.
The first decode was received only 10 minutes after the broadcast finished, with the rest coming in within the 72-hour time limit.

Here's the Numbers transmission as sent, using CW and RTTY, on 7 HF frequencies plus 425 kc:

CQ CQ CQ DE KPH KPH KPH
CQ CQ CQ DE KPH KPH KPH
NUMBERS MESSAGE FOLLOWS
=
447 447 447
=
14408  22398  89277  37674  58289
07722  15378  84975  30552  61128
69986  02108  68467  10079  92331
32982  54092  37446  22905  15340
17129  81152  39418  67073  25414
81456  43361
=

Using the one-time-pad and Mission Critical information found at https://www.radiomarine.org/mrhs-events,
the above message decoded as follows:

TO AGENT 447
CURRENT OP COMPROMISED. ABORT.
TRAVEL IMMEDIATELY TO ISTANBUL VIA SWISS PASSPORT.
CONTACT AGENT  MAX. DANGER, INSIST ON MOSCOW RULES.
BURN   AFTER   READING.

(Note: The "Moscow Rules" were a set of trade-craft procedures used by Western spies stationed in the Soviet capitol, where counterspies, policemen,  militia, and other threats are concentrated, making for an extremely hostile environment in which to operate. The Moscow Rules were also applied to other cities that were a dangerous locale for clandestine operatives. If a contact asks for a meeting and declares “Moscow Rules,” it means he thinks he or you are being watched and to take extra precautions)

A sampling of the many positive comments we received:

"Now they want the three of us to all get radios so we can talk using Morse code whenever we want.
Mission accomplished!" - from an OM who participated with his young grandsons.

"This was a kick. Thank you for doing this."

"I appreciate the event and am delighted to have participated. Your +10dB signal in Brazil is impressive."

"Please do this again . . . had a blast!"

"I very much enjoyed this crypto challenge, and hope to see more like
it in the future, especially the Enigma event from previous years."

"I am very happy to contact you from Japan. I really enjoyed the event:)"

"Many thanks From Czech Republic for this great cryptographic challenge!"

"I hope Agent Max is okay :)"

"Thank you so much for holding this exercise, it was fun for several youngsters
ages 8-10 to decode, they felt 'like spies' and learned some history too!"

/Kevin McGrath