Sistem pemungutan suara di Indonesia yang lebih dikenal dengan nama pemilihan umum (pemilu) sampai saat ini masih dilaksanakan secara manual. Dalam sistem tersebut, dibutuhkan waktu yang lama serta tenaga yang besar untuk menghitung hasil dari pemlihan umum tersebut. Sistem manual juga memiliki banyak kelemahan yang bisa dimanfaatkan oleh pihak tertentu untuk memanipulasi hasil pemilihan umum . Untuk mengatasi masalah ini, salah satu solusinya adalah dengan menerapkan sistem pemilihan umum dengan sistem berbasis perangkat elektronik yang lebih dikenal dengan istilah E-Vote . Berbagai macam metode telah diterapkan dalam sistem E-Vote untuk mengatasi kecurangan, salah satunya dengan menggunakan sistem enkripsi-dekripsi data dari pemilih ke sistem. Namun hal ini kurang efektif apabila kecurangan terjadi ketika data sudah dirubah sebelum masuk ke sistem. Dengan menerapkan mekanisme rantai kepercayaan (chain of trust) untuk mendeteksi adanya perubahan surat suara serta sistem autentikasi digital, mekanisme keamanan bagi peserta pemungutan suara bisa diwujudkan. Proses autentikasi digital menggunakan ponsel pintar dengan teknologi NFC dipadukan dengan sistem enkripsi asimetris dan digital signature . Pemilih bisa mendeteksi adanya perubahan surat suara melalui digital signature yang ada dan sistem E-Vote bisa mengenali peserta dari kunci publik yang ditawarkan oleh autentikator. Kemudian sistem E-Vote bisa memverifikasi keaslian kunci publik peserta melalui autentikasi berbasis zero-knowledge proof challenge . Hasil pilihan peserta kemudian dikirimkan ke autentikator untuk ditandatangani dan tandatangan tersebut digunakan sebagai bukti peserta telah melakukan pemilihan. Dari hasil uji coba yang dilakukan, terbukti bahwa autentikator bisa mendeteksi ketidaksamaan antara data dengan signature, dan autentikator bisa melakukan autentikasi dengan sistem E-Vote dengan tepat. Data hasil pilihan peserta bisa diverifikasi dengan signature yang ada untuk memeriksa integritas data.
Smart grid enables two-way communications between operation centers and smart meters to collect power consumption and achieve demand response to improve flexibility, reliability, and efficiency of electricity system. However, power consumption data may contain users' privacy, e.g., activities, references, and habits. Many smart metering schemes have been proposed utilizing homomorphic encryption for users' privacy preservation. Unfortunately, some abnormality of smart meter reading, e.g., caused by electricity theft, cannot be discovered since data is encrypted. Meanwhile, operation centers could become curious in reality. To address the above issues, we propose a new privacy-preserving smart metering scheme for smart grid, which supports data aggregation, differential privacy, fault tolerance, and range-based filtering simultaneously. Specifically, we extend lifted ElGamal encryption to aggregate users' consumption reports at the gateway to reduce communication overhead, while supporting fault tolerance of malfunctioning smart meters effectively. We also leverage zero-knowledge range proof to filter abnormal measurements caused by electricity theft or false data injection attacks without exposing individual measurements. In addition, our scheme can resist differential attacks, by which the curious operation center can violate users' privacy through comparing two aggregations of the similar data set. Finally, we discuss the properties of the proposed scheme and evaluate its performance in terms of security and efficiency.
This paper presents an all-passive negative feedback network that performs autonomous radio-frequency (RF) front-end beam-forming and dynamic beam-tracking toward the direction of the incident RF signal. The proposed feedback network consists of a passive RF signal processing network, voltage rectifiers, and voltage-controlled delay-line phased shifters, all of which are passive-only circuits. The negative feedback loop is realized by passive phase detection, phase-to-voltage conversion, and voltage-controlled phase shifting, achieving a large loop-gain and autonomous operation with zero DC power consumption. The nonlinear behavior of the loop is exploited to substantially expand the array field of view (FoV). A proof-of-concept broadband four-element all-passive self-steering beam-former at 5 GHz with a wide FoV is implemented in a standard 130 nm CMOS process. A high-quality four-element synthesized array factor is measured for the input progressive phase shift φinfrom -180° to 180°. When the proposed negative feedback loop is enabled, the normalized array factor is -2.87/-2.8 dB at φin= +90°/-90° with an input RF power Pin of -17 dBm/element at 5 GHz, achieving >25 dB array factor improvement over the open-loop operation. Moreover, the nonlinear feedback loop allows for significant array factor improvement even at φin= +180°/-180°. The proposed beam-former also achieves high-quality self-steering beamforming from 4 to 5.68 GHz with 34.7% fractional bandwidth. Therefore, the proof-of-concept all-passive self-steering beamformer outperforms the state-of-the-art active designs in terms of beam-forming quality, FoV, and fractional bandwidth. To the best of the authors' knowledge, this is the first demonstration of an all-passive negative feedback network for a broadband and wide FoV self-steering beam-forming with zero DC power consumption.
