diff --git a/cabal.project b/cabal.project
index 9bbbfda98d..1a7b52f2ce 100644
--- a/cabal.project
+++ b/cabal.project
@@ -7,7 +7,7 @@ constraints: zip +disable-bzip2 +disable-zstd
 source-repository-package
     type: git
     location: https://github.com/simplex-chat/simplexmq.git
-    tag: e4842f4f47fb60ef8843dbce6fd43dec96f157d2
+    tag: fb21d9836e07706c7498baa967f932cb11b818e5
 
 source-repository-package
     type: git
diff --git a/scripts/nix/sha256map.nix b/scripts/nix/sha256map.nix
index 088650ba66..c744faa348 100644
--- a/scripts/nix/sha256map.nix
+++ b/scripts/nix/sha256map.nix
@@ -1,5 +1,5 @@
 {
-  "https://github.com/simplex-chat/simplexmq.git"."e4842f4f47fb60ef8843dbce6fd43dec96f157d2" = "191h2v5jcn51haj0mi5y5pm8x8fi9pz49ydxwwzqr3m6zjp21ngg";
+  "https://github.com/simplex-chat/simplexmq.git"."fb21d9836e07706c7498baa967f932cb11b818e5" = "0dl08ag38d1azzil1xxi6xrzqwfcv550wi5kjdmxn4h820icl2ja";
   "https://github.com/simplex-chat/direct-sqlcipher.git"."34309410eb2069b029b8fc1872deb1e0db123294" = "0kwkmhyfsn2lixdlgl15smgr1h5gjk7fky6abzh8rng2h5ymnffd";
   "https://github.com/simplex-chat/sqlcipher-simple.git"."5e154a2aeccc33ead6c243ec07195ab673137221" = "1d1gc5wax4vqg0801ajsmx1sbwvd9y7p7b8mmskvqsmpbwgbh0m0";
   "https://github.com/simplex-chat/aeson.git"."3eb66f9a68f103b5f1489382aad89f5712a64db7" = "0kilkx59fl6c3qy3kjczqvm8c3f4n3p0bdk9biyflf51ljnzp4yp";
diff --git a/simplex-chat.cabal b/simplex-chat.cabal
index b99e41b437..dc06e6b5ab 100644
--- a/simplex-chat.cabal
+++ b/simplex-chat.cabal
@@ -65,6 +65,7 @@ library
       Simplex.Chat.Migrations.M20221115_server_cfg
       Simplex.Chat.Migrations.M20221129_delete_group_feature_items
       Simplex.Chat.Migrations.M20221130_delete_item_deleted
+      Simplex.Chat.Migrations.M20221209_verified_connection
       Simplex.Chat.Mobile
       Simplex.Chat.Options
       Simplex.Chat.ProfileGenerator
diff --git a/src/Simplex/Chat.hs b/src/Simplex/Chat.hs
index de5ca2ed1c..bbad35301b 100644
--- a/src/Simplex/Chat.hs
+++ b/src/Simplex/Chat.hs
@@ -758,24 +758,53 @@ processChatCommand = \case
     case memberConnId m of
       Just connId -> withAgent (\a -> switchConnectionAsync a "" connId) $> CRCmdOk
       _ -> throwChatError CEGroupMemberNotActive
+  APIGetContactCode contactId -> withUser $ \user -> do
+    ct@Contact {activeConn = conn@Connection {connId}} <- withStore $ \db -> getContact db user contactId
+    code <- getConnectionCode (contactConnId ct)
+    ct' <- case contactSecurityCode ct of
+      Just SecurityCode {securityCode}
+        | sameVerificationCode code securityCode -> pure ct
+        | otherwise -> do
+          withStore' $ \db -> setConnectionVerified db user connId Nothing
+          pure (ct :: Contact) {activeConn = conn {connectionCode = Nothing}}
+      _ -> pure ct
+    pure $ CRContactCode ct' code
+  APIGetGroupMemberCode gId gMemberId -> withUser $ \user -> do
+    (g, m@GroupMember {activeConn}) <- withStore $ \db -> (,) <$> getGroupInfo db user gId <*> getGroupMember db user gId gMemberId
+    case activeConn of
+      Just conn@Connection {connId} -> do
+        code <- getConnectionCode $ aConnId conn
+        m' <- case memberSecurityCode m of
+          Just SecurityCode {securityCode}
+            | sameVerificationCode code securityCode -> pure m
+            | otherwise -> do
+              withStore' $ \db -> setConnectionVerified db user connId Nothing
+              pure (m :: GroupMember) {activeConn = Just $ (conn :: Connection) {connectionCode = Nothing}}
