The system provides both electronic signature and message verification with a minimum of excess coding information on an instantaneous basis and is easily restartable in a store and forward environment. The system is based on the concept of a vault or central authority. The vault is in essence a physically secured Authenticator designed as a hardware automation which is not under control of any operating system. The system is a terminal based network wherein all terminals or users may communicate directly or through a central CPU. All secure electronic signature verification transactions must be transacted through the central facility which includes said vault. The vault and all terminals include an identical key-controlled block-cipher cryptographic facility wherein each user at a terminal has access only to his own key and wherein the vault has access to all user keys. At the end of a transaction, a user A (originator) and a user B (receiver) each have uniquely encrypted messages which can be utilized in later arbitration proceedings wherein user A cannot later deny having sent a message or its contents and similarly user B cannot deny having received the message or its specific content. The vault provides facilities for effective legal arbitration and is also simple to operate in such a n-to-n network without using more than one key per person.