For three years, the Federal Bureau of Investigation and the Australian Federal Police owned and operated a commercial encrypted phone app, called AN0M, that was used by organized crime around the world. Of course, the police were able to read everything — I don’t even know if this qualifies as a backdoor. This week, the world’s police organizations announced 800 arrests based on text messages sent over the app. We’ve seen law enforcement take over encrypted apps before: for example, EncroChat. This operation, code-named Trojan Shield, is the first time law enforcement managed an app from the beginning.
If there is any moral to this, it’s one that all of my blog readers should already know: trust is essential to security. And the number of people you need to trust is larger than you might originally think. For an app to be secure, you need to trust the hardware, the operating system, the software, the update mechanism, the login mechanism, and on and on and on. If one of those is untrustworthy, the whole system is insecure.
It’s the same reason blockchain-based currencies are so insecure, even if the cryptography is sound.