Coins and Codes: Joan E. L. Murray (Clarke)

The Imitation Game (released December 25, 2014) was a movie about Alan Turing and the cryptanalysts at Bletchley Park. Keira Knightley played the role of Joan Clarke. Joan Elisabeth Lowther Murray (nee Clarke) was a brilliant mathematician, and an accomplished code-breaker. Clarke was also a numismatist. 

(An earlier version of this article appeared as “Numismatics and Cryptography” in The E-Sylum, Vol. 17, No. 53, Dec. 28, 2014, art. 17. www.CoinBooks.org) 

The British Numismatic Society granted her a Sanford Saltus Gold Medal in 1986. By then she was married; and to the BNS, she was Joan E. L. Murray. You can find a brief biography in Wikipedia, of course, but as Joan Clarke. 

Lord Stewartby (Bernard Harold Ian Halley Stewart), one of her collaborators in the coinage of Scotland, wrote the obituary for the British Numismatic Journal Vol. 67 No. 13, pg 162-167. That essay provided a bibliography, including papers she read at society meetings, but did not publish. 

Her husband, Lieutenant-Colonel John Kenneth Ronald (Jock) Murray, who also worked at the Government Communications Headquarters, introduced her to the problems attendant in sequencing the gold unicorns and heavy groats of the kings James III and James IV of Scotland. Joan E. L. Murray stands out among Saltus awardees for having done all of her work in the area of Scottish numismatics.

The intersection of numismatics and cryptography may be a rich field. We know that Masonic Pennies present cryptic messages. (I suggest that the earliest known coins, lumps of electrum with a simple punch could also have been created as gate passes to secret meetings.) Coins with secret compartments are well known to us; and they are associated with spies and smugglers. Since the invention of the Alberti cipher disk in 1467, the “decoder ring” has been a collectible.

Sometimes collectors of cryptographic memorabilia call them “cipher coins.” They continue today because they are popular with geocachers. Geocaching is a treasure hunting game that includes both tracking via GPS coordinates and the unraveling of secret messages at each stop. The museum shop of the National Security Agency has sold replicas of the Confederate cipher disk of the War Between the States.

Computer security professionals have taken up the military challenge coin; and included codes ciphers and hidden messages in them.

The SANS Institute (www.sans.org) delivers computer security training. An important feature of computer security is penetration testing (“pen testing” for short). At conventions, workshops, and club meetings, computer security enthusiasts often have “capture the flag” challenges in which hackers attack a computer that is defended by a knowledgeable team. Some SANS Institute trainers have created challenge coins as awards and rewards.

Successful students are called “forensicators”. “The Coin, Round Metal Object (RMO), is designed to be awarded to those who demonstrate exceptional talent, contributions, or helps to lead in the digital forensics profession and community. The Coin is meant to be an honor to receive it; it is also intended to be rare. Those who join the Lethal Forensicators Unit will have all privileges and recognition.” 

The coins quickly evolved into a set with embedded codes and ciphers. The superior student now must win each of the coins in turn and then solve the puzzle.

Last year, my wife, Laurel, and I volunteered to work the Lone Star Application Security Conference (LASCON). Our convention badges were metal plaquettes on which were printed in thin disguise the first key to a puzzle. Each clue led to another. Laurel solved the challenge and won a coin.

7 years ago
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