Patent ID: 8769705

Claim:
A secure content publishing method implemented by a content provider coupled to a cloud service, comprising: encrypting a content object using a data encryption key to obtain an encrypted content object; re-encrypting the encrypted content object using a secret key to obtain a dual-encrypted content object; publishing the dual-encrypted content object to the cloud service to obtain a published content object; distributing a group decryption key for decrypting the published content object to a plurality of users in a group via a content delivery network (CDN); distributing an updated group decryption key for the users in the group when a user joins, leaves, or is revoked from the group; and forwarding an updated re-encryption key to the cloud service for re-encrypting the published content object, wherein the published content object is stored in the cloud service and comprises a first component that depends on a random secret and a secret key, a second component that depends on the random secret and a data encryption key, and a third component that depends on the random secret and the content object, and wherein the first component and the second component is smaller in data size than the third component.