In recent years, the concept of Zero Knowledge Protocols (ZKP) as a useful approach to nuclear warhead verification has become increasingly popular. Several implementations of ZKP have been proposed, driving technology development toward proof of concept demonstrations. Whereas proposed implementations seem to fall within the general class of template-based techniques, all physical implementations of ZKPs proposed to date have a complication: once the instrumentation is prepared, it is no longer authenticatable; the instrument physically contains sensitive information. In this work we explore three different concepts that may offer more authenticatable and practical ZKP implementations and evaluate the sensitive information that may be at risk when doing so: sharing a subset of detector counts in a preloaded image (with spatial information removed), real-time image subtraction, and a new concept, CONfirmation using a Fast-neutron Imaging Detector with Anti-image NULL-positive Time Encoding (CONFIDANTE). CONFIDANTE promises to offer an almost ideal implementation of ZKP: a positive result is indicated by a constant rate at all times enabling the monitoring party the possibility of full access to the instrument before, during, and after confirmation. A prototype of CONFIDANTE was designed, built, and its performance evaluated in a series of measurements of several objects including a set of plutonium dioxide Hemispheres. Very encouraging results proving feasibility are presented. 1 Rebecca is currently a graduate student in Nuclear Engineering at UC Berkeley
The main purpose of Password-Authenticated Key Exchange (PAKE) is to allow secure authenticated communication over insecure networks between two or more parties who only share a low-entropy password. It is common practice that the secret key derived from a PAKE execution is used to authenticate and encrypt some data payload using symmetric key protocols. Unfortunately, most PAKEs of practical interest, including three protocols considered in this thesis, are studied using so-called game-based models, which -- unlike simulation models -- do not guarantee secure composition per se. However, Brzuska et al. (CCS 2011) have shown that a middle ground is possible in the case of authenticated key exchange that relies on Public-Key Infrastructure (PKI): the game-based models do provide secure composition guarantees when the class of higher-level applications is restricted to symmetric-key protocols. The question that we pose in this thesis is whether or not a similar result can be exhibited for PAKE. Our work answers this question positively. More specifically, we show that PAKE protocols secure according to the game-based Real-or-Random (RoR) definition of Abdalla et al. (PKC 2005) allow for automatic, secure composition with arbitrary, higher-level symmetric key protocols. Since there is evidence that most PAKEs secure in the Find-then-Guess (FtG) model of Bellare et al. (EUROCRYPT 2000) are in fact secure according to the RoR definition, we can conclude that nearly all provably secure PAKEs enjoy a certain degree of composition, one that at least covers the case of implementing secure channels. Although many different protocols that accomplish PAKE have been proposed over last two decades, only a few newcomers managed to find their way to real world applications - albeit lacking an intense and prolonged public scrutiny. As a step in the direction of providing one, this dissertation considers the security and efficiency of two relatively recently proposed PAKE protocols - Dragonfly and J-PAKE. In particular, we prove the security of a very close variant of Dragonfly employing the standard FtG model which incorporates forward secrecy. Thus, our work confirms that Dragonfly's main flows are sound. Furthermore, we contribute to the discussion by proposing and examining (in the RoR model of security) two variants of J-PAKE - which we call RO-J-PAKE and CRS-J-PAKE - that each makes the use of two less zero-knowledge proofs than the original protocol, at the cost of an additional security assumption. Our work reveals that CRS-J-PAKE has an edge in terms of efficiency over J-PAKE for both standard group choices: subgroups of finite fields and elliptic curves. The same is true for RO-J-PAKE, but only when instantiated with elliptic curves.
Hardy's theorem for the Riemann zeta-function ζ(s) says that it admits infinitely many complex zeros on the line (s) = 1 2. In this note, we give a simple proof of this statement which, to the best of our knowledge, is new.
Roman M. Shapiro, Michelle P. Zeller, Theodore E. Warkentin
A 38-year-old woman was brought in to the emergency room (ER) because of altered level of consciousness. She had a known history of seizure disorder but was not on any prescription medications. She also had a history of intravenous (IV) drug abuse, including cocaine, methamphetamine, and heroin. She recently described herself as being “pill-sick” which according to her partner meant that she felt unwell after a recent administration of an illicit drug. In the ER, she was hypoxemic and was intubated. She was febrile, her blood pressure was 90 systolic, heart rate 120/min, and oxygen saturation undetectable by the digital probe. Admission hemoglobin was 11.6 g/dL (mean corpuscular volume [MCV] 86), white blood count 0.8 × 109/L (absolute neutrophil count [ANC], 0.2), and platelet count 97 × 109/L. Rare nucleated red blood cells were seen, but no myeloblasts or other primitive cells. Coagulation studies showed INR 3.1, activated partial thromboplastin time (aPTT) 81 s, and fibrinogen 1.9 g/L. The serum creatinine was 320 µmol/L (reference range, 50–98); serum lactate measured 13.0 mmol/L (reference range, 0.5–2.2). A chest X-ray showed multiple pulmonary infiltrates and right-sided pleural effusion. A CT head scan was negative for any acute abnormality. CT chest was suspicious for a right-sided empyema, but no vegetations were seen on the heart valves. The most striking finding on her admission blood work was leukopenia with near-absence of neutrophils in the peripheral blood. The clinical picture of hypotension, tachycardia, lactic acidosis, renal failure, pulmonary infiltrates, and pleural effusion in the setting of IV drug abuse, together with thrombocytopenia, coagulopathy, and normoblastemia, suggests septicemia in the setting of pneumonia or right-sided infective endocarditis, most likely complicated