An information processor includes a data processing portion which generates content for delivery to a client. The data processing portion generates and provides a sub-image in which identification information of a content delivery client is recorded in image data formed only of a partial area of image data and a main image in which the image signal of the sub-image area is deleted or substituted with a dummy signal to the client, generates management information in which the identification information recorded in the sub-image is associated with client information of the content provision destination, and records the management information in a storage portion.