Is one who created a program that does not deal with usury sinful if his professor sold it to entities that deal with usury?

Studying and producing useful programs is a requirement for Muslims to specialize in, rather than relying on others. The questioner is urged to strive diligently in his studies to produce a beneficial and distinctive program. The fear that the program might be used by interest-based banks or sold to them should not be an impediment. A Muslim is not held accountable in Islamic law if his program is used for an unlawful benefit, as long as the program was not designed for such purposes and has no connection to them.