3. Header and Payload Formats
3. Header and Payload Formats
In the tables in this section, some cryptographic primitives and configuration attributes are marked as "UNSPECIFIED". These are items for which there are no known specifications and therefore interoperability is currently impossible. A future specification may describe their use, but until such specification is made, implementations SHOULD NOT attempt to use items marked as "UNSPECIFIED" in implementations that are meant to be interoperable.