Ivan

The Google Authenticator plugin for WordPress gives you two-factor authentication using the Google Authenticator app for Android/iPhone/Blackberry.
If you are security aware, you may already have the Google Authenticator app installed on your smartphone, using it for two-factor authentication on Gmail/Dropbox/Lastpass/Amazon etc.
The two-factor authentication requirement can be enabled on a per-user basis. You could enable it for your administrator account, but log in as usual with less privileged accounts.
If You need to maintain your blog using an Android/iPhone app, or any other software using the XMLRPC interface, you can enable the App password feature in this plugin, 
but please note that enabling the App password feature will make your blog less secure.
<h3>Credits</h3>
Thanks to:
<a href="https://profiles.wordpress.org/evinak/" rel="nofollow ugc">Oleksiy</a> for a bugfix in multisite.
<a href="https://github.com/pancek" rel="nofollow ugc">Paweł Nowacki</a> for the Polish translation
<a href="https://github.com/FabioZumbi12" rel="nofollow ugc">Fabio Zumbi</a> for the Portuguese translation
<a href="https://www.guidoschalkx.com/" rel="nofollow ugc">Guido Schalkx</a> for the Dutch translation.
<a href="https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=henrik%40schack%2edk&lc=US&item_name=Google%20Authenticator&item_number=Google%20Authenticator&no_shipping=0&no_note=1&tax=0&bn=PP%2dDonationsBF&charset=UTF%2d8" rel="nofollow ugc">Henrik.Schack</a> for writing/maintaining versions 0.20 through 0.48
<a href="http://tobias.baethge.com/" rel="nofollow ugc">Tobias Bäthge</a> for his code rewrite and German translation.
<a href="http://blog.pcode.nl/" rel="nofollow ugc">Pascal de Bruijn</a> for his “relaxed mode” idea.
<a href="http://technobabbl.es/" rel="nofollow ugc">Daniel Werl</a> for his usability tips.
<a href="http://dd32.id.au/" rel="nofollow ugc">Dion Hulse</a> for his bugfixes.
<a href="https://profiles.wordpress.org/users/aldolat/" rel="nofollow ugc">Aldo Latino</a> for his Italian translation.
<a href="http://www.kaijia.me/" rel="nofollow ugc">Kaijia Feng</a> for his Simplified Chinese translation.
<a href="http://www.buayacorp.com/" rel="nofollow ugc">Alex Concha</a> for his security tips.
<a href="http://jetienne.com/" rel="nofollow ugc">Jerome Etienne</a> for his jquery-qrcode plugin.
<a href="http://orizhial.com/" rel="nofollow ugc">Sébastien Prunier</a> for his Spanish and French translation.

Google Authenticator

Personally I feel 2FA should be a part of WordPress core. But since it isn't, plugins like this one are a must-have to secure your sites.

The configuration interface is clearly layed out and the login page fits in perfectly with the default WP login page styling.

This plugin is light-weight, unobtrusive, free and adds that extra layer of security. Should your admin credentials ever be compromised, 2FA will keep your site secure.

Must-have security plugin

Awesome plugin, which is almost always in first group of plugin I've install on new website. Thank you for create and maintain it.

One on few my first-to-install plugin

Google Authenticator for your WordPress blog.

