Save procedure code in a file called cbt_trig1.sql
then wrap using the following command
e:\raj\YKR_SQL>wrap iname=cbt_trig1.sql
PL/SQL Wrapper: Release 10.1.0.2.0- Production on Fri Aug 07
16:58:27 2009
Copyright (c) 1993, 2004, Oracle. All rights reserved.
Processing cbt_trig1.sql to cbt_trig1.plb
Now execute the .plb file and the procedure code is encrypted
SQL>@cbt_trig1.plb