Privacy Type,Description,Registrant,Reference
user,"Request that privacy services           
provide a user-level privacy function",[Jon_Peterson],[RFC3323]
header,"Request that privacy services modify    
headers that cannot be set arbitrarily  
by the user (Contact/Via).",[Jon_Peterson],[RFC3323]
session,"Request that privacy services provide   
privacy for session media",[Jon_Peterson],[RFC3323]
none,"Privacy services must not perform any   
privacy function",[Jon_Peterson],[RFC3323]
critical,"Privacy service must perform the        
specified services or fail the request",[Jon_Peterson],[RFC3323]
id,"Privacy requsted for Third-Party        
Asserted Identity",[Cullen_Jennings],[RFC3325]
history,"Privacy requested for                   
History-Info header field(s)",[Mary_Barnes],[RFC7044]