An app was at the centre of a major transnational sting - including 35 arrests and $3.7 million in assets in New Zealand.
Tech commentator Paul Brislen said the FBI's app, Anom, was installed on black market mobile phones that had been stripped of all their normal functions, like the ability to make phone calls or send text messages.
For law enforcement to get the app into the criminal circles, the app was unwittingly distributed by fugitive Australian drug trafficker Hakan Ayik, after he was given a handset by undercover agents, the ABC reported.
Ayik recommended the app to criminal associates who would purchase the handset pre-loaded with Anom on the black market, the ABC said.
For over 18 months, Anom's criminal users unknowingly communicated on the system operated by FBI agents.
There were 57 devices being used in New Zealand, each for "criminal needs", National Organised Crime Group director detective superintendent Greg Williams said today.
Brislen says the devices are phones that run on the same network as normal mobile phones, but the only thing that can be installed on them is the app.
"It's much like Whatsapp. That means it should be very, very secure but, of course, it wasn't. It was totally compromised from the very outset."
Operation Trojan Shield is the name of the law enforcement operation that infiltrated these encrypted devices used by crime groups, led by the FBI and co-ordinated with the DEA, AFP, Europol and other law enforcement partners from more than a dozen countries,
New Zealand Police began working with the FBI on the operation in January 2020 to monitor the communication of platform users in New Zealand.
Brislen says the Anom app was a "cheeky" way around the proliferation of encrypted communication channels, which can be very hard for authorities to crack.
"The devices were encrypted, totally secure. The communication point-to-point was totally secure. But the FBI was listening in all along and the keys to unlock it. It's almost as if the FBI had set up a meeting for criminals to come and discuss things."
New Zealand police announced today they had arrested 35 people as part of the trans-national sting, and seized $3.7 million in assets, including 14 vehicles, drugs, firearms and more than $1 million in cash.
Among those arrested were members of the Mongrel Mob, Head Hunters and Comancheros gangs.
Brislen described the use of the app in Operation Trojan Shield as "almost a stunt" with a huge impact - but unlikely to be repeated again as criminals were now aware of it.
"All the publicity from this on a global scale, you'll now have people with ill intent go - I'll get rid of my phone and go back to just using email or talking in code. It's a bit obvious now."
In the longer term, it raises the question of encryption and the way authorities view encryption as something nasty that only criminals had, he said.
Encryption is a fundamental part of our interaction with interaction with the internet, Brislen said.
The credit card details of our Netflix account, Facebook messages and text messages - they're all encrypted.