A document is created and digitally signed using an author's private key. The signed document is provided to an electronic notary who notarizes (provides a time/date stamp and signs the time/date stamp using the notary's private key) the authors signed document. A reviewer requests and verifies the origin...http://www.google.es/patents/US6587945?utm_source=gb-gplus-sharePatente US6587945 - Transmitting reviews with digital signatures
