Two content protection schemes for digital items

Abstract

Modern techniques make digital articles easy to copy and manipulate. Content protection systems aim at protecting the rights of producers and distributors. These mostly rely on data encryption, digital watermarking, and special-purpose devices. In this paper, we describe two content protection schemes, both of which make use of tamper-resistant devices and devicer dependent decryption keys. One of the schemes uses a modified El Gamal system, in the other one we combine watermarking with encryption.