It's not just Apple. The U.S. Department of Justice is considering waging another court fight against WhatsApp, the popular messaging app, to crack encryption technology that makes it almost impossible for police investigators to access user communications with a warrant.

WhatsApp, owned by Facebook, is the world's most popular messaging service, enabling more than 1 billion users to send messages and make phone calls on their mobile devices. It protects the contents of those messages with end-to-end encryption, a security measure that scrambles the contents of messages at all points between the sender and recipient. Now, according to a New York Times report Sunday, federal officials have discussed “how to proceed” in a criminal investigation where that encryption has blocked access to a suspect's communications.

Authorities have not made a decision on whether to initiate a court fight, the Times reported, and the case remains under seal. The case is not a terrorism investigation.

This coincides with the current battle between the Justice Department and Apple, which is fighting a government request to unlock the passcode on the iPhone 5c used by one of the shooters in the San Bernardino terrorist attack. FBI Director James Comey and other officials have called on Apple to unlock the phone so police can see if the shooter, who is dead, had any contact with overseas terrorists before carrying out the attack. A range of technology companies warn that Apple would need to rewrite its software to decipher the encryption, thus setting a precedent for similar cases in the future.

WhatsApp plans to beef up its secure messaging service to encrypt voice calls, the Guardian reported Monday. Facebook, Snapchat and Google are also reportedly at work on implementing more security.