Not every secure messaging app is as safe as it would like us to think. And some are safer than others.

A recently disclosed FBI training document shows how much access to the content of encrypted messages from secure messaging services US law enforcement can gain and what they can learn about your usage of the apps.

The infographic shows details about iMessage, Line, Signal, Telegram, Threema, Viber, WeChat, WhatsApp, and Wickr. All of them are messaging apps that promise end-to-end encryption for their users. And while the FBI document does not say this isn’t true, it reveals what type of information law enforcement will be able to unearth from each of the listed services.

Note: A pen register is an electronic tool that can be used to capture data regarding all telephone numbers that are dialed from a specific phone line. So if you see that mentioned below it refers to the FBI’s ability to find out who you have been communicating with.

iMessage

iMessage is Apple’s instant messaging service. It works across Macs, iPhones, and iPads. Using it on Android is hard because Apple uses a special end-to-end encryption system in iMessage that secures the messages from the device they’re sent on, through Apple’s servers, to the device receiving them. Because the messages are encrypted, the iMessage network is only usable by devices that know how to decrypt the messages. Here’s what the document says it can access for 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.

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