diff --git a/modules/client/back/methods/tpv-transaction/confirm.js b/modules/client/back/methods/tpv-transaction/confirm.js
index 6c8ecebaf..74eb9510c 100644
--- a/modules/client/back/methods/tpv-transaction/confirm.js
+++ b/modules/client/back/methods/tpv-transaction/confirm.js
@@ -69,7 +69,7 @@ module.exports = Self => {
         const cipher = crypto.createCipheriv('des-ede3-cbc', secretKey, iv);
         cipher.setAutoPadding(false);
         const orderKey = cipher.update(zeroPad(orderId, 8), 'utf8', 'base64')
-            + cipher.final('base64');
+            + cipher.final();
 
         const res = crypto.createHmac('sha256', Buffer.from(orderKey, 'base64'))
             .update(merchantParameters)