Abstract: Methods and systems for applying a transaction digital watermark to content being downloaded over a content delivery network. The digital watermark carries information about the transaction pursuant to which the content was downloaded, which can be useful in establishing a “chain of custody” that facilitates piracy detection and/or other tracking and monitoring applications. Moreover, the digital watermark is applied by an edge caching server, which enables downstream entities in the content delivery chain, such as Internet service providers, to influence the information carried in the digital watermark and enables transaction details that become known after the content leaves the content provider network to be carried in the digital watermark, but without opening up a security hole at the end user premises.