Utility-Enhanced Image Obfuscation With Block Differential Privacy

With the popularity of cloud servers, an increasing number of people utilize cloud platforms to manage their images. Images uploaded to the cloud are no longer directly controlled by the owner, which has raised concerns among users about privacy leakage. In response, some thumbnail-preserving encryption methods have been proposed to protect image privacy. However, since privacy lacks a clear definition, these methods face challenges in quantifying privacy, making it difficult for users to assess the effectiveness of privacy protection. To address this issue, we propose an image obfuscation method based on novel differential privacy mechanism, which provides provable privacy protection while preserving thumbnails. Additionally, our method can maintain the consistency of image distributions to enhance the utility of protected images. Extensive experimental results demonstrate that our method significantly outperforms existing work in terms of privacy and utility.