diff --git a/adnl/adnl-peer.cpp b/adnl/adnl-peer.cpp
index febbdac6..d82486fe 100644
--- a/adnl/adnl-peer.cpp
+++ b/adnl/adnl-peer.cpp
@@ -269,7 +269,11 @@ void AdnlPeerPairImpl::send_messages_in(std::vector<OutboundAdnlMessage> message
     size_t ptr = 0;
     bool first = true;
     do {
+      respond_with_nop_after_ = td::Timestamp::in(td::Random::fast(1.0, 2.0));
       bool try_reinit = try_reinit_at_ && try_reinit_at_.is_in_past();
+      if (try_reinit) {
+        try_reinit_at_ = td::Timestamp::in(td::Random::fast(0.5, 1.5));
+      }
       bool via_channel = channel_ready_ && !try_reinit;
       size_t s = (via_channel ? channel_packet_header_max_size() : packet_header_max_size());
       if (first) {
@@ -504,12 +508,6 @@ void AdnlPeerPairImpl::create_channel(pubkeys::Ed25519 pub, td::uint32 date) {
 
 void AdnlPeerPairImpl::process_message(const adnlmessage::AdnlMessageCreateChannel &message) {
   create_channel(message.key(), message.date());
-  if (respond_to_channel_create_after_.is_in_past()) {
-    respond_to_channel_create_after_ = td::Timestamp::in(td::Random::fast(1.0, 2.0));
-    std::vector<OutboundAdnlMessage> messages;
-    messages.emplace_back(adnlmessage::AdnlMessageNop{}, 0);
-    send_messages(std::move(messages));
-  }
 }
 
 void AdnlPeerPairImpl::process_message(const adnlmessage::AdnlMessageConfirmChannel &message) {
@@ -526,6 +524,7 @@ void AdnlPeerPairImpl::process_message(const adnlmessage::AdnlMessageConfirmChan
 }
 
 void AdnlPeerPairImpl::process_message(const adnlmessage::AdnlMessageCustom &message) {
+  respond_with_nop();
   td::actor::send_closure(local_actor_, &AdnlLocalId::deliver, peer_id_short_, message.data());
 }
 
@@ -538,6 +537,7 @@ void AdnlPeerPairImpl::process_message(const adnlmessage::AdnlMessageReinit &mes
 }
 
 void AdnlPeerPairImpl::process_message(const adnlmessage::AdnlMessageQuery &message) {
+  respond_with_nop();
   auto P = td::PromiseCreator::lambda([SelfId = actor_id(this), query_id = message.query_id(),
                                        flags = static_cast<td::uint32>(0)](td::Result<td::BufferSlice> R) {
     if (R.is_error()) {
@@ -556,6 +556,7 @@ void AdnlPeerPairImpl::process_message(const adnlmessage::AdnlMessageQuery &mess
 }
 
 void AdnlPeerPairImpl::process_message(const adnlmessage::AdnlMessageAnswer &message) {
+  respond_with_nop();
   auto Q = out_queries_.find(message.query_id());
 
   if (Q == out_queries_.end()) {
@@ -573,6 +574,7 @@ void AdnlPeerPairImpl::process_message(const adnlmessage::AdnlMessageAnswer &mes
 }
 
 void AdnlPeerPairImpl::process_message(const adnlmessage::AdnlMessagePart &message) {
+  respond_with_nop();
   auto size = message.total_size();
   if (size > huge_packet_max_size()) {
     VLOG(ADNL_WARNING) << this << ": dropping too big huge message: size=" << size;
@@ -635,6 +637,14 @@ void AdnlPeerPairImpl::delete_query(AdnlQueryId id) {
   }
 }
 
+void AdnlPeerPairImpl::respond_with_nop() {
+  if (respond_with_nop_after_.is_in_past()) {
+    std::vector<OutboundAdnlMessage> messages;
+    messages.emplace_back(adnlmessage::AdnlMessageNop{}, 0);
+    send_messages(std::move(messages));
+  }
+}
+
 void AdnlPeerPairImpl::reinit(td::int32 date) {
   if (reinit_date_ == 0) {
     reinit_date_ = date;
diff --git a/adnl/adnl-peer.hpp b/adnl/adnl-peer.hpp
index e9a5d428..40c9eb08 100644
--- a/adnl/adnl-peer.hpp
+++ b/adnl/adnl-peer.hpp
@@ -122,6 +122,7 @@ class AdnlPeerPairImpl : public AdnlPeerPair {
   }
 
  private:
+  void respond_with_nop();
   void reinit(td::int32 date);
   td::Result<std::pair<td::actor::ActorId<AdnlNetworkConnection>, bool>> get_conn(bool direct_only);
   void create_channel(pubkeys::Ed25519 pub, td::uint32 date);
@@ -214,7 +215,7 @@ class AdnlPeerPairImpl : public AdnlPeerPair {
   pubkeys::Ed25519 channel_pub_;
   td::int32 channel_pk_date_;
   td::actor::ActorOwn<AdnlChannel> channel_;
-  td::Timestamp respond_to_channel_create_after_;
+  td::Timestamp respond_with_nop_after_;
 
