Security of classical noise-based cryptography

Abstract

We examine the security of a protocol on cryptographic key distribution proposed by Yuen and Kim (1998 Phys. Lett. A 241 135). Theoretical and experimental analysis shows that, even if the eavesdropper could receive more photons than the legitimate receiver, secure key distribution is possible as long as the signal-to-noise-ratio of the eavesdropper does not exceed eight times (9 dB) that of the receiver. Secure key distribution was demonstrated using conventional fiber optics. The secure key transmission rate in the experiment was estimated to be 2 Mb/s at its maximum (0.04 bit per sender's bit.) The present protocol has advantages over other quantum key distribution protocols in that it is more efficient and more easily implemented, but careful design and management are necessary to ensure the security of the cryptosystem.

Quantum key disribution with unconditional security for all-optical fiber network

“…It is called YK protocol. A simple experimental demonstration of YK protocol based on classical noise was reported [9]. Thus the unconditionally secure key distribution does not require a realization of single photon communications and also even quantum phenomena.…”

Noise-based Stego-ECC

“…In a sense, this is a mix of steganography and cryptography. It has been proven that a message can be transmitted securely if it is coded and decoded by a sequence of random bits (key) whose length is equal to that of the message [7]. This is the reason of why inserting noise can add the level of security of a sequence of messages.…”

Secure Communication Using Mesoscopic Coherent States

“…A specific protocol has been proposed by Yuen, [3,4] which has been called the YK protocol. A particular implementation of this YK protocol has been demonstrated, [5] in which detector noise is utilized and hence it is not unconditionally secure. However, the YK protocol can be made unconditionally secure by utilizing the fundamental, unavoidable quantum noise in a quantum signaling scheme.…”

“…[6] The other known secure scheme is, of course, the BB84, [1] or its variant that involves features of B92, [7] where coherent states instead of Fock states are employed. The implementations of the YK protocol, [5] and BB84, both suffer from the intrinsic limitation that very weak signals with no more than one photon per mode have to be used, making them severely rate-limited in a lossy channel. This problem can be alleviated in a new protocol, where mesoscopic coherent states are employed to overcome loss and to allow ordinary amplification, switching and routing.…”