Hmmmm ... well, in the docs is a link to an example at

http://samples.gotdotnet.com/quickstart/util/srcview.aspx?path=/quickstart/howto/samples/cryptography/fileencrypt/encrypt.src&file=CS\fileencrypt.cs&font=3

This is probably not exactly what you want (it's writing some encrypted text string to a file), but it should give you some idea of what you need to do.

~~Bonnie


>Yes .. I read it but I didnot find example for this? could you please provide me information where can I find complete example for this? many thanks
>
>Best Regards
>Winan