   td::uint64 in_seqno_ = 0;
   td::uint64 out_seqno_ = 0;
diff --git a/crypto/vm/bls.cpp b/crypto/vm/bls.cpp
index f6ccc275..ff5179c7 100644
--- a/crypto/vm/bls.cpp
+++ b/crypto/vm/bls.cpp
@@ -93,12 +93,13 @@ bool aggregate_verify(const std::vector<std::pair<P1, td::BufferSlice>> &pubs_ms
       return false;
     }
     std::unique_ptr<blst::Pairing> pairing = std::make_unique<blst::Pairing>(true, DST);
+    blst::P2_Affine p2_zero;
     for (const auto &p : pubs_msgs) {
       blst::P1_Affine p1(p.first.data(), P1_SIZE);
       if (!p1.in_group() || p1.is_inf()) {
         return false;
       }
-      pairing->aggregate(&p1, nullptr, (const td::uint8 *)p.second.data(), p.second.size());
+      pairing->aggregate(&p1, &p2_zero, (const td::uint8 *)p.second.data(), p.second.size());
     }
     pairing->commit();
     blst::P2_Affine p2(sig.data(), P2_SIZE);
diff --git a/dht/dht-in.hpp b/dht/dht-in.hpp
index c2d20455..0d668d43 100644
--- a/dht/dht-in.hpp
+++ b/dht/dht-in.hpp
@@ -179,6 +179,7 @@ class DhtMemberImpl : public DhtMember {
   void get_value(DhtKey key, td::Promise<DhtValue> result) override {
     get_value_in(key.compute_key_id(), std::move(result));
   }
+  void get_value_many(DhtKey key, std::function<void(DhtValue)> callback, td::Promise<td::Unit> promise) override;
 
   void alarm() override {
     alarm_timestamp() = td::Timestamp::in(1.0);
diff --git a/dht/dht-query.cpp b/dht/dht-query.cpp
index b84ef8c3..3d43b106 100644
--- a/dht/dht-query.cpp
+++ b/dht/dht-query.cpp
@@ -210,8 +210,11 @@ void DhtQueryFindValue::on_result(td::Result<td::BufferSlice> R, adnl::AdnlNodeI
                   send_get_nodes = true;
                   return;
                 }
-                promise_.set_value(std::move(value));
-                need_stop = true;
+                if (on_value_found(std::move(value))) {
+                  send_get_nodes = true;
+                } else {
+                  need_stop = true;
+                }
               },
               [&](ton_api::dht_valueNotFound &v) {
                 add_nodes(DhtNodesList{std::move(v.nodes_), our_network_id()});
@@ -244,7 +247,32 @@ void DhtQueryFindValue::on_result_nodes(td::Result<td::BufferSlice> R, adnl::Adn
 }
 
 void DhtQueryFindValue::finish(DhtNodesList list) {
-  promise_.set_error(td::Status::Error(ErrorCode::notready, "dht key not found"));
+}
+
+bool DhtQueryFindValueSingle::on_value_found(DhtValue value) {
+  promise_.set_value(std::move(value));
+  found_ = true;
+  return false;
+}
+
+void DhtQueryFindValueSingle::tear_down() {
+  if (!found_) {
+    promise_.set_error(td::Status::Error(ErrorCode::notready, "dht key not found"));
+  }
+}
+
+bool DhtQueryFindValueMany::on_value_found(DhtValue value) {
+  callback_(std::move(value));
+  found_ = true;
+  return true;
+}
+
+void DhtQueryFindValueMany::tear_down() {
+  if (found_) {
+    promise_.set_value(td::Unit());
+  } else {
+    promise_.set_error(td::Status::Error(ErrorCode::notready, "dht key not found"));
+  }
 }
 
 DhtQueryStore::DhtQueryStore(DhtValue key_value, DhtMember::PrintId print_id, adnl::AdnlNodeIdShort src,
diff --git a/dht/dht-query.hpp b/dht/dht-query.hpp
index e4740361..e305f107 100644
--- a/dht/dht-query.hpp
+++ b/dht/dht-query.hpp
@@ -126,16 +126,11 @@ class DhtQueryFindNodes : public DhtQuery {
 };
 