by disseminated intravascular coagulation (DIC)–although fibrin D-dimer levels would be helpful in supporting the last diagnosis. Severe sepsis can result in a transient leukopenia/neutropenia,1 although complete absence of circulating neutrophils is unusual and points to a possible de novo neutropenic disorder such as drug-induced agranulocytosis2, 3 (although the patient was not receiving any prescription medications). Current guidelines do not recommend starting this patient on G-CSF on admission due to lack of proven mortality benefit.4, 5 Circulating nucleated red blood cells (normoblastemia) portend a poor prognosis in a critically ill patient.6 She had a central venous catheter inserted into her right internal jugular vein and was transferred to the intensive care unit (ICU) on vasopressin and norepinephrine. Blood and urine cultures were sent and the patient was started on piperacillin-tazobactam and vancomycin. Repeat blood work showed progressive thrombocytopenia, with the platelet count measuring 9 × 109/L 20 h later, and with the leukocytes and ANC remaining profoundly reduced at 0.1 and 0, respectively. Repeat coagulation studies showed INR 3.9, aPTT >150, fibrinogen 2.0, and D-dimer > 20,000 μg/L fibrin equivalent units (reference range, <500), antithrombin activity 0.26 U/mL (reference range, 0.77–1.25), and protein C activity 0.14 U/mL (reference range, 0.70–1.80). Chemistry studies showed lactate dehydrogenase (LDH) 769 U/mL (reference range, 100–220), creatine kinase (CK) 3,800 U/mL (reference range, <168), total bilirubin 182 μmol/L (reference range, <21), conjugated bilirubin 117 μmol/L (reference range, <8.6), alanine aminotransferase (ALT) 67 U/L (reference range, <28), alkaline phosphatase 68 U/mL (reference range, 40–120), and creatinine (following initiation of continuous renal replacement therapy [CRRT]) had declined to 130 μmol/L. She was noted to have cold and dusky extremities and several necrotic ulcers were noted over the dorsum of her left hand. All peripheral pulses were intact, without peripheral cyanosis or other evidence of overt limb ischemia. She was started on IV heparin with dose adjusted by anti-factor Xa levels and given antithrombin concentrates (988 units, administered at 12-h intervals) as well as frozen plasma by infusion. HIV testing was ordered, along with hepatitis B and C serology. The fibrin D-dimer was measured to evaluate the presence of DIC. Although D-dimer levels are elevated in many or most hospital patients, greatly elevated levels as seen in this patient (>20,000) are consistent with a diagnosis of DIC.7 The elevated LDH, CK, bilirubin, and creatinine values likely reflect tissue (muscle) injury and organ (liver, renal) dysfunction.8, 9 The antithrombin and protein C activity levels were measured because of the potential role for acquired severe depletion of protein C and antithrombin activity in predisposing to ischemic limb necrosis/gangrene with pulses in critically ill patients who have DIC and acute ischemic hepatitis (“shock liver”).10 Though this patient had only mildly increased liver enzymes, the possibility of chronic liver disease due to viral hepatitis (frequently observed in IV drug abusers) or another etiology could represent an alternative at-risk scenario for limb ischemia.11 Although treatment for DIC-associated limb ischemia is uncertain, we followed a recent suggestion12 to treat with unfractionated heparin, antithrombin concentrates, and plasma infusion. In this patient, the presence of necrotic ulcers on the dorsum of her left hand along with cool, dusky extremities, and elevated LDH and CK levels (indicating possible tissue ischemia13), prompted her medical team to initiate preemptive heparin therapy to minimize the risk of developing acral limb ischemia/gangrene in the setting of liver dysfunction. Of note, with this therapy, the appearance of the limbs improved, becoming warm and of normal color, and there was no development of overt limb ischemia at any later time. On the fourth hospital day, the patient's blood work yielded a hemoglobin 6.7 g/dL, MCV 85.6, WBC 0.2 × 109/L (with ANC 0), platelet count 8 × 109/L, INR 1.2, aPTT 64, anti-factor Xa level 0.18 U/mL (therapeutic range, 0.35–0.70), fibrinogen 3.3, D-dimer 11,500, total bilirubin 270 μmol/L. Blood cultures and pleural fluid cultures were positive for methicillin-sensitive Staphylococcus aureus (MSSA), while hepatitis B and C serology came back negative. Antinuclear antibody (ANA) was sent as part of an autoimmune screen. Bone marrow aspirate and biopsy were attempted in order to better characterize the cause of her persistent profound neutropenia but the patient was too hemodynamically unstable to have the procedure done. She was started on G-CSF (300 μg/day). At this point, the differential diagnosis for neutropenia included septic shock, chronic liver disease, HIV, autoimmune disease, or drug-induced neutropenia/agranulocytosis. As she was receiving appropriate antibiotics since admission, it seemed less likely that infection was the cause of ongoing neutropenia. Severe sepsis is associated with bone marrow dysfunction, but more often as a result (not a cause) of underlying bone marrow suppression.1, 14, 15 Certain infections are known to cause neutropenia, including tuberculosis, HIV, cytomegalovirus, Epstein-Barr virus, and any of the hepatitis viruses.16-19 Although this patient had risk factors for HIV and viral hepatitis, serological studies ruled out these infections. A common association of infection with profound neutropenia occurs following systemic antineoplastic chemotherapy (“febrile neutropenia”). For patients who develop severe sepsis with persisting neutropenia, the pathophysiology is believed sometimes to be hematopoietic stem cell “exhaustion.”14 However, this tends to occur in infants and the elderly where the bone marrow reserve of granulocytic precursors is smaller than in adults.14, 15 The finding of an ANC of zero on presentation to hospital also argues against sepsis-induced bone marrow exhaustion. As persisting absence of circulating neutrophils strongly indicated the possibility of drug-induced agranulocytosis, a thorough re-review of any medications the patient might have received prior to and following admission was undertaken. Although both vancomycin and piperacillin-tazobactam may cause neutropenia,3 these antibiotics were only started after the patient already had an ANC of