+          _ -> pure m
+        pure $ CRGroupMemberCode g m' code
+      _ -> throwChatError CEGroupMemberNotActive
+  APIVerifyContact contactId code -> withUser $ \user -> do
+    Contact {activeConn} <- withStore $ \db -> getContact db user contactId
+    verifyConnectionCode user activeConn code
+  APIVerifyGroupMember gId gMemberId code -> withUser $ \user -> do
+    GroupMember {activeConn} <- withStore $ \db -> getGroupMember db user gId gMemberId
+    case activeConn of
+      Just conn -> verifyConnectionCode user conn code
+      _ -> throwChatError CEGroupMemberNotActive
   ShowMessages (ChatName cType name) ntfOn -> withUser $ \user -> do
     chatId <- case cType of
       CTDirect -> withStore $ \db -> getContactIdByName db user name
       CTGroup -> withStore $ \db -> getGroupIdByName db user name
       _ -> throwChatError $ CECommandError "not supported"
     processChatCommand $ APISetChatSettings (ChatRef cType chatId) $ ChatSettings ntfOn
-  ContactInfo cName -> withUser $ \user -> do
-    contactId <- withStore $ \db -> getContactIdByName db user cName
-    processChatCommand $ APIContactInfo contactId
-  GroupMemberInfo gName mName -> withUser $ \user -> do
-    (gId, mId) <- withStore $ \db -> getGroupIdByName db user gName >>= \gId -> (gId,) <$> getGroupMemberIdByName db user gId mName
-    processChatCommand $ APIGroupMemberInfo gId mId
-  SwitchContact cName -> withUser $ \user -> do
-    contactId <- withStore $ \db -> getContactIdByName db user cName
-    processChatCommand $ APISwitchContact contactId
-  SwitchGroupMember gName mName -> withUser $ \user -> do
-    (gId, mId) <- withStore $ \db -> getGroupIdByName db user gName >>= \gId -> (gId,) <$> getGroupMemberIdByName db user gId mName
-    processChatCommand $ APISwitchGroupMember gId mId
+  ContactInfo cName -> withContactName cName APIContactInfo
+  GroupMemberInfo gName mName -> withMemberName gName mName APIGroupMemberInfo
+  SwitchContact cName -> withContactName cName APISwitchContact
+  SwitchGroupMember gName mName -> withMemberName gName mName APISwitchGroupMember
+  GetContactCode cName -> withContactName cName APIGetContactCode
+  GetGroupMemberCode gName mName -> withMemberName gName mName APIGetGroupMemberCode
+  VerifyContact cName code -> withContactName cName (`APIVerifyContact` code)
+  VerifyGroupMember gName mName code -> withMemberName gName mName $ \gId mId -> APIVerifyGroupMember gId mId code
   ChatHelp section -> pure $ CRChatHelp section
   Welcome -> withUser $ pure . CRWelcome
   AddContact -> withUser $ \User {userId} -> withChatLock "addContact" . procCmd $ do
@@ -802,12 +831,8 @@ processChatCommand = \case
   ConnectSimplex -> withUser $ \user ->
     -- [incognito] generate profile to send
     connectViaContact user adminContactReq
-  DeleteContact cName -> withUser $ \user -> do
-    contactId <- withStore $ \db -> getContactIdByName db user cName
-    processChatCommand $ APIDeleteChat (ChatRef CTDirect contactId)
-  ClearContact cName -> withUser $ \user -> do
-    contactId <- withStore $ \db -> getContactIdByName db user cName
-    processChatCommand $ APIClearChat (ChatRef CTDirect contactId)
+  DeleteContact cName -> withContactName cName $ APIDeleteChat . ChatRef CTDirect
+  ClearContact cName -> withContactName cName $ APIClearChat . ChatRef CTDirect
   ListContacts -> withUser $ \user -> CRContactsList <$> withStore' (`getUserContacts` user)
   CreateMyAddress -> withUser $ \User {userId} -> withChatLock "createMyAddress" . procCmd $ do
