It is increasingly important for applications to protect the privacy and security of data. Unfortunately, it is often non-trivial for programmers to enforce privacy policies. We have developed Jeeves to make it easier for programmers to enforce information flow policies: policies that describe who can see what information flows through a program. Jeeves allows the programmer to write policy-agnostic programs, separately implementing policies on sensitive values from other functionality.
To implement programs adhering to information flow policies in state-of-the art systems, programmers must write checks and filters across the program. Jeeves is the first language that aims to factor these checks and filters out of the program, allowing the programmer to write them once alongside the program. While there exist approaches for checking that programs do not leak information, they do not automatically manage these policy checks. To use an analogy to memory management, the other approaches do something like what valgrind does for finding memory leaks, while Jeeves is the equivalent of a memory-managed language, but for information flow policies.
Just like Wooster's clever valet Jeeves in Wodehouse's stories, the Jeeves runtime does the hard work, automatically enforcing the policies to show the appropriate output to each viewer. We have implementations of Jeeves as embedded domain-specific languages in Scala, Python, and Haskell. We are looking at using Jeeves for web frameworks and other applications. Try it out!