When I put a string YWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWE= (base64 for "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa") as a secret with unchecked checkbox, it will produce same result as I get from java library.
YWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWE=
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"