On Monday, Federal Bureau of Investigation Director James Comey penned an op-ed in the national security blog Lawfare which claimed that data encryption techniques that are effective enough to challenge the government’s ability to crack them are a threat to national security.

“The logic of encryption will bring us, in the not-to-distant future, to a place where devices and data in motion are protected by universal strong encryption. That is, our conversations and our ‘papers and effects’ will be locked in such a way that permits access only by participants to a conversation or the owner of the device holding the data,” said Comey. After paying brief lip service to the benefits of strong encryption, Comey began to lay out why he thinks future advancements in encryption technology will “inexorably affect my ability to do [my] job.”

“When the government’s ability—with appropriate predication and court oversight—to see an individual’s stuff goes away, it will affect public safety,” asserted Comey. He continued, evoking terrorism, “That tension is vividly illustrated by the current ISIL threat, which involves ISIL operators in Syria recruiting and tasking dozens of troubled Americans to kill people, a process that increasingly takes part through mobile messaging apps that are end-to-end encrypted, communications that may not be intercepted, despite judicial orders under the Fourth Amendment. But the tension could as well be illustrated in criminal investigations all over the country. There is simply no doubt that bad people can communicate with impunity in a world of universal strong encryption.”

According to National Journal, Comey will testify on Wednesday before the US Senate’s Intelligence and Judiciary committees on the challenges law enforcement agencies face in keeping up with encryption techniques.

Earlier this year, President Obama took a position similar to Comey’s on the issue and said, “If we get into a situation which the technologies do not allow us at all to track somebody we’re confident is a terrorist… that’s a problem.”

National Journal’s Dustin Volz wrote, “Many believe there is no such thing as a ‘golden key’ for encryption that could allow law-enforcement or national security professionals access into an encrypted device without also creating a vulnerability that malicious hackers could exploit.“