A Novel High-Capacity Reversible Data Hiding Scheme for Encrypted JPEG Bitstreams

As cloud storage becomes more common, concerns about the invasion of privacy are increasing. When images are stored in an encrypted form in the public cloud, reversible data hiding in the encrypted domain can be applied to embed additional data within the encrypted images for ease of management. Most existing works focus on uncompressed images and are not applicable to JPEG images, which are widely used throughout the Internet. Therefore, in this paper, a novel reversible data hiding scheme for encrypted JPEG bitstreams is proposed. First, an effective method of bitstream-based JPEG image encryption is employed to encrypt plaintext JPEG images. Then, we present a reversible data hiding technique for encrypted JPEG images based on invariant zero-run length in the zero-run value pairs. In the cloud, additional data, such as labels, timestamps, origins, and authentication messages, are directly embedded into the encrypted JPEG images with our proposed data hiding technique. From the marked encrypted JPEG images, the extraction of the hidden data and the recovery of the original images can be done independently. Extensive experiments performed on several typical images and three well-known image databases show that the proposed scheme can achieve much higher embedding capacity than that of most recent schemes, and the file sizes of the marked encrypted JPEG images are well preserved compared to those of the related methods. In addition, we provide further analysis to show that the proposed scheme has good format compatibility and low computational complexity.