Aultmore and Balvenie want to agree on a common secret key. They have at their disposal a noisy channel and an error free public channel. The situation is complicated by an adversary, Ellen, who eavesdrops the noisy channel and the public channel. Fortunately for Aultmore and Balvenie, the eavesdropping channel is noisy as well. This will enable them to generate a secret key. In the literature, this is done in three phases; the advantage distillation phase, the information reconciliation phase, and the privacy amplification phase. We show that the first two phases are based on the same concept and that presently known techniques used in both phases are basically special cases of a more general technique.
Aultmore and Balvenie want to agree on a common secret key. They have at their disposal a noisy channel and an error free public channel. The situation is complicated by an adversary, Ellen, who eavesdrops the noisy channel and the public channel. Fortunately for Aultmore and Balvenie, the eavesdropping channel is noisy as well. This will enable them to generate a secret key. In the literature, this is done in three phases; the advantage distillation phase, the information reconciliation phase, and the privacy amplification phase. We show that the first two phases are based on the same concept and that presently known techniques used in both phases are basically special cases of a more general technique.
Aultmore and Balvenie want to agree on a common secret key. They have to their disposal a noisy channel and an error free public channel. The situation is complicated by an adversary, Ellen, who eavesdrops the noisy channel and the public channel. Fortunately for Aultmore and Balvenie, the eaves- dropping channel is noisy as well. This will enable them to generate a secret key. In the literature, this is done in three phases; the advantage distillation phase, the information reconciliation phase, and the privacy amplification phase. We will show that the first two phases are based on the same concept and that presently known tech- niques used in both phases are basically special cases of a more general technique.
Many military and civil applications using underwater acoustic channels (UWACs) are paired with security services, providing, for instance, secrecy and authenticity to the communication.These mechanisms however often require periodically renewed symmetric keys among two communicating devices, namely Alice and Bob.To this end, secret keys can be agreed upon using the physicallayer communication channel, leveraging, in particular, the reciprocity and randomness of the UWAC to extract a common key that remains secret to an attacker (Eve).In this paper, we propose a novel solution for the advantagedistillation part of the secret key generation procedure.After channel probing, the advantage of distillation lets Alice and Bob extract a sequence of bits from their own (analog) measurements.We propose an asymmetric advantage-distillation protocol with two novel features: i) the quantizers used by Alice and Bob are derived maximizing the secret key capacity cooperating through a public channel and ii) Alice transmits a correction over a public authenticated side channel.Numerical results prove the effectiveness of our approach, showing that exchanging a few bits of information before information reconciliation allows extracting more secret bits from the channel.
Secret-key distillation (SKD) is the technique used to convert some given random variables, shared among the legitimate parties and a potential eavesdropper Eve, into a secret key. Secret-key distillation is generally described as a protocol between the legitimate parties, who exchange messages over the public classical authenticated channel as a function of their key elements X and Y , aiming to agree on a common secret key K . We assume here that the eavesdropper's knowledge can be modeled as a classical random variable. For more general assumptions on the eavesdropping techniques, please refer to Chapter 12. The quantum transmission is assumed to be from Alice to Bob. In order to be able to specify another direction for secret-key distillation, we use the Claude-and-Dominique naming convention. Here, the random variables X and Y model the variables obtained by Claude and Dominique, respectively, using the quantum channel, and the random variable Z contains anything that Eve was able to infer from eavesdropping on the quantum channel. As detailed in Section 11.3.2, both assignments (Alice = Claude ∧ Bob = Dominique) and (Alice = Dominique ∧ Bob = Claude) are useful. In this chapter, I first propose a general description of the reconciliation and privacy amplification approach. I then list the different characteristics that a SKD protocol can have. And finally, I overview several important classes of known results and treat the specific case of SKD with continuous variables.
We study the problem of key-distillation for a source model, with a one-way and rate-limited public communication between two legitimate users. Although, the secret-key capacity is already known, we provide an alternative achievability scheme, that directly translates into practical designs. We consider a sequential key-distillation strategy, which consists of a reconciliation phase followed by a privacy amplification phase performed with extractors. We determine the reconciliation capacity and show that, for a degraded source, such a sequential strategy leads to an optimal key-distillation strategy that achieves the secret-key capacity. We illustrate our results in the case of a binary source model.
The classical secret-key agreement (SKA) scheme includes three phases: (a) advantage distillation (AD), (b) reconciliation, and (c) privacy amplification. Define the transmission rate as the ratio between the number of raw key bits obtained by the AD phase and the number of transmitted bits in the AD. The unidirectional SKA, whose transmission rate is 0 . 5, can be realized by using the original two-way wiretap channel as the AD phase. In this paper, we establish an efficient bidirectional SKA whose transmission rate is nearly 1 by modifying the two-way wiretap channel and using the modified two-way wiretap channel as the AD phase. The bidirectional SKA can be extended to multiple rounds of SKA with the same performance and transmission rate. For multiple rounds of bidirectional SKA, we have provided the bit error rate performance of the main channel and eavesdropper’s channel and the secret-key capacity. It is shown that the bit error rate (BER) of the main channel was lower than the eavesdropper’s channel and we prove that the transmission rate was nearly 1 when the number of rounds was large. Moreover, the secret-key capacity C s was from 0 . 04 to 0 . 1 as the error probability of channel was from 0 . 01 to 0 . 15 in binary symmetric channel (BSC). The secret-key capacity was close to 0 . 3 as the signal-to-noise ratio increased in the additive white Gaussian noise (AWGN) channel.