MISCELLANEOUS

Limiting rate of secret-key generation in quantum cryptography in spacetime

S. N. Molotkov

Institute of Solid State Physics, Russian Academy of Sciences

Abstract: The fundamental restrictions on the maximum admissible rate of secret-key commitment in quantum cryptography in real time are discussed. It is shown that the maximum rate in a quantum channel with limited transmission band is achieved in a cryptosystem on orthogonal states. The dimensionless rate (the number of bits per unit time frequency band through unit of the channel) is determined by the universal function $C(\lambda_0(\Delta k\cdot T))/\Delta k\cdot T$ [where $C(\lambda_0(\Delta k\cdot T))$ is the transmission capacity of a classical binary channel, $\Delta k$ is the transmission band width, $1/T$ is the transmission frequency of quantum states, and $\lambda_0$ is the maximum eigenvalue of a certain integral equation].

PACS: 03.65.Bz, 42.50.Dv, 89.70.+c

Received: 02.04.2002

 English version: Journal of Experimental and Theoretical Physics Letters, 2002, 75:10, 521–526

Bibliographic databases:

•