PEID: A Perceptually Encrypted Image Database for Visual Security Evaluation

Perceptual image encryption provides an efficient and effective way to preserve the confidentiality of visual information, and the measurement of content leakage is of fundamental importance for perceptually encrypted images. Numerous visual security indexes (VSIs) have been proposed to evaluate visual content leakage. Due to the lack of perceptually encrypted image databases, image quality assessment (IQA) databases are widely adopted to evaluate the performance of existing VSIs. However, there are huge differences between VSIs and IQAs. The misuse of databases may lead to an inaccurate evaluation. In this paper, we propose a perceptually encrypted image database (PEID) which contains 1080 encrypted images from 20 plain images with 10 well-known perceptual encryption techniques. Both visual quality and content leakage scores of the encrypted images are obtained through a comprehensive subjective evaluation. We also propose a systemic methodology to accurately evaluate the monotonicity, fitness, and accuracy of VSIs. We conduct extensive experiments on the proposed PEID to evaluate the performance of existing state-of-the-art VSIs. We have made the database publicly available for download and hope that the proposed PEID can facilitate the research of visual security evaluation and beyond.