Surf'N'Sign: Client signatures on Web documents

The emergence of World Wide Web-based systems and Web transactions has led to the need to find a mechanism that provides electronic signature capabilities as a replacement for written signatures. Such a mechanism should guarantee authentication and nonrepudiation. Many Web applications could benefit greatly from such a mechanism, e.g., banking systems, tax filing, reservation systems, and corporate procedures. This paper discusses the various approaches that could be taken to provide such a mechanism and suggests a solution that provides client commitment on Web documents by means of digital signatures. The architecture and implementation of the solution, called Surf'N'Sign, is outlined in detail. Our design of the solution gives special consideration to the semantics of such a signature and to its proper and secure use on the Web. Its prototype was implemented at the IBM Haifa Research Laboratory as a plug-in to the Netscape Navigator browser and is integrated naturally into the browsing process. It provides a signing mechanism at the client, as well as the capability to archive and preview the signed documents. Surf'N'Sign lends itself to easy integration with existing applications on the Web.