Patent ID: 8321690

Claim:
A computer-implemented method with a client-receiver computer having a public/private key pair, and at least one server-transmitter computer having a public key of the client-receiver computer, the method comprising steps of: generating a root content key using the public key of the client-receiver computer; transmitting the root content key to the client-receiver computer, the root content key being decryptable using the client-receiver computer's private key and usable by the client-receiver computer to decrypt leaf content keys; dividing a single media file into multiple data segments, each data segment associated with a different digital rights management policy; encrypting each of the data segments with a respective leaf content key to provide encrypted data segments appending a descriptor to each of the encrypted data segments, each descriptor identifying the leaf content key with which the data segment was encrypted and the associated digital rights management policy; and transmitting the encrypted data segments and descriptors to the client-receiver computer.