diff --git a/td/mtproto/PacketInfo.h b/td/mtproto/PacketInfo.h
index c49df9fb5..2d8c9d388 100644
--- a/td/mtproto/PacketInfo.h
+++ b/td/mtproto/PacketInfo.h
@@ -7,7 +7,6 @@
 #pragma once
 
 #include "td/utils/common.h"
-#include "td/utils/UInt.h"
 
 namespace td {
 namespace mtproto {
@@ -16,7 +15,6 @@ struct PacketInfo {
   enum { Common, EndToEnd } type = Common;
   uint64 auth_key_id{0};
   uint32 message_ack{0};
-  UInt128 message_key;
 
   uint64 salt{0};
   uint64 session_id{0};
diff --git a/td/mtproto/Transport.cpp b/td/mtproto/Transport.cpp
index ef0440ef6..f949d2263 100644
--- a/td/mtproto/Transport.cpp
+++ b/td/mtproto/Transport.cpp
@@ -362,19 +362,13 @@ void Transport::write_crypto_impl(int X, const Storer &storer, const AuthKey &au
   Random::secure_bytes(pad.ubegin(), pad.size());
   MutableSlice to_encrypt = MutableSlice(header->encrypt_begin(), pad.uend());
 
-  if (info->version == 1) {
-    std::tie(info->message_ack, info->message_key) = calc_message_ack_and_key(*header, data_size);
-  } else {
-    std::tie(info->message_ack, info->message_key) = calc_message_key2(auth_key, X, to_encrypt);
-  }
-
-  header->message_key = info->message_key;
-
   UInt256 aes_key;
   UInt256 aes_iv;
   if (info->version == 1) {
+    std::tie(info->message_ack, header->message_key) = calc_message_ack_and_key(*header, data_size);
     KDF(auth_key.key(), header->message_key, X, &aes_key, &aes_iv);
   } else {
+    std::tie(info->message_ack, header->message_key) = calc_message_key2(auth_key, X, to_encrypt);
     KDF2(auth_key.key(), header->message_key, X, &aes_key, &aes_iv);
   }