Denis V (Artprima)

Each time you login to your blog WordPress creates a session cookie which is used to authenticate you. 
By default if someone somehow gets your cookies he (or she) is able to use them to compromise your blog 
(even without having to know your password!). To prevent this you may want to make your auth cookies 
ip-dependent so that they could be valid only for that ip which you used during login.
Use this plugin only if you have a static IP or dynamic which doesn’t change too often. Otherwise, you’ll 
have to enter your login and password each time your IP changes.

IP Dependent Cookies

Plugin IP Dependent Cookies makes your Wordpress installation more secure adding your IP to salt (which makes cookies IP-dependent).

David Leonard

Secure your WordPress site with WordPress Secure Login.
WordPress Secure Login provides 2-step verification on login. Once a user submits their login credentials, a One Time Pin (OTP) is emailed to them. They need to enter this OTP in order to continue to login.
Stop Brute force hacking attempts, and keep your data safe!
<pre><code>* Easy to install!
* Easy to replace the Email system with an SMS Gateway
* WordPress 4.0 Ready!
</code></pre>

Secure Login

Secure, 2 step Verification for WordPress login, via One Time Pin (OTP).

IP Dependent Cookies vs Secure Login