 class DhtQueryFindValue : public DhtQuery {
- private:
-  td::Promise<DhtValue> promise_;
-
  public:
   DhtQueryFindValue(DhtKeyId key, DhtMember::PrintId print_id, adnl::AdnlNodeIdShort src, DhtNodesList list,
                     td::uint32 k, td::uint32 a, td::int32 our_network_id, DhtNode self, bool client_only,
-                    td::actor::ActorId<DhtMember> node, td::actor::ActorId<adnl::Adnl> adnl,
-                    td::Promise<DhtValue> promise)
-      : DhtQuery(key, print_id, src, k, a, our_network_id, std::move(self), client_only, node, adnl)
-      , promise_(std::move(promise)) {
+                    td::actor::ActorId<DhtMember> node, td::actor::ActorId<adnl::Adnl> adnl)
+      : DhtQuery(key, print_id, src, k, a, our_network_id, std::move(self), client_only, node, adnl) {
     add_nodes(std::move(list));
   }
   void send_one_query(adnl::AdnlNodeIdShort id) override;
@@ -146,6 +141,48 @@ class DhtQueryFindValue : public DhtQuery {
   std::string get_name() const override {
     return "find value";
   }
+
+  virtual bool on_value_found(DhtValue value) = 0;
+};
+
+class DhtQueryFindValueSingle : public DhtQueryFindValue {
+ public:
+  DhtQueryFindValueSingle(DhtKeyId key, DhtMember::PrintId print_id, adnl::AdnlNodeIdShort src, DhtNodesList list,
+                          td::uint32 k, td::uint32 a, td::int32 our_network_id, DhtNode self, bool client_only,
+                          td::actor::ActorId<DhtMember> node, td::actor::ActorId<adnl::Adnl> adnl,
+                          td::Promise<DhtValue> promise)
+      : DhtQueryFindValue(key, print_id, src, std::move(list), k, a, our_network_id, std::move(self), client_only, node,
+                          adnl)
+      , promise_(std::move(promise)) {
+    add_nodes(std::move(list));
+  }
+  bool on_value_found(DhtValue value) override;
+  void tear_down() override;
+
+ private:
+  td::Promise<DhtValue> promise_;
+  bool found_ = false;
+};
+
+class DhtQueryFindValueMany : public DhtQueryFindValue {
+ public:
+  DhtQueryFindValueMany(DhtKeyId key, DhtMember::PrintId print_id, adnl::AdnlNodeIdShort src, DhtNodesList list,
+                         td::uint32 k, td::uint32 a, td::int32 our_network_id, DhtNode self, bool client_only,
+                         td::actor::ActorId<DhtMember> node, td::actor::ActorId<adnl::Adnl> adnl,
+                         std::function<void(DhtValue)> callback, td::Promise<td::Unit> promise)
+      : DhtQueryFindValue(key, print_id, src, std::move(list), k, a, our_network_id, std::move(self), client_only, node,
+                          adnl)
+      , callback_(std::move(callback))
+      , promise_(std::move(promise)) {
+    add_nodes(std::move(list));
+  }
+  bool on_value_found(DhtValue value) override;
+  void tear_down() override;
+
+ private:
+  std::function<void(DhtValue)> callback_;
+  td::Promise<td::Unit> promise_;
+  bool found_ = false;
 };
 
 class DhtQueryStore : public td::actor::Actor {
diff --git a/dht/dht.cpp b/dht/dht.cpp
index 8d7b02b7..b774b5f9 100644
--- a/dht/dht.cpp
+++ b/dht/dht.cpp
@@ -470,7 +470,7 @@ void DhtMemberImpl::get_value_in(DhtKeyId key, td::Promise<DhtValue> result) {
                                        network_id = network_id_, id = id_,
                                        client_only = client_only_](td::Result<DhtNode> R) mutable {
     R.ensure();
-    td::actor::create_actor<DhtQueryFindValue>("FindValueQuery", key, print_id, id, std::move(list), k, a, network_id,
+    td::actor::create_actor<DhtQueryFindValueSingle>("FindValueQuery", key, print_id, id, std::move(list), k, a, network_id,
                                                R.move_as_ok(), client_only, SelfId, adnl, std::move(promise))
         .release();
   });
@@ -478,6 +478,21 @@ void DhtMemberImpl::get_value_in(DhtKeyId key, td::Promise<DhtValue> result) {
   get_self_node(std::move(P));
 }
 
+void DhtMemberImpl::get_value_many(DhtKey key, std::function<void(DhtValue)> callback, td::Promise<td::Unit> promise) {
+  DhtKeyId key_id = key.compute_key_id();
+  auto P = td::PromiseCreator::lambda(
+      [key = key_id, callback = std::move(callback), promise = std::move(promise), SelfId = actor_id(this),
+       print_id = print_id(), adnl = adnl_, list = get_nearest_nodes(key_id, k_ * 2), k = k_, a = a_,
+       network_id = network_id_, id = id_, client_only = client_only_](td::Result<DhtNode> R) mutable {
+        R.ensure();
+        td::actor::create_actor<DhtQueryFindValueMany>("FindValueManyQuery", key, print_id, id, std::move(list), k, a,
+                                                       network_id, R.move_as_ok(), client_only, SelfId, adnl,
+                                                       std::move(callback), std::move(promise))
+            .release();
+      });
+  get_self_node(std::move(P));
+}
+
 void DhtMemberImpl::register_reverse_connection(adnl::AdnlNodeIdFull client, td::Promise<td::Unit> promise) {
   auto client_short = client.compute_short_id();
   td::uint32 ttl = (td::uint32)td::Clocks::system() + 300;
diff --git a/dht/dht.h b/dht/dht.h
index b9c65c8a..5abff94a 100644
--- a/dht/dht.h
+++ b/dht/dht.h
@@ -53,6 +53,7 @@ class Dht : public td::actor::Actor {
 
   virtual void set_value(DhtValue key_value, td::Promise<td::Unit> result) = 0;
   virtual void get_value(DhtKey key, td::Promise<DhtValue> result) = 0;
+  virtual void get_value_many(DhtKey key, std::function<void(DhtValue)> callback, td::Promise<td::Unit> promise) = 0;
 
   virtual void register_reverse_connection(adnl::AdnlNodeIdFull client, td::Promise<td::Unit> promise) = 0;
   virtual void request_reverse_ping(adnl::AdnlNode target, adnl::AdnlNodeIdShort client,
diff --git a/keyring/keyring.cpp b/keyring/keyring.cpp
index 529a6b8b..0f45879d 100644
--- a/keyring/keyring.cpp
+++ b/keyring/keyring.cpp
@@ -27,6 +27,16 @@ namespace ton {
 
