Anonymity and trust in the electronic world

Privacy has never been an explicit goal of authorization mechanisms. The traditional approach to authorisation relies on strong authentication of a stable identity using long term credentials. Audit is then linked to authorization via the same identity. Such an approach compels users to enter into a trust relationship with large parts of the system infrastructure, including entities in remote domains. In this dissertation we advance the view that this type of compulsive trust relationship is unnecessary and can have undesirable consequences. We examine in some detail the consequences which such undesirable trust relationships can have on individual privacy, and investigate the extent to which taking a unified approach to trust and anonymity can actually provide useful leverage to address threats to privacy without compromising the principal goals of authentication and audit. We conclude that many applications would benefit from mechanisms which enabled them to make authorization decisions without using long-term credentials. We next propose specific mechanisms to achieve this, introducing a novel notion of a short-lived electronic identity, which we call a surrogate. This approach allows a localisation of trust and entities are not compelled to transitively trust other entities in remote domains. In particular, resolution of stable identities needs only ever to be done locally to the entity named. Our surrogates allow delegation, enable role-based access control policies to be enforced across multiple domains, and permit the use of non-anonymous payment mechanisms, all without compromising the privacy of a user. The localisation of trust resulting from the approach proposed in this dissertation also has the potential to allow clients to control the risks to which they are exposed by bearing the cost of relevant countermeasures themselves, rather than forcing clients to trust the system infrastructure to protect them and to bear an equal share of the cost of all countermeasures whether or not effective for them. This consideration means that our surrogate-based approach and mechanisms are of interest even in Kerberos-like scenarios where anonymity is not a requirement, but the remote authentication mechanism is untrustworthy

Better Call Saltzer \& Schroeder: A Retrospective Security Analysis of SolarWinds \& Log4j

Saltzer \& Schroeder's principles aim to bring security to the design of computer systems. We investigate SolarWinds Orion update and Log4j to unpack the intersections where observance of these principles could have mitigated the embedded vulnerabilities. The common principles that were not observed include \emph{fail safe defaults}, \emph{economy of mechanism}, \emph{complete mediation} and \emph{least privilege}. Then we explore the literature on secure software development interventions for developers to identify usable analysis tools and frameworks that can contribute towards improved observance of these principles. We focus on a system wide view of access of codes, checking access paths and aiding application developers with safe libraries along with an appropriate security task list for functionalities

Helioseismic Investigation of Quasi-biennial Oscillation Source Regions

We studied the temporal evolution of quasi-biennial oscillations (QBOs) using acoustic mode oscillation frequencies from the Global Oscillation Network Group. The data used here span over more than 25 yr, covering solar cycles 23 and 24 and the ascending phase of cycle 25. The analysis reveals that the QBO-like signals are present in both the cycles, but with different periods. The dominant QBO period in cycle 23 is found to be about 2 yr while it is about 3 yr in cycle 24. Furthermore, the quasi-biennial oscillatory signals are present only during the ascending and high-activity phases of cycle 23 and quickly weaken around 2005 during the declining phase. In comparison, the QBO signals are present throughout the cycle 24, starting from 2009 to 2017. We also explored the depth dependence in QBO signals and obtained a close agreement at all depths, except in the near-surface shear layer. A detailed analysis of the near-surface shear layer suggests that the source region of QBOs is probably within a few thousand kilometers just below the surface.Comment: The Astrophysical Journal (in press); 17 pages, 10 figure

Periodicity of ~155 days in solar electron fluence

In this paper we have investigated the occurrence rate of high energetic(E>10 MeV) solar electron flares measured by IMP-8 spacecraft of NASA for solar cycle 21 (June, 1976 to August, 1986) first time by three different methods to detect periodicities accurately. Power-spectrum analysis confirms a periodicity ~155 days which is in consistent with the result of Chowdhury and Ray (2006), that "Rieger periodicity" was operated throughout the cycle 21 and it is independent on the energy of the electron fluxes.Comment: 11 pages of PDF version of MSWORD, 3 figures with 1 tabl

