How to single user mode protected with password

Edit the grub boot loader configuration file
# vim  /etc/grub.conf

After the hiddenmenu type password=newpassword then save & reboot
Example :
[Here we have to type]
Password = redhat [any Password]

Stop the Menu bar Press ‘Space bar’.
Now press ‘p’ for password,Password: redhat [any password]

Now press ‘e’ for editing mode,Press Escape & Enter for booting.  

Encrypt the password for security reasons:

Open two terminal,For generate a encryption password just type grub-md5-crypt

Select & Copy the encrypted password & in terminal-1 
Edit the grub configuration file from terminal-2,Paste the password in password prompt, like...  vim /etc/grub.conf