In the past, several deenitions of information ow based upon process algebras have been presented. Unfortunately, these appear to have all been either too weak|failing to identify certain subtle forms of information ow|or too strong|indicating information ow when there is none. In this paper, we produce a deenition that aims to overcome these shortcomings. We base our deenition upon an operatio...

Consider a tree network T , where each edge acts as an independent copy of a given channel M , and information is propagated from the root. For which T and M does the configuration obtained at level n of T typically contain significant information on the root variable? This problem arose independently in biology, information theory and statistical physics. • For all b, we construct a channel fo...

We present an information flow monitoring mechanism for sequential programs. The monitor executes a program on standard data that are tagged with labels indicating their security level. We formalize the monitoring mechanism as a big-step operational semantics that integrates a static information flow analysis to gather information flow properties of non-executed branches of the program. Using t...

Along with our colleagues at the Oregon Graduate Institute and Georgia Institute of Technology, we have recently been experimenting with real-rate systems, that is, systems that are required to move data from one place to another at defined rates, such as 30 items per second. Audio conferencing or streaming video systems are typical: they are required to deliver video or audio frames from a sou...

There are a variety of mobile technologies currently available that have increased the potential for healthcare practitioners to access clinical decision support resources delivered over an array of mobile devices as a component of clinical workflow. Mobile devices ranging from smartphones to iPads, to netbooks are frequently used by clinical practitioners to gain access to vital patient and op...

Information flow modeling describes how information can be transferred between different locations within a software and/or hardware system. In this chapter, we define a notion of information flow based on traces that is useful for describing flow relations for synchronous dataflow languages such as Simulink [11] and SCADETM [4] that are often used for hardware/software co-design. We then defin...

We present a method to support the gradual evolution of secure scripts by formalizing an extension of the simply-typed lambda calculus that provides information flow constructs. These constructs allow initially insecure programs to evolve via targeted refactoring and to provide dynamic information flow guarantees via casts, as well as static information flow guarantees via labeled types.