Seeking the Source: Criminal Defendants’ Constitutional Right to Source Code

The right to a fair trial is fundamental to American jurisprudence. The Fifth Amendment of the Bill of Rights guarantees “due process,” while the Sixth provides the accused with the right to be “confronted with the witnesses against him.” But “time works changes, brings into existence new conditions and purposes.” So it is with software. From the smartphones we access multiple times a day to more exotic tools—the software “genies” of Amazon Echo and Google Home—software is increasingly embedded in day-to-day life. It does glorious things, such as flying planes and creating CAT scans, but it also has problems: software errors. Software has also found its way into trials. Software’s errors have meant that defendants are often denied their fundamental rights. In this paper, we focus on “evidentiary software”—computer software used for producing evidence—that is routinely introduced in modern courtrooms. Whether from breathalyzers, computer forensic analysis, data taps, or even FitBits, computer code increasingly provides crucial trial evidence. Yet despite the central role software plays in convictions, computer code is often unavailable to examination by the defense. This may be for proprietary reasons—the vendor wishes to protect its confidential software—or it may result from a decision by the government to withhold the code for security reasons. Because computer software is far from infallible—software programs can create incorrect information, erase details, vary data depending on when and how they are accessed—or fail in a myriad of other ways—the only way that the accused can properly and fully defend himself is to have an ability to access the software that produced the evidence. Yet often the defendants are denied such critical access. In this paper, we do an in-depth examination of the problem. Then, providing a variety of examples of software failure and discussing the limitations of technologists’ ability to prove software programs correct, we suggest potential processes for disclosing software that enable fair trials while nonetheless prevent wide release of the code.