modifying {HEAD ~ the directory manager file} by deleting {TAIL ~ a reference} to the target file, wherein the reference includes a target file encryption key; and 
by deleting
modifying { HEAD ~ the directory manager file } by deleting { TAIL ~ a reference } to the target file , wherein the reference includes a target file encryption key ; and
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH