Chapter 12. Encryption 607
Placement of hardware encryption and software encryption in the Storwize code stack are 
shown in Figure 12-4. The functions that are implemented in software are shown in blue. The 
external storage system is shown in yellow. The hardware encryption on the SAS chip is 
marked in pink. As compression is performed before encryption, it is possible to get benefits 
of compression for the encrypted data.
Figure 12-4   Encryption placement in the IBM Spectrum Virtualize software stack
Each volume copy can use different encryption methods (hardware and software). It is also 
allowed to have volume copies with different encryption status (encrypted versus 
unencrypted). The encryption method depends only on the pool that is used for the specific 
copy. You can migrate data between different encryption methods by using volume migration 
or volume mirroring.
12.2.3  Encryption keys
Hardware and software encryption use the same encryption key infrastructure. The only 
difference is the object that is encrypted by using the keys. The following objects can be 
encrypted:
/SM590000Pools (software encryption)
/SM590000Child pools (software encryption)
/SM590000Arrays (hardware encryption)