Digital content is rendered on a device by transferring the content to the
device and obtaining a digital license corresponding to the content. A
sub-license corresponding to and based on the obtained license is
composed and transferred to the device, and the content is rendered on
the device only in accordance with the terms of the sub-license. The
content is encrypted and decryptable according to a content key, and the
sub-license includes the content key encrypted and decryptable according
to a secret. The sub-license also includes indexing information
identifying the secret to the device. The indexing information in the
sub-license is obtained to identify the secret, and the secret is
acquired based at least in part on the indexing information. The secret
is then applied to the encrypted content key to decrypt and obtain the
content key, and the obtained content key is applied to the encrypted
content to decrypt and obtain the content. To compose the sub-license and
also to render the content, the secret is derived by obtaining a device
identifier, acquiring a super-secret, and applying the obtained device
identifier and super-secret to a function to derive the secret.