Abstract
The security of quantum key distribution is typically defined in terms of the mutual information between the distributed key and the outcome of an optimal measurement applied to the adversary’s system. We show that even if this so-called accessible information is small, the key might not be secure enough to be used in applications such as one-time pad encryption. This flaw is due to a locking property of the accessible information: one additional (physical) bit of information can increase the accessible information by more than one bit.
- Received 13 December 2005
DOI:https://doi.org/10.1103/PhysRevLett.98.140502
©2007 American Physical Society