Patent ID: 8086535

Claim:
A method for authorizing a copy of a digital content unit to a first user's device without downloading the copy from a digital content store, the method comprising: obtaining, by the digital content store, information related to an encrypted copy of the digital content unit associated with a second user, the encrypted copy of the digital content unit encrypted with a first encrypt key associated with the second user and having a first set of permissions permitting access to a first portion of the digital content unit; storing, by the digital content store, the first encrypt key; providing, from the digital content store, a right to obtain a legitimate copy of the digital content unit and a second set of permissions permitting access to a second portion of the digital content unit, wherein the first set of permissions and the second set of permissions differ; and generating, by the digital content store, the legitimate copy of the digital content unit from the encrypted copy of the digital content unit, wherein generating the legitimate copy of the digital content unit comprises: decrypting by the digital content store the encrypted copy of the digital content unit using the first encrypt key to generate a decrypted copy of the digital content unit; and encrypting by the digital content store the decrypted copy of the digital content unit with a second encrypt key associated with the first user; and storing, by the digital content store, the second encrypt key providing a first decrypt key associated with the second user to a first user's device for generating the decrypted copy of the digital content unit; wherein the first decrypt key comprises a cryptographic hash of a header of the digital content unit and the first decrypt key associated with the second user's device.