Partial or selective encryption is a well-known concept in multimedia security. It aims to achieve a level of security of multimedia encryption comparable to common encryption by encrypting only a relevant subset of the complete stream or file. The prime benefit of partial encryption is better performance due to fewer encryption operations. In addition, partially encrypted media data can often be parsed as well as unencrypted media if no header data is encrypted. The focus of partial encryption evaluation has almost always been the level of security that can be achieved. In this work, we discuss another aspect: when partial encryption of MP3 files is used in a DRM scenario, how many resources can be saved by it? As DRM usually is attacked by key sniffing or analogue recording, the security of the encryption itself is of lesser importance as long as it provides a sufficient hindrance to access the media data.
Martin Steinebach, Waldemar Berchtold, "MP3 Partial Encryption for DRM" in Proc. IS&T Int’l. Symp. on Electronic Imaging: Media Watermarking, Security, and Forensics, 2017, pp 28 - 35, https://doi.org/10.2352/ISSN.2470-1173.2017.7.MWSF-322