Digital watermarking is a promising technology to embed information as unperceivable signáis in digital contents. Various watermarking techniques have been proposed to protect copyrights of multimedia digital contents over Internet trading so that ownership of the contents can be determined in subsequent copyrights disputes. However, their applications in preventing unauthorized distribution of intelligence document have not been studied. In this paper, we propose a watermark-based document distribution protocol, which complements conventional cryptography-based access control schemes, to address the problem of tracing unauthorized distribution of sensitive intelligence documents. The reinforcement of document distribution policies requires a concrete support of non-repudiation in the distribution process. The distribution protocol is adapted from our previous work on the watermarking infrastructure for enterprise document management. It makes use of intelligence user certificates to embed the identity of the users into the intelligence documents to whom are distributed. In particular, keeping the identity secrecy between document providers and users (but yet traceable upon disputes) is a key contribution of this protocol in order to support for intelligence applications. We also outline an implementation of the distribution protocol and watermarking scheme employed.