Quantum cryptography kinda sorta hacked

By Nilay Patel | May 1, 2007

It’s always only a matter of time. A little less than a year after the first quantum cryptographic network was demoed, a group of researchers at MIT have announced a working implementation of a hack that’s been around in theory since 1998 but never implemented. Skirting around ol’ Wernie Heisenberg and that Principle of his, the team exploited quantum entanglement to read the encryption keys encoded in photon polarizations from their momentums, avoiding detection by either end — in other words, doing what was once thought impossible by cryptographers. The system isn’t perfect, however — in this early incarnation it can only nab 40% of transmitted data before giving itself away, and more importantly, it requires the invention of a “quantum non-demolition box” before the attacker can be anywhere but the same room as the receiver, since right now both attacker and receiver need to be using the same photon detector. Sounds like that might put a damper on that whole “undetectable” thing. Still, the researchers sound upbeat — they’re saying the work proves that no secret is truly safe. We’re just wondering if they’re pushing MIT to rename their department SETEC ASTRONOMY.