MobiOffice lets you protect your Presentation on a file level, allowing no one to view the file, unless they have the password.
Password-protect a Presentation
1. Open the Presentation. Tap the menu in the top right. Tap Protect.
2. Type and retype the password.
3. Tap OK.
4. Save or Save as the Presentation.
Remove the password
1. Open the Presentation. Tap the menu in the top right. Tap Unprotect.
2. Type the password.
3. Tap OK.