A method and system for generating a completed payment document ready for signature in image form. The document is signed by a customer and a copy of the signature is captured in digital form. Thereafter the signature is encrypted and saved along with a digital record of the transaction....http://www.google.com.hk/patents/US5297202?utm_source=gb-gplus-share專利 US5297202 - Apparatus and method for producing a digitized transaction record including an encrypted signature
