A hierarchical encryption scheme for secure distribution of predetermined content

摘要

A method is provided for distributing an electronic data set of predetermined content. The method includes partitioning the electronic data set into a plurality of files. The electronic data set has at least a first file which represents a version of the predetermined content. The plurality of files are differentially encrypted and distributed. The first encrypted file of the plurality of encrypted files is selected for decryption and the selected first encrypted file of the plurality of encrypted files is decrypted with a decryption key to recover the version of the predetermined content. The entire electronic data set is transmitted to a customer but only the decryption keys needed to decode a selected version are provided. Thus, the customer selects and pays for a version having desired qualities while encrypted data that may be used to recover all versions of the content. Higher quality versions of the content may be provided by transmitting only the keys needed to decode the higher quality versions in response the customer paying the appropriate fee. <IMAGE>