You can lock directory with a password by using the cPanel Password Protected Directories option.
Log into your cPanel account.
In the Security section, click on the IP Blocker Icon.
Here is Example:
Single IP Address: 192.168.0.1
Range: 192.168.0.1-192.168.0.40
Implied Range: 192.168.0.1-40
CIDR Format: 192.168.0.1/32
Implies 10...* -- 192.