A first party (e.g. educational testing service) provides through the internet to a control server information (e.g. test server) relating to a second party (e.g. a student taking tests prepared by the service). The server provides and may store a verification (e.g. an encrypted digital signature) of,...http://www.google.de/patents/US20060112165?utm_source=gb-gplus-sharePatent US20060112165 - System and method for verifying delivery and integrity of electronic messages
