It’s probably safe to say that no one has forgotten about the revelation earlier this year of the NSA’s PRISM program. At that time, it was found that many of the U.S.’s top technology companies — including the likes of Google, Apple and Microsoft — had been asked to give up its users’ information. However, it was recently uncovered that the National Security Agency has also relied on other, less direct means of acquiring such information.

In particular, the NSA has apparently been eavesdropping on the communications of Google and Yahoo users without direct access to either companies’ data centers. Of course, this has led many to asked just how the agency has been getting the data. According to The New York Times, the NSA has been exploiting a weak spot in the companies’ infrastructure: the fiber optic cables that connect their data centers.

Since these cables are actually owned by third parties — Verizon Communications, the VT Group, the Vodafone Group and Level 3 Communications were specifically named —the NSA wouldn’t need Google’s or Yahoo’s permission. This does imply that one of those providers would have given permission instead, though, with most pointing to Level 3.

The company, one of the largest Internet backbone providers in the world, would only say that, “It is our policy and our practice to comply with laws in every country where we operate, and to provide government agencies access to customer data only when we are compelled to do so by the laws in the country where the data is located.”

Indeed, both Google and Yahoo have top-of-the-line security and surveillance protecting their data centers, making unwanted intrusion troublesome if not next to impossible for the NSA. However, between data centers, information is unencrypted, making it the obvious target for interception.

That said, nobody knows just exactly how the NSA managed to get to this data so, to be safe, Google and Yahoo have started encrypting data that runs between their data centers. Microsoft is said to be considering similar precautions.

As for users looking to keep their data out of the hands of the NSA or anyone else, but no willing to give up the Internet altogether, Twitter seems to be the best bet for privacy protection.