Below is an example of storing any strings (eg passwords) in your database in a more secure and encrypted way.

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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) := 'ZJDCQTLTM85X893HOAFHU2KBDXHJBP';
begin

-- This function should be wrapped, as the hash algorhythm is exposed here.
-- You can change the value of l_salt or the method of which to call the
-- DBMS_OBFUSCATOIN toolkit, but you much 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;