Signal posted a summary of what happened when it receive a search warrant from Santa Clara County requesting data on one of its users.
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. Once again, this request sought a wide variety of information we don’t have, including the user’s name, address, correspondence, contacts, groups, call records.
As usual, 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 can provide: Unix timestamps for when each account was created and the date that each account last connected to the Signal service.