How to I secure a PPT doc so it cannot be changed by others?

From: remin (reminworld_at_mac.com)
Date: 02/25/05 

Date: 25 Feb 2005 12:34:21 -0800

Hi folks,

I have just bought the latest PPT and am still trying to get the hang
of it.

I have a company PPT presentation done but cannot figure out how I make
it secure from change by others that I send it to. Is there a way?

Thanks
joe