New paper: Sanitizing sensitive data: how to get it right (or at least less wrong…)

Here’s the paper that I presented at Ada Europe this week in Vienna.

It deals with the tricky issue of how to erase or “sanitize” data in running software, so that it can’t be observed. Many coding standards and guidance documents for secure software say that we should do this for “sensitive” data such as the plaintext of passwords, cryptographic keys, and so on, but offer very little technical advice on how to do it properly. I had to implement this kind of thing for a recent development project and it turns out to be much harder to get right than you might think. The paper describes why it’s hard, what you can do about it.

Post conference note: the “further work” section proposes a special compiler switch that automatically erases local data before it goes out of scope. Recently, I have discovered that this has actually been implemented in LLVM by the team at Embecosm. See their blog entry here for details.  It doesn’t look like their work has been contributed upstream to the main LLVM sources yet.

Stop press: I was awarded “Best presentation” for my talk on this work.