Tushar Sharma

<p>Email OTP Login adds an additional layer of security to your WordPress site by requiring users to verify an OTP sent to their email after entering their username and password. This ensures that only users with access to the registered email can log in.</p>
<p>Features:</p>
<ul>
<li>Email OTP verification during <strong>login</strong>.</li>
<li>OTP expires in 5 minutes (configurable).</li>
<li>OTP stored securely using WordPress password hashing.</li>
<li>Works with the default WordPress login form.</li>
<li>Uses WordPress built-in <code>wp_mail()</code> function (works with SMTP plugins).</li>
</ul>
<p>This plugin does <strong>not modify WordPress core files</strong>.</p>
<h3>License</h3>
<p>This plugin is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2 or later.</p>
<p>This plugin is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.</p>


Email OTP Login

Adds OTP (One-Time Password) verification after login for enhanced security in WordPress. OTP is sent to the user's email.

rishav001

<p>Rishav AuthNova OTP adds a one-time-password verification layer to core WordPress authentication flows.</p>
<p>Features include:</p>
<ul>
<li>Configurable OTP length and charset (numeric or alphanumeric)</li>
<li>OTP expiry and retry limits with temporary lockouts</li>
<li>Login OTP verification step (after password check)</li>
<li>OTP-gated registration flow</li>
<li>OTP-gated password reset flow</li>
<li>Delivery via wp_mail, SendGrid, and Twilio</li>
<li>OTP storage using hashes (never plaintext)</li>
<li>Resend OTP with cooldown and challenge rotation</li>
</ul>
<p>Security highlights:</p>
<ul>
<li>OTP values are hashed before storage and are never saved as plaintext</li>
<li>OTP hashes use keyed HMAC storage and constant-time verification</li>
<li>OTP challenges expire automatically and enforce retry limits per challenge</li>
<li>Request throttling applies cooldown and exponential backoff per IP and identifier</li>
<li>Lockout windows reduce repeated invalid OTP submissions</li>
<li>Nonces are applied on sensitive form submissions</li>
<li>Public auth responses are intentionally generic to reduce account-enumeration leakage</li>
<li>Delivery uses synchronous-first send with bounded async retry fallback and challenge-level delivery status tracking</li>
</ul>
<p>Security limitations:</p>
<ul>
<li>This plugin does not replace passwords, HTTPS, WAF/rate-limiting at the edge, or secure hosting controls</li>
<li>OTP delivery depends on the configured email/SMS provider uptime and deliverability</li>
<li>Administrators should combine this plugin with standard WordPress hardening and monitoring</li>
</ul>
<p>Reliability notes:</p>
<ul>
<li>OTP delivery is attempted synchronously first to reduce silent failures</li>
<li>If synchronous delivery fails and background delivery is healthy, the plugin schedules bounded retries</li>
<li>If background delivery is unhealthy (for example DISABLE_WP_CRON), fallback queueing is skipped and users receive a retry-safe error</li>
<li>Resend cooldown state is server-authoritative and exposed through a status endpoint used by frontend countdown UX</li>
<li>Background queue payload contains only challenge ID (no raw OTP or destination data)</li>
</ul>
<h3>External Services</h3>
<p>This plugin can connect to third-party services to deliver OTP messages. These services are optional and only used if enabled in plugin settings.</p>
<h4>Twilio (SMS Delivery)</h4>
<ul>
<li>Service: Twilio Programmable Messaging API</li>
<li>Purpose: Send OTP codes by SMS</li>
<li>Data sent: destination phone number, sender phone number, OTP message text, account SID for authentication</li>
<li>Credential handling: Twilio credentials are stored in WordPress options and used only when sending OTP messages</li>
<li>When sent: when OTP delivery method includes SMS and an OTP is generated for login, registration, password reset, or resend</li>
<li>Why sent: to deliver time-sensitive OTP codes to the user by SMS</li>
<li>Terms of Service: https://www.twilio.com/legal/tos</li>
<li>Privacy Policy: https://www.twilio.com/en-us/legal/privacy</li>
</ul>
<h4>SendGrid (Email Delivery)</h4>
<ul>
<li>Service: SendGrid Mail Send API</li>
<li>Purpose: Send OTP codes by email</li>
<li>Data sent: recipient email address, sender email/name, message subject, OTP message body, API key for authentication</li>
<li>Credential handling: SendGrid API key is stored in WordPress options and used only when sending OTP messages</li>
<li>When sent: when email provider is set to SendGrid and an OTP is generated for login, registration, password reset, or resend</li>
<li>Why sent: to deliver time-sensitive OTP codes to the user by email</li>
<li>Terms of Service: https://sendgrid.com/policies/terms/</li>
<li>Privacy Policy: https://sendgrid.com/policies/privacy/</li>
</ul>
<h3>Configuration</h3>
<ol>
<li>Set OTP length, type, expiry, retry limit, and lockout duration.</li>
<li>Choose delivery method: Email, SMS, or Both.</li>
<li>Configure provider credentials for SendGrid and/or Twilio if needed.</li>
<li>Enable or disable OTP on login, registration, and password reset flows.</li>
</ol>


Rishav AuthNova OTP

OTP verification for WordPress login, registration, and password reset using email and SMS delivery.

Email OTP Login vs Rishav AuthNova OTP