A content security protection scheme in JPEG compressed domain

• The proposed scheme integrates encryption and digital fingerprinting.
• The scheme is implemented in JPEG compressed domain with no need for decompression.
• The cipher-image is kept format-compliant.
• A single encrypted copy of the media content is distributed for different users.
• Users who decrypt the data with different keys obtains unique fingerprinted copies.

The access and distribution convenience of public networks opens a considerable content security threat when sending, receiving, and using multimedia information. In this paper, a content security protection scheme that integrates encryption and digital fingerprinting is proposed to provide comprehensive security protection for multimedia information during its transmission and usage. In contrast to other schemes, this method is implemented in the JPEG compressed domain with no transcoding or decompression, therefore, this scheme is highly efficient and suitable for multimedia information, which is seldom available in an uncompressed form. In addition, a variable modular encryption method is proposed to solve the invalid variable length coding (VLC) problem when a compressed data stream is encrypted directly. Experimental results demonstrate improved security and the efficiency provided by the proposed scheme. The experiments also demonstrate imperceptibility and collusion resistance of fingerprints.