qemu-nbd connect an encrypted image - ?

[lejeczek]

    Hi guys
        
        I'm trying to connect to an encrypted image but my fiddling - as
        I never known this one - fails.
        Very bare cmd fails:
        
        -> $ qemu-nbd --connect=/dev/nbd0 /00-VMs/enc.ommie.qcow2 
        qemu-nbd: Failed to blk_new_open '/00-VMs/enc.ommie.qcow2':
        Parameter 'encrypt.key-secret' is required for cipher
        
        so I tried:
        -> $ qemu-nbd --connect=/dev/nbd0 /00-VMs/enc.ommie.qcow2
        --object
        encrypt.key-secret=bl........................................
        qemu-nbd: Parameter 'qom-type' is missing
        and so on I continued to no avail and soon gave up, in hope that
        some wizard has already a working cmd.
        
        many thanks, L.