HMAC operations are performed in software.

If the FIRST rule is used to start a series of chained calls:

• The key used to initiate the chained calls must not be deleted until the chained calls are complete.
• The application should make a LAST call to free ICSF resources allocated. If processing is to be aborted without making a LAST call and the chain_data parameter indicates that a cryptographic state object has been allocated, the caller must free the object by calling CSFPTRD (or CSFPTRD6 for 64-bit callers) passing the state object's handle.