Abstract: A semi-fragile digital watermarking algorithm was proposed to verify the authenticity and integrity of image content. Firstly, the algorithm extracted the edge of the scaled image as the feature information, and the feature information was chaotically modulated and ciphered with the private key to generate watermark information. Secondly, the watermark information was embedded into the wavelet domain of the host image by using Human Visual System (HVS). Finally, a user could extract the feature information from the watermarked image with the public key, and compared it with the reconstructed feature information of the watermarked image to achieve authentication. The experimental results show that the proposed algorithm has the immunity to common image operation, and can also achieve accurate authentication and tampering localization to malicious processing.

Key words: semi-fragile watermarking, feature information, chaotic sequences, public key, Human Visual System (HVS)

摘要： 提出一种半脆弱数字水印算法，用于确认图像内容的真实性和完整性。算法首先将缩放图像的边缘作为特征信息，并对特征信息进行混沌调制和私钥加密得到水印信息；然后结合人类视觉系统将水印信息嵌入到载体图像的小波域中；最后用户利用公钥从水印图像中提取特征信息，并与重建的特征信息进行匹配来实现认证。实验结果表明：该算法对常规操作具有免疫性，对恶意处理能够实现准确认证和篡改定位。

关键词: 半脆弱水印, 特征信息, 混沌序列, 公钥, 人类视觉系统