"The field of software security analysis stands at a critical juncture.Applications have become too large for security experts to examine by hand,automated verification tools do not scale, and the risks of deploying insecure software are too great to tolerate anything less than mathematical proof.A radical shift of strategy is needed if programming and analysis techniques are to keep up in a networked world where increasing amounts of governmental and individual information are generated, manipulated, and accessed through web-based software applications.The basic tenet of this proposal is that the main roadblock to the security verification of a large program is not its size, but rather the lack of precise security specifications for the underlying libraries and security-critical application code. Since, large-scale software is often a collaborative effort, no single programmer knows all the design goals. Hence, this proposal advocates a collaborative specification and verification framework that helps teams of programmers write detailed security specifications incrementally and then verify that they are satisfied by the source program.The main scientific challenge is to develop new program verification techniques that can be applied collaboratively, incrementally, and modularly to application and library code written in mainstream programming languages. The validation of this approach will be through substantial case studies. Our aim is to produce the first verified open source cryptographic protocol library and the first web applications with formal proofs of security.The proposed project is bold and ambitious, but it is certainly feasible, and has the potential to change how software security is analyzed for years to come."