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