TR-31 key block header and optional block data

This section describes the format of the TR-31 key block header and the header values supported by CCA. It also describes the TR-31 optional blocks that can be used by CCA.

The use of TR-31 key blocks are described in Introduction to TR-31 symmetric key management. See ANSI X9.143-2022: Retail Financial Services Interoperable Secure Key Block Specification for the definition of a TR-31 key block (originally from the ASC X9 TR 31-2018: Interoperable Secure Key Exchange Block Specification).

Available CCA services for TR-31 symmetric-key management are described in TR-31 symmetric key management.