Patent ID: 7356711

Claim:
A method of secure communication between first and second network servers on a data communication network, said method comprising: receiving a request from a user of a client computer for a selected service to be provided by the second network server, said request being received at the second network server via a browser of the client computer, said client computer and said second network server being coupled to the data communication network; initiating a transaction between the second network server and the first network server in response to the request, said first network server also being coupled to the data communication network; said second network server: defining a data structure associated with the transaction; generating a digital signature of the data structure; adding the digital signature to the data structure; generating an index associated with the transaction, wherein the index corresponds to a value generated as a function of data associated with the transaction, the first network server, and the second network server, said value being unique to the transaction and to the first network server and to the second network server; adding the index to the data structure; and directing the client computer from the second network server to the first network server with the data structure and the added digital signature, wherein the first network server stores one or more indices from previous transactions in a memory area, and wherein the first network server compares the index in the data structure received from the client computer against the stored indices to prevent a replay attack.