Establishing secure encrypted link between linked servers

Hi everyone - hoping someone can help me.

I am wanting to send data from our local sql server residing within the
corporate intranet, across to a remote sql server. I have set them up
as linked servers using both the sp_addlinkedserver and
sp_addlinkedsrvlogin stored procedures. All works.. but...

What I would like to establish is the security of the session. How
secure are the login/password credentials as expressed via the
sp_addlinkedsrvlogin stored proc? Are these credentials being sent as
clear text across to the internet sql server? What about the parameters
i am passing in my user stored procedures? Are they being delivered as
clear text?

I would like to have all encrypted somehow.

Would anyone have any suggestions?

Any help most appreciated!

cheers,
peter