Why is this important for the criminal defense lawyer? Closed-source software (source code) is used to convict our clients, but it may contain bugs or programing errors. Sadly, most criminal defense attorneys have no idea what source code is in the first place. Eaves dropping equipment, wire tapping, radar guns, tasers, breath testing machines, and everything else electronic runs on software. How can you rely on the accuracy of such equipment without looking at the instructions that drive the hardware?
Closed-source software is generally considered proprietary and a trade secret of the company that created it. Closed source software (e.g. Microsoft Windows and Office) is developed by a single person or company. Only the final product run on your computer is made available, while the source code for making the software is kept a secret. Open-source software (e.g. Linux and Open Office), on the other hand, is available by all to read. The software code for those projects is scrutinized by more people than even the biggest software company can hire. Software flaws are more easily discovered and repaired. Most open-source projects allow anyone to contribute and problems are normally resolved quickly and cleanly.
Look here for discussion of source-code issues in DWI cases. Look here for the 2005 Florida case where the makers of the Intoxilizer 5000 were ordered to turn over their closed-source code to defense lawyers.
A fascinating article by Curtis Poe discussed this closed-source software dilemma. Poe talked about a Minnesota man who won the right to examine the closed-source code of the breathtest machine used to accuse him. He demanded to see the source code in order to make sure the machine worked as advertised. Poe commented: "Closed-source software is allowed to take the witness stand and accuse you of crimes and you’re not allowed to cross-examine it." He stated further:
This is why I firmly believe that any software with substantial risk to harm your life or liberty must be open source. I’m not saying that it should be free or that manufacturers should not be allowed protections, but the protection of the people must come first. Certainly we could come up with schemes for various systems which might purport to thoroughly test them without opening up the code, but there are too many systems and too many parameters for us to do this safely on a case-by-case basis.We may never see open-source software running the devices used to accuse our clients. But criminal defense lawyers must go after the closed-source software that is. When confronted with any type of technical device used to prosecute our clients, everything from breath testing machines to traffic speed cameras, we should be demanding the code for inspection.