Facebook, after personal data leaks (read more ) is finally tightening its log-in verification to hopefully prevent unauthorized access to your own account.

The new security feature is called Login Approvals and it’s a double authentication process. This is how it will work: FB will send you a numeric code via SMS to the mobile number linked to your account.

When a login attempt is made from a device that is not the approved one, Facebook will request, together with your usual username and password, the numeric code.

If someone has your username and password and tries to login into your account, you’ll be notified about the attempt.

Facebook may consider incorporating other technology to Login Approvals beyond SMS, but it is holding off on it until those other forms of two-factor authentication become simpler.

“One challenge in building login approvals was balancing security and usability. Similar features on other websites require you to download authentication apps or purchase physical tokens to act as your second factor. These are good approaches, and we’re considering incorporating them in the future, but they require a lot from the user before being able to turn on the feature,” wrote Andrew Song, a Facebook engineering intern, in the blog post.

The Login Approval feature is already in place and you can turn it on under your Account Security section under the account settings page.