+ - "RSA PRIV OP KEY EXP" feature flag means PMD support RSA private key
+ operation (Sign and Decrypt) using exponent key type only.
+
+ - "RSA PRIV OP KEY QT" feature flag means PMD support RSA private key
+ operation (Sign and Decrypt) using quintuple (crt) type key only.
+
+ - "Digest encrypted" feature flag means PMD support hash-cipher cases,
+ where generated digest is appended to and encrypted with the data.
+