However, for maximum security, it should run on a dedicated processor with a good firewall, such as Windows NT or Linux. All messages between servers can be sent over the public Internet because they are encrypted with the public key of the recipient. This is much cheaper than building a private network, and much more secure. Each party can be identified uniquely by a Digital Certificate, which is a public key signed by a trusted authority. Through encryption and digital identification, it makes the entire accounting system secure, private, robust and verifiable.
Every transaction is stored on at least two servers for redundance.
All transactions are structured as contracts between the parties involved. For example, if Mr. B wants to exchange some Microsoft PromoDollars for an Office Plug-In that Ms. A makes, he writes a contract between them and specifies the amount to be moved from his account at Microsoft to her account. Ms. A's Office Plug-In in return. All contracts are signed by the impacted parties using their Public Keys. This makes the contracts binding in many legal jurisdictions and hard to repudiate.