 namespace keyring {
 
+KeyringImpl::PrivateKeyDescr::PrivateKeyDescr(PrivateKey private_key, bool is_temp)
+    : public_key(private_key.compute_public_key()), is_temp(is_temp) {
+  auto D = private_key.create_decryptor_async();
+  D.ensure();
+  decryptor_sign = D.move_as_ok();
+  D = private_key.create_decryptor_async();
+  D.ensure();
+  decryptor_decrypt = D.move_as_ok();
+}
+
 void KeyringImpl::start_up() {
   if (db_root_.size() > 0) {
     td::mkdir(db_root_).ensure();
@@ -45,23 +55,19 @@ td::Result<KeyringImpl::PrivateKeyDescr *> KeyringImpl::load_key(PublicKeyHash k
 
   auto name = db_root_ + "/" + key_hash.bits256_value().to_hex();
 
-  auto R = td::read_file(td::CSlice{name});
+  auto R = td::read_file_secure(td::CSlice{name});
   if (R.is_error()) {
     return R.move_as_error_prefix("key not in db: ");
   }
   auto data = R.move_as_ok();
-  auto R2 = PrivateKey::import(td::SecureString(data));
+  auto R2 = PrivateKey::import(data);
   R2.ensure();
 
   auto key = R2.move_as_ok();
-  auto pub = key.compute_public_key();
-  auto short_id = pub.compute_short_id();
+  auto desc = std::make_unique<PrivateKeyDescr>(key, false);
+  auto short_id = desc->public_key.compute_short_id();
   CHECK(short_id == key_hash);
-
-  auto D = key.create_decryptor_async();
-  D.ensure();
-
-  return map_.emplace(short_id, std::make_unique<PrivateKeyDescr>(D.move_as_ok(), pub, false)).first->second.get();
+  return map_.emplace(short_id, std::move(desc)).first->second.get();
 }
 
 void KeyringImpl::add_key(PrivateKey key, bool is_temp, td::Promise<td::Unit> promise) {
@@ -76,10 +82,7 @@ void KeyringImpl::add_key(PrivateKey key, bool is_temp, td::Promise<td::Unit> pr
   if (db_root_.size() == 0) {
     CHECK(is_temp);
   }
-  auto D = key.create_decryptor_async();
-  D.ensure();
-
-  map_.emplace(short_id, std::make_unique<PrivateKeyDescr>(D.move_as_ok(), pub, is_temp));
+  map_.emplace(short_id, std::make_unique<PrivateKeyDescr>(key, is_temp));
 
   if (!is_temp && key.exportable()) {
     auto S = key.export_as_slice();
@@ -139,7 +142,7 @@ void KeyringImpl::sign_message(PublicKeyHash key_hash, td::BufferSlice data, td:
   if (S.is_error()) {
     promise.set_error(S.move_as_error());
   } else {
-    td::actor::send_closure(S.move_as_ok()->decryptor, &DecryptorAsync::sign, std::move(data), std::move(promise));
+    td::actor::send_closure(S.move_as_ok()->decryptor_sign, &DecryptorAsync::sign, std::move(data), std::move(promise));
   }
 }
 
@@ -161,7 +164,7 @@ void KeyringImpl::sign_add_get_public_key(PublicKeyHash key_hash, td::BufferSlic
         }
         promise.set_value(std::pair<td::BufferSlice, PublicKey>{R.move_as_ok(), id});
       });
-  td::actor::send_closure(D->decryptor, &DecryptorAsync::sign, std::move(data), std::move(P));
+  td::actor::send_closure(D->decryptor_sign, &DecryptorAsync::sign, std::move(data), std::move(P));
 }
 
 void KeyringImpl::sign_messages(PublicKeyHash key_hash, std::vector<td::BufferSlice> data,
@@ -171,7 +174,7 @@ void KeyringImpl::sign_messages(PublicKeyHash key_hash, std::vector<td::BufferSl
   if (S.is_error()) {
     promise.set_error(S.move_as_error());
   } else {
-    td::actor::send_closure(S.move_as_ok()->decryptor, &DecryptorAsync::sign_batch, std::move(data),
+    td::actor::send_closure(S.move_as_ok()->decryptor_sign, &DecryptorAsync::sign_batch, std::move(data),
                             std::move(promise));
   }
 }
@@ -182,7 +185,8 @@ void KeyringImpl::decrypt_message(PublicKeyHash key_hash, td::BufferSlice data,
   if (S.is_error()) {
     promise.set_error(S.move_as_error());
   } else {
-    td::actor::send_closure(S.move_as_ok()->decryptor, &DecryptorAsync::decrypt, std::move(data), std::move(promise));
+    td::actor::send_closure(S.move_as_ok()->decryptor_decrypt, &DecryptorAsync::decrypt, std::move(data),
+                            std::move(promise));
   }
 }
 
