Verify properties of mobile code

Summary form only given. Given a program and a specification, you may want to verify mechanically and efficiently that this program satisfies the specification. Software verification techniques typically involve theorem proving. If a formal specification is easily available, consumption of computational resources is a major issue. Meanwhile, we shall not overlook the psychological factors. Often, you need extra expertise to verify a program. Tools that can automatically verify programs are helpful. On the other hand, ubiquitous computing has made the correctness of a program both a security and a performance issue. If you run a piece of mobile code on your machine, you will expect that the code does not access storages unlawfully. To make sure bad things won't happen, performance is sacrificed. If programs are written in an intermediate language that is able to capture and verify properties mentioned above, your host machine will benefit from it. This paper focuses on providing a type-theoretic solution to the verification of mobile programs. One of our primary tools is index types. Index types are a form of non-traditional types. An index type system extends the type system of a language with indices and predicates on those indices. Index types can express properties of program. To type check a program annotated with index types, we often will call an external decision procedure. Another concept used is the proof-carrying code. One of the major advantages of proof-carrying code is that a lot of theorem proving is shifted offline. When we use proof-carrying code to verify a property, the time spent on verification is mainly on proof-checking, which is considerably cheaper than theorem proving.