The layers may be encrypted using {TAIL ~ a separate key} for each layer, and rights to a key granted by {HEAD ~ permission} 
The layers may be encrypted using { TAIL ~ a separate key } for each layer , and rights to a key granted by { HEAD ~ permission }
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD