While quantum computers don't really exist at useful scales, nor are they likely to in the very near future, their emergence at some point seems reasonably assured. And this will be very, very bad for encryption as we know it—where "bad" translates roughly to "completely destroy."

At the moment, the NSA's Information Assurance Directorate (IAD) uses Suite Balgorithms for protecting classified and unclassified National Security Systems. This is a collection of four NIST-specified algorithms employed for such ends as digital signatures, message hashing, anonymous key agreement protocols, and symmetric encryption. The Suite B algorithms have been around since 2005 and are an open standard widely employedin the private sector via the Internet Engineering Task Force.