diff --git a/keyring/keyring.hpp b/keyring/keyring.hpp
index fc67bd0f..ec658305 100644
--- a/keyring/keyring.hpp
+++ b/keyring/keyring.hpp
@@ -30,12 +30,11 @@ namespace keyring {
 class KeyringImpl : public Keyring {
  private:
   struct PrivateKeyDescr {
-    td::actor::ActorOwn<DecryptorAsync> decryptor;
+    td::actor::ActorOwn<DecryptorAsync> decryptor_sign;
+    td::actor::ActorOwn<DecryptorAsync> decryptor_decrypt;
     PublicKey public_key;
     bool is_temp;
-    PrivateKeyDescr(td::actor::ActorOwn<DecryptorAsync> decryptor, PublicKey public_key, bool is_temp)
-        : decryptor(std::move(decryptor)), public_key(public_key), is_temp(is_temp) {
-    }
+    PrivateKeyDescr(PrivateKey private_key, bool is_temp);
   };
 
  public:
diff --git a/keys/encryptor.cpp b/keys/encryptor.cpp
index 0b93d36f..8fef9a09 100644
--- a/keys/encryptor.cpp
+++ b/keys/encryptor.cpp
@@ -29,28 +29,6 @@
 
 namespace ton {
 
-td::Result<std::unique_ptr<Encryptor>> Encryptor::create(const ton_api::PublicKey *id) {
-  td::Result<std::unique_ptr<Encryptor>> res;
-  ton_api::downcast_call(
-      *const_cast<ton_api::PublicKey *>(id),
-      td::overloaded([&](const ton_api::pub_unenc &obj) { res = std::make_unique<EncryptorNone>(); },
-                     [&](const ton_api::pub_ed25519 &obj) { res = std::make_unique<EncryptorEd25519>(obj.key_); },
-                     [&](const ton_api::pub_overlay &obj) { res = std::make_unique<EncryptorOverlay>(); },
-                     [&](const ton_api::pub_aes &obj) { res = std::make_unique<EncryptorAES>(obj.key_); }));
-  return res;
-}
-
-td::Result<std::unique_ptr<Decryptor>> Decryptor::create(const ton_api::PrivateKey *id) {
-  td::Result<std::unique_ptr<Decryptor>> res;
-  ton_api::downcast_call(
-      *const_cast<ton_api::PrivateKey *>(id),
-      td::overloaded([&](const ton_api::pk_unenc &obj) { res = std::make_unique<DecryptorNone>(); },
-                     [&](const ton_api::pk_ed25519 &obj) { res = std::make_unique<DecryptorEd25519>(obj.key_); },
-                     [&](const ton_api::pk_overlay &obj) { res = std::make_unique<DecryptorFail>(); },
-                     [&](const ton_api::pk_aes &obj) { res = std::make_unique<DecryptorAES>(obj.key_); }));
-  return res;
-}
-
 td::Result<td::BufferSlice> EncryptorEd25519::encrypt(td::Slice data) {
   TRY_RESULT_PREFIX(pk, td::Ed25519::generate_private_key(), "failed to generate private key: ");
   TRY_RESULT_PREFIX(pubkey, pk.get_public_key(), "failed to get public key from private: ");
diff --git a/keys/encryptor.h b/keys/encryptor.h
index 3035a0ce..818c97d6 100644
--- a/keys/encryptor.h
+++ b/keys/encryptor.h
@@ -31,7 +31,6 @@ class Encryptor {
   virtual td::Result<td::BufferSlice> encrypt(td::Slice data) = 0;
   virtual td::Status check_signature(td::Slice message, td::Slice signature) = 0;
   virtual ~Encryptor() = default;
-  static td::Result<std::unique_ptr<Encryptor>> create(const ton_api::PublicKey *id);
 };
 
 class Decryptor {
@@ -40,7 +39,6 @@ class Decryptor {
   virtual td::Result<td::BufferSlice> sign(td::Slice data) = 0;
   virtual std::vector<td::Result<td::BufferSlice>> sign_batch(std::vector<td::Slice> data);
   virtual ~Decryptor() = default;
-  static td::Result<std::unique_ptr<Decryptor>> create(const ton_api::PrivateKey *id);
 };
 
 class EncryptorAsync : public td::actor::Actor {
@@ -61,16 +59,6 @@ class EncryptorAsync : public td::actor::Actor {
   void encrypt(td::BufferSlice data, td::Promise<td::BufferSlice> promise) {
     promise.set_result(encryptor_->encrypt(data.as_slice()));
   }
-  template <class T>
-  static td::Result<td::actor::ActorOwn<EncryptorAsync>> create(T &id) {
-    TRY_RESULT(d, Encryptor::create(id));
-    return td::actor::create_actor<EncryptorAsync>("encryptor", std::move(d));
-  }
-  template <class T>
-  static td::Result<td::actor::ActorOwn<EncryptorAsync>> create(T *id) {
-    TRY_RESULT(d, Encryptor::create(id));
-    return td::actor::create_actor<EncryptorAsync>("encryptor", std::move(d));
-  }
 };
 
 class DecryptorAsync : public td::actor::Actor {
@@ -94,16 +82,6 @@ class DecryptorAsync : public td::actor::Actor {
     }
     return decryptor_->sign_batch(v);
   }
-  template <class T>
-  static td::Result<td::actor::ActorOwn<DecryptorAsync>> create(T &id) {
-    TRY_RESULT(d, Decryptor::create(id));
-    return td::actor::create_actor<DecryptorAsync>("decryptor", std::move(d));
-  }
-  template <class T>
-  static td::Result<td::actor::ActorOwn<DecryptorAsync>> create(T *id) {
-    TRY_RESULT(d, Decryptor::create(id));
-    return td::actor::create_actor<DecryptorAsync>("decryptor", std::move(d));
-  }
 };
 
