US Patent 7663789 Method of printing security documents

A method of providing a security document having a security feature includes creating the security document and determining an identity associated with the security document. The identity is then used to generate a digital signature of at least part of the identity. Coded data is generated including a number of coded data portions, each of which is indicative of the identity of the security document and, at least part of the signature. The coded data is then printed on the security document.