1. Entrust authority roaming server. http://www.entrust.com/pki/roaming/index.htm.
2. Higgins trust framework project home. http://www.eclipse.org/higgins/.
3. Introducing windows cardspace. http://msdn2.microsoft.com/en-us/library/aa480189.aspx.
4. Liberty allicance project. http://www.projectliberty.org/.
5. Verisign roaming. http://www.verisign.com/products-services/security-services/pki/pkisecurity/ wireless-roaming/index.html.