 }  // namespace ton
diff --git a/keys/encryptor.hpp b/keys/encryptor.hpp
index dbe88239..bcc841dc 100644
--- a/keys/encryptor.hpp
+++ b/keys/encryptor.hpp
@@ -83,7 +83,7 @@ class EncryptorEd25519 : public Encryptor {
   td::Result<td::BufferSlice> encrypt(td::Slice data) override;
   td::Status check_signature(td::Slice message, td::Slice signature) override;
 
-  EncryptorEd25519(td::Bits256 key) : pub_(td::SecureString(as_slice(key))) {
+  EncryptorEd25519(const td::Bits256& key) : pub_(td::SecureString(as_slice(key))) {
   }
 };
 
@@ -94,7 +94,7 @@ class DecryptorEd25519 : public Decryptor {
  public:
   td::Result<td::BufferSlice> decrypt(td::Slice data) override;
   td::Result<td::BufferSlice> sign(td::Slice data) override;
-  DecryptorEd25519(td::Bits256 key) : pk_(td::SecureString(as_slice(key))) {
+  DecryptorEd25519(const td::Bits256& key) : pk_(td::SecureString(as_slice(key))) {
   }
 };
 
@@ -129,12 +129,15 @@ class EncryptorAES : public Encryptor {
   td::Bits256 shared_secret_;
 
  public:
+  ~EncryptorAES() override {
+    shared_secret_.set_zero_s();
+  }
   td::Result<td::BufferSlice> encrypt(td::Slice data) override;
   td::Status check_signature(td::Slice message, td::Slice signature) override {
     return td::Status::Error("can no sign channel messages");
   }
 
-  EncryptorAES(td::Bits256 shared_secret) : shared_secret_(shared_secret) {
+  EncryptorAES(const td::Bits256& shared_secret) : shared_secret_(shared_secret) {
   }
 };
 
@@ -143,11 +146,14 @@ class DecryptorAES : public Decryptor {
   td::Bits256 shared_secret_;
 
  public:
+  ~DecryptorAES() override {
+    shared_secret_.set_zero_s();
+  }
   td::Result<td::BufferSlice> decrypt(td::Slice data) override;
   td::Result<td::BufferSlice> sign(td::Slice data) override {
     return td::Status::Error("can no sign channel messages");
   }
-  DecryptorAES(td::Bits256 shared_secret) : shared_secret_(shared_secret) {
+  DecryptorAES(const td::Bits256& shared_secret) : shared_secret_(shared_secret) {
   }
 };
 
diff --git a/keys/keys.cpp b/keys/keys.cpp
index 7d6c0c2c..01afb26d 100644
--- a/keys/keys.cpp
+++ b/keys/keys.cpp
@@ -21,6 +21,7 @@
 #include "td/utils/overloaded.h"
 #include "tl-utils/tl-utils.hpp"
 #include "encryptor.h"
+#include "encryptor.hpp"
 #include "crypto/Ed25519.h"
 
 namespace ton {
@@ -63,12 +64,31 @@ td::Result<PublicKey> PublicKey::import(td::Slice s) {
   return PublicKey{x};
 }
 
+td::Result<std::unique_ptr<Encryptor>> pubkeys::Ed25519::create_encryptor() const {
+  return std::make_unique<EncryptorEd25519>(data_);
+}
+
+td::Result<std::unique_ptr<Encryptor>> pubkeys::AES::create_encryptor() const {
+  return std::make_unique<EncryptorAES>(data_);
+}
+
+td::Result<std::unique_ptr<Encryptor>> pubkeys::Unenc::create_encryptor() const {
+  return std::make_unique<EncryptorNone>();
+}
+
+td::Result<std::unique_ptr<Encryptor>> pubkeys::Overlay::create_encryptor() const {
+  return std::make_unique<EncryptorOverlay>();
+}
+
 td::Result<std::unique_ptr<Encryptor>> PublicKey::create_encryptor() const {
-  return Encryptor::create(tl().get());
+  td::Result<std::unique_ptr<Encryptor>> res;
+  pub_key_.visit([&](auto &obj) { res = obj.create_encryptor(); });
+  return res;
 }
 
 td::Result<td::actor::ActorOwn<EncryptorAsync>> PublicKey::create_encryptor_async() const {
-  return EncryptorAsync::create(tl().get());
+  TRY_RESULT(encryptor, create_encryptor());
+  return td::actor::create_actor<EncryptorAsync>("encryptor", std::move(encryptor));
 }
 
 bool PublicKey::empty() const {
@@ -109,6 +129,22 @@ privkeys::Ed25519::Ed25519(td::Ed25519::PrivateKey key) {
   data_.as_slice().copy_from(td::Slice(s));
 }
 
