A group of accused drunk drivers in Florida are demanding to see the source code for the breathalyzer software that fingered them for being over the limit. The prosecutors say that the software is a trade secret belonging to the company that sells the breathalyzer. It’s a fascinating problem: what’s more important, the trade secrets of a vendor or the constitutional right to due process, which surely includes the right to examine a machine used to determine one’s guilt? Does selling breathalyzer software for use in evidence in a court of law mean that you waive your right to keep the software’s workings a secret?
Ed Felten’s got a great editorial on this on Freedom-to-Tinker:
So this issue is not about open source, but about ensuring fairness for the accused. If they’re going to be accused based on what some machine says, then they ought to be allowed to challenge the accuracy of the machine. And they can’t do that unless they’re allowed to know how the machine works.
You might argue that the machine’s technical manuals convey enough information. Having read many manuals and examine the innards of many software systems, I’m skeptical of such claims. Often, knowing how the maker says a machine works is a poor substitute for knowing how it actually works. If a machine is flawed, it’s likely the maker will either (a) not know about the flaw or (b) be unwilling to admit it exists.