Robust Watermarking of Compressed JPEG Images in Encrypted Domain

Abstract

Digital media is often handled in a compressed and encrypted form in Digital Asset Management Systems (DAMS). Therefore, watermarking of these compressed encrypted media items in the compressedencrypted domain itself is required for copyright violation detection or other purposes. Compression process might compactly pack the raw data of the media and encryption would randomize the compressed data. Thus, embedding a watermark in such a compressed randomized data can cause a dramatic degradation of the media quality. Towards this, the encryption of the compressed media should be such that, it is both secure and will allow watermarking in a predictable manner in the compressed encrypted domain. Further, the encryption mechanism should be such that the bit rate overhead is considerably low as compared to the original compressed VLC codestream. In this paper, we propose a robust watermarking algorithm to watermark JPEG partially compressed and encrypted images, encrypted using a stream cipher. While the proposed technique embeds watermark in the partially compressed-encrypted domain, the extraction of watermark can be done in the encrypted, decrypted or decompressed domain.