Enhancing Privacy in Cryptographic Protocols

For the past three decades, a wide variety of cryptographic protocols have been proposed to solve secure communication problems even in the presence of adversaries. The range of this work varies from developing basic security primitives providing confidentiality and authenticity to solving more complex, application-specific problems. However, when these protocols are deployed in practice, a significant challenge is to ensure not just security but also privacy throughout these protocols' lifetime. As computer-based devices are more widely used and the Internet is more globally accessible, new types of applications and new types of privacy threats are being introduced. In addition, user privacy (or equivalently, key privacy) is more likely to be jeopardized in large-scale distributed applications because the absence of a central authority complicates control over these applications. In this dissertation, we consider three relevant cryptographic protocols facing user privacy threats when deployed in practice. First, we consider matchmaking protocols among strangers to enhance their privacy by introducing the "durability" and "perfect forward privacy" properties. Second, we illustrate the fragility of formal definitions with respect to password privacy in the context of password-based authenticated key exchange (PAKE). In particular, we show that PAKE protocols provably meeting the existing formal definitions do not achieve the expected level of password privacy when deployed in the real world. We propose a new definition for PAKE that is tightly connected to what is actually desired in practice and suggest guidelines for realizing this definition. Finally, we answer to a specific privacy question, namely whether privacy properties of symmetric-key encryption schemes obtained by non-tight reduction proofs are retained in the real world. In particular, we use the privacy notion of "multi-key hiding" property and show its non-tight relation with the IND$-CPA property of symmetric-key schemes. We use the experimental result by Gligor et al. to show how a real attack breaks the "multi-key hiding" property of IND$-CPA symmetric-key encryption schemes with high probability in practice. Finally, we identify schemes that satisfy the "multi-key hiding" and enhance key privacy in the real world

The diluted atropine for inhibition of myopia progression in Korean children

AIM: To evaluate the efficacy and safety of three different concentrations of diluted atropine for the control of myopia in Korean children, and to assess the risk factors associated with rapid myopia progression. METHODS: A total of 285 children, with refractive errors within the range of -6 diopters (D) between 5 and 14 years of age were included. After using 0.01%, or 0.025%, or 0.05% atropine, for about 1y, changes in refraction, axial lengths and frequency of adverse events were analyzed. Logistic regression analyses were performed to evaluate the risk factors associated with rapid myopia progression. RESULTS: The changes in the mean spherical equivalent values were -0.134 D/mo in the before atropine group, -0.070 D/mo in the 0.01% atropine group, -0.047 D/mo in the 0.025% atropine group, and -0.019 D/mo in the 0.05% atropine group, with significant differences between the groups (P<0.001). The axial elongation was 0.046 mm/mo, 0.037 mm/mo, 0.025 mm/mo, and 0.019 mm/mo respectively, with significant differences between the groups (P=0.003). The incidence of photophobia and near vision difficulty was not different among the three atropine groups (P=0.425 and P=0.356, respectively). Multivariate logistic regression analyses showed that only highly myopic parents were a significant predictive factor of rapid myopia progression in Korean children (odds ratio, 8.155; 95% confidence interval, 3.626-18.342; P<0.001). CONCLUSION: Treatment with 0.01%, 0.025% and 0.05% atropine solution inhibits myopia progression in Korean children in a dose-dependent manner. Children with highly myopic parents preferentially shows a rapid myopia progression rate

Modeling Insider Attacks on Group Key-Exchange Protocols

Protocols for authenticated key exchange (AKE) allow parties within an insecure network to establish a common session key which can then be used to secure their future communication. It is fair to say that group AKE is currently less well understood than the case of two-party AKE; in particular, attacks by malicious insiders --- a concern specific to the group setting --- have so far been considered only in a relatively ``ad-hoc\u27\u27 fashion. The main contribution of this work is to address this deficiency by providing a formal, comprehensive model and definition of security for group AKE which automatically encompasses insider attacks. We do so by defining an appropriate ideal functionality for group AKE within the universal composability (UC) framework. As a side benefit, any protocol secure with respect to our definition is secure even when run concurrently with other protocols, and the key generated by any such protocol may be used securely in any subsequent application. In addition to proposing this definition, we show that the resulting notion of security is strictly stronger than the one proposed by Bresson, et al. (termed ``AKE-security\u27\u27), and that our definition implies all previously-suggested notions of security against insider attacks. We also show a simple technique for converting any AKE-secure protocol into one secure with respect to our definition

Effects of the Rho-Kinase Inhibitor Y-27632 on Extraocular Muscle Surgery in Rabbits

Purpose. To evaluate the effect of the Rho-kinase inhibitor Y-27632 on postoperative inflammation and adhesion following extraocular muscle surgery in rabbits. Methods. The superior rectus muscle reinsertion was performed on both eyes of 8 New Zealand white rabbits. After reinsertion, the rabbits received subconjunctival injections of the Rho-kinase inhibitor and saline on each eye. To assess acute and late inflammatory changes, Ki-67, CD11β+, and F4/80 were evaluated and the sites of muscle reattachment were evaluated for a postoperative adhesion score and histopathologically for collagen formation. Results. F4/80 antibody expression was significantly different in the Rho-kinase inhibitor-injected group at both postoperative day 3 and week 4 (p=0.038, 0.031). However, Ki-67 and CD11β+ were not different the between two groups. The difference in the SRM/conjunctiva adhesion score between the two groups was also significant (p=0.034). Conclusion. Intraoperative subconjunctival injection of the Rho-kinase inhibitor may be effective for adjunctive management of inflammation and fibrosis in rabbit eyes following extraocular muscle surgery

