It’s been six months since former intelligence contractor Edward Snowden leaked a massive trove of classified documents that detailed the U.S. National Security Agency’s controversial surveillance operations. According to government officials, the agency still has no idea what he took. And some officials would dearly to find out.

As one senior official told the New York Times, the NSA “spent hundreds and hundreds of man-hours trying to reconstruct everything he has gotten, and they still don’t know all of what he took."

“I know that seems crazy, but everything with this is crazy,” the official added.

There is considerable interest in defining Snowden’s take. It would allow the agency to preempt news reports about sensitive operations before they were disclosed to the public. And given the number of leaks that have implicated the agency in spying on United Nations members and South American and European allies, knowing what Snowden took could help the U.S. privately ease tensions with these targets ahead of news reports.

Here’s what the agency does know: Snowden apparently used the login and password information of his colleagues to cover his tracks and hacked past firewalls designed to block his access to sensitive materials. As one FBI official heading up the Snowden investigation told the Times, they believe the contractor worked alone, spending months systematically removing classified documents from his office in Hawaii.

Further, the agency appears to now believe that Snowden may not have turned over all the documents to journalists Glenn Greenwald and Laura Poitras. The Times did not elaborate on the NSA's reasoning.

If Snowden does have files that have not yet been handed over to journalists,  he NSA may be willing to pay a steep price for them. On 60 Minutes, the head of the task force investigating the leaks, Rick Ledgett, said he thought that the idea of giving Snowden amnesty in exchange for the remaining files was “worth having a conversation about.”

The comment appears to be his personal view, but nonetheless suggests a growing willingness to bargain with Snowden. Furthermore, it would seem to indicate that the NSA is engaged in highly secretive surveillance practices that have yet to be published by the media. Already, it has been revealed that the agency taps undersea Internet cables, breaks encryption, tracks cell phones, records chats and browser histories, and obtains social media data and phone records from major U.S. companies. What more they NSA could be doing is difficult to speculate.

Not everyone shares Ledgett’s view, though. Current NSA director Gen. Keith Alexander, who is set to step down in 2014, disagreed with the idea of giving Snowden amnesty. “This is analogous to a hostage taker taking 50 people hostage, shooting 10 and then say, 'If you give me full amnesty I'll let the other 40 go.’ What do you do?”

Good question.

Photo by Malakhi Helel/Flickr