Message guaranty system

Abstract

A message guaranty system for having a reliable third party (evidence preparing server) prepare evidence information attesting to the transmission and reception of a message by a transmitting and a receiving terminal. When the transmitting terminal furnishes the target message with evidence information before transmitting them to the destination, the system attests to the transmission and reception of that message once they are completed. When a message is to be sent illustratively from a workstation (WS) 1 to a workstation (WS) 2, the third-party evidence preparing server on the network first prepares transmission evidence based on a request from the WS 1 and sends it to the WS 1 . The WS 1 sends the message along with the evidence to the WS 2. The evidence preparing server then prepares reception evidence based on a request from an evidence verifying server (a third party) acting for the WS 2. The reception evidence thus prepared is retained by the evidence preparing server and is also returned to the evidence varying server. The evidence verifying server retains the reception evidence. When an application program on the WS 1 requests verification of the reception evidence, the evidence verifying means verifies the presence of the reception evidence and returns the result of the verification to the WS 1 .

What is claimed is:  
     
         1 . A message guaranty system connected with a plurality of terminals on a network, comprising: 
 message delivery means for delivering a message from a transmitting terminal to a receiving terminal;    evidence information preparing means for getting a third party to prepare evidence information attesting to the transmission and reception of said message; and    evidence information furnishing means for furnishing to said message said evidence information prepared by said evidence information preparing means.    
     
     
         2 . A message guaranty system according to  claim 1 , wherein said evidence information preparing means includes converting means for converting said evidence information into a format immune to intentional tampering.  
     
     
         3 . A message guaranty system according to  claim 1 , further comprising verifying means for verifying the authenticity of said evidence information when the verification thereof is requested.  
     
     
         4 . A message guaranty system according to  claim 1 , further comprising delayed message delivery means for delivering said message directly to said receiving terminal on behalf of said transmitting terminal when said transmitting terminal requests said delivering of said message.  
     
     
         5 . A message guaranty system according to any one of claims  1  through  3 , wherein said evidence information comprises the terminal name of said transmitting terminal, the terminal name of said receiving terminal, the time of transmission of said message, and the length of said message.