Sending encrypted to the client and vice versa?

Question

Hi. I'm just wondering how I could accomplish an encrypted connection between the server and client when sending data via for instance ado.net or whatever. How would you say I encrypt it, and how would I then send the encrypted string and decrypt it at the server or client? I mean, anyone can decrypt base64, rot13 etc, so should one come up with an own encryption algoritm or what? Thanks alot. - Tobias, student.