The cyberspies at the Australian Signals Directorate (ASD) are challenging puzzle-solvers to find a message clocked in layers of secret code on a 50-cent coin released to mark their 75th anniversary.

The Directorate is responsible for signals intelligence, cyber warfare, and cyber security. The brainteaser may be difficult for some but a 14-year-old Tasmanian boy cracked the code in just over an hour. "So we're hoping to meet him soon," Rachel Noble, ASD Director-General, told Australian television.

ASD’s cryptographic experts collaborated with the Royal Australian Mint to help design the coin, which has unique layers of code that - if broken - contain messages about the Directorate
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The Royal Australian Mint is selling the coin while supplies last - there’s only 50,000 of them in circulation - but entrepreneurial Australians are already re-selling the coins on eBay.

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Collectively the ciphers trace ASD’s historical evolution, combining codes thousands of years old through to modern binary code invented during the age of computing, the Mint said. 

Still need a hint? An Australian web developer who also cracked the cipher provided this advice: “The first word of the clue is in that cipher, and then the key is the second word, and the third word is the key." So, pretty obvious then…

Still puzzled? You’ll find the solution here.

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‍Australian Signals Directorate’s history‍‍

ASD was created in WWII when civilians and military worked together to decipher signals, support Allied fighters, and protect Australia’s own communications. From early 1942, Australian, American, and British personnel worked together in Central Bureau, Melbourne, attached to General MacArthur’s HQ, while the joint Australian-American Fleet Radio Unit Melbourne supported the US Navy’s 7th Fleet.