Isospin asymmetric nuclear matter and properties of axisymmetric neutron stars

Pure hadronic compact stars, above a limiting value ($\approx$1.6 M$_\odot$) of their gravitational masses, to which predictions of most of other equations of state (EoSs) are restricted, can be reached from the equation of state (EoS) obtained using DDM3Y effective interaction. This effective interaction is found to be quite successful in providing unified description of elastic and inelastic scattering, various radioactivities and nuclear matter properties. We present a systematic study of the properties of pure hadronic compact stars. The $\beta$-equilibrated neutron star matter using this EoS with a thin crust is able to describe highly-massive compact stars, such as PSR B1516+02B with a mass M=1.94$^{+0.17}_{-0.19}$ M$_\odot$ and PSR J0751+1807 with a mass M=2.1$\pm$0.2 M$_\odot$ to a 1$\sigma$ confidence level.Comment: 5 pages, 4 figure

Diagnostics and Selective Nano-Therapeutics to Combat Multidrug-Resistant Bacteria

Due to extensive use of antibiotics various strains multidrug resistant bacteria are emerging rapidly. In USA alone according to CDC report 2013 more than 2 million is affected by these strains of multidrug resistant bacteria causing several deaths. Hence an effective way of diagnostics and therapeutics need to be designed which can successfully combat the menace ofmultidrug drug resistant bacteria.In the present thesis, we discuss about novel strategies for both diagnostics and therapeutics for multidrug resistant bacteria. In the 1st chapter we discuss a novel DNA sequencing technique utilizing purely optical spectroscopy techniques like surface enhanced Raman and FTIR spectroscopy using 3D plasmonic nano focusing. This technique can be effective in doing single molecular study, detecting any mutations or epigenetic influences that can result in development of multi drug resistance in bacteria. In the 2nd chapter we show that among different ROS, only superoxide was found to be bactericidal, killing a range of multidrug-resistant (MDR) pathogens without affecting the viability or growth of mammalian cells. In our in vitro studies, intracellular superoxide generation using light-activated quantum dots yielded highly selective and effective antimicrobial action. These results can pave the way for rational design of nanoscale therapies as precision medicine.In the 3rd chapter we show the design of superoxide-generating QDs using optimal QD material and size well-matched to superoxide redox potential, negatively charged ligands to modulate their uptake in cells and selective redox interventions, and core/shell structures to improve their stability for therapeutic action.In the 4th chapter we discuss about alloy quantum dots lowering cadmium content and replacing it with more benign zinc content. Using QDs with low cadmium content as alternative candidates for selective light-activated therapy, we show negligible toxicity of these QDs to mammalian cells, while maintaining high treatment efficacy against MDR pathogens. These results provide design principles for developing different QDs as selective therapeutics to counter the growing threat of antimicrobial resistant infections

New-onset hyperglycemia: a potential clue to detect early pancreatic cancer

Pancreatic adenocarcinoma has an incidence rate nearly equal to the mortality rate and this is mostly due to late symptom onset and diagnosis. Evidence has indicated that new-onset diabetes may be a manifestation of occult pancreatic carcinoma. Authors report the case of a young female who presented with new-onset severe hyperglycemia and superficial thrombophlebitis. She was subsequently diagnosed with pancreatic cancer confirmed by histopathology. Her glycemic status evaluated 6 months prior to her presentation during institutional health check-up was entirely normal. This case report will serve to emphasize that new-onset diabetes in certain patients could be a presenting feature of pancreatic cancer.Pancreatic adenocarcinoma has an incidence rate nearly equal to the mortality rate and this is mostly due to late onset of symptoms and delay in diagnosis. Early diagnosis of this cancer gives the opportunity for total resection of pancreas and creates hope for a full recovery. Compelling evidence now indicates that new-onset diabetes may be a manifestation of occult pancreatic carcinoma. Authors report a young female who presented with new-onset severe hyperglycemia and superficial thrombophlebitis. She was subse­quently diagnosed with pancreatic cancer confirmed by histopathology. Her glycemic status evaluated 6 months prior to her presentation during institutional health check-up was entirely normal. This case report will serve to emphasize that new-onset diabetes in certain patients could be a presenting feature of pancreatic cancer. (Clin Diabetol 2017; 6, 3: 115–117