The technique exploits the arcana of quantum mechanics to let two computers swap a cryptographic key (and thus the means to decode a message) with perfect security.

ECONOMIST: Optical communications

The secure element doesn't necessarily need to have power running through it or to be in the midst of near-field communication in order to yield up its cryptographic key to a clever intruder who has sufficient time and sufficient desire to breach the security of a smartphone, bank card or national border.

ENGADGET