A message delivery system which can guarantee the authenticity of a user, the reliability of a message delivery, and the authenticity of the message delivery, while preventing an illegal act, and which can prove them at a later time. The system has an information provider terminal including a user authentication...http://www.google.com.au/patents/US6044463?utm_source=gb-gplus-sharePatent US6044463 - Method and system for message delivery utilizing zero knowledge interactive proof protocol
