Signal, the popular messaging service with end-to-end encryption, stores precious little user data — "Unix timestamps for when each account was created and the date that each account last connected to the Signal service."
So when Homeland Security subpoenaed Signal to turn over "a wide variety of information… including the addresses of the users, their correspondence, and the name associated with each account," Signal enlisted the aid of the ACLU, which replied to the FBI with a polite version of the Willy Winka "you get nothing" meme.
Because everything in Signal is end-to-end encrypted by default, the broad set of personal information that is typically easy to retrieve in other apps simply doesn't exist on Signal's servers. The subpoena requested a wide variety of information that fell into this nonexistent category, including the addresses of the users, their correspondence, and the name associated with each account.
Just like last time, we couldn't provide any of that. It's impossible to turn over data that we never had access to in the first place. Signal doesn't have access to your messages; your chat list; your groups; your contacts; your stickers; your profile name or avatar; or even the GIFs you search for. As a result, our response to the subpoena will look familiar. It's the same set of "Account and Subscriber Information" that we provided in 2016: Unix timestamps for when each account was created and the date that each account last connected to the Signal service.
This is almost as funny as when the FBI opened an investigation into Cory Doctorow for linking to a Popular Mechanics article.