By expanding application of digital content in the world of information technology, supervision and control over the data, and also preventing the copy of documents is considered. In this relation digital rights management systems are responsible for the secure distribution of digital content, and for this purpose the common functions in the field of cryptography and utilize Digital watermarking have used. On the other hand, the key management is very important in digital rights management systems, and methods such as Digital watermarking methods are not effective in preventing copying files and digital documents. In this paper, we have proposed a model to improve the performance of digital rights management systems. This method is based on multi-part encryption and control on documents publication. The main distinction of this approach with other methods employed is using Obfuscation techniques to protect the key generation algorithm against reverse engineering.