libvirt/tests/qemublocktestdata/xml2json/file-qcow2-backing-chain-encryption.xml

<disk type='file' device='disk'>
  <driver name='qemu' type='qcow2'/>
  <source file='/var/lib/libvirt/images/a'>
    <encryption format='luks'>
      <secret type='passphrase' uuid='0a81f5b2-8403-7b23-c8d6-21ccc2f80d6f'/>
    </encryption>
    <privateData>
      <nodenames>
        <nodename type='storage' name='node-a-s'/>
        <nodename type='format' name='node-b-f'/>
      </nodenames>
    </privateData>
  </source>
  <backingStore type='file' index='1'>
    <format type='qcow2'/>
    <source file='/var/lib/libvirt/images/b'>
      <privateData>
        <nodenames>
          <nodename type='storage' name='node-b-s'/>
          <nodename type='format' name='node-b-f'/>
        </nodenames>
      </privateData>
      <encryption format='luks'>
        <secret type='passphrase' uuid='0a81f5b2-8403-7b23-c8d6-21ccc2f80d6f'/>
      </encryption>
    </source>
    <backingStore/>
  </backingStore>
  <target dev='vda' bus='virtio'/>
  <alias name='virtio-disk0'/>
</disk>