Application and evaluation of the RF charge-pumping technique

In this paper, we will discuss the extendibility of the charge-pumping (CP) technique toward frequencies up to 4 GHz. Such high frequencies are attractive when a significant gate leakage current flows, obscuring the CP current at lower pumping frequencies.\ud It is shown that using RF gate excitation, accurate CP curves can be obtained on MOS devices with a leakage current density exceeding 1 A•cm−2 . A theoretical analysis of the trap response to RF gate voltage signals is presented, giving a clear insight on the benefits and limitations of the technique.\u

Analyzing the BrowserID SSO System with Primary Identity Providers Using an Expressive Model of the Web

BrowserID is a complex, real-world Single Sign-On (SSO) System for web applications recently developed by Mozilla. It employs new HTML5 features (such as web messaging and web storage) and cryptographic assertions to provide decentralized login, with the intent to respect users' privacy. It can operate in a primary and a secondary identity provider mode. While in the primary mode BrowserID runs with arbitrary identity providers (IdPs), in the secondary mode there is one IdP only, namely Mozilla's default IdP. We recently proposed an expressive general model for the web infrastructure and, based on this web model, analyzed the security of the secondary IdP mode of BrowserID. The analysis revealed several severe vulnerabilities. In this paper, we complement our prior work by analyzing the even more complex primary IdP mode of BrowserID. We do not only study authentication properties as before, but also privacy properties. During our analysis we discovered new and practical attacks that do not apply to the secondary mode: an identity injection attack, which violates a central authentication property of SSO systems, and attacks that break an important privacy promise of BrowserID and which do not seem to be fixable without a major redesign of the system. Some of our attacks on privacy make use of a browser side channel that has not gained a lot of attention so far. For the authentication bug, we propose a fix and formally prove in a slight extension of our general web model that the fixed system satisfies all the requirements we consider. This constitutes the most complex formal analysis of a web application based on an expressive model of the web infrastructure so far. As another contribution, we identify and prove important security properties of generic web features in the extended web model to facilitate future analysis efforts of web standards and web applications.Comment: arXiv admin note: substantial text overlap with arXiv:1403.186

The Web SSO Standard OpenID Connect: In-Depth Formal Security Analysis and Security Guidelines

Web-based single sign-on (SSO) services such as Google Sign-In and Log In with Paypal are based on the OpenID Connect protocol. This protocol enables so-called relying parties to delegate user authentication to so-called identity providers. OpenID Connect is one of the newest and most widely deployed single sign-on protocols on the web. Despite its importance, it has not received much attention from security researchers so far, and in particular, has not undergone any rigorous security analysis. In this paper, we carry out the first in-depth security analysis of OpenID Connect. To this end, we use a comprehensive generic model of the web to develop a detailed formal model of OpenID Connect. Based on this model, we then precisely formalize and prove central security properties for OpenID Connect, including authentication, authorization, and session integrity properties. In our modeling of OpenID Connect, we employ security measures in order to avoid attacks on OpenID Connect that have been discovered previously and new attack variants that we document for the first time in this paper. Based on these security measures, we propose security guidelines for implementors of OpenID Connect. Our formal analysis demonstrates that these guidelines are in fact effective and sufficient.Comment: An abridged version appears in CSF 2017. Parts of this work extend the web model presented in arXiv:1411.7210, arXiv:1403.1866, arXiv:1508.01719, and arXiv:1601.0122

An Expressive Model for the Web Infrastructure: Definition and Application to the BrowserID SSO System

The web constitutes a complex infrastructure and as demonstrated by numerous attacks, rigorous analysis of standards and web applications is indispensable. Inspired by successful prior work, in particular the work by Akhawe et al. as well as Bansal et al., in this work we propose a formal model for the web infrastructure. While unlike prior works, which aim at automatic analysis, our model so far is not directly amenable to automation, it is much more comprehensive and accurate with respect to the standards and specifications. As such, it can serve as a solid basis for the analysis of a broad range of standards and applications. As a case study and another important contribution of our work, we use our model to carry out the first rigorous analysis of the BrowserID system (a.k.a. Mozilla Persona), a recently developed complex real-world single sign-on system that employs technologies such as AJAX, cross-document messaging, and HTML5 web storage. Our analysis revealed a number of very critical flaws that could not have been captured in prior models. We propose fixes for the flaws, formally state relevant security properties, and prove that the fixed system in a setting with a so-called secondary identity provider satisfies these security properties in our model. The fixes for the most critical flaws have already been adopted by Mozilla and our findings have been rewarded by the Mozilla Security Bug Bounty Program.Comment: An abridged version appears in S&P 201

The transition from linear to-parabolic growth of Cu3Si phase in Cu/a-Si system

K

Hillock formation of Pt thin films on Yttria stabilized Zirconia single crystals

The stability of a metal thin films on a dielectric substrate is conditioned by the magnitude of the interactive forces at the interface. In the case of a non-reactive interface and weak adhesion, the minimization of free surface energy gives rise to an instability of the thin film. In order to study these effects, Pt thin films with a thickness of 50 nm were deposited via ion-beam sputtering on yttria stabilized zirconia single crystals. All Pt films were subjected to heat treatments up to 973 K for 2 h. The morphological evolution of Pt thin films has been investigated by means of scanning electron microscopy (SEM), atomic force microscopy (AFM) and standard image analysis techniques. Three main observations have been made: i) the deposition method has a direct impact on the morphological evolution of the film during annealing. Instead of hole formation, that is typically observed as response to a thermal treatment, anisotropic pyramidal shaped hillocks are formed on top of the film. ii) It is shown by comparing the hillocks' aspect ratio with finite element method (FEM) simulations that the hillock formation can be assigned to a stress relaxation process inside the thin film. iii) By measuring the equilibrium shapes and the shape fluctuations of the formed Pt hillocks the anisotropy of the step free energy and its stiffness have been derived in addition to the anisotropic kink energy of the hillock's edges.Comment: 8 pages, 7 figure