A Video On Demand (VOD) method consistent with certain embodiments involves processing content to be delivered in a VOD method by selecting first portions of the content for encryption under a selective encryption system and selecting second portions of the content to remain unencrypted. The first and...http://www.google.co.uk/patents/US7263187?utm_source=gb-gplus-sharePatent US7263187 - Batch mode session-based encryption of video on demand content
