Use the vxencrypt command to view the list of encrypted volumes.

# vxencrypt list
Disk group: mydg
        VOLUME       STATUS
        vol01         encrypted
        vol02         encrypted

Disk group: mydg1
        VOLUME       STATUS
        vol03         encrypted
        vol04         not encrypted

# vxencrypt -g mydg1 list
        VOLUME       STATUS
        vol03         encrypted
        vol04         not encrypted