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