The AN0M fake secure chat app may have been too clever for its own good • The Register

Comment In April 1943, Japanese admiral Isoroku Yamamoto was killed when the US Air Force shot down the plane carrying him to Balalae Airfield in the Solomon Islands.

The attack was made possible by the USA cracking Japanese codes and decrypting a message that revealed Yamamoto’s flight plan would just take him within range of America’s scarce long-range aircraft.

The chances of those aircraft happening upon Yamamoto were very small so US strategists worried Japanese analysts might conclude an attack was only possible had their codes been broken.

The US chose to kill Yamamoto, because he was felt to be so important to the war effort that losing access to decrypted intelligence was worth the risk. But on other occasions in World War II, troops were sent into harm’s way to protect intelligence sources.

Which brings me to last week’s news that Australian and US law enforcement agencies seeded a backdoored encrypted chat app named AN0M into the criminal underworld, then intercepted word of a great many crimes and swooped to arrest those responsible.

Late last week, FBI International Operations Division legal attaché for Australia Anthony Russo added another important piece of information: speaking to Australian newspapers he said one reason for discontinuing use of AN0M was that it produced too much intelligence.

“The volume [of content] was increasing at a scale and our ability to resource it and monitoring it really wasn’t scalable commensurate to the growth,” he reportedly said.

Russo said authorities therefore decided enough was enough, so revealed AN0M’s existence. We also noted that, in March, someone poking around in the software’s code spotted what looked like a backdoor and raised the alarm in a later-deleted blog post.

I’d been thinking about the Yamamoto story since news of AN0M’s existence was revealed….