Snowden’s favorite messaging app receives first federal subpoena

An encrypted communications application popular with digital security advocates received its first ever subpoena from a federal grand jury earlier this year, it revealed on Tuesday.

The San Francisco-based company, Open Whisper Systems, gave the Eastern District of Virginia jury a minimal amount of information about one user of its Signal service, it said in a blog post.

{mosads}Much of the information about the user is either encrypted or was not stored by the company, though it was able to hand over the date and time the user registered with the app and the last date that the user logged on, it said.

“We’ve designed the Signal service to minimize the data we retain about Signal users,” the company said.

“Notably, things we don’t have stored include anything about a user’s contacts … anything about a user’s groups … or any records of who a user has been communicating with,” it added.

“All message contents are end to end encrypted, so we don’t have that information either.”

The government sought to obtain information about two phone numbers, but only one was connected to a Signal account, the American Civil Liberties Union (ACLU) said on behalf of the company in a filing with the government made public on Tuesday. Authorities asked for names, addresses, email addresses and other data about two accounts, but the company was unable to provide that information.

The ACLU is representing Open Whisper Systems in responding to the subpoena.

The demand for information was issued at some point in the first half of this year, but the company was not able to be more precise. The government initially barred the firm from revealing the existence of the subpoena, but that gag order was lifted following a petition from the ACLU.

Information about the user was wanted in connection with an FBI criminal investigation.

Services like Signal have risen in popularity in recent years due to increased public anxiety about the government’s ability to monitor digital communications.

Government leaker Edward Snowden has personally advocated for people to start communicating on Signal.

“It’s very good. I know the security model,” he said last year.

Staffers for Hillary Clinton’s presidential campaign have also been urged to switch to the app, which they called “Snowden-approved,” to avoid detection from hackers.

Encryption technologies use complicated algorithms to scramble communications and other data to prevent people from accessing the information without a particular digital code.

The proliferation of encrypted devices and messages in recent years has frustrated U.S. law enforcement officials, who say that it is hampering their ability to monitor suspected criminals and terrorists.