One or both key labels may be specified. If only one key label is specified, specification of either KEYLABL1 or KEYLABL2 is allowed; it does not have to be specified as KEYLABL1.

If only one key label and encoding mechanism is specified, the same key label and encoding mechanism is used for both key label and encoding parameters.

If no key label is specified, either through the DD statement or through data class, externally specified key manager defaults will be used.