     (connId, cReq) <- withAgent $ \a -> createConnection a True SCMContact Nothing
@@ -977,12 +1002,8 @@ processChatCommand = \case
   JoinGroup gName -> withUser $ \user -> do
     groupId <- withStore $ \db -> getGroupIdByName db user gName
     processChatCommand $ APIJoinGroup groupId
-  MemberRole gName groupMemberName memRole -> do
-    (groupId, groupMemberId) <- getGroupAndMemberId gName groupMemberName
-    processChatCommand $ APIMemberRole groupId groupMemberId memRole
-  RemoveMember gName groupMemberName -> do
-    (groupId, groupMemberId) <- getGroupAndMemberId gName groupMemberName
-    processChatCommand $ APIRemoveMember groupId groupMemberId
+  MemberRole gName gMemberName memRole -> withMemberName gName gMemberName $ \gId gMemberId -> APIMemberRole gId gMemberId memRole
+  RemoveMember gName gMemberName -> withMemberName gName gMemberName APIRemoveMember
   LeaveGroup gName -> withUser $ \user -> do
     groupId <- withStore $ \db -> getGroupIdByName db user gName
     processChatCommand $ APILeaveGroup groupId
@@ -1135,6 +1156,20 @@ processChatCommand = \case
     withStoreChanged a = checkChatStopped $ a >> setStoreChanged $> CRCmdOk
     checkStoreNotChanged :: m ChatResponse -> m ChatResponse
     checkStoreNotChanged = ifM (asks chatStoreChanged >>= readTVarIO) (throwChatError CEChatStoreChanged)
+    withContactName :: ContactName -> (ContactId -> ChatCommand) -> m ChatResponse
+    withContactName cName cmd = withUser $ \user ->
+      withStore (\db -> getContactIdByName db user cName) >>= processChatCommand . cmd
+    withMemberName :: GroupName -> ContactName -> (GroupId -> GroupMemberId -> ChatCommand) -> m ChatResponse
+    withMemberName gName mName cmd = withUser $ \user ->
+      getGroupAndMemberId user gName mName >>= processChatCommand . uncurry cmd
+    getConnectionCode :: ConnId -> m Text
+    getConnectionCode connId = verificationCode <$> withAgent (`getConnectionRatchetAdHash` connId)
+    verifyConnectionCode :: User -> Connection -> Text -> m ChatResponse
+    verifyConnectionCode user conn@Connection {connId} code = do
+      code' <- getConnectionCode $ aConnId conn
+      let verified = sameVerificationCode code code'
+      when verified . withStore' $ \db -> setConnectionVerified db user connId $ Just code'
+      pure $ CRCodeVerification verified code'
     getSentChatItemIdByText :: User -> ChatRef -> ByteString -> m Int64
     getSentChatItemIdByText user@User {userId, localDisplayName} (ChatRef cType cId) msg = case cType of
       CTDirect -> withStore $ \db -> getDirectChatItemIdByText db userId cId SMDSnd (safeDecodeUtf8 msg)
@@ -1253,8 +1288,8 @@ processChatCommand = \case
         _ -> throwChatError CEFileNotReceived {fileId}
       where
         forward = processChatCommand . sendCommand chatName
-    getGroupAndMemberId :: GroupName -> ContactName -> m (GroupId, GroupMemberId)
-    getGroupAndMemberId gName groupMemberName = withUser $ \user -> do
+    getGroupAndMemberId :: User -> GroupName -> ContactName -> m (GroupId, GroupMemberId)
+    getGroupAndMemberId user gName groupMemberName =
       withStore $ \db -> do
         groupId <- getGroupIdByName db user gName
         groupMemberId <- getGroupMemberIdByName db user groupId groupMemberName
@@ -3391,6 +3426,14 @@ chatCommandP =
       "/_switch @" *> (APISwitchContact <$> A.decimal),
       "/switch #" *> (SwitchGroupMember <$> displayName <* A.space <* optional (A.char '@') <*> displayName),
