With the advancement of information technology, counterfeit methods for paper documents have become increasingly sophisticated. Traditional anti-counterfeiting technologies suffer from issues such as ease of replication, difficulty in verification, and poor real-time performance, making them inadequate for modern security needs. This paper presents a novel anti-counterfeiting system for paper documents, leveraging digital signatures and image processing. By integrating digital certificates and USB Key technologies, the system provides an efficient and reliable solution. Anti-counterfeiting information is embedded into the document using grid encoding and SM2 digital signatures. Verification can be performed through a mobile phone app, making it both accessible and convenient. Experimental results demonstrate that the system achieves 96% verification accuracy, ensuring strong security and scalability for other document anti-counterfeiting applications.