Oracle: USER$

select
   usr.user#,
   case usr.type# when 0 then 'user' when 1 then 'role' else '?' end user_or_role,
   usr.name,
   usr.tempts#,
   usr.astatus,
   usr.audit$,
   usr.ctime,
   usr.datats#,
   usr.defgrp#,
   usr.defgrp_seq#,
   usr.defrole,           -- See also defrole$
   usr.defschclass,
   usr.exptime,
   usr.ext_username,
   usr.lcount,
   usr.ltime,
   usr.password,
   usr.ptime,
   usr.resource$,
   usr.spare1,            -- Used for schema level supplemental logging (see ktscts.h)
   usr.spare2,            -- Seems to be related to an edition id [ sys_context('userenv', 'current_edition_id') ]
   usr.spare3,            -- Schema level default collation
   usr.spare4,            -- Hashed values of passwords.
   usr.spare5,
   usr.spare6,            -- Last successful logon time
   usr.spare7,
   usr.spare8,
   usr.spare9,            -- Default local temporary tablespace
   usr.spare10,           -- Creation application ID
   usr.spare11
from
   SYS.user$ usr;

column digest_enabled format a3
column digest_value   format a32

select
   case when instr(spare4, 'H:') > 0 then 'Yes' else 'No' end digest_enabled
from
   sys.user$ where name ='RENE';
--
-- Dig
-- ---
-- No
--
   
alter user rene digest enable;  

select
   case when instr(spare4, 'H:') > 0 then 'Yes' end digest_enabled,
   regexp_replace(spare4, '.*H:(.{32}).*', '\1')    digest_value
from
   sys.user$ where name ='RENE';
--
-- DIG DIGEST_VALUE                    
-- --- --------------------------------
-- Yes 00000000000000000000000000000000   
   
alter user rene identified by rene;   


select
   case when instr(spare4, 'H:') > 0 then 'Yes' end digest_enabled,
   regexp_replace(spare4, '.*H:(.{32}).*', '\1')    digest_value
from
   sys.user$ where name ='RENE';
--
-- DIG DIGEST_VALUE                    
-- --- --------------------------------
-- Yes D52D963CF546B9AFF1878A99107DA061