Digital watermarking is an essential technique for copyright protection and content authentication in the digital era. This paper explores the use of SHA-256 (Secure Hash Algorithm-256) as a robust and efficient method for watermark embedding and extraction. SHA-256, a cryptographic hash function, provides a high level of security and integrity for watermarking applications. We discuss the principles of watermarking and present an algorithm for SHA-256-based watermark embedding and extraction. Experimental results demonstrate the effectiveness and resilience of the proposed method against common attacks, making it suitable for a wide range of digital media, including images, audio, and video