silverlight and message encryption

If I did not want to use ssl and transport security does silverlight 4 sup开发者_运维知识库port message encryption or some sort of alternative?

Silverlight doesn't support message encryption because it doesn't provide (as of SL4, I haven't looked in SL5 beta) asymmetric crypto support. You can do some custom message security if you are willing to create your own channel (which is really, really hard to do, unfortunately) which uses some out-of-band shared key and use the symmetric crypto (which is available on SL).