The FBI has been trying to ban working cryptography since the Clinton years, a losing battle whose stakes go up with each passing day as the number of devices that depend on working crypto to secure them and their users goes up and up and up.
The FBI has been working on Congress to help them out with legislation that would ban tech companies from selling products with working crypto. To make the case for this, the Bureau likes to cite statistics about how many uncrackable criminals' phones they have seized and thus how many crimes remain unsolved because of the stubborn intransigence of nerds who refuse to simply NERD HARDER and make a crypto that works 100% of the time, except when the FBI needs it to fail.
Two years ago, the FBI was complaining that it had 880 unbreakable crimephones. Then, last year, the number shot up to 7,775. The Electronic Frontier Foundation filed a Freedom of Information Act request asking how the FBI had come up with this figure, and today the FBI sheepishly admitted to the Washington Post that it had made it up. The "real number" is now thought to be between 1,000 and 2,000 (maybe).
Marcy Wheeler has covered this story for a long time, and her play-by-play is a great backgrounder.
Frankly, we're not surprised. FBI Director Christopher Wray and others argue that law enforcement needs some sort of backdoor "exceptional access" in order to deal with the increased adoption of encryption, particularly on mobile devices. And the 7,775 supposedly unhackable phones encountered by the FBI in 2017 have been central to Wray's claim that their investigations are "Going Dark." But the scope of this problem is called into doubt by services offered by third-party vendors like Cellebrite and Grayshift, which can reportedly bypass encryption on even the newest phones. The Bureau's credibility on this issue was also undercut by a recent DOJ Office of the Inspector General report, which found that internal failures of communication caused the government to make false statements about its need for Apple to assist in unlocking a seized iPhone as part of the San Bernardino case.