One-Shot Memories...

The "one-shot" memory devices that recent NIST research might make possible can be envisioned as physical keys that can only be used a single time, a useful feature for computer security applications.
Credit: Talbott/NIST

Computer security systems may one day get a boost from quantum physics, as a result of recent research from the National Institute of Standards and Technology (NIST). Computer scientist Yi-Kai Liu has devised a way to make a security device that has proved notoriously difficult to build—a "one-shot" memory unit, whose contents can be read only a single time.

The research, which Liu is presenting at this week's Innovations in Theoretical Computer Science conference,* shows in theory how the laws of quantum physics could allow for the construction of such memory devices. One-shot memories would have a wide range of possible applications such as protecting the transfer of large sums of money electronically. A one-shot memory might contain two authorization codes: one that credits the recipient's bank account and one that credits the sender's bank account, in case the transfer is canceled. Crucially, the memory could only be read once, so only one of the codes can be retrieved, and hence, only one of the two actions can be performed—not both.

"When an adversary has physical control of a device—such as a stolen cell phone—software defenses alone aren't enough; we need to use tamper-resistant hardware to provide security," Liu says. "Moreover, to protect critical systems, we don't want to rely too much on complex defenses that might still get hacked. It's better if we can rely on fundamental laws of nature, which are unassailable."

Unfortunately, there is no fundamental solution to the problem of building tamper-resistant chips, at least not using classical physics alone. So scientists have tried involving quantum mechanics as well, because information that is encoded into a quantum system behaves differently from a classical system.

NIST: Quantum Physics Could Make Secure, Single-Use Computer Memories Possible