PGM=KEYSTORE is a program that allows you to avoid storing your software key in your individual driver code or in individual pbfn.cfg files. The method for storing your software key differs based on whether you are running in a 31-bit mode or a 64-bit mode.
Note: Finalist Compatibility Interface users are required to use PGM=KEYSTORE. CICS and IMS transactions use the Compatibility Interface internally and therefore require the Finalist software key to be stored.