+td::Result<std::unique_ptr<Decryptor>> privkeys::Ed25519::create_decryptor() const {
+  return std::make_unique<DecryptorEd25519>(data_);
+}
+
+td::Result<std::unique_ptr<Decryptor>> privkeys::AES::create_decryptor() const {
+  return std::make_unique<DecryptorAES>(data_);
+}
+
+td::Result<std::unique_ptr<Decryptor>> privkeys::Unenc::create_decryptor() const {
+  return std::make_unique<DecryptorNone>();
+}
+
+td::Result<std::unique_ptr<Decryptor>> privkeys::Overlay::create_decryptor() const {
+  return std::make_unique<DecryptorFail>();
+}
+
 pubkeys::Ed25519::Ed25519(td::Ed25519::PublicKey key) {
   auto s = key.as_octet_string();
   CHECK(s.length() == 32);
@@ -188,11 +224,14 @@ tl_object_ptr<ton_api::PrivateKey> PrivateKey::tl() const {
 }
 
 td::Result<std::unique_ptr<Decryptor>> PrivateKey::create_decryptor() const {
-  return Decryptor::create(tl().get());
+  td::Result<std::unique_ptr<Decryptor>> res;
+  priv_key_.visit([&](auto &obj) { res = obj.create_decryptor(); });
+  return res;
 }
 
 td::Result<td::actor::ActorOwn<DecryptorAsync>> PrivateKey::create_decryptor_async() const {
-  return DecryptorAsync::create(tl().get());
+  TRY_RESULT(decryptor, create_decryptor());
+  return td::actor::create_actor<DecryptorAsync>("decryptor", std::move(decryptor));
 }
 
 }  // namespace ton
diff --git a/keys/keys.hpp b/keys/keys.hpp
index 6ed51f08..2e517b2e 100644
--- a/keys/keys.hpp
+++ b/keys/keys.hpp
@@ -110,6 +110,7 @@ class Ed25519 {
   tl_object_ptr<ton_api::pub_ed25519> tl() const {
     return create_tl_object<ton_api::pub_ed25519>(data_);
   }
+  td::Result<std::unique_ptr<Encryptor>> create_encryptor() const;
   bool operator==(const Ed25519 &with) const {
     return data_ == with.data_;
   }
@@ -141,6 +142,7 @@ class AES {
   tl_object_ptr<ton_api::pub_aes> tl() const {
     return create_tl_object<ton_api::pub_aes>(data_);
   }
+  td::Result<std::unique_ptr<Encryptor>> create_encryptor() const;
   bool operator==(const AES &with) const {
     return data_ == with.data_;
   }
@@ -172,6 +174,7 @@ class Unenc {
   tl_object_ptr<ton_api::pub_unenc> tl() const {
     return create_tl_object<ton_api::pub_unenc>(data_.clone_as_buffer_slice());
   }
+  td::Result<std::unique_ptr<Encryptor>> create_encryptor() const;
   bool operator==(const Unenc &with) const {
     return data_.as_slice() == with.data_.as_slice();
   }
@@ -203,6 +206,7 @@ class Overlay {
   tl_object_ptr<ton_api::pub_overlay> tl() const {
     return create_tl_object<ton_api::pub_overlay>(data_.clone_as_buffer_slice());
   }
+  td::Result<std::unique_ptr<Encryptor>> create_encryptor() const;
   bool operator==(const Overlay &with) const {
     return data_.as_slice() == with.data_.as_slice();
   }
@@ -223,6 +227,9 @@ class PublicKey {
     td::uint32 serialized_size() const {
       UNREACHABLE();
     }
+    td::Result<std::unique_ptr<Encryptor>> create_encryptor() const {
+      UNREACHABLE();
+    }
     bool operator==(const Empty &with) const {
       return false;
     }
@@ -320,6 +327,7 @@ class Ed25519 {
   }
   tl_object_ptr<ton_api::PublicKey> pub_tl() const;
   pubkeys::Ed25519 pub() const;
+  td::Result<std::unique_ptr<Decryptor>> create_decryptor() const;
   static Ed25519 random();
 };
 
@@ -363,6 +371,7 @@ class AES {
   pubkeys::AES pub() const {
     return pubkeys::AES{data_};
   }
+  td::Result<std::unique_ptr<Decryptor>> create_decryptor() const;
 };
 
 class Unenc {
@@ -397,6 +406,7 @@ class Unenc {
   pubkeys::Unenc pub() const {
     return pubkeys::Unenc{data_.clone()};
   }
+  td::Result<std::unique_ptr<Decryptor>> create_decryptor() const;
 };
 
 class Overlay {
@@ -431,6 +441,7 @@ class Overlay {
   pubkeys::Overlay pub() const {
     return pubkeys::Overlay{data_.clone()};
   }
+  td::Result<std::unique_ptr<Decryptor>> create_decryptor() const;
 };
 