cs7.in

Services :-
<ul>
<li>SIGNIN : Login with an OTP.</li>
<li>SIGNUP : Register with an OTP.</li>
<li>2FA : Two Factor Authentication.</li>
<li>RWL : Ratify (users) Without Login.</li>
<li>RWA : Ratify (guests) Without Account. 
.</li>
</ul>
Seamless OTP Login, Registration & Session 
Enhance your website’s user experience with this powerful and easy-to-use plugin. Let users login or register using a secure One-Time Password (OTP) sent directly to their email—no password required!
You can also enable Two-Factor Authentication (2FA) for an extra layer of security during login or registration.
KEY HIGHLIGHTS
<ul>
<li>
OTP via Email – Send quick, secure, and your own server-based emails.
</li>
<li>
Quick Signin & Signup – Instant, easy, and password-free; Login & signup with OTP.
</li>
<li>
Two-Factor Authentication (2FA) – Add advanced protection to Login or Registration.
</li>
<li>
Guest Access (RWA) – Allow visitors temporary or premium access without registration.
</li>
<li>
Verified Access (RWL) – Allow registered users temporary or premium access without login.
</li>
<li>
Zero External Dependency – Works independently, no Google/Facebook/B2B API required.
</li>
</ul>
Why Choose This Plugin ?
<ul>
<li>
FAST – Lightning-quick OTP delivery and smooth user experience
</li>
<li>
FRIENDLY – Simple and intuitive for both users and admins
</li>
<li>
SMART – Intelligent access handling and user behavior adaptation
</li>
<li>
SMOOTH – Clean UI integration for a frictionless flow
</li>
<li>
SECURED – Robust protection using email verification and secure tokens
</li>
</ul>
This plugin is ideal for membership sites, e-commerce platforms, SaaS applications, and content-based websites looking to offer seamless, secure, and flexible user access. 
.
F E A T U R E S :
Features For Registered Users :
<ul>
<li>Login with OTP.</li>
<li>Verify email to grant actions even without Login. (RWL)</li>
<li>Lock specific pages or URLs for verified users. (RWL)</li>
<li>Re-verify logged-in users for sensitive actions.</li>
<li>Auto Log-out after limited wrong OTP attempts. 
.</li>
</ul>
Features For Visitors (Guests):
<ul>
<li>Serve facilities even without account.</li>
<li>Quick registration with an email and OTP only.</li>
<li>Lock specific pages or URLs for verified visitors. (RWA)</li>
<li>Verify email to grant actions even without registration. (RWA) 
.</li>
</ul>
Features For All :
<ul>
<li>Set 2FA Lock for all.</li>
<li>Set the OTP expiry time.</li>
<li>Set the OTP sending Limit.</li>
<li>Set max wrong attempts Limit.</li>
<li>Block unwanted email addresses.</li>
<li>Block unwanted email providers.</li>
<li>Allow specific email providers. 
.</li>
</ul>
Operational Features :
<ul>
<li>Manage complete form CSS.</li>
<li>Customize email to send OTP.</li>
<li>Supportcode to change the language.</li>
<li>Generate OTP attempts log for review.</li>
<li>Customize popup and inline form layout.</li>
<li>Create Menus, Links or auto-popup the form.</li>
<li>Manage complete form template without CSS.</li>
<li>Use or customize from 27 ready-made templates.</li>
<li>Use multiple inline or popup forms on a single page.</li>
<li>Integrate external functions and custom support code.</li>
<li>Operate through Menu editor, Shortcode or HTML code.</li>
<li>Zero dependency on other APIs as Google/Facebook/B2B etc.</li>
<li>Provide EASY and SECURE Login/Register/Verification features. 
.</li>
</ul>
Additional Features :
<ul>
<li>Add multiple layers of security and access control.</li>
<li>Re-verify logged-in users before sensitive actions.</li>
<li>Provide subscriber/member access without login or registration.</li>
<li>Lock user accounts to re-verify OTP without logout or session loss.</li>
</ul>
.
Compatible With :
<ul>
<li>Youzify</li>
<li>Profilegrid</li>
<li>Forminator</li>
<li>ARMember</li>
<li>ProfilePress</li>
<li>Buddypress</li>
<li>Profile Builder</li>
<li>MemberPress</li>
<li>User Meta Lite</li>
<li>WooCommerce</li>
<li>Ultimate Member</li>
<li>User Registration</li>
<li>RegistrationMagic</li>
<li>WP User Manager</li>
<li>Pie Register–Basic</li>
<li>Login/Signup Popup</li>
<li>Paid Memberships Pro</li>
<li>Paid Member Subscriptions</li>
<li>N-Media WP Member Registration</li>
<li>And Many More . . . 
.</li>
</ul>
The plugin can act as a standalone authentication system or integrate smoothly with your favorite membership and user management tools/plugins.
The facilities of this plugin will put your website far ahead of everyone else. Install it, and use its features to check out the effects.
This free version includes all Addon+Prime features. Premium access is exclusive.
<a href="https://youtu.be/uxmdxKb2vTI" rel="nofollow ugc">See the plugin intro video (version:5.2.6)</a>
<iframe loading="lazy" class="youtube-player" width="750" height="422" src="https://www.youtube.com/embed/uxmdxKb2vTI?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-US&autohide=2&wmode=transparent" allowfullscreen="true" style="border:0;" sandbox="allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox"></iframe>
<h3>Feedback & Support</h3>
Your feedback helps make this plugin even better. 
Share your suggestions or report issues directly 
to the plugin author : <a href="mailto:Mr.Chandan.Shrivastava@gmail.com" rel="nofollow ugc">Mr.Chandan.Shrivastava@gmail.com</a>

Email OTP Authenticator – for Login, Registration or 2FA, RWL, RWA Services

Use an OTP to Login, Register, 2FA OR allow interim premium access WITHOUT Login, even WITHOUT Account. It is FAST, FRIENDLY, SMART, SMOOTH & SECURED.

Google Authenticator vs Email OTP Authenticator – for Login, Registration or 2FA, RWL, RWA Services