Video sensor network is evolving from an isolated system to an integral component of the global information infrastructure. In this paper, we argue that when video sensor network becomes a public information source on the Internet, DRM (Digital Rights Management) must be enforced, due to the sensitivity and the privacy natures of sensor content. Moreover, existing DRM solutions do not suffice because the explicit one-to-one mapping between content producer and consumer does not apply in the sensor network domain. We propose a DRM-enabled content service architecture for video sensor network. Within this architecture, we propose a binary-tree-based hierarchical key generation scheme for data encryption, and adopt a label-guided watermarking strategy to address the unique challenges of video sensor content. We present the evaluation results of our solution based on a preliminary video sensor testbed system.