diff --git a/assets/js/tinkoff-antifraud.js b/assets/js/tinkoff-antifraud.js
new file mode 100644
index 000000000..e9c9002f7
--- /dev/null
+++ b/assets/js/tinkoff-antifraud.js
@@ -0,0 +1,104 @@
+(() => {
+  const COOKIE_NAME = 'leyka_tk_af';
+  const TTL_DAYS = 7;
+
+  function setCookie(name, value, days) {
+    const expires = new Date(Date.now() + days * 864e5).toUTCString();
+    document.cookie = `${name}=${encodeURIComponent(value)}; Expires=${expires}; Path=/; SameSite=Lax`;
+  }
+
+  function base64urlEncodeUtf8(str) {
+    const bytes = new TextEncoder().encode(str);
+    let binary = '';
+    for (let i = 0; i < bytes.length; i++) {
+      binary += String.fromCharCode(bytes[i]);
+    }
+    const b64 = btoa(binary);
+    return b64.replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/g, '');
+  }
+
+  function getCookieNames() {
+    const raw = document.cookie || '';
+    if (!raw.trim()) return '';
+    const names = raw
+      .split(';')
+      .map((p) => p.split('=')[0].trim())
+      .filter(Boolean);
+
+    const uniq = Array.from(new Set(names));
+    return uniq.join(',').slice(0, 100);
+  }
+
+  async function sha256Hex(str) {
+    if (window.crypto?.subtle?.digest) {
+      const enc = new TextEncoder().encode(str);
+      const buf = await crypto.subtle.digest('SHA-256', enc);
+      return Array.from(new Uint8Array(buf))
+        .map((b) => b.toString(16).padStart(2, '0'))
+        .join('');
+    }
+
+    let h = 0;
+    for (let i = 0; i < str.length; i++) h = (h * 31 + str.charCodeAt(i)) | 0;
+    return String(h >>> 0);
+  }
+
+  function getOrCreateDeviceId() {
+    const key = 'leyka_tk_device_id';
+    let id = localStorage.getItem(key);
+
+    if (!id) {
+      id = crypto?.randomUUID
+        ? crypto.randomUUID()
+        : `${Date.now()}-${Math.random().toString(16).slice(2)}`;
+      localStorage.setItem(key, id);
+    }
+
+    return id.slice(0, 100);
+  }
+
+  function detectOS() {
+    const uaData = navigator.userAgentData;
+    if (uaData && Array.isArray(uaData.brands)) {
+      if (typeof uaData.platform === 'string' && uaData.platform) {
+        return uaData.platform.slice(0, 100);
+      }
+    }
+
+    const ua = (navigator.userAgent || '').toLowerCase();
+
+    if (ua.includes('windows')) return 'Windows';
+    if (ua.includes('mac os') || ua.includes('macintosh')) return 'macOS';
+    if (ua.includes('android')) return 'Android';
+    if (ua.includes('iphone') || ua.includes('ipad') || ua.includes('ipod')) return 'iOS';
+    if (ua.includes('cros')) return 'Chrome OS';
+    if (ua.includes('linux')) return 'Linux';
+    return 'Unknown';
+  }
+
+  async function main() {
+    try {
+      const deviceId = getOrCreateDeviceId();
+      const os = detectOS();
+      const referrer = (document.referrer || '').slice(0, 100);
+
+      const cookieNames = getCookieNames();
+      const cookieHash = (await sha256Hex(document.cookie || '')).slice(0, 100);
+
+      const payload = {
+        v: 1,
+        deviceId,
+        os,
+        referrer,
+        cookieNames,
+        cookieHash,
+      };
+
+      setCookie(COOKIE_NAME, base64urlEncodeUtf8(JSON.stringify(payload)), TTL_DAYS);
+    } catch (_) {
+        
+    }
+  }
+
+  main();
+})();
\ No newline at end of file
diff --git a/gateways/tinkoff/leyka-class-tinkoff-gateway.php b/gateways/tinkoff/leyka-class-tinkoff-gateway.php
index d41165939..3ced12dfa 100644
--- a/gateways/tinkoff/leyka-class-tinkoff-gateway.php
+++ b/gateways/tinkoff/leyka-class-tinkoff-gateway.php
@@ -16,7 +16,109 @@ protected function _set_attributes() {
         $this->_receiver_types = ['legal',];
         $this->_may_support_recurring = true;
 
