Environment variables for the key storage files

These environment variables contain the name of the key storage files.

There is one environment variable for each type: AES, DES, PKA, and CMB.
CSUAESDS
AES key storage file.
CSUDESDS
DES key storage file.
CSUPKADS
PKA key storage file.
CSUCMBDS
CMB key storage file (combined key storage file).