Abstract: Various techniques have been employed till date to ensure the achievement of three basic needs of security: authenticity, integrity and confidentiality. With sharing of documents becoming a mundane phenomenon and the risk of copyright infringement becoming even more predominant with the easy availability of digital media, the need of better ways to ensure integrity and authentication was never more palpable. These growing issues led to the evolution of digital watermarking. In this paper the proposed algorithm generates a watermark which modifies the inter-word space based on the content of the document. The value being too small remains unnoticeable to the human eyes which increases the robustness. The watermark can be extracted to ensure the authenticity and the integrity of the document. The content of the document remains unchanged which ensures one of the advantages of this algorithm.