+        // === AntiFraud ADDITION START: enqueue JS on frontend (once) ===
+        static $af_hooked = false;
+        if (!$af_hooked) {
+            add_action('wp_enqueue_scripts', [$this, 'enqueue_antifraud_assets']);
+            $af_hooked = true;
+        }
+        // === AntiFraud ADDITION END ===
+    }
+
+    // === AntiFraud ADDITION START: enqueue JS file ===
+    public function enqueue_antifraud_assets() {
+        if (is_admin()) {
+            return;
+        }
+
+        wp_enqueue_script(
+            'leyka-tinkoff-antifraud',
+            LEYKA_PLUGIN_BASE_URL . 'assets/js/tinkoff-antifraud.js',
+            [],
+            defined('LEYKA_VERSION') ? LEYKA_VERSION : false,
+            true
+        );
+    }
+    // === AntiFraud ADDITION END ===
+
+    // === AntiFraud ADDITION START: parse cookie payload from JS ===
+    protected function get_antifraud_payload() {
+        if (empty($_COOKIE['leyka_tk_af'])) {
+            return [];
+        }
+
+        $raw = sanitize_text_field(wp_unslash($_COOKIE['leyka_tk_af']));
+
+        // base64url -> base64
+        $b64 = strtr($raw, '-_', '+/');
+        $pad = strlen($b64) % 4;
+        if ($pad) {
+            $b64 .= str_repeat('=', 4 - $pad);
+        }
+
+        $json = base64_decode($b64, true);
+        if (!$json) {
+            return [];
+        }
+
+        $data = json_decode($json, true);
+        if (!is_array($data)) {
+            return [];
+        }
+
+        // DATA limits: key <= 20 chars, value <= 100 chars (we keep values <= 100)
+        $out = [];
+        $out['deviceId']   = !empty($data['deviceId'])  ? substr((string)$data['deviceId'], 0, 100) : '';
+        $out['os']         = !empty($data['os'])        ? substr((string)$data['os'], 0, 100) : '';
+        $out['referrer']   = !empty($data['referrer'])  ? substr((string)$data['referrer'], 0, 100) : '';
+        $out['cookieHash'] = !empty($data['cookieHash']) ? substr((string)$data['cookieHash'], 0, 100) : '';
+
+        return $out;
     }
+    // === AntiFraud ADDITION END ===
+
+    // === AntiFraud ADDITION START: apply fields to Init params ===
+    protected function apply_antifraud_to_init_params(array &$params) {
+        if (empty($params['DATA']) || !is_array($params['DATA'])) {
+            $params['DATA'] = [];
+        }
+
+        // IP
+        $ip = leyka_get_client_ip();
+        if ($ip) {
+            $params['DATA']['ClientIP'] = substr((string)$ip, 0, 100);
+        }
+
+        $af = $this->get_antifraud_payload();
+
+        // Referrer (prefer JS; fallback server)
+        if (!empty($af['referrer'])) {
+            $params['DATA']['Referrer'] = sanitize_text_field($af['referrer']);
+        } else {
+            $server_ref = wp_get_raw_referer();
+            if ($server_ref) {
+                $params['DATA']['Referrer'] = substr((string)$server_ref, 0, 100);
+            }
+        }
+
+        // Device ID
+        if (!empty($af['deviceId'])) {
+            $params['DATA']['DeviceId'] = sanitize_text_field($af['deviceId']);
+        }
+
+        // OS (top-level + duplicate in DATA for visibility in logs)
+        if (!empty($af['os'])) {
+            $os = sanitize_text_field($af['os']);
+            $params['DeviceOs'] = substr($os, 0, 100);
+            $params['DATA']['OS'] = substr($os, 0, 100);
+        }
+
+        // Cookies: hash only (send as random_cookie)
+        if (!empty($af['cookieHash'])) {
+            $params['DATA']['random_cookie'] = sanitize_text_field($af['cookieHash']);
+        }
+    }
+    // === AntiFraud ADDITION END ===
 
     protected function _set_options_defaults() {
 
@@ -95,11 +197,17 @@ public function do_recurring_donation(Leyka_Donation_Base $init_recurring_donati
             leyka_options()->opt($this->_id.'_password')
         );
 
-        $api->init([
+        // === AntiFraud ADDITION START: build params for Init + enrich ===
+        $init_params = [
             'OrderId' => $new_recurring_donation->id,
             'Amount' => 100 * absint($new_recurring_donation->amount),
             'DATA' => ['Email' => $init_recurring_donation->donor_email,],
-        ]);
+        ];
+
+        $this->apply_antifraud_to_init_params($init_params);
+
+        $api->init($init_params);
+        // === AntiFraud ADDITION END ===
 
         if($api->error){
             $this->_handle_donation_failure($new_recurring_donation, $api);
@@ -162,6 +270,10 @@ public function process_form($gateway_id, $pm_id, $donation_id, $form_data) {
 
         }
 
+        // === AntiFraud ADDITION START: enrich Init params before calling Init ===
+        $this->apply_antifraud_to_init_params($params);
+        // === AntiFraud ADDITION END ===
+
         $api->init($params);
 
         if($api->error){
@@ -478,4 +590,4 @@ public function has_recurring_support() {
 function leyka_add_gateway_tinkoff() { // Use named function to leave a possibility to remove/replace it on the hook
     leyka_add_gateway(Leyka_Tinkoff_Gateway::get_instance());
 }
-add_action('leyka_init_actions', 'leyka_add_gateway_tinkoff');
\ No newline at end of file
+add_action('leyka_init_actions', 'leyka_add_gateway_tinkoff');