In general people use same same passwords across all social networks and other web accounts because remembering many usernames and passwords is not always easy for people who don’t spend much time on Internet. But this is risky because if in case one of your account’s password gets hacked or cracked, it can put your other accounts in danger. Other than strengthening your passwords you can increase your website’s security by enabling a two-step authentication so that if any brute force or hacker cracks your username & password then still they will not be able to use it without a code or token, which in most cases connected to your smartphone device. Here are some good authentication plugins you can use in your WordPress site.
The plugin provides you two-factor authentication using the Google Authenticator app for Android/iPhone/Blackberry.
Controls access to your WordPress administration panel by sending a code to your mobile phone when you try and login. Configurable for different user groups with a variety of options.
Easily add Duo Security two-factor authentication to your WordPress website. Enable two-factor authentication for your admins and/or users.
Allows WordPress to provide and consumer OpenIDs for authentication of users and comments.
Authy helps you proctect your WordPress site from hackers using simple two-factor authentication.