Dreaded System.Security.SecurityException: Security Error... Silverlight and WCF REST

Recently I faced the dreaded System.Security.SecurityException: Security Error.. while developing the SL4 application consuming the WCF REST service. After a lot of trials fixed this dreaded issue. So thought of sharing my experince on SL4 consuming WCF REST service.

1) Ensure that crossdomain.xml and clientaccesspolicy.xml files are available in C:\Inetpub\wwwroot folder.

2) If you are using HTTPS, ensure the following;

• Ensure clientaccesspolicy.xml contains explicit <domain uri="https://*"></domain>
• Ensure only SSL access is enabled. The SL app and WCF REST service should not be accessible in HTTP mode.
• Ensure crossdomain.xml contains <site-control permitted-cross-domain-policies="master-only"/> <allow-access-from domain="*" />

Do IISRESET. Then you should be able to get rid of this dreaded error.