Systems and methods are described to enable delivery of streaming content while inhibiting or preventing removal, blocking, or skipping of portions within that streaming content. A content delivery system can generate a manifest indicating content portions that form the streaming content. Each content portion can be identified in the manifest using a concealed identifier, which conceals the actual identifier of the content portion from the client to inhibit or prevent the client from automatically removing or modifying the content portion. On receiving a request for a content portion, the content delivery system can convert the concealed identifier into the actual identifier, and return the appropriate content portion to the client. In some instances, the specific identifiers included within a concealed manifest may be modified or adapted based on monitoring information of the client device, to ensure clients view given portions of streaming content.