The goal of the grid computing paradigm is to make computer power as easy to access as an electrical power grid. Unlike the power grid, the computer grid uses remote resources located at a service provider. Malicious users can abuse the provided resources, which not only affects their own systems but also those of the provider and others. As a consequence, most commercial customers are not convinced that their intellectual property in the form of software and data is protected in the grid. This book proposes a novel infrastructural security solution that advances the concept of virtualized grid computing. This includes the description of a software that transforms a traditional grid into a virtualized grid including security measures like a grid demilitarized zone, dynamic firewalls and several solutions to protect the grid node itself.