312 research outputs found

    CaSE: Cache-Assisted Secure Execution on ARM Processors

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    Recognizing the pressing demands to secure embedded applications, ARM TrustZone has been adopted in both academic research and commercial products to protect sensitive code and data in a privileged, isolated execution environment. However, the design of TrustZone cannot prevent physical memory disclosure attacks such as cold boot attack from gaining unrestricted read access to the sensitive contents in the dynamic random access memory (DRAM). A number of system-on-chip (SoC) bound execution solutions have been proposed to thaw the cold boot attack by storing sensitive data only in CPU registers, CPU cache or internal RAM. However, when the operating system, which is responsible for creating and maintaining the SoC-bound execution environment, is compromised, all the sensitive data is leaked. In this paper, we present the design and development of a cache-assisted secure execution framework, called CaSE, on ARM processors to defend against sophisticated attackers who can launch multi-vector attacks including software attacks and hardware memory disclosure attacks. CaSE utilizes TrustZone and Cache-as-RAM technique to create a cache-based isolated execution environment, which can protect both code and data of security-sensitive applications against the compromised OS and the cold boot attack. To protect the sensitive code and data against cold boot attack, applications are encrypted in memory and decrypted only within the processor for execution. The memory separation and the cache separation provided by TrustZone are used to protect the cached applications against compromised OS. We implement a prototype of CaSE on the i.MX53 running ARM Cortex-A8 processor. The experimental results show that CaSE incurs small impacts on system performance when executing cryptographic algorithms including AES, RSA, and SHA1

    Pharmacokinetics, safety and tolerability of L-3-n-butylphthalide tablet after single and multiple oral administrations in healthy Chinese volunteers

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    L-3-n-butylphthalide (L-NBP) is a naturally occurring antioxidant, which can be used for the treatment of acute ischemic stroke and vascular dementia. This study evaluated the safety, tolerability and pharmacokinetics of L-NBP tablets in healthy Chinese volunteers. This was a single-center, randomized, double-blind, placebo-controlled, single- and multiple-dose study. Subjects were assigned to receive a single dose of L-NBP tablet at either 80, 160, 320, or 480 mg (n=40), or multiple doses of 160 mg twice daily for 7 days (n=12). Plasma samples were analyzed with LC-MS/MS. Pharmacokinetic parameters of L-NBP were calculated using non-compartmental analysis with WinNonlin software. Statistical analysis was performed using SPSS software. All adverse events (AEs) were mild and of limited duration; AEs in this study occurred less frequently and more mildly than AEs listed for the DL-NBP soft capsule. No serious adverse event (SAE), death or withdrawal from the study was observed. In the single-dose study, Cmax was reached at about 1 h, and the mean t1/2 was approximately 13.76 h. Area under curve (AUC) and Cmax increased with dose escalation, but dose proportionality was not observed over the range of 160 to 480 mg. In the multiple-dose study, the steady-state was reached within 3 days with slight accumulation. In summary, the L-NBP tablet was well tolerated in healthy Chinese subjects. Slight accumulation appeared after repeated doses.L-3-n-butilftalida (L-NMP) é um antioxidante natural, que pode ser utilizado para o tratamento do acidente isquêmico agudo e demência vascular. Este estudo avaliou segurança, tolerância e farmacocinética de comprimidos de L-NBP em chineses voluntários sadios. Este foi um estudo monocêntrico, randomizado, duplo cego, com controle por placebo e doses única e múltipla. Os indivíduos receberam dose única de comprimido de L-NBP de 80, 160, 320 ou 480 mg (n=40) e doses múltiplas de 160 mg duas vezes ao dia, por sete dias (n=12). Amostras de plasma foram analisadas com LC-MS/MS. Os parâmetros farmacocinéticos do L-NBP foram calculados utilizando análise não compartimental, com o programa WinNonlin. A análise estatística foi realizada utilizando-se o programa SPSS. Todos os eventos adversos (EAs) foram moderados e de duração limitada. EAs nesse estudo ocorreram menos frequentemente e mais moderadamente do que os EAs relacionados para cápsulas moles de DL-NBP. Não se observaram eventos adversos graves (EAG), morte ou abandono do estudo. Com dose única, atingiu-se o Cmax em cerca de 1 hora e o t1/2 médio foi de, aproximadamente, 13,76 h. A área sob a curva (ASC) e o Cmax aumentaram com o aumento da dose, mas não se observou proporcionalidade na faixa acima de 160 a 480 mg. No estudo de dose múltipla, o equilíbrio foi alcançado em três dias, com pequeno acúmulo. Em resumo, o comprimido de L-NMP foi bem tolerado em indivíduos chineses saudáveis. O acúmulo pequeno apareceu após doses repetidas

    TruSpy: Cache Side-Channel Information Leakage from the Secure World on ARM Devices

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    As smart, embedded devices are increasingly integrated into our daily life, the security of these devices has become a major concern. The ARM processor family, which powers more than 60% of embedded devices, introduced TrustZone technology to offer security protection via an isolated execution environment called secure world. Caches in TrustZone-enabled processors are extended with a non-secure (NS) bit to indicate whether a cache line is used by the secure world or the normal world. This cache design improves system performance by eliminating the need to perform cache flush during world switches; however, it also enables cache contention between the two worlds. In this work, we present TruSpy, the first study of timingbased cache side-channel information leakage of TrustZone. Our proposed attack exploits the cache contention between normal world and secure world to recover secret information from secure world. Two attacks are proposed in TruSpy, namely, the normal world OS attack and the normal world Android app attack. In the OS-based attack, the attacker is able to access virtual-to-physical address translation and high precision timers. In the Android app-based attack, these tools are unavailable to the attacker, so we devise a novel method that uses the expected channel statistics to allocate memory for cache probing. We also show how an attacker might use the less accurate performance event interface as a timer. Using the T-table based AES implementation in OpenSSL 1.0.1f as an example, we demonstrate that it is possible for a normal world attacker to steal a fine-grained secret from the secure world using a timing-based cache side-channel. We can recover the full AES encryption key via either the OSbased attack or the Android app-based attack. Since our zero permission TruSpy attack is based on the cache design in TrustZone enabled ARM processors, it poses a significant threat to a wide array of devices. To mitigate the newly discovered threat, we also propose both application-based and system-oriented countermeasures

    A comprehensive checklist of the deciduous photinia genus Pourthiaea (Maleae, Rosaceae), with emphasis on their validity and typification

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    Due to the complicated evolutionary history in Pourthiaea, ninety-seven taxa have been described since 1784, and ninety-one of them are validly published taxa, five are naked names, and one is an invalid name. After a comprehensive and critical evaluation, 213 names have been published, including new combinations, new status, and new names; this may be due to the controversial taxonomic position of Pourthiaea in the apple tribe, Maleae. We herewith provide a taxonomic checklist of Pourthiaea for further taxonomic and evolutionary studies. We also lectotypify two taxa: Photinia amphidoxa var. stylosa and P. glabra var. fokienensis

    Measuring Technical Efficiency and Returns to Scale in Taiwan’s Baking Industry―A Case Study of the 85 °C Company

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    [[abstract]]Under an intense internationally competitive business environment, it is important to understand the production efficiency of the baking industry, where efficient management is becoming increasingly important to ensure the sustainable development of the company. Thus, this study uses data envelopment analysis (DEA) to appraise the performance of a well-known baking company (85 °C) and uses input and output constructs to measure its technical efficiency and scale efficiency scores to understand the major reasons for efficiency losses from 2011 to 2016. The empirical results indicate that low technical efficiency is the major reason for lower pure technical efficiency, since the scale efficiency is higher than pure technical efficiency. This means 85 °C is still improving overall operating efficiency and space efficiency. Moreover, the results also show that the III-generation operations style is more technically efficient and pure-technically efficient compared to those of I-generation and II-generation. Furthermore, the company’s financial performance is dependent upon the producer’s ability to stay on the production frontier due to the result of a positive relationship between return on assets (ROA) and technical efficiency. Last but not least, this study shows that 85 °C can gain higher performance and efficiency by enhancing technical efficiency and reinforcing strategic alignments with business goals.[[notice]]補正完

    Concept for a Future Super Proton-Proton Collider

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    Following the discovery of the Higgs boson at LHC, new large colliders are being studied by the international high-energy community to explore Higgs physics in detail and new physics beyond the Standard Model. In China, a two-stage circular collider project CEPC-SPPC is proposed, with the first stage CEPC (Circular Electron Positron Collier, a so-called Higgs factory) focused on Higgs physics, and the second stage SPPC (Super Proton-Proton Collider) focused on new physics beyond the Standard Model. This paper discusses this second stage.Comment: 34 pages, 8 figures, 5 table

    Mapping the distribution of Anthrax in Mainland China, 2005-2013

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    Anthrax in China was characterized by significant seasonality and spatial clustering. The spatial distribution of human anthrax was largely driven by livestock husbandry, human density, land cover, elevation, topsoil features and climate. Enhanced surveillance and intervention for livestock and human anthrax in the high-risk regions, particularly on the Qinghai-Tibetan Plateau, is the key to the prevention of human infections

    Emerging tick-borne infections in mainland China: an increasing public health threat

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    Since the beginning of the 1980s, 33 emerging tick-borne agents have been identified in mainland China, including eight species of spotted fever group rickettsiae, seven species in the family Anaplasmataceae, six genospecies in the complex Borrelia burgdorferi sensu lato, 11 species of Babesia, and the virus causing severe fever with thrombocytopenia syndrome. In this Review we have mapped the geographical distributions of human cases of infection. 15 of the 33 emerging tick-borne agents have been reported to cause human disease, and their clinical characteristics have been described. The non-specific clinical manifestations caused by tick-borne pathogens present a major diagnostic challenge and most physicians are unfamiliar with the many tick-borne diseases that present with non-specific symptoms in the early stages of the illness. Advances in and application of modern molecular techniques should help with identification of emerging tick-borne pathogens and improve laboratory diagnosis of human infections. We expect that more novel tick-borne infections in ticks and animals will be identified and additional emerging tick-borne diseases in human beings will be discovered
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