Secure logging of transactions

摘要

A method of generating a secure transaction log recording transaction data established between a first 10 and a second 20 data processing device. The transaction log includes transaction data derived from the first device that is digitally signed by the second device, and then digitally re-signed by the first device, with copies being stored locally to both devices. Any interference with the data by either device, or during transfer of data between them is evident to both devices. The transaction data may include data received and signed by an independent third party as a trusted third party.