Abstract: A scheme for content extraction signature with support for verifiable modification is proposed to address the problems of unverifiable modification of signed data, data leakage and lack of user control over personal privacy information. The data can still be verified after the data owner hides part of the information in the absence of interaction, and solves the problem that traditional extracted signatures can be verified by any third party. The algorithm was implemented based on the discrete logarithm problem on elliptic curves, uploading part of the digest value to the blockchain, outlawing bilinear pair operations, improving signature efficiency, and demonstrating that the algorithm satisfies unforgeability. The security analysis and performance analysis show that the scheme has significant advantages in terms of data security, privacy protection and algorithmic efficiency.