zero; and because only 4 days had elapsed following admission, the timeline was too soon for superimposed antibiotic-induced neutrophil-reactive antibodies to be plausible. Accordingly, further consideration for a medication or other drug taken prior to admission was given. Of the illicit IV drugs she used, cocaine has been associated with agranulocytosis due to the presence of levamisole as an adulterant.20, 21 On the sixth day of admission, her bloodwork yielded a hemoglobin 8.1 g/dL, WBC 0.6 × 109/L with ANC 0, platelet count 19 × 109/L, INR 1.2, aPTT 46. Her HIV test as well as ANA came back negative. Repeat blood cultures from the fourth day of hospital admission also came back negative. She continued to be hemodynamically unstable requiring increasing vasopressor and inotropic support. Blood culture obtained on the sixth day of hospitalization from the dialysis catheter site yielded budding yeast cells and pseudohyphae (after 28-h incubation), and the infectious disease consultant diagnosed superimposed Candida albicans infection in this patient with persisting profound neutropenia. Despite adding anidulafungin, she died on the eighth day due to multiorgan failure as a result of septic shock. Her ANC remained at 0 throughout her hospitalization. Figure 1 summarizes the patient's clinical course, including serial platelet count and ANC values (panel A), fibrinogen and INR values (panel B), aPTT and anti-factor Xa levels (panel C), with evidence for initially disturbed “procoagulant-anticoagulant” balance,10, 12 with greatly elevated fibrin D-dimer levels and markedly reduced antithrombin and protein C activity levels (panel D), which improved during treatment with heparin, antithrombin concentrates, and frozen plasma infusion. Summary of the patient's clinical course. (A) Serial platelet count and absolute neutrophil count (ANC) levels; timing and dose of intravenous heparin infusion rate is also shown. (B) Serial INR (international normalized ratio) and fibrinogen levels. (C) Serial partial thromboplastin time (aPTT) and anti-factor Xa levels. (D) Serial D-dimer, antithrombin (AT) and protein C (PC) activity levels; timing and dosing of AT concentrates and of plasma infusion are also shown. The patient died 7 days following admission Persistence of agranulocytosis unresponsive to G-CSF suggested an ongoing profound bone marrow suppression effect. Levamisole-induced agranulocytosis appeared likely given this patient's known habitual use of cocaine: it is estimated that 70%–80% of all cocaine in North America contains levamisole as an adulterant.21 Studies on levamisole identified long-term exposure to the drug as a significant risk factor for development of agranulocytosis.21, 22 Drug clearance is normally rapid with normally functioning kidneys, but this patient was anuric. Furthermore, levamisole is not cleared by dialysis, suggesting that plasma levels would not be lowered by CRRT.23 As this patient was injecting cocaine in the dorsum of her hand and had several necrotic lesions located at prior injection sites, the possibility of a persistent depot of levamisole was also considered to explain sustained agranulocytosis due to prolonged exposure to the drug or a relevant metabolite. Neutropenia is a common phenomenon frequently encountered in patients on antineoplastic chemotherapy, as an infection-related event, in certain autoimmune conditions, and in nutritional deficiency.2, 3 In contrast, agranulocytosis is a rare immune-mediated phenomenon triggered by certain medications3 or IV drugs.20, 21 Several medications have a known association with agranulocytosis, with the more common mechanism presumed to be antibodies to a neoepitope formed by a combination of the medication (or metabolite) and a receptor on the neutrophil membrane.24, 25 However, definitive proof is often lacking because detection of such antibodies is challenging and rarely performed. On some occasions, drug-dependent anti-neutrophil antibodies have been detected in the serum of patients with agranulocytosis.25, 26 A recent review of drug-induced agranulocytosis identified medications with the greatest likelihood of inducing agranulocytosis (Table 1), including clozapine, propylthiouracil, carbamazepine, trimethoprim-sulfamethoxazole, beta-lactams, and levamisole, among others.3 Among these, clozapine has the highest frequency of triggering agranulocytosis, estimated at 1 in 125 patients.24, 25 Beta-lactams Vancomycin Dapsone Trimethoprim-sulfamethoxazole 25 days24 82 days27 39 days24 UNKa 0.42/106 per year28 UNK UNK 5.6/106 per year29 Immune-mediated25 Immune-mediated25 Reactive metabolite induces apoptosis25 Immune-mediated29 Diclofenac Sulfasalazine UNK 42 days24 0.14/106 per year28 1:1600 in IBD29 1:6100 in RA29 Inhibit myelopoiesis25 Direct toxicity, immune-mediated30 Methimazole Propylthiouracil 42 days24 36 days24 0.25/106 per year28 0.2-0.5% 31 Immune-mediated32 Reactive metabolite induces apoptosis25, 33, immune-mediated29 Clozapine Chlorpromazine 56 days24 45 days24 0.8% 29 UNK Reactive metabolite induces apoptosis25, 33, inhibit myelopoiesis25 Inhibit myelopoiesis29 Phenytoin Carbamazepine 14 days33 49 days24 UNK 0.09/106 per year28 Reactive metabolite induces apoptosis25 Inhibit myelopoiesis29 Procainamide Captopril Ticlopidine 47 days24 32 days24 39 days24 UNK UNK 0.39/106 per year28 Reactive metabolite induces apoptosis25 Immune-mediated25 Reactive metabolite Induces apoptosis25 Levamisole Deferiprone Rituximabb 60 days24 UNK 4 cycles24 UNK 0.2-0.4/100 patient years29 UNK Immune-mediated25 UNK Immune-mediated25 Among IV drug users, levamisole is becoming a more recognized etiological agent due to its near-ubiquitous presence in cocaine distributed in North America.21, 22 Its association with agranulocytosis was first recognized in patients who received levamisole for treatment of rheumatoid arthritis during in the 1990s.22 Due to its relatively high risk for causing agranulocytosis, levamisole was withdrawn from the market in 2000, but it continues to find use in the veterinary world as an antihelminthic.21, 34 Its physical resemblance to cocaine and the relative ease of acquisition at a low price explain its common use as an adulterant in the manufacture of cocaine.23 Pharmacokinetic studies of levamisole injected into the muscle and fat of animals yielded a short plasma half-life and rapid elimination via the urinary tract within 24 hours.35, 36 However, repeated