Using the WSDK to Digitally Sign SOAP Messages

This sample application demonstrates how to authenticate users via username and password and digitally sign a SOAP message to ensure no tampering of the message occurred as it was sent to the Web Service. It includes a sample web.config file with the necessary WSDK entries, a sample class that implements the IPasswordProvider interface, a test proxy, and other code to show you this SOAP signing technique.

http://www.xmlforasp.net/codeSection.aspx?csID=82