If your spreadsheet contains confidential information, you want to secure it against unauthorized access.The best way to achieve this is,enabling password protection.
You can allow a file to be read, but a user will need a password to be able to modify the file. This is good when you want to share information with your team, but you don't want them to change the information.Hear we are giving 'READ ONLY' permissions.
Please find the attached modified native excel emitter and sample program.We can make both XLS and XLSX reports password protected.
use below line to set your own password and make sure option name is SheetPassword only.
please visit 'http://code.google.com/a/eclipselabs.org/p/native-excel-emitter-birt-plugin/' to know more about naive excel emiter.
Let me know if you require any more information.