With the rapid development of cloud computing, software applications are shifting onto cloud storage rather than remaining within local networks. Software distributions within the cloud are subject to security breaches, privacy abuses, and access control violations. In this paper, we identify an insider threat to access control which is not completely eliminated by the usual techniques of encryption, cryptographic hashes, and access-control labels. We address this threat using software watermarking. We evaluate our access-control scheme within the context of a Collaboration-oriented Architecture, as defined by The Jericho Forum.