PHP Base64 encode with salt string

How can I encode string using PHP Base64_encode function with passing some Salt String

I don't want others to hack my string. If some one is having little knowledge in php, he can easily hack if I directly encode string. Because this is the only function allow you to decode encoded content. As far as I know.

In the tutorials I see above function will accept only one parameter.

Any Help ?

You should use mcrypt php extension.