I found some information about the encryption and embedded password features in Interbase 2009, but it does not prevent database users to see the source code. Is it possible to hide the stored procedures and triggers codes from all user including SYSDBA too? If not at least I can hide it from some users.
Figured out how to do it:
update rdb$Triggers set rdb$Trigger_source = ""
where
rdb$system_flag = 0
and rdb$trigger_name not like "CHECK%";
update rdb$procedures set rdb$procedure_source="";