FBI Director Christopher Wray again has called for a solution to what the bureau calls the "Going Dark" problem, the idea that the prevalence of default strong encryption on digital devices makes it more difficult for law enforcement to extract data during an investigation.

However, in a Wednesday speech at Boston College, Wray again did not outline any specific piece of legislation or technical solution that would provide both strong encryption and allow the government to access encrypted devices when it has a warrant.

A key escrow system, with which the FBI or another entity would be able to unlock a device given a certain set of circumstances, is by definition weaker than what cryptographers would traditionally call "strong encryption." There's also the problem of how to compel device and software makers to impose such a system on their customers—similar efforts were attempted during the Clinton administration, but they failed.

A consensus of technical experts has said that what the FBI has asked for is impossible.

"I recognize this entails varying degrees of innovation by the industry to ensure lawful access is available," Wray said Wednesday. "But I just don’t buy the claim that it’s impossible."

Wray reiterated that during fiscal year 2017, the FBI was unable to get into nearly 7,800 encrypted devices—"more than half of all the devices we attempted to access in that timeframe."

"Let me be clear: the FBI supports information security measures, including strong encryption," he continued. "Actually, the FBI is on the front line fighting cyber crime and economic espionage. But information security programs need to be thoughtfully designed so they don’t undermine the lawful tools we need to keep the American people safe."

For nearly a decade, the FBI has been pushing for increased access to digital devices, particularly as the public has become more security-conscious in the wake of the Edward Snowden revelations of 2013.

This battle notably came to a head during the 2016 showdown that was popularly dubbed "FBI vs. Apple," when the iPhone maker steadfastly resisted the government's attempts to order it to re-engineer iOS firmware so that the government could access a handset used by a deceased terrorist.

However, in recent months, top FBI and Department of Justice officials have stepped up their public efforts in decrying "Going Dark."

What Wray didn't say, however, is that the FBI is not taking encryption lying down.

The FBI maintains an office, known as the National Domestic Communications Assistance Center (NDCAC), which actively provides technical assistance to local law enforcement in high-profile cases. In its most recently published minutes from May 2017, the NDCAC said that one of its goals is to make commercial tools like those from Israeli data extraction company Cellebrite "more widely available" to state and local law enforcement. In 2017, the NDCAC even provided money to Miami authorities to pay Cellebrite to successfully get into a seized iPhone in a local sextortion case.