Security Flaws in Several Group Signatures Proposed by Popescu

In resent years, Popescu proposed several group signature schemes based on the Okamoto-Shiraishi assumption in [8-11], and claimed his schemes are secure. However, this paper demonstrates that all these schemes are insecure by identifying some security flaws. Exploiting these flaws, an attacker without any secret can mount universally forging attacks. That is, anybody (not necessarily a group member) can forge valid group signatures on arbitrary messages of his/her choice

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

a practical alternative to domain and type enforcement integrity formal models

Chinese Acad Sci, State Key Lab Informat Secur, Inst Software, Chinese Acad Sci, CAS, Grad Univ, Natl Nat Sci Fdn ChinaMuch secure system policy development uses the DTE (Domain and Type Enforcement) model, but the DTE model cannot explicitly provide the security goals of the policy. The invariants of the only based-DTE integrity protection formal model are t

a dynamic information flow model of secure systems

ACM Special Interest Group on Security, Audit, and ControlWe characterize the information flow features of an information system in a state machine model, which emphasizes on the subject properties of information flows. We ague that the legality of a flow mainly depends on the subjects exploit it rather than th

design of secure operating systems with high security levels

综述了国内外指示植物法、电镜技术、血清学法、分子生物学等方法检测核果类果树病毒的进展,提出了国内核果类果树病毒的研究方向

information and communications security: preface

National Natural Science Foundation of China (NNSFC); The Microsoft Corporation; Beijing Tip Technology Corporation; Trusted Computing Group (TCG

Security Flaws in Several Group Signatures Proposed by Popescu. Cryptology ePrint archive, report 2003/207

Abstract. In resent years, Popescu proposed several group signature schemes based on the Okamoto-Shiraishi assumption in [8–11], and claimed his schemes are secure. However, this paper demonstrates that these schemes are all insecure by identifying some security flaws. Exploiting these flaws, an attacker without any secret can mount universally forging attacks. That is, anybody (not necessarily a group member) can forge valid group signatures on arbitrary messages of his/her choice

design of a micro-kernel based secure system architecture

We describe the Trium secure system architecture. It is based on Fiasco - an implementation of the L4 microkernel interface - and LAEnv - a programming environment for 1.4 systems. Compared to previous work on microkernel based secure systems