The FBI Kavanaugh report is being held in a “SCIF.” What makes the room so special?

One by one, senators filed into a secure, locked room called a “SCIF” Thursday to look at the single copy of a single report: the findings of the FBI’s investigation into sexual assault allegations against Supreme Court nominee Brett Kavanaugh.

The senators can’t remove the document, can’t take pictures of it, and can’t release its contents to the public. Journalists aren’t allowed inside, and neither is any unauthorized person.

So what is a SCIF, anyway?

“SCIF” actually stands for Sensitive Compartmented Information Facility, according to the National Counterintelligence and Security Center.

A SCIF can be a specially designed room or a makeshift secure area, depending on the need, according to ABC News, as long as it has measures built in to prevent intrusion and keep whatever happens inside the room inside the room.

The White House Situation Room is a permanent SCIF, for example. A conference room at Trump Tower was turned into a SCIF early in President Trump’s term, according to WIRED. And the Kavanaugh report is inside a SCIF in the Senate’s CVC building.

“You’ve got to go through security, badge readers, access control before you can even reach that room,” said Jaye Andone, president and CEO of SCIF Global Technologies, according to ABC News. “It can be portable. As long as there were barriers around it, say military personnel that had guns on them that could protect it and had a stand-off distance so that no one could get near the area so that no one could hear what was going on.”

The office of the Director of National Intelligence has a detailed checklist for evaluating a SCIF. It includes space for marking the dimensions of fences, numbers of gates, types of recording equipment, number of windows, alarms, keys, codes, ventilation ducts, whether those ventilation ducts could transmit sound, the type of floor, strength of the doorframe and much more.

A 174-page document from the office provides even greater detail in how such should be built, maintained and standardized. One notable restriction: only U.S. citizens and businesses are allowed to construct SCIFs for the government.

“The whole purpose is to not let your enemies to get your information,” said Rep. Dutch Ruppersberger (D-Maryland), a former member of the House Intelligence Committee, according to The Atlantic. “A SCIF is important to protect classified information from getting out. The technology has developed so much today to the point where our enemies, our Russias, our Chinas, can penetrate right through [the wall] if there’s no SCIF.”

Protesters gathered in Washington, D.C. on Thursday to protest Judge Brett Kavanaugh's nomination to the Supreme Court after he was accused of sexual assault.