Consider using MAP instead of ORDER member functions

[jgebal]

MAP member functions would have to use:
http://docs.oracle.com/cd/B28359_01/appdev.111/b28419/d_crypto.htm#i1002022
like in the below example

declare
  a varchar2(100);
begin
   for i in 1..100000 loop
      a := dbms_crypto.hash( to_char(i) ,dbms_crypto.HASH_SH1);
   end loop;
   dbms_output.put_line(a);
end;
/