You’ve all heard the old argument, “if you’re not doing anything wrong, you have nothing to hide!” It simply doesn’t hold water. There are many reasons ordinary people take steps to safeguard their privacy, and government surveillance is near the top of that list. That’s one reason why encrypted messaging apps such as Telegram, Signal, WhatsApp, and Threema have skyrocketed in popularity recently. In January 2021, Signal became the most-downloaded free app for both Apple and Android devices, with nearly 18 million downloads in a single week — that’s a lot of users who want to keep their conversations private.
Privacy is a never-ending arms race. Every time individuals take steps to encrypt their data, those who wish to access it take steps to circumvent that encryption. We’ve often wondered just how much access three-letter agencies have to our sensitive information, and a recently discovered internal document from the Federal Bureau of Investigation gives us a rare glimpse at the answer.
FBI’s Ability to Access Encrypted Messaging Apps
A recently discovered FBI training document shows that US law enforcement can gain limited access to the content of encrypted messages from secure messaging services like iMessage, Line, and WhatsApp, but not to messages sent via Signal, Telegram, Threema, Viber, WeChat, or Wickr.
The Document was Dated January 7, 2021, the document doesn’t include any new information but does a good job at providing an up-to-date summary of what type of information the FBI can currently obtain from each of the listed services.
The following document was obtained through a Freedom of Information Act (FOIA) request filed by Property of the People, a nonprofit organization that works to promote government transparency.
Since this text appears to be scanned from a degraded photocopy of the document, The Record converted it into an easy-to-read table:
|App||Legal process & additional details|
|Apple iMessage||*Message content limited.
*Subpoena: can render basic subscriber information.
*18 USC §2703(d): can render 25 days of iMessage lookups and from a target number.
*Pen Register: no capability.
*Search Warrant: can render backups of a target device; if target uses iCloud backup, the encryption keys should also be provided with content return can also acquire iMessages from iCloud returns if target has enabled Messages in iCloud.
|Line||*Message content limited.
*Suspect’s and/or victim’s registered information (profile image, display name, email address, phone number, LINE ID, date of registration, etc.)
*Information on usage.
*Maximum of seven days worth of specified users’ text chats (Only when E2EE has not been elected and applied and only when receiving an effective warrant; however, video, picture, files, location, phone call audio and other such data will not be disclosed).
|Signal||*No message content.
*Date and time a user registered.
*Last date of a user’s connectivity to the service.
|Telegram||*No message content.
*No contact information provided for law enforcement to pursue a court order. As per Telegram’s privacy statement, for confirmed terrorist investigations, Telegram may disclose IP and phone number to relevant authorities.
|Threema||*No message content.
*Hash of phone number and email address, if provided by user.
*Push Token, if push service is used.
*Date (no time) of Threema ID creation.
Date (no time) of last login.
|Viber||*No message content.
*Provides account (i.e. phone number)) registration data and IP address at time of creation.
*Message history: time, date, source number, and destination number.
|*No message content.
*Accepts account preservation letters and subpoenas, but cannot provide records for accounts created in China.
*For non-China accounts, they can provide basic information (name, phone number, email, IP address), which is retained for as long as the account is active.
|*Message content limited.
*Subpoena: can render basic subscriber records.
*Court order: Subpoena return as well as information like blocked users.
*Search warrant: Provides address book contacts and WhatsApp users who have the target in their address book contacts.
*Pen register: Sent every 15 minutes, provides source and destination for each message.
*If target is using an iPhone and iCloud backups enabled, iCloud returns may contain WhatsApp data, to include message content.
|Wickr||*No message content.
*Date and time account created.
*Type of device(s) app installed on.
*Date of last use.
*Number of messages.
*Number of external IDs (email addresses and phone numbers) connected to the account, bot not to plaintext external IDs themselves.
*Limited records of recent changes to account setting such as adding or suspending a device (does not include message content or routing and delivery information).
*Wickr version number.
To summarize, there’s some good news and bad news here. The FBI says it can retrieve “no message content” from six of the nine encrypted messaging apps, with the remaining three — Apple’s built-in iMessage, Line, and Facebook’s WhatsApp — only providing limited message content. From a privacy standpoint, Signal and Telegram appear to be the most secure based on this report. The former only provides date/time of registration and date of last connection; the latter may give authorities a user’s IP address and phone number if there’s evidence of terrorist activity.
Whether you’re wary of domestic government overreach, foreign nation-states, or rogue hackers trying to read your messages, it’s worthwhile to consider which encrypted messaging app you use.
Note: the table above does not include details about Keybase, a recent end-to-end encrypted (E2EE) service that has been gaining in popularity