WooCommerce Fraud Order Protection by Match Captcha

// Add Math CAPTCHA to WooCommerce Checkout
add_action('woocommerce_after_order_notes', 'custom_math_captcha_checkout');

function custom_math_captcha_checkout($checkout) {
    $num1 = rand(1, 10); // Generate first random number
    $num2 = rand(1, 10); // Generate second random number
    $sum = $num1 + $num2; // Calculate the sum

    // Store the sum in a session for later validation
    WC()->session->set('math_captcha_sum', $sum);

    echo '<div id="math-captcha">';
    echo '<p><strong>Anti-spam verification:</strong></p>';
    echo '<p>What is ' . $num1 . ' + ' . $num2 . '?</p>';
    woocommerce_form_field('math_captcha', [
        'type' => 'number',
        'class' => ['form-row-wide'],
        'required' => true,
        'placeholder' => 'Enter the result',
    ], $checkout->get_value('math_captcha'));
    echo '</div>';
}

// Validate Math CAPTCHA on Checkout
add_action('woocommerce_checkout_process', 'custom_math_captcha_validate');

function custom_math_captcha_validate() {
    $sum = WC()->session->get('math_captcha_sum');
    $answer = isset($_POST['math_captcha']) ? intval($_POST['math_captcha']) : 0;

    if ($answer !== $sum) {
        wc_add_notice(__('Incorrect anti-spam answer. Please try again.', 'woocommerce'), 'error');
    }
}

// Clear Math CAPTCHA after Order Completion
add_action('woocommerce_thankyou', 'custom_math_captcha_clear_session');

function custom_math_captcha_clear_session() {
    WC()->session->__unset('math_captcha_sum');
}