Strongly Secure Privacy Amplification Cannot Be Obtained by Encoder of Slepian-Wolf Code

The privacy amplification is a technique to distill a secret key from a random variable by a function so that the distilled key and eavesdropper's random variable are statistically independent. There are three kinds of security criteria for the key distilled by the privacy amplification: the normalized divergence criterion, which is also known as the weak security criterion, the variational distance criterion, and the divergence criterion, which is also known as the strong security criterion. As a technique to distill a secret key, it is known that the encoder of a Slepian-Wolf (the source coding with full side-information at the decoder) code can be used as a function for the privacy amplification if we employ the weak security criterion. In this paper, we show that the encoder of a Slepian-Wolf code cannot be used as a function for the privacy amplification if we employ the criteria other than the weak one.Comment: 10 pages, no figure, A part of this paper will be presented at 2009 IEEE International Symposium on Information Theory in Seoul, Korea. Version 2 is a published version. The results are not changed from version 1. Explanations are polished and some references are added. In version 3, only style and DOI are edite

Secret Key Agreement by Soft-decision of Signals in Gaussian Maurer's Model

We consider the problem of secret key agreement in Gaussian Maurer's Model. In Gaussian Maurer's model, legitimate receivers, Alice and Bob, and a wire-tapper, Eve, receive signals randomly generated by a satellite through three independent memoryless Gaussian channels respectively. Then Alice and Bob generate a common secret key from their received signals. In this model, we propose a protocol for generating a common secret key by using the result of soft-decision of Alice and Bob's received signals. Then, we calculate a lower bound on the secret key rate in our proposed protocol. As a result of comparison with the protocol that only uses hard-decision, we found that the higher rate is obtained by using our protocol.Comment: 10 pages, 4 figures, to be appear in Proc. of 2008 IEEE International Symposium on Information Theory in Toronto, Canad

Key rate available from mismatched mesurements in the BB84 protocol and the uncertainty principle

We consider the mismatched measurements in the BB84 quantum key distribution protocol, in which measuring bases are different from transmitting bases. We give a lower bound on the amount of a secret key that can be extracted from the mismatched measurements. Our lower bound shows that we can extract a secret key from the mismatched measurements with certain quantum channels, such as the channel over which the Hadamard matrix is applied to each qubit with high probability. Moreover, the entropic uncertainty principle implies that one cannot extract the secret key from both matched measurements and mismatched ones simultaneously, when we use the standard information reconciliation and privacy amplification procedure.Comment: 5 pages, no figure, ieice.cls. Title was changed from version 1. To appear in IEICE Trans. Fundamentals (http://ietfec.oxfordjournals.org/), vol. E91-A, no. 10, Oct. 200

A novel role of interleukin-6 as a regulatory factor of inflammation-associated deterioration in osteoblast arrangement

Inflammatory disorders are associated with bone destruction; that is, deterioration in bone cell activities are under the control of the innate immune system. Macrophages play a central role in innate immunity by switching their polarized phenotype. A disturbed immune system causes aberrance in the ordered bone matrix microarrangement, which is a dominant determinant of bone tissue functionalization. However, the precise relationship between the immune system and bone tissue organization is unknown. In this study, the controlled in vitro co-culture assay results showed that M1-polarized macrophages disrupted the osteoblast alignment, which directly modulate the oriented bone matrix organization, by secreting pro-inflammatory cytokines. Notably, interleukin6 was found to be a key regulator of unidirectional osteoblast alignment. Our results demonstrated that inflammatory diseases triggered bone dysfunction by regulating the molecular interaction between the immune system and bone tissue organization. These findings may contribute to the development of therapeutic targets for inflammatory disorders, including rheumatoid arthritis.Matsugaki A., Matsumoto S., Nakano T.. A novel role of interleukin-6 as a regulatory factor of inflammation-associated deterioration in osteoblast arrangement. International Journal of Molecular Sciences, 21, 18, 1. https://doi.org/10.3390/ijms21186659

Noise Tolerance of the BB84 Protocol with Random Privacy Amplification

We prove that BB84 protocol with random privacy amplification is secure with a higher key rate than Mayers' estimate with the same error rate. Consequently, the tolerable error rate of this protocol is increased from 7.5 % to 11 %. We also extend this method to the case of estimating error rates separately in each basis, which enables us to securely share a longer key.Comment: 26 pages, 1 figure, version 2 fills a logical gap in the proof. Version 3 includes an upper bound on the mutual information with finete code length by using the decoding error probability of the code. Version 4 adds a paragraph clarifying that no previous paper has proved that the BB84 with random privacy amplification can tolerate the 11% error rat

Ignition Condition for p-^11B Reactor with LHD type Magnetic Field Configuration

Proton-Boron fusion reactor (p-^11B reactor) might be able to be achieved by the combination of the LHD type magnetic field configuration and the ion cyclotron range of frequency (ICRF) heating scheme of protons. The LHD magnetic field has the excellent ability for the high energy particle confinements. This characteristic is studied by numerical computations of high energetic particles in the LHD magnetic field where the strong ICRF field is applied. It is shown by the Langevin equation analysis that the steady state distribution function of ICRF heated proton becomes to the quasilinear plateau distribution function (QPDF). The fusion reaction rate of p-11B is calculated for QPDF protons and studied the ignition condition. It is found that the ignition condition becomes possible to be satisfied if effective temperature of proton is of the order of 300 keV and nτ >~ 10^22 s/m3

Low-Complexity Strategies for Multiple Access Relaying

In this paper, we propose three low-complexity strategies for Multiple Access Relay Channel (MARC) based on the concept of bit-flipping model. By estimating the error rates of the links between the sources and the relay, and by utilizing the estimate as side information at the destination, it is shown that the proposed relay strategies are superior to the Decode-and-Forward (DF) relay strategy when all links are suffering from Additive White Gaussian Noise (AWGN). Furthermore, extrinsic information transfer (EXIT) analysis is used to track the convergence property with the aim of being able to search for suitable codes, the proposed relay strategies can achieve the performance close to those strategies utilizing relatively strong codes, such as turbo code or LDPC code, with iterative decoding at the relay in order to make intra links error free