Methods and devices provide for creating, managing, modifying, and/or enforcing flexible digital rights management license policies for protecting games, media, data, or other software with a time-based license. Embodiments are especially directed toward situations in which a source of time is unavailable, untrustworthy, or unreliable. Licenses are defined by a small number of parameters. Parameter values may be defined by and included with protected content or applications. The parameter values may be chosen to define and enforce a desired level of compromise between usability and security characteristics.