exposure to low doses of the drug over a period of months can induce the formation of antibodies implicated in agranulocytosis.26 The clinical presentation of patients who develop agranulocytosis during exposure to levamisole-adulterated cocaine is variable, with many patients either asymptomatic or developing a nonspecific flu-like illness. Around 50% of patients may initially present to the ER with mouth ulcers or odynophagia.21 A vasculitic rash has been associated with levamisole exposure that develops in the setting of an occlusive thrombotic vasculopathy. The latter most frequently involves the cheeks and ears and tends to be ANCA-positive.37 However, as there are cases of levamisole-induced agranulocytosis not associated with positive ANA or ANCA, the absence of these autoimmune markers does not rule out levamisole as the culprit drug38 (note: we did not measure ANCA in our patient case). In addition, case reports of patients who develop an autoimmune marker such as ANA, c-ANCA, p-ANCA, or antiphospholipid antibody in the setting of known levamisole exposure describe the disappearance of this marker within 14 months of discontinuation of drug exposure.21 It is not yet clear why a relatively high proportion (approximately 2%–4%) of patients who habitually use cocaine and who are likely chronically exposed to levamisole develop agranulocytosis.21 In previous studies of rheumatoid arthritis patients, risk factors for levamisole-induced agranulocytosis included female sex, HLA-B27, and frequency of drug exposure.21, 39 The expected time for recovery of drug-induced agranulocytosis after stopping the offending drug, without the addition of growth factor support, is a median of 9 days;40 the addition of G-CSF reduces the time for neutrophil recovery to approximately 4-7 days.40 When severe agranulocytosis persists beyond this period, unusual circumstances have been reported. For example, some patients with persisting agranulocytosis unresponsive to G-CSF have parvovirus B19 infection, and recover after administration of IVIgG (implicating removal of circulating virus by IgG anti-parvovirus antibody, reversing virus-induced inhibition of granulopoiesis).41 The typical course of levamisole-associated agranulocytosis usually involves improvement in the neutrophil count beginning several days after discontinuation of the drug, with recombinant G-CSF hastening recovery.21 Given that levamisole is normally metabolized in the liver and secreted via the renal system, the presence of significant liver and/or kidney dysfunction is likely to significantly prolong its half-life.21, 23 Furthermore, hemodialysis does not clear the drug.23 When injected intramuscularly or into adipose tissue a depot of the drug may develop that results in continuous long-term exposure. Given our had an ANC of zero that persisted for 8 days following admission (until death) without any other clear precipitant or cause identified and despite starting G-CSF, we hypothesize that the combination of an intramuscular or subcutaneous depot of levamisole, together with absent renal clearance and hepatic dysfunction, resulted in ongoing exposure to levamisole (or a metabolite) that potentiated pathological effects of levamisole-dependent anti-neutrophil antibodies. The recommended management of levamisole-induced agranulocytosis is drug withdrawal and supportive care.21 Reported experience, mainly based on cocaine users who were not critically ill, typically show rapid recovery within a few days of drug discontinuation. There is a paucity of data in patients who are critically ill with multiorgan dysfunction; indeed, to our knowledge, presentation as septic shock (due to MSSA septicemia) in the setting of agranulocytosis presumed to be caused by levamisole-adulterated cocaine has not been previously reported. The authors have no conflicts of interest to report.
Japan establishes the goals to realize ZEBs (net zero energy building) in average newly constructed public and private buildings by 2030. The primary energy consumption of the illumination in the office building accounts for around 20% of the whole building. Therefore, thorough saving energy is demanded for illumination to achieve ZEB. The effective method for the saving energy of illumination is the use of day light. The natural light of the workplace in office building is generally adopted through a side window. Venetian blinds are installed in the window for solar shading. In the automatic blind control system installed at the large scale building, slats of blind are uniformly controlled by illuminance censor fixed on the top of the building. This is not able to detect direct sunlight and the light from adjacency building at the side window. We devised technique to detect not only the direct sunlight but also the dazzling borrowed light from adjacency building based on a luminance image provided with a CCD camera for the purpose of the development of the higher precise judgment of solar shading. We built the system which could perform shading immediately at the time of the detection and introduced it into the actual work office. As a result of proof experiment, the following knowledge was provided in conclusion. 1) A method to measure high range of luminance including direct sun light and the borrowed light by a fisheye lens and the CCD camera which attached two kinds of filters which varied in the spectral transmittance was showed. 2) Using luminance contrast (C value) and the logarithm luminance mean (A value) to be provided by N filter and the averaging filter developed by Nakamura, detect direct rays of the sun and borrowed light can be identified in luminance image. 3) The threshold of C value: 0.4 and A value: 4.5 that can detect direct rays of the sun and borrowed light using the luminance image measured at single shutter speed of 1/200 second by the CCD camera are identified for speedup of the control. 4) The evaluation method proposed in this study applied to blind control system in actual workplace could detect direct sun light and borrowed light of neighboring buildings with high precision and was able to confirm the usefulness and effectiveness. 5) The possibility that could contribute to increase of the day lighting and view-related improvement by controlling every window is showed 6) The result of this study showed the possibility that could help it toward the spread of blind control systems with higher precision.
