At operation 2004 the reader retrieves a signing authority {HEAD ~ public key} , also known as a master public key, from {TAIL ~ a signing authority} 
from
At operation 2004 the reader retrieves a signing authority { HEAD ~ public key } , also known as a master public key , from { TAIL ~ a signing authority }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL