On the copyright claim, the court noted that unlike patents, copyright protection cannot be applied to ideas, but only to particular, creative expressions of ideas. Distinguishing between an unprotectable idea and a protectable creative expression is difficult in the context of computer programs; even though it may be possible to express the same idea in many different programs, "practical realities"—hardware and software constraints, design standards, industry practices, etc.—may make different expressions impractical. "Lock-out" codes—codes that must be performed in a certain way in order to bypass a security system—are generally considered functional rather than creative, and thus unprotectable.