Protein crystallography has made the largest contribution to our knowledge of protein structure. However, it is well known that many biologically important proteins do not readily form large enough crystals for traditional crystallography. Successful serial microcrystallography (SMX) studies have been performed at X-ray Free-Electron Lasers, but they are limited in experimental availability. We look to more accessible light sources, such as storage ring sources, for the development of SMX. However, improvements to the conventional experiment are required to make SMX viable at storage rings. Here, we explore several devices and techniques designed given this consideration. To isolate crystal diffraction, the sample environment should contribute zero background scatter outside the crystal, since excess scatter obscures the weak microcrystal signal. We will show the feasibility of using atomically-thin, gas-tight graphene to reduce background scatter as a crystal mount and suggest using it as a window material for SMX. We will also explore two microcrystal delivery devices, a microfluidic chip and a viscous jet injector, for use in SMX. While both of these devices show promise for optimizing various aspects of the crystal delivery system, both contribute more background scatter than is acceptable for an ideal SMX experiment at a storage ring source. Merging diffraction from multiple microcrystals is necessary when a complete data set cannot be determined from a single microcrystal. When microcrystal diffraction is weak enough that Bragg peaks are no longer visible, merging through conventional techniques fails since crystal orientation cannot be obtained through Bragg peak indexing. We will explore proof-of-principle experiments which show that indexing data frames on a per-frame basis is unnecessary for a structure solution, when reciprocal space intensities can be reconstructed using the EMC algorithm. In principle, serial microcrystallography is feasible at storage ring sources if improvements in beamline setups, sample chamber construction and microcrystal diffraction analysis evolve to optimize the diffraction of microcrystals.
The Riemann-Roch theorem is a useful tool to calculate the dimension of the space of meromorphic functions with prescribed zeros and poles. There are severals versions of the theorem such as the Riemann-Roch theorem for line bundles, for (algebraic) curves, for surfaces and for higher dimensions. In this thesis, we will focus on the Riemann-Roch theorem for algebraic curves over an algebraically closed eld, which is a very important result in complex analysis and algebraic geometry. The study of the elds of rational functions on curves can be very useful in the proof. So we will recall some pre-knowledges in commutative algebra and some facts about a ne varieties. Then talk about function elds, discrete valuation rings and Weil di erentials to prove the theorem, using the methods of Andre Weil.
Secure multiparty protocols are useful tools for parties wishing to jointly compute a function while keeping their input data secret. The millionaires’ problem is the first secure two-party computation problem, where the goal is to securely compare two private numbers without a trusted third-party. There have been several solutions to the problem, including Yao’s protocol [Yao, 1982] and Mix and Match [Jakobsson and Juels, 2000]. However, Yao’s Protocol is not secure in the malicious model and Mix and Match unnecessarily releases theoretically breakable encryptions of information about the data that is not needed for the comparison. In addition, neither protocol has any verification of the validity of the inputs before they are used. In this thesis, we introduce Variance, a privacy-preserving two-party protocol for solving the Yao’s millionaires’ problem in a Bitcoin setting, in which each party controls several Bitcoin accounts (public Bitcoin addresses) and they want to find out who owns more bitcoins without revealing (1) how many accounts they own and the balance of each account, (2) the addresses associated with their accounts, and (3) their total wealth of bitcoins while assuring the other party that they are not claiming more bitcoin than they possess. We utilize commitments, encryptions, zero knowledge proofs, and homomorphisms as the major computational tools to provide a solution to the problem, and subsequently prove that the solution is secure against active adversaries in the malicious model.
Low-power Ad Hoc systems are the most challenging aspect for secured Ad Hoc systems. The resource constrained devices were easily tampered due to the limited operated environment. Over the past decade, the usage rate of Ad Hoc systems are rapidly increased in modern communication systems. However, the security is still a research factor for Lowpower Ad Hoc systems. Offering Security and Anonymity is an important research issue in Low-power Mobile Ad Hoc Networks (LPMANET). Various anonymous routing protocols presented to maintain anonymity in adverse environment, these protocols proven significant results in Ad Hoc systems but failure to improved the anonymity efficiency in Low-power Ad hoc networks. In this paper, a Lightweight Energy Efficient Anonymous Routing (LEEAR) protocol is proposed to offer energy efficient anonymity and security in an adverse environment by combining modified zero knowledge proof, bloom filter and cryptography techniques. We designed the LEEAR protocol to determine the efficiency in-terms security and energy against routing level and traffic level attacks. We simulated the experiment in NS2 simulator the determine the results and ensure importance of the proposed LEEAR protocol in accomplishing energy efficiency and anonymity.
