def signing_input(payload, protected_binary = nil)
      if b64 == true or b64.nil?
        payload = JOSE.urlsafe_encode64(payload)
      end
      protected_binary ||= JOSE.urlsafe_encode64(to_binary)
      return [protected_binary, '.', payload].join
    end
def signing_input(payload, protected_binary = nil)
      if b64 == true or b64.nil?
        payload = JOSE.urlsafe_encode64(payload)
      end
      protected_binary ||= JOSE.urlsafe_encode64(to_binary)
      return [protected_binary, '.', payload].join
    end
Combines `payload` and `protected_binary` based on the `"b64"` setting on the `jws` for the signing input used by {JOSE::JWS.sign JOSE::JWS.sign}.
 @see JOSE::JWS.signing_input