Matching in security-by-contract for mobile code

We propose the notion of security-by-contract, a mobile contract that an application carries with itself. The key idea of the framework is that a digital signature should not just certify the origin of the code but rather bind together the code with a contract. We provide a description of the workflow for the deployment and execution of mobile code in the setting of security-by-contract, describe a structure for a contractual language and propose a number of algorithms for one of the key steps in the process, the contractpolicy matching issue. We also describe the prototype for matching policies with security claims of mobile applications that we have currently implemented. We argue that security-by-contract would provide a semantics for digital signatures on mobile code thus being a step in the transition from trusted code to trustworthy code.