How might new technical verification capabilities enhance the prospects of success in future nuclear arms control negotiations? Both theory and evidence suggest that verification technologies can influence the dynamics of arms control negotiations by shaping and constraining the arguments and strategies that are available to the involved stakeholders. In the future, new technologies may help transcend the specific verification challenge of high-security warhead authentication, which is a verification capability needed in future disarmament scenarios that address fewer warheads, limit new categories of warheads, and involve nuclear weapons states other than the United States and Russia. Under these circumstances, the core challenge is maintaining the confidentiality of the classified information related to the warheads under inspection, while providing transparency in the verification process. This analysis focuses on a set of emerging warhead authentication approaches that rely on the cryptographic concept of zero-knowledge proofs and intend to solve the paradox between secrecy and transparency, making deeper reductions in warhead arsenals possible and thus facilitating future nuclear arms control negotiations.
Within the phenomenon known as the Internet of Things (IoT), an enormous growth is taking place. IoT systems exist in different ways, ranging from industrial applications to user focused systems. A specific subset of a user-focused IoT system is found as Smart Home environments. At Smart Homes, themultiple Smart Objects or Smart Devices are working together, frequently based on sensor input, to increase the comfort and user experience of the home inhabitant(s) and guest(s). Smart Objects can have automated tasks, home security enabling functions or efficiency improving functionality. Apart from great applications of Smart Home devices, threats from a cyber security perspective are present: cyber risks arise due to a variety of threats on such IoT systems. We show that in the development of new Smart Home products or systems, vendors fail to meet requirements for security and privacy are not met. Comparing the current state of the market, the four most used Smart Home ecosystems (Samsung Smartthings, Apple Homekit, Amazon Echo and IFTTT) are surveyed based on three key focus areas: 1. The regulatory compliance of the systems according to the upcoming General Data Protection Regulation (GDPR). 2. The commercial threats due to data profiling. 3. The risk of data leaks due to insufficient security. This analysis results in four key observations: 1. Security- and Privacy-By-Design is usually not in place due to the fact that the focus lies on launching a product as soon as possible, e.g. due to market competition; 2. Vendors process (meta)data on the vendors locations resulting in data profiling, which can compromise user privacy; 3. Smart Home ecosystems are not ready for the GDPR; 4. A trade off between privacy, security and utility usually results to the detriment of the first two and favors the latter. We propose a new design for a Smart Home ecosystem. In this design, the focus lies at the privacy of the end-user. We design a network for device-fitting encrypted communication between Smart Devices and User Devices and the Privacy Enforcing Arbiter (or Peter). Peter functions like a hub in the network, managing among others all traffic, user privileges and key distribution. With Peter, the centralized cloud party (vendor) for data storage and data analysis is replaced with a decentralized personal storage and computation entity at home. With our network design, we facilitate the use of IoT devices in home in a privacy-friendly way. Within the network, devices are authenticated using PhysicallyUnclonable Function technology and users are authenticated with a Zero Knowledge Proof. We analyze the privacy and security of our proposed network, based on a series of possible cyber attacks and the upcoming GDPR. Furthermore, we analyze the computational complexity and scalability of the network, based on market conform device power.
Internet voting has long been a topic both of public discussion and also of scientific research. While the introduction of Internet voting may bring many advantages, it is further important to ensure an adequate level of security of the systems and underlying schemes that are used for casting and tallying the votes in order to encourage faith and acceptance for this relatively new way of voting.
A number of cryptographic schemes have been proposed, that enable secure Internet voting. One of the most established and well-researched solutions is the Helios scheme, which is also implemented as an open-source system. Both its implementation and the scheme behind it has been extensively studied in the literature, and the Helios system has been used for numerous elections in practice, such as the IACR elections.
However, there are election settings for which Helios is currently not appropriate, either due to infrastructure demands, required functionality for the voters or assurance of the security requirements. These kinds of election settings could benefit from the advantages that secure Internet voting provides.
In this thesis we identify the election settings not currently supported by Helios, propose our extensions for each one of these settings and evaluate their security. Hence, this work describes four Internet voting schemes that are build upon Helios, with each scheme developed towards a specific setting.
The first scheme presented here enables elections within the so-called boardroom voting setting. This setting is characterized by its decentralization, whereby all the tasks within the election are distributively performed by the voters themselves, without the support of a centralized infrastructure. The election in the boardroom voting setting are further conducted in an ad-hoc manner, so that limited time is available for preparation beforehand. We propose an extension of Helios that distributes the tasks of the voting system components in Helios among the voters. For this, we use cryptographic primitives such as decentralized key exchange with short authentication strings, distributed secret sharing and distributed decryption and Byzantine agreement.
The second scheme extends Helios with proxy voting functionality. Proxy voting, as a newly emerged form of voting, enables the voter to delegate her voting right in the election to a trusted third-party, the so-called proxy, who is authorized to vote on the voter's behalf. This extension facilitates such delegation while assuring the security for delegating voters and for the proxies and preserves the security guarantees provided by Helios for the voters who vote directly (instead of delegating). For ensuring the security of our extension, we introduce the so-called delegation credentials that are assigned to the voters and are used to compute anonymized delegation tokens sent to the proxies to enable delegation. We further use cryptographic primitives such as proofs of knowledge and signatures of knowledge.
The third scheme combines the first two settings to extend Helios towards the proxy boardroom voting setting, namely, a setting in which the elections are performed in a decentralized way as in boardroom voting, yet the voters who cannot participate in the election themselves are allowed to delegate their voting right to a trusted proxy before the election. The security of our extension is assured with threshold secret sharing and Pedersen commitments.
The fourth scheme extends Helios by improving its security.