Erratum to: Macroscopic and microscopic assessments of the glenohumeral and subacromial synovitis in rotator cuff disease

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made

Macroscopic and microscopic assessments of the glenohumeral and subacromial synovitis in rotator cuff disease

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background Whereas synovitis is one of most common findings during arthroscopic surgery in patients with rotator cuff diseases, no study has investigated its characteristics. We propose a macroscopic assessment system for investigating the characteristics of synovitis. Methods Fifty-four patients with a full-thickness rotator cuff tear undergoing arthroscopic rotator cuff repair with an average age of 62.5 ± 7.0 years were included. For the macroscopic assessment, 3 parameters, villous hypertrophy, hyperemia, and density, were measured and translated into grades in 3 regions-of-interest (ROI) in the glenohumeral joint and 4 ROIs in the subacromial space. For the microscopic assessments, 4 commonly used microscopic assessment systems were used. The reliability and association between the macroscopic and microscopic assessments were investigated. Results The inter- and intra-observer reliability of all of the macroscopic and microscopic assessments were excellent. The severity of synovitis was significantly greater in the glenohumeral joint than that in the subacromial space, 1.54 ± 0.61 versus 0.94 ± 0.56 (p < 0.001). Synovitis varied with respect to location, and was generally more severe near the tear with the macroscopic assessment system. Meanwhile, none of the microscopic assessment systems demonstrated differences between different ROIs in both the glenohumeral joint and the subacromial space. Conclusions The macroscopic assessment system for synovitis in rotator cuff disease in this study showed excellent reliability. It critically described characteristics of synovitis that microscopic assessment systems could not. Therefore, this system could be a useful tool for investigating synovitis in rotator cuff disease

Simultaneous recording of cervical and ocular vestibular-evoked myogenic potentials

Objective: To increase clinical application of vestibular-evoked myogenic potentials (VEMPs) by reducing the testing time by evaluating whether a simultaneous recording of ocular and cervical VEMPs can be achieved without a loss in diagnostic sensitivity and specificity.Methods: Simultaneous recording of ocular and cervical VEMPs on each side during monaural stimulation, bilateral simultaneous recording of ocular VEMPs and cervical VEMPs during binaural stimulation, and conventional sequential recording of ocular and cervical VEMPs on each side using air-conducted sound (500 Hz, 5-millisecond tone burst) were compared in 40 healthy participants (HPs) and 20 patients with acute vestibular neuritis.Results: Either simultaneous recording during monaural and binaural stimulation effectively reduced the recording time by approximate to 55% of that for conventional sequential recordings in both the HP and patient groups. The simultaneous recording with monaural stimulation resulted in latencies and thresholds of both VEMPs and the amplitude of cervical VEMPs similar to those found during the conventional recordings but larger ocular VEMP amplitudes (156%) in both groups. In contrast, compared to the conventional recording, simultaneous recording of each VEMP during binaural stimulation showed reduced amplitudes (31%) and increased thresholds for cervical VEMPs in both groups.Conclusion: sThe results of simultaneous recording of cervical and ocular VEMPs during monaural stimulation were comparable to those obtained from the conventional recording while reducing the time to record both VEMPs on each side.ClinicalTrials.gov identifierNCT03049683

High resolution crystal structure of PedB: a structural basis for the classification of pediocin-like immunity proteins

<p>Abstract</p> <p>Background</p> <p>Pediocin-like bacteriocins, ribosomally-synthesized antimicrobial peptides, are generally coexpressed with cognate immunity proteins in order to protect the bacteriocin-producer from its own bacteriocin. As a step for understanding the mode of action of immunity proteins, we determined the crystal structure of PedB, a pediocin-like immunity protein conferring immunity to pediocin PP-1.</p> <p>Results</p> <p>The 1.6 Å crystal structure of PedB reveals that PedB consists of an antiparallel four-helix bundle with a flexible C-terminal end. PedB shows structural similarity to an immunity protein against enterocin A (EntA-im) but some disparity to an immunity protein against carnobacteriocin B2 (ImB2) in both the C-terminal conformation and the local structure constructed by α3, α4, and their connecting loop. Structure-inspired mutational studies reveal that deletion of the last seven residues of the C-terminus of PedB almost abolished its immunity activity.</p> <p>Conclusion</p> <p>The fact that PedB, EntA-im, and ImB2 share a four-helix bundle structure strongly suggests the structural conservation of this motif in the pediocin-like immunity proteins. The significant difference in the core structure and the C-terminal conformation provides a structural basis for the classification of pediocin-like immunity proteins. Our mutational study using C-terminal-shortened PedBs and the investigation of primary sequence of the C-terminal region, propose that several polar or charged residues in the extreme C-terminus of PedB which is crucial for the immunity are involved in the specific recognition of pediocin PP-1.</p