LinkedIn has just jumped on the (very important) two-factor authentication wagon. You can — and should — now enable this enhanced security layer for the professional network.
Like other online accounts where you should have two-factor authentication turned on, LinkedIn's two-factor authentication requires a code sent to your phone if you try to log in from an unknown computer or device. This makes it harder for unauthorised users to gain access to your account.
To enable the feature on LinkedIn, head to Settings, then the Account tab, and "Manage security settings" option.
Protecting Your LinkedIn Account with Two-Step Verification [LinkedIn Blog]