Patent ID: 7324648

Claim:
A method for secure key delivery for decrypting a distribution archive file containing a plurality of digital content documents at an unsecured site that receives a stream of distribution archive files from a publishing site, the method comprising: (a) at the publishing site, encrypting each digital content document with a key to generate encrypted document content; (b) at the publishing site, computing for each document a document identifier that is computed from, but cannot be derived solely from, the encrypted content of that document, wherein the document identifier is computed using a text string embedded in program code in the publishing site; (c) at the publishing site, creating a list of document identifier and decryption key pairs; (d) at the publishing site, assembling the encrypted document content for each content document and the key pair list into a distribution archive file; (e) at the publishing site, encrypting the distribution archive file with a scheduled key unique to that distribution archive file and placing the encrypted distribution file on the stream; (f) at the unsecured site, selecting a distribution archive file from the stream; (g) at the unsecured site, extracting a scheduled key from the selected distribution archive file in the stream; (h) at the unsecured site, using the extracted scheduled key to decrypt the next subsequent distribution archive file in the stream following the selected distribution archive file; (i) removing the encrypted document content and the key pair list from the decrypted distribution archive file and storing them at the unsecured site; (j) selecting the distribution archive file decrypted in step (h); and (k) repeating steps (g), (h), (i) and (j) for each distribution archive file in the stream.