base64Encode
Description: Returns a Base64 encoded string. This is useful for being able to transfer binary data as ascii.
Subject Type: String
Arguments: No arguments
Return Type: String
Examples: We can Base64-Encoded an attribute named "payload" by using the Expression ${payload:base64Encode()}
If the attribute payload had a value of "admin:admin" then the Expression ${payload:base64Encode()}
will return "YWRtaW46YWRtaW4=".