The Rise of Certificate Transparency and Its Implications on the Internet Ecosystem

In this paper, we analyze the evolution of Certificate Transparency (CT) over time and explore the implications of exposing certificate DNS names from the perspective of security and privacy. We find that certificates in CT logs have seen exponential growth. Website support for CT has also constantly increased, with now 33% of established connections supporting CT. With the increasing deployment of CT, there are also concerns of information leakage due to all certificates being visible in CT logs. To understand this threat, we introduce a CT honeypot and show that data from CT logs is being used to identify targets for scanning campaigns only minutes after certificate issuance. We present and evaluate a methodology to learn and validate new subdomains from the vast number of domains extracted from CT logged certificates.Comment: To be published at ACM IMC 201

A comprehensive evaluation of physical and environmental performances for wet-white leather manufacture

This paper presents the comprehensive evaluation results of physical and environmental performances for a novel wet-white (chrome-free) leather manufacturing. The tanning process is optimized as 15 wt% tannic acid (TA) combination with 4 wt% Laponite nanoclay, giving the leather with shrinkage temperature (Ts) above 86 °C. Inductively coupled plasma-atomic emission spectrometry (ICP-AES) measurements indicate that Laponite can be evenly and tightly bound within the leather matrix, which is further confirmed by scanning electron microscopy and energy dispersive X-ray (SEM-EDX) spectroscopy analysis. The resultant wet-white leathers have reasonable good physical properties that can meet the standard requirements for furniture leather without containing hazardous Cr(VI) and formaldehyde. Further life cycle assessment (LCA) studies shows that tanning process is the main contributor to environmental impact categories in the wet-white tanning process, and tannic acid is the most significant substance factor. Compared to conventional chrome tanning, the wet-white tanning process exhibits much lower abiotic depletion potential (ADP), and reduced global warming potential (GWP) and human toxicity potential (HTP) impacts due to the nature of vegetable tanning; whereas, GWP excluding biogenic carbon and energy consumption are higher owing to prolonged run time.Peer ReviewedPostprint (published version

HTML5 video on mobile browsers

This paper reports on research investigating the current ability of HTML5 to play video in mobile browsers. Smartphones and the Mobile Internet are rapidly becoming an important platform for access to information anytime and anywhere. HTML5, the new HTML standard incorporates features like video playback that have been previously dependent on third-party browser plug-ins but there are no browsers that currently provide 100% support for HTML5. All the tests reported in this paper were carried out using smartphones with screen sizes 3.0 to 4.8 inches and the ability to replay videos of a range of formats, move directly to time points in the video and display closed captions were investigated. Key findings were that: video cannot be started programmatically; only selecting on the screen can trigger playback; no visual elements sitting over the <video> will receive click events while the video is visible (playing or paused); there are many HTML5 video players but MediaElement.js was found to currently be the open source player satisfying the greatest number of requirements

Molecular Basis and Consequences of the Cytochrome c-tRNA Interaction.

The intrinsic apoptosis pathway occurs through the release of mitochondrial cytochrome c to the cytosol, where it promotes activation of the caspase family of proteases. The observation that tRNA binds to cytochrome c revealed a previously unexpected mode of apoptotic regulation. However, the molecular characteristics of this interaction, and its impact on each interaction partner, are not well understood. Using a novel fluorescence assay, we show here that cytochrome c binds to tRNA with an affinity comparable with other tRNA-protein binding interactions and with a molecular ratio of ∼3:1. Cytochrome c recognizes the tertiary structural features of tRNA, particularly in the core region. This binding is independent of the charging state of tRNA but is regulated by the redox state of cytochrome c. Compared with reduced cytochrome c, oxidized cytochrome c binds to tRNA with a weaker affinity, which correlates with its stronger pro-apoptotic activity. tRNA binding both facilitates cytochrome c reduction and inhibits the peroxidase activity of cytochrome c, which is involved in its release from mitochondria. Together, these findings provide new insights into the cytochrome c-tRNA interaction and apoptotic regulation

Scale-invariance underlying the logistic equation and its social applications

On the basis of dynamical principles we derive the Logistic Equation (LE), widely employed (among multiple applications) in the simulation of population growth, and demonstrate that scale-invariance and a mean-value constraint are sufficient and necessary conditions for obtaining it. We also generalize the LE to multi-component systems and show that the above dynamical mechanisms underlie large number of scale-free processes. Examples are presented regarding city-populations, diffusion in complex networks, and popularity of technological products, all of them obeying the multi-component logistic equation in an either stochastic or deterministic way. So as to assess the predictability-power of our present formalism, we advance a prediction, regarding the next 60 months, for the number of users of the three main web browsers (Explorer, Firefox and Chrome) popularly referred as "Browser Wars"

Measurements of the Secondary Electron Emission of Some Insulators

Charging up the surface of an insulator after beam impact can lead either to reverse sign of field between the surface and collector of electrons for case of thick sample or appearance of very high internal field for thin films. Both situations discard correct measurements of secondary electron emission (SEE) and can be avoided via reducing the beam dose. The single pulse method with pulse duration of order of tens microseconds has been used. The beam pulsing was carried out by means of an analog switch introduced in deflection plate circuit which toggles its output between "beam on" and "beam off" voltages depending on level of a digital pulse. The error in measuring the beam current for insulators with high value of SEE was significantly reduced due to the use for this purpose a titanium sample having low value of the SEE with DC method applied. Results obtained for some not coated insulators show considerable increase of the SEE after baking out at 3500C what could be explained by the change of work function. Titanium coatings on alumina exhibit results close to the ones for pure titanium and could be considered as an effective antimultipactor coating.Comment: 8 pages, 13 figure