Storage and authentication of data transactions

摘要

By periodically creating, 20, a table including hash values of data files (e.g. e-mails) held at an audit location, and sending, 28, a hash of the table and/or a hashed encryption key (070, Fig 4A) for the files to a third party for publication, the invention affords the provision, protection and validation of audit trails relating to data generated by and communicated between nodes of a network; authentication of communicating parties; enforcement of proof of receipt of data communications; and the detection of compromised user identifiers. Should a dispute arise over the substance of an authenticated data item, it would be possible to prove the following features of the communication: the content of the message sent; the e-mail location to which the message was addressed; the fact that the message was despatched; the time and date of despatch; the fact that the message was received; the time and date it was received; the fact that the content of the message had not been changed since it was sent; the identity of the sender and the identity of the recipient.