US Patent 7178030 Electronically signing a document

A method of electronically signing a document includes initializing a user, including generating an asymmetric key pair including a private signing key and a public signing key, and storing the private signing key and the public signing key; and providing an electronic signature, including receiving document data corresponding to at least one selected portion of the document, binding the stored private signing key and the document data to create an electronic signature, and providing the electronic signature for a recipient.