You might have heard about the 14-year-old Tasmanian boy who solved the codes on a coin released by an Australian intelligence agency.
The coin, released on Thursday by the Australian Signals Directorate (ASD), commemorated its 75th anniversary and included several codes to crack.
But the puzzles were already being discussed 10 days earlier online.
This was because the Australian Government was required to include the characters in legislation, posted online, prior to the altered coin being made available for purchase on September 1.
The legislation requirement meant that on August 20 some of the codes had already been solved, while others relied on being able to physically see the coin.
The coin could also be part of the ASD's attempt to get its name out there, with the government agency recruiting 1,900 more people over the coming decade as part of a $9.9 billion expansion.
But first, the coin (spoiler alert!).
Why did some people get the jump?
University of Queensland research fellow Richard Bean has cracked more than a few historical cryptograms.
Among them, a 1920s Irish Republican Army message, a Cambridge professor's attempt to communicate with the living after his death, and supposed recipe for the elixir of life on the original Philosopher's Stone.
Naturally, he had a go at the ASD coin as soon as he could, solving it in about two hours.
On the scale of challenging codes, Dr Bean said it was relatively simple for those with some experience.
"It's not designed to be super challenging," he said.
"The unfortunate thing with these puzzles is that the legislation was posted explaining what the letters and numbers are on the coin. On August 20, someone just posted most of the solutions straight away."
By the way, you can download a high-resolution image of the coin's front and the coin's back on the Australian Signals Directorate's website.
So how do you crack it?
The coin might look daunting at first, but most code crackers would start at the simplest point — the six braille numbers around Queen Elizabeth II.
They spell "Atbash", one of the most common tools for cracking codes using a simple reverse-order alphabet.
This gives a clue as to solving the characters around the rim on the other side, replacing A for Z, B for Y and so on.
Applying it to the outer circle results in:
"We are audacious in concept and meticulous in execution. Find clarity in 7 width x 5 depth."
Now stay with us, it's about to get a bit more complicated.
This is where a pen and paper come in handy.
The 7x5 part is an instruction to arrange the inner rim of letters in grids of rows of seven, starting from BGOAMVO at the bottom of the coin and continuing on around the coin.
There are 70 letters, so they need to be arranged in two grids of 35 letters with five columns.
The two grids are then read from top to bottom to give the message:
"Belonging to a great team striving for excellence we make a difference XOR HEX A5D75."
Still with us?
The next part is where Dr Bean says he faced the biggest challenge — attempting to decipher the block of letters and numbers in the bottom right third wedge.
The "XOR HEX A5D75" at the end of the last answer is the clue for this next step, and it requires a fair bit of code-breaking know-how.
XOR is a common and highly secure type of encryption, creating sequences of letters and numbers using binary digits.
Without a key, it's pretty much impossible to crack, and that is why it's a common defence in encryption software.
Fortunately, the key is "A5D75" and the "hex" means it's in hexadecimal form, or there are 16 different characters. Solving this one by hand is almost so tedious that it's pointless.
Or you can put the slab of letters into an online program like Cyber Chef, with the key, and it'll give you the answer:
"For 75 years the Australian Signals Directorate has brought together people with the skills, adaptability and imagination to operate in the slim area between the difficult and the impossible".
The last code couldn't be solved before the physical coin was released.
It involves the shading of the two rings of characters. The inner one is in binary — so unshaded is a 0, shaded is a 1 and can be decoded to mean "ASDCbr2022".
The outer ring is in Morse code, and results in "1947 DSB Albert Park".
They're both nods to the ASD.
So what's the point?
It's all about lifting profiles.
This isn't the first time a government agency has put codes into an uncirculated commemorative coin.
Australian Security Intelligence Organisation (ASIO) released a coin in 2019 with an encrypted message, which Dr Bean said was a creative way of getting the public to engage with it, and build its public profile.
He said the idea was to plant the seed in the minds of those who might be interested in a career with the ASD or ASIO.
"The kind of people who would sit down and solve this kind of code on the coin, they're the kind of people the ASD wants to attract — innovative thinkers to solve difficult problems in cryptography in both an offensive and defensive sense," Dr Bean said.
"So solving other nation's codes and protecting Australian government communications security.
"It's about attracting the right candidates and putting the ASD in their mind, instead of having to go out in traditional recruitment channels."
Over the coming decade, the ASD will be expanding beyond Canberra with new sites in Melbourne, Brisbane and Perth recruiting a further 1,900 workers in a program known as REDSPICE.
It's part of the federal government's response to instability in the Asia-Pacific, and the growing use of cyber attacks.
So who is the teenage whiz kid?
The identity of the 14-year-old Tasmanian boy who solved the code has not been revealed.
Distinguished Professor Willy Susilo is the Director of the University of Wollongong's Institute of Cybersecurity and Cryptology.
He said it was clear whoever cracked the ASD's code had talent and instinct, given they probably hadn't had formal training.
"[What] is very important is actually not about whether you can crack the code or not, [what] is important is the thinking behind it, how to solve this kind of puzzle," he said.
"To me, I think to get a person who, especially in this case, is 14 years old, can crack the code within just one or two hours is actually incredible in my opinion.
"That really is the kind of skill needed in the Australian Signals Directorate."
