Abstract: A digital signature system includes a data receiver for receiving an electronic document over a network; an encryption key database, and a signature processor in communication with the encryption key database and the data receiver. The encryption key database includes encryption key records, each being associated with a subscriber of the database and identifying an encryption key uniquely associated with the subscriber. The signature processor is configured for receiving an indicator of one of the subscribers and for deriving a digital signature from the received electronic data and the encryption key associated with the one subscriber. Upon receipt of electronic data and an indicator of one of the database subscribers, the digital signature system derives a digital signature from the received electronic data and the encryption key associated with the one database subscriber.