Abstract. Almost all of the current public-key cryptosystems (PKCs) are based on number theory, such as the integer factoring problem and the discrete logarithm problem (which will be solved in polynomial-time after the emergence of quantum computers). While the McEliece PKC is based on another theory, i.e. coding theory, it is vulnerable against several practical attacks. In this paper, we carefully review currently known attacks to the McEliece PKC, and then point out that, without any decryption oracles or any partial knowledge on the plaintext of the challenge ciphertext, no polynomial-time algorithm is known for inverting the McEliece PKC whose parameters are carefully chosen. Under the assumption that this inverting problem is hard, we propose slightly modified versions of McEliece PKC that can be proven, in the random oracle model, to be semantically secure against adaptive chosen-ciphertext attacks. Our conversions can achieve the reduction of the redundant data down to 1/3 ∼ 1/4 compared with the generic conversions for practical parameters.

In this paper, we formally prove that padding the plaintext with a random bit-string provides the semantic security against chosen plaintext attack (IND-CPA) for the McEliece (and its dual, the Niederreiter) cryptosystems under the standard assumptions. Such padding has recently been used by Suzuki, Kobara and Imai in the context of RFID security. Our proof relies on the technical result by Katz and Shin from Eurocrypt '05 showing "pseudorandomness" implied by the learning parity with noise (LPN) problem. We do not need the random oracles as opposed to the known generic constructions which, on the other hand, provide a stronger protection as compared to our scheme-against (adaptive) chosen ciphertext attack, i.e., . In order to show that the padded version of the cryptosystem remains practical, we provide some estimates for suitable key sizes together with corresponding workload required for successful attack.

Background and purpose: Slumped sitting is known to increase disc pressure and aggravate chronic low back pain. In addition, it has been recognized that co-contraction of the deep spine-stabilizing muscles enhances lumbar segmental stability and the sacro-iliac joint. The purpose of this study was to compare the electromyographic (EMG) activity of the trunk muscles and the muscle thickness of the transverse abdominis (TrA) during slumped sitting with the same parameters during co-contraction and investigate how co-contraction influences spinal curvature.Subjects and methods: Nine healthy male volunteers participated in the study. EMG signals were recorded during both sitting postures. In order to measure the muscle thickness of the TrA, ultrasound images were captured. While the subjects performed both sitting postures, spinal curvature was measured using a hand-held device.Results: Significantly more activity of the trunk muscles, with the exception of the rectus abdominis muscle, and significantly greater muscle thickness of the TrA were observed during co-contraction of the trunk muscles than during slumped sitting.Co-contraction also resulted in significantly increased lumbar lordosis and a greater sacral angle when compared to slumped sitting.Conclusion: In this study, it was demonstrated that the instructions given to the subjects on co-contraction of the trunk muscles during sitting increased muscle activity with the exception of the rectus abdominis muscle, muscle thickness of the TrA, and lumbar lordosis.

This paper describes truncated and impossible differential cryptanalysis of the 128-bit block cipher Camellia, which was proposed by NTT and Mitsubishi Electric Corporation. Our work improves on the best known truncated and impossible differential cryptanalysis. As a result, we show a nontrivial 9-round byte characteristic, which may lead to a possible attack of reduced-round version of Camellia without input/output whitening, F L or F L −1 in a chosen plain text scenario. Previously, only 6-round differentials were known, which may suggest a possible attack of Camellia reduced to 8-rounds. Moreover, we show a nontrivial 7-round impossible differential, whereas only a 5-round impossible differential was previously known. This cryptanalysis is effective against general Feistel structures with round functions composed of S-D (Substitution and Diffusion) transformation.

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This study suggested that the gait indices calculated from trunk acceleration that were relevant to balance were those in the VT direction. These may be useful for evaluating dynamic gait balance in patients with stroke.

In this study, the properties of physical unclonable functions (PUFs) for 28-nm process field-programmable gate arrays (FPGAs) are examined. A PUF is a circuit that generates device-specific IDs by extracting device variations. Owing to device variation, no two PUFs will generate the same ID even if they have identical structures and are manufactured on the same silicon wafer. However, because the influence of device variation increases as the size of the process node shrinks, it is uncertain whether PUFs can be built using recently developed small-scale process nodes, even though the technology of variation control is constantly advancing. While many PUFs using 40-nm or larger process nodes have been reported, smaller devices have not yet been studied to the authors' knowledge, and this is the first published journal article on PUFs for 28-nm process FPGAs. In this paper, within-die reproducibility, die-to-die uniqueness, and other properties are evaluated, and the feasibility of PUFs on 28-nm FPGAs is discussed.

Cyber-attacks and cybersecurity used to be the issues for those who use Internet and computers. The issues, however, are expanding to anyone who does not even use them directly. The society is gradually and heavily depending on networks and computers. They are not closed within a cyberspace anymore and having interaction with our real world with sensors and actuators. Such systems are known as CPS (Cyber Physical Systems), IoT/E (Internet of Things/Everything), Industry 4.0, Industrial Internet, M2M, etc. No matter what they are called, exploitation of any of these systems may cause a serious influence to our real life and appropriate countermeasures must be taken to mitigate the risks. In this paper, cybersecurity in ICS (Industrial Control Systems) is reviewed as a leading example of cyber physical security for critical infrastructures. Then as a future aspect of it, IoT security for consumers is explained.