DECRYPTION KEY REUSE IN ANCRYPTED DIGITAL DATA STREAM DISTRIBUTION SYSTEMS

摘要

A data processing apparatus for a first encrypted digital datum in a digital data stream distributed in a distribution system. The apparatus includes a key extractor for obtaining a symmetric encryption key used to encrypt the first encrypted digital datum; a decryption system for creating a plaintext digital datum from the first encrypted digital datum using the symmetric encryption key; a processing system for operating on the plaintext digital datum to produce a modified plaintext digital datum; an encryption system for creating a second encrypted digital datum from the modified plaintext digital datum using the symmetric encryption key; and a transmitter for introducing the second encrypted digital datum into the digital data stream. ® KIPO & WIPO 2009