Patent ID: 7487354

Claim:
In a network system that includes a server computer system and a client computer system, wherein the server computer system is capable of transmitting a document that contains Uniform Resource Locators (URLs) to the client computer system, a method of the server computer system dispatching the document to the client computer system in a manner that increases the security of one or more of the Uniform Resource Locators in the document even if the document is intercepted during transmission, the method comprising the following: a) obtaining a document that contains original URLs; b) calculating a digital signature that is unique to the client computer system or unique to a user of the client computer system, wherein at least a portion of the digital signature is generated using a hash function that receives as input at least a unique client identifier for the client computer system to which the document is to be dispatched and a secret key known to the server computer system and to the client computer system; c) for at least one of the original URLs, performing the following: i) including the digital signature in the original URL to modify the original URL; and ii) replacing the original URL in the document with the modified URL; and d) initiating the transfer of the document with the modified URLs to the client computer system.