US Patent 8171564 Systems and methods for one-to-many secure video encryption

A video encryption/decryption scheme is provided allowing an originator of video content to encrypt the video content using a session key, wherein the encrypted content and an encrypted form of the session key are provided to a destination. The session key is encrypted using a long term key value, and the long term key value itself is encrypted using shared secret information that is only stored in the main memory of the originator and destination's systems. The long term key is encrypted, typically by a third party, and provided to the originator and destination systems for encrypting/decrypting the session key. The third party also provides a pass phrase file, which the originator and destination systems can use as input with shared secret information to a certain cryptographic hashing algorithm to encrypt/decrypt the long term key.