As the nation watches the FBI battle Apple in court over access to a terrorist’s iPhone data, a conflict with another Silicon Valley company simmers in the background.

With over a billion users, the Facebook-owned mobile app WhatsApp is one of the world’s largest messaging platforms and allows users to send text messages and make phone calls abroad without incurring the international data costs associated with traditional text and voice communication. Similar to Telegram, an app popular with ISIS members, WhatsApp offers end-to-end encrypted text messaging and, according to the Guardian, will in the coming weeks be offering encrypted voice and group messaging.

At present, the Department of Justice is unsure how to proceed in an ongoing criminal investigation in which a federal judge ordered a wiretap, as the department is unable to get access the ordered data thanks to WhatsApp’s encryption.

As encryption plays an increasing role in electronic communication, government and law enforcement agencies are facing an impending dilemma the FBI refers to as the “Going Dark” issue. Despite legal authority, governing agencies have found it increasingly difficult to access communications made on apps or platforms that are often just years old. Compounding the issue for law enforcement is the outdated Communications Assistance for Law Enforcement Act that was enacted in 1994. The law applies only to traditional communications carriers and leaves companies like WhatsApp or Apple (via iMessage) exempt from the requirement of developing intercept capabilities for law enforcement.

The Guardian elaborates on the problem:

“For more than half a century, the Justice Department has relied on wiretaps as a fundamental crime-fighting tool. To some in law enforcement, if companies like WhatsApp, Signal, and Telegram can design unbreakable encryption, then the future of wiretapping is in doubt.

‘You’re getting useless data,’ said Joseph DeMarco, a former federal prosecutor who now represents law enforcement agencies that filed briefs supporting the Justice Department in its fight with Apple. ‘The only way to make this not gibberish is if the company helps. As we know from intercepted prisoner wiretaps, prisoners think that advanced encryption is great.’ “

Even though Facebook and Twitter have have worked with law enforcement in efforts to keep terrorist material off social media, tech companies are standing by their commitment to user privacy via encryption. “I don’t think requiring backdoors into encryption is either going to be an effective way to increase security or is really the right thing to do for the direction the world is going in,” Facebook CEO Mark Zuckerberg said in February.

To security and technology experts, however, the WhatsApp and Apple issues have fundamental differences. Bruce Schneier outlines the difference:

In [the Apple] case, the FBI is demanding that Apple create a hacking tool to exploit an already existing vulnerability in the iPhone 5c, because they want to get at stored data on a phone that they have in their possession. In the WhatsApp case, chat data is end-to-end encrypted, and there is nothing the company can do to assist the FBI in reading already encrypted messages. This case would be about forcing WhatsApp to make an engineering change in the security of its software to create a new vulnerability — one that they would be forced to push onto the user’s device to allow the FBI to eavesdrop on future communications. This is a much further reach for the FBI, but potentially a reasonable additional step if they win the Apple case.

Internationally, WhatsApp’s parent company Facebook has already sparred with governments over privacy issues. In 2014, Brazilian police arrested a Facebook executive after the company refused to provide information about a user who was the subject of a drug trafficking investigation.

As WhatsApp’s popularity and encryption features expand, it is only a matter of time before the company that prides itself on privacy is forced to make its case in court.