It’s taken more than six months, but top officials at the National Security Agency are finally discussing some of the details of how former agency contractor Edward Snowden got access to all of the documents he stole and what kind of damage they believe the publication of the information they contain could do.

It’s taken more than six months, but top officials at the National Security Agency are finally discussing some of the details of how former agency contractor Edward Snowden got access to all of the documents he stole and what kind of damage they believe the publication of the information they contain could do. A senior NSA employee tasked with investigating what Snowden did and how he did it said that Snowden simply used the legitimate access he had as a systems administrator to steal and store the millions of documents he’s been slowly leaking to the media, and that the information in those documents could give U.S. enemies a “road map” of the country’s intelligence capabilities and blind spots.

The data that Snowden has leaked over the course of the last few months has detailed a variety of programs run by the NSA to collect intelligence on foreign citizens and governments, including the phone metadata program, PRISM and many others. Those programs are at the heart of what the agency does, and intelligence officials and lawmakers have decried their publication, saying that the leaks could make the U.S. intelligence community less effective and give foreign adversaries a detailed blueprint of how to avoid U.S. eavesdropping systems and other intelligence assets.

In an interview broadcast Sunday by 60 Minutes, the NSA official who is heading up the task force investigating the Snowden leaks said that the former contractor essentially used the legitimate access he had for his job to steal the information.

“So, the people who control that, the access to those machines, are called system administrators and they have passwords that give them the ability to go around those security measures and that’s what Snowden did,” said Rick Ledgett, a 25-year NSA employee who was part of a much-criticized 60 Minutes piece on the agency’s response to the Snowden scandal and its collection methods.

Ledgett said that Snowden, who worked in an NSA office in Hawaii, simply grabbed everything he wanted and moved it to another location where he could then download it.

“He did something that we call scraping, where he went out and just used tools to scrape information from web sites, and put it into a place where he could download it,” Ledgett said in the interview.

The volume and scope of what Snowden has taken has been a topic of much discussion among security experts and government officials, as the reporters to whom he has leaked the documents have said that only a tiny percentage of the information has been published. Ledgett didn’t specify a number but said that he wouldn’t argue with the estimate of more than 1.7 million documents that has been used. The thing that worries him the most, Ledgett said, is that the publication of some of the data on exactly what the NSA and the rest of the U.S. intelligence community knows about other countries’ activities and what its limitations are.

“It’s an exhaustive list of requirements that have been levied against the National Security Agency. It would give them a road map of what we know and what we don’t know,” he said, “and give them, implicitly, a way to protect their information from the U.S. intelligence community’s view.”

In the same interview, NSA Director Gen. Keith Alexander defended the agency’s methods and said that it does not deliberately target the communications of huge numbers of Americans, but rather only does what is allowed under the authorities granted to it by the courts.

“There’s no reason that we would listen to the phone calls of Americans. There’s no intelligence value in that. There’s no reason that we’d want to read their email. There is no intelligence value in that,” Alexander said.