“CUSTOM_HASH Function create or replace function custom_hash (p_username in varchar2, p_password in varchar2) return varchar2 is l_password varchar2(4000); l_salt varchar2(4000) := 'XV1MH24EC1IHDCQHSS6XQ6QTJSANT3'; begin -- This function should be wrapped, as the hash algorithm is exposed here.  You can change the value of l_salt or the --method of which to call the DBMS_OBFUSCATOIN toolkit, but you must reset all of your passwords if you choose to do --this. l_password := utl_raw.cast_to_raw(dbms_obfuscation_toolkit.md5 (input_string => p_password || substr(l_salt,10,13) || p_username || substr(l_salt, 4,10))); return l_password; end;   CUSTOM_AUTH Function create or replace function custom_auth (p_username in VARCHAR2, p_password in VARCHAR2) return BOOLEAN is l_password varchar2(4000); l_stored_password varchar2(4000); l_expires_on date; l_count number; begin -- First, check to see if the user is in the user table select count(*) into l_count from demo_users where user_name = p_username; if l_count > 0 then -- Fetch the stored hashed password & expire date select password, expires_on into l_stored_password, l_expires_on from demo_users where user_name = p_username; -- Next, check whether the user's account is expired. If it isn’t, execute the next statement, else return FALSE if l_expires_on > sysdate or l_expires_on is null then -- If the account is not expired, apply the custom hash function to the password l_password := custom_hash(p_username, p_password); -- Finally, compare them to see if they are the same and return either TRUE or FALSE if l_password = l_stored_password then return true; else return false; end if; else return false; end if; else -- The username provided is not in the DEMO_USERS table return false; end if; end;”