A DRM scheme that may be optionally invoked by the owner. With the DRM
protection turned on, the media is encrypted before it is distributed in
a P2P network, and is decrypted prior to its use (play back). The peers
may still efficiently distribute and serve without authorization from the
owner. Nevertheless, when the media is used (played back), the client
node must seek proper authorization from the owner. The invention further
provides a hierarchical DRM scheme wherein each packet of the media is
associated with a different protection level. In the hierarchical DRM
scheme of the invention there is usually an order of the protection
level. As a result, in one embodiment of the invention, the decryption
key of a lower protection layer is the hash of the decryption key at the
higher protection level. That way, a user granted access to the high
protection layer may simply hold a single license of that layer, and
obtain decryption keys of that layer and below. The invention further
provides for a process for managing digital rights to a scalable media
file wherein a different encryption/decryption key is used to encrypt
each truncatable media packet with a base layer without requiring
additional storage space to store the key.