In a world awash in high-tech security tools like passkeys, quantum-safe algorithms, and public-key cryptography, it can be refreshing to get back to the simple things… like a good old-fashioned canary trap.
The canary trap is a simple tool often used to identify leakers or double agents. To make one, you simply share a document, image, or database but make tiny changes that are unique to each recipient. That way, if those changes show up verbatim in any leak of the information, you know immediately which recipient was behind the leak.
You don’t often see canary traps in the news, though they have long been a staple of spy fiction (and practice), so an account out of Canada last week caught my eye.
The Canadian province of Alberta has been the site of recent drama around its electoral list, a database that contains information such as names, addresses, and voting districts for millions of citizens. Political parties can legally get access to the electoral list, though they operate under significant restrictions on how they can use the data. They cannot, for instance, share the list with a third party.
Despite this, The Centurion Project, described by the CBC as a “separatist group,” used the list to power an online database of voters. Elections Alberta, which maintains the list, went to court last week and obtained an order to shut down the Centurion site.
But how had Centurion obtained the data?
Elections Alberta quickly investigated and announced that the list used by Centurion was a copy of one legitimately released to the Republican Party of Alberta. Election officials were confident in their claim because, whenever they release a copy of the electoral list, they salt it with additional but bogus entries. The fake entries inserted in the Republican Party version of the list showed up in Centurion’s online tool, too.
Exactly how the data had passed from the Republican Party to Centurion remains unclear, but the canary trap enabled Elections Alberta to lean quickly on both groups. Each publicly pledged to respect the law, and Centurion took down its tool.
Canaries—from Clancy to AI
The canary trap has been used by companies ranging from Tesla to Apple; it was even used to stop the leak of Star Trek film scripts. Though the concept comes from the world of espionage, the actual term appears to stem from Tom Clancy’s 1980s thriller, Patriot Games. The idea is to find out which “canary” did the “singing.”
Ars Technica’s own Clancy aficionado, Lee Hutchinson, tracked down his copy of the book and found the passage in which protagonist Jack Ryan explains the term after an admiral asks him, “What the devil is this Canary Trap?” Ryan says:
“Well, you know about all the problems CIA has with leaks. When I was finishing off the first draft of the report, I came up with an idea to make each one unique…
“Each summary paragraph has six different versions, and the mixture of those paragraphs is unique to each numbered copy of the paper. There are over a thousand possible permutations, but only ninety-six numbered copies of the actual document. The reason the summary paragraphs are so—well, lurid, I guess—is to entice a reporter to quote them verbatim in the public media. If he quotes something from two or three of those paragraphs, we know which copy he saw and, therefore, who leaked it. They’ve got an even more refined version of the trap working now. You can do it by computer. You use a thesaurus program to shuffle through synonyms, and you can make every copy of the document totally unique.”
Thesaurus program? We can do better than that, Jack Ryan; this is the age of artificial intelligence!
Indeed, as far back as 2021, Dartmouth professor V.S. Subrahmanian built an AI tool called (really) WE-FORGE that “automatically creates false documents to protect intellectual property such as drug design and military technology.” The goal was to create “documents that are sufficiently similar to the original to be plausible, but sufficiently different to be incorrect,” said Subrahmanian at the time.
However it’s done, this old system continues to work pretty well. Just ask Elections Alberta.
