1. Introduction

The Internet Open Trading Protocol (IOTP) provides a payment system independent interoperable framework for Internet commerce as documented in [RFC2801]. All IOTP messages are XML documents. XML, the Extensible Markup Language [XML], is a syntactical standard promulgated by the World Wide Web Consortium. XML is intended primarily for structuring data exchanged and served over the World Wide Web.

Although IOTP assumes that any payment system used with it provides its own security, there are numerous cases where IOTP requires authentication and integrity services for portions of the XML messages it specifies.