Commercial digital music is typically distributed in the music source market via Digital Rights Management systems (DRM). DRM systems help remotely control the music contents. The Open Mobile Alliance (OMA) DRM became the de facto standard after major market adoption because of its support for a wide variety of different business and usage models. In OMA DRM, a popular business model is a (monthly) subscription enforced by controlling the period of playback time; once the given period of time expires, the music cannot be played. In this paper, we demonstrate how to bypass the integrity checking of the rights object in the OMA DRM system through a case study of MelOn (a well-known music distribution service in South Korea) by reverse engineering its media player equipped with a DRM agent. Categories and Subject Descriptors K.6.5 [Management of Computing and Information]: Security and Protection—Digital Rights Management; D.2.7 [Software Engineering]: Distribution and debugging—Rest...