As such, it introduces participation privacy, meaning that the voting system does not reveal which voters have participated in the election, while supporting verification that only the eligible voters have cast their ballots in the election. The extension furthermore introduces receipt-freeness, ensuring that the voter cannot create a receipt that proves to a third party how she voted, thus preventing vote selling. To ensure the security of the extension, a new kind of entity is introduced, the posting trustee, and a new kind of ballot, the so-called dummy ballot that is indistinguishable from a normal ballot cast by the voter, but does not modify the election result. We furthermore use disjunctive zero-knowledge proofs and proofs of signature knowledge to prove, that a sender of a particular ballot knows the private signature key of an eligible voter, or that the ballot is a dummy ballot.
For each one of the extensions, the security model is provided, which describes the security requirements and the assumptions that are necessary for ensuring the security requirements (i.e. vote privacy or vote integrity), is provided. For the first three extensions, the security model is used as a base for the informal security evaluation, in which an informal argument is used to show, that the security requirements hold under the described assumptions. Conducting a formal security evaluation for these extensions is considered an important part of the future work, in which new formal definitions have to be developed.
For the fourth extension, we provide a formal security analysis that relies on the formal definitions for the security requirements of vote privacy, vote integrity and eligibility, available in the literature. We furthermore introduce new formal definitions for participation privacy, receipt-freeness and fairness, which we also use for the formal proofs of our extension.
The class TFNP is the search analog of NP with the additional guarantee that any instance has a solution. TFNP has attracted extensive attention due to its natural syntactic subclasses that capture the computational complexity of important search problems from algorithmic game theory, combinatorial optimization and computational topology. Thus, one of the main research objectives in the context of TFNP is to search for efficient algorithms for its subclasses, and at the same time proving hardness results where efficient algorithms cannot exist. Currently, no problem in TFNP is known to be hard under assumptions such as NP hardness, the existence of one-way functions, or even public-key cryptography. The only known hardness results are based on less general assumptions such as the existence of collision-resistant hash functions, one-way permutations less established cryptographic primitives (e.g. program obfuscation or functional encryption). Several works explained this status by showing various barriers to proving hardness of TFNP. In particular, it has been shown that hardness of TFNP hardness cannot be based on worst-case NP hardness, unless NP=coNP. Therefore, we ask the following question: What is the weakest assumption sufficient for showing hardness in TFNP? In this work, we answer this question and show that hard-on-average TFNP problems can be based on the weak assumption that there exists a hard-on-average language in NP. In particular, this includes the assumption of the existence of one-way functions. In terms of techniques, we show an interesting interplay between problems in TFNP, derandomization techniques, and zero-knowledge proofs.
With the rise of Bitcoin, cryptographic currencies have attracted more and more attention. Subsequently, other cryptographic currencies were gradually created, such as Zcash, Moreno, Dash and so on. In cryptographic currency, privacy preserving and expansion are two key technical points. In terms of privacy preserving, more effective solutions were proposed in Zcach, Moreno, Dash and other cryptographic currencies systems, in which ring signature, zero knowledge proof and other cryptographic techniques played important roles. But these schemes mainly considered protecting the addresses of both sides of the transaction. In terms of expansion, lightning network and other projects also give solutions. But most of these projects will bring other problems. In this paper, a signature scheme based on the aggregate signature and the elliptic curve algorithm is proposed to hide the transaction value of a single sender and receiver in the transactions which contain multiple inputs and outputs. This signature scheme achieves the purpose of privacy preserving from the transaction value. Further, the correctness proof and security analysis are given in this paper. In addition to that, another signature scheme that combines aggregation signature with bilinear ring signature is proposed. This aggregate ring signature scheme gives another attempt to solve the problem of expansion in the cryptographic currency system only using cryptographic technologies. At the same time, the sender's addresses can be hidden. Similarly, we also confirmed the correctness of this signature scheme.
The modeling of trapdoor permutations has evolved over the years. Indeed, finding an appropriate abstraction that bridges between the existing candidate constructions and the needs of applications has proved to be challenging. In particular, the notions of certifying permutations (Bellare and Yung, 96), enhanced and doubly enhanced trapdoor permutations (Goldreich, 04, 08, 11, Goldreich and Rothblum, 13) were added to bridge the gap between the modeling of trapdoor permutations and needs of applications. We identify an additional gap in the current abstraction of trapdoor permutations: Previous works implicitly assumed that it is easy to recognize elements in the domain, as well as uniformly sample from it, even for illegitimate function indices. We demonstrate this gap by using the (Bitansky-Paneth-Wichs, 16) doubly-enhanced trapdoor permutation family to instantiate the Feige-Lapidot-Shamir (FLS) paradigm for constructing non-interactive zero-knowledge (NIZK) protocols, and show that the resulting proof system is unsound. To close the gap, we propose a general notion of certifiably injective doubly enhanced trapdoor functions (DECITDFs), which provides a way of certifying that a given key defines an injective function over the domain defined by it, even when that domain is not efficiently recognizable and sampleable. We show that DECITDFs suffice for instantiating the FLS paradigm; more generally, we argue that certifiable injectivity is needed whenever the generation process of the function is not trusted. We then show two very different ways to construct DECITDFs: One is via the traditional method of RSA/Rabin with the Bellare-Yung certification mechanism, and the other using indistinguishability obfuscation and injective pseudorandom generators. In particular the latter is the first candidate injective trapdoor function, from assumptions other than factoring, that suffices for the FLS paradigm. Finally we observe that a similar gap appears also in other paths proposed in the literature for instantiating the FLS paradigm, specifically via verifiable pseudorandom generators and verifiable pseudorandom functions. Closing the gap there can be done in similar ways to the ones proposed here.