 }  // namespace privkeys
@@ -454,6 +465,9 @@ class PrivateKey {
     PublicKey pub() const {
       UNREACHABLE();
     }
+    td::Result<std::unique_ptr<Decryptor>> create_decryptor() const {
+      UNREACHABLE();
+    }
   };
   td::Variant<Empty, privkeys::Ed25519, privkeys::AES, privkeys::Unenc, privkeys::Overlay> priv_key_{Empty{}};
 
diff --git a/overlay/overlay.cpp b/overlay/overlay.cpp
index e93d698a..345d18e6 100644
--- a/overlay/overlay.cpp
+++ b/overlay/overlay.cpp
@@ -321,11 +321,14 @@ void OverlayImpl::alarm() {
     }
     if (next_dht_query_ && next_dht_query_.is_in_past() && overlay_type_ == OverlayType::Public) {
       next_dht_query_ = td::Timestamp::never();
-      auto P = td::PromiseCreator::lambda([SelfId = actor_id(this)](td::Result<dht::DhtValue> res) {
-        td::actor::send_closure(SelfId, &OverlayImpl::receive_dht_nodes, std::move(res), true);
-      });
-      td::actor::send_closure(dht_node_, &dht::Dht::get_value, dht::DhtKey{overlay_id_.pubkey_hash(), "nodes", 0},
-                              std::move(P));
+      std::function<void(dht::DhtValue)> callback = [SelfId = actor_id(this)](dht::DhtValue value) {
+        td::actor::send_closure(SelfId, &OverlayImpl::receive_dht_nodes, std::move(value));
+      };
+      td::Promise<td::Unit> on_finish = [SelfId = actor_id(this)](td::Result<td::Unit> R) {
+        td::actor::send_closure(SelfId, &OverlayImpl::dht_lookup_finished, R.move_as_status());
+      };
+      td::actor::send_closure(dht_node_, &dht::Dht::get_value_many, dht::DhtKey{overlay_id_.pubkey_hash(), "nodes", 0},
+                              std::move(callback), std::move(on_finish));
     }
     if (update_db_at_.is_in_past() && overlay_type_ == OverlayType::Public) {
       std::vector<OverlayNode> vec;
@@ -350,30 +353,30 @@ void OverlayImpl::alarm() {
   }
 }
 
-void OverlayImpl::receive_dht_nodes(td::Result<dht::DhtValue> res, bool dummy) {
+void OverlayImpl::receive_dht_nodes(dht::DhtValue v) {
   CHECK(overlay_type_ == OverlayType::Public);
-  if (res.is_ok()) {
-    auto v = res.move_as_ok();
-    auto R = fetch_tl_object<ton_api::overlay_nodes>(v.value().clone(), true);
-    if (R.is_ok()) {
-      auto r = R.move_as_ok();
-      VLOG(OVERLAY_INFO) << this << ": received " << r->nodes_.size() << " nodes from overlay";
-      VLOG(OVERLAY_EXTRA_DEBUG) << this << ": nodes: " << ton_api::to_string(r);
-      std::vector<OverlayNode> nodes;
-      for (auto &n : r->nodes_) {
-        auto N = OverlayNode::create(n);
-        if (N.is_ok()) {
-          nodes.emplace_back(N.move_as_ok());
-        }
+  auto R = fetch_tl_object<ton_api::overlay_nodes>(v.value().clone(), true);
+  if (R.is_ok()) {
+    auto r = R.move_as_ok();
+    VLOG(OVERLAY_INFO) << this << ": received " << r->nodes_.size() << " nodes from overlay";
+    VLOG(OVERLAY_EXTRA_DEBUG) << this << ": nodes: " << ton_api::to_string(r);
+    std::vector<OverlayNode> nodes;
+    for (auto &n : r->nodes_) {
+      auto N = OverlayNode::create(n);
+      if (N.is_ok()) {
+        nodes.emplace_back(N.move_as_ok());
       }
-      add_peers(std::move(nodes));
-    } else {
-      VLOG(OVERLAY_WARNING) << this << ": incorrect value in DHT for overlay nodes: " << R.move_as_error();
     }
+    add_peers(std::move(nodes));
   } else {
-    VLOG(OVERLAY_NOTICE) << this << ": can not get value from DHT: " << res.move_as_error();
+    VLOG(OVERLAY_WARNING) << this << ": incorrect value in DHT for overlay nodes: " << R.move_as_error();
   }
+}
 
+void OverlayImpl::dht_lookup_finished(td::Status S) {
+  if (S.is_error()) {
+    VLOG(OVERLAY_NOTICE) << this << ": can not get value from DHT: " << S;
+  }
   if (!(next_dht_store_query_ && next_dht_store_query_.is_in_past())) {
     finish_dht_query();
     return;
diff --git a/overlay/overlay.hpp b/overlay/overlay.hpp
index 8cf9e9b0..b08aaf46 100644
--- a/overlay/overlay.hpp
+++ b/overlay/overlay.hpp
@@ -206,7 +206,8 @@ class OverlayImpl : public Overlay {
   }
   void update_member_certificate(OverlayMemberCertificate cert) override;
 
-  void receive_dht_nodes(td::Result<dht::DhtValue> res, bool dummy);
+  void receive_dht_nodes(dht::DhtValue v);
+  void dht_lookup_finished(td::Status S);
   void update_dht_nodes(OverlayNode node);
 
   void update_neighbours(td::uint32 nodes_to_change);
diff --git a/tdutils/td/utils/Status.h b/tdutils/td/utils/Status.h
index 9c4f1b7d..8bc210db 100644
--- a/tdutils/td/utils/Status.h
+++ b/tdutils/td/utils/Status.h
@@ -555,6 +555,12 @@ class Result {
     };
     return status_.move_as_error_suffix(suffix);
   }
+  Status move_as_status() TD_WARN_UNUSED_RESULT {
+    if (status_.is_error()) {
+      return move_as_error();
+    }
+    return Status::OK();
+  }
   const T &ok() const {
     LOG_CHECK(status_.is_ok()) << status_;
     return value_;