On the security of Y-00 under fast correlation and other attacks on the key

Abstract

The potential weakness of the Y-00 direct encryption protocol when the encryption box ENC is not chosen properly is demonstrated in a fast correlation attack by S. Donnet et al in Phys. Lett. A 356 (2006) 406-410. In this paper, we show how this weakness can be eliminated with a proper design of ENC. In particular, we present a Y-00 configuration that is more secure than AES under known-plaintext attack. It is also shown that under any ciphertext-only attack, full information-theoretic security on the Y-00 seed key is obtained for any ENC when proper deliberate signal randomization is employed. * yuen@ece.northwestern.edu

Exposed-key weakness of αη

“…Independently, a similar observation regarding the exposure of the key has been recently made by H. Yuen in [8] (and see also [6] and [7]). In [6,8], it is argued that a technique that is called Deliberate Signal Randomization (DSR) will serve to add information-theoretic security to the key.…”

“…In this paper, we show that αη has an additional disadvantage that current classical ciphers do not have: transmission of the "encrypted" states actually leaks information about the key to an eavesdropper, even if that eavesdropper has no information about the message. Such a weakness has been independently described briefly in [6], and in more depth in [7] and [8]; here, we calculate information loss and estimate a bound on the efficacy of explicit attacks such as [7]. In the remainder of this paper, we will describe the αη scheme, show that in practice there is no advantage created for Bob over Eve via quantum limits on measurement, and estimate how much information Eve can learn about the key from Alice's transmission.…”

“…In [6,8], it is argued that a technique that is called Deliberate Signal Randomization (DSR) will serve to add information-theoretic security to the key. This technique simply involves Alice sending a random state in the half-plane around the state she would send under the non-DSR version given above.…”

Security Analysis of Generalized Confidential Modulation

“…The detailed analysis and estimation are shown in [2], [7], [6], [10] and so on. In many cases, the attack by Algorithm A is either a correlation attack or a fast correlation attack, and the target PRNG is an M sequence generator.…”

Security Analysis of Generalized Confidentialmodulation for Quantum Communication

“…Because of limited space, we omit the details of estimation of the abovementioned necessary costs. The detailed analysis and estimation are shown in [4], [11], [10], [17] and so on. In many cases, the attack by Algorithm A is eithera correlation attack or a fast correlation attack, and the target PRNG is anM sequence generator.…”