Why sign my xap?

Why should I sign my XAP? Is their any advantages to t开发者_运维知识库he average silverlight user?

does it offer me any tamper protection on my XAP? If I use a bootstrapper to chain download my xaps and someone changes one of the xaps, will it help?

First of all it insures your users that this application is developed by you. Secondary you're not allowed to update the XAP file automatically if running OOB with elevated trust unless the XAP file is signed.

You basically need it if you want to have an elevated trust application. if you don't then signing isn't all that important.

See John Papa's articles on this topic:

1. http://channel9.msdn.com/learn/courses/Silverlight4/Overview/Overview/Moving-Beyond-the-Browser--Elevated-Trust-Applications/
2. http://johnpapa.net/silverlight/digitally-signing-a-xap-silverlight/