Quantitative Information Flow as Safety and Liveness Hyperproperties

We employ Clarkson and Schneider's "hyperproperties" to classify various verification problems of quantitative information flow. The results of this paper unify and extend the previous results on the hardness of checking and inferring quantitative information flow. In particular, we identify a subclass of liveness hyperproperties, which we call "k-observable hyperproperties", that can be checked relative to a reachability oracle via self composition.Comment: In Proceedings QAPL 2012, arXiv:1207.055

Transformational typing and unification for automatically correcting insecure programs

Before starting a rigorous security analysis of a given software system, the most likely outcome is often already clear, namely that the system is not entirely secure. Modifying a program such that it passes the analysis is a difficult problem and usually left entirely to the programmer. In this article, we show that and how unification can be used to compute such program transformations. This opens a new perspective on the problem of correcting insecure programs. We also demonstrate that integrating our approach into an existing transforming type system can improve the precision of the analysis and the quality of the resulting program

Metallocene o-Phenylenebis(phenylphosphido) Chelates of Molybdenum and Tungsten

The reaction of the metallocene dichlorides Cp2MCl2 (Cp = η5-C5H5; M = Mo, W) with equimolar amounts of dilithium-o-phenylenebis(phenylphosphide) 1,2-(LiPPh)2C6H4 yields the five-membered chelate complexes Cp2M[1,2-(PPh)2C6H4] (M = Mo. 1; W, 2). Compounds 1 and 2 are characterized by IR, NMR and mass spectra

Molecular and Crystal Structure of l,r-Dimethylsilylene Titanocene Dichloride, (CH3)2Si(C5H4)2TiCl2

The molecular structure of the bridged [1]-titanocenophane 1,1'-dimethylsilylene titanocene dichloride, (CH3)2Si(C5H4)2TiCl2, has been investigated by an X-ray structure determination. Crystal data: monoclinic, space group C2/c, Z = 4, a = 1332.9(3), 6 = 988.7(3), c = 1068.9(3) pm, β = 113.43(2)°. The results are compared with the structural dimensions of similar compounds: 1,1'-methylene titanocene dichloride, CH2(C5H4)TiCl2, with the unbridged titanocene dichloride, (C5H5)2TiCl2 and the ethylene-bridged compound (CH2)2(C5H4)2TiCl2