       ("/switch @" <|> "/switch ") *> (SwitchContact <$> displayName),
+      "/_get code @" *> (APIGetContactCode <$> A.decimal),
+      "/_get code #" *> (APIGetGroupMemberCode <$> A.decimal <* A.space <*> A.decimal),
+      "/_verify code @" *> (APIVerifyContact <$> A.decimal <* A.space <*> textP),
+      "/_verify code @" *> (APIVerifyGroupMember <$> A.decimal <* A.space <*> A.decimal <* A.space <*> textP),
+      ("/code @" <|> "/code ") *> (GetContactCode <$> displayName),
+      "/code #" *> (GetGroupMemberCode <$> displayName <* A.space <* optional (A.char '@') <*> displayName),
+      ("/verify @" <|> "/verify ") *> (VerifyContact <$> displayName <* A.space <*> textP),
+      "/verify #" *> (VerifyGroupMember <$> displayName <* A.space <* optional (A.char '@') <*> displayName <* A.space <*> textP),
       ("/help files" <|> "/help file" <|> "/hf") $> ChatHelp HSFiles,
       ("/help groups" <|> "/help group" <|> "/hg") $> ChatHelp HSGroups,
       ("/help address" <|> "/ha") $> ChatHelp HSMyAddress,
diff --git a/src/Simplex/Chat/Controller.hs b/src/Simplex/Chat/Controller.hs
index bef8de88c2..1235542409 100644
--- a/src/Simplex/Chat/Controller.hs
+++ b/src/Simplex/Chat/Controller.hs
@@ -200,11 +200,19 @@ data ChatCommand
   | APIGroupMemberInfo GroupId GroupMemberId
   | APISwitchContact ContactId
   | APISwitchGroupMember GroupId GroupMemberId
+  | APIGetContactCode ContactId
+  | APIGetGroupMemberCode GroupId GroupMemberId
+  | APIVerifyContact ContactId Text
+  | APIVerifyGroupMember GroupId GroupMemberId Text
   | ShowMessages ChatName Bool
   | ContactInfo ContactName
   | GroupMemberInfo GroupName ContactName
   | SwitchContact ContactName
   | SwitchGroupMember GroupName ContactName
+  | GetContactCode ContactName
+  | GetGroupMemberCode GroupName ContactName
+  | VerifyContact ContactName Text
+  | VerifyGroupMember GroupName ContactName Text
   | ChatHelp HelpSection
   | Welcome
   | AddContact
@@ -276,6 +284,9 @@ data ChatResponse
   | CRGroupMemberInfo {groupInfo :: GroupInfo, member :: GroupMember, connectionStats_ :: Maybe ConnectionStats}
   | CRContactSwitch {contact :: Contact, switchProgress :: SwitchProgress}
   | CRGroupMemberSwitch {groupInfo :: GroupInfo, member :: GroupMember, switchProgress :: SwitchProgress}
+  | CRContactCode {contact :: Contact, connectionCode :: Text}
+  | CRGroupMemberCode {groupInfo :: GroupInfo, member :: GroupMember, connectionCode :: Text}
+  | CRCodeVerification {verified :: Bool, expectedCode :: Text}
   | CRNewChatItem {chatItem :: AChatItem}
   | CRChatItemStatusUpdated {chatItem :: AChatItem}
   | CRChatItemUpdated {chatItem :: AChatItem}
diff --git a/src/Simplex/Chat/Migrations/M20221209_verified_connection.hs b/src/Simplex/Chat/Migrations/M20221209_verified_connection.hs
new file mode 100644
index 0000000000..f7e4a8aee9
--- /dev/null
+++ b/src/Simplex/Chat/Migrations/M20221209_verified_connection.hs
@@ -0,0 +1,13 @@
+{-# LANGUAGE QuasiQuotes #-}
+
+module Simplex.Chat.Migrations.M20221209_verified_connection where
+
+import Database.SQLite.Simple (Query)
+import Database.SQLite.Simple.QQ (sql)
+
+m20221209_verified_connection :: Query
+m20221209_verified_connection =
+  [sql|
+ALTER TABLE connections ADD COLUMN security_code TEXT NULL;
+ALTER TABLE connections ADD COLUMN security_code_verified_at TEXT NULL;
+|]
diff --git a/src/Simplex/Chat/Migrations/chat_schema.sql b/src/Simplex/Chat/Migrations/chat_schema.sql
index 2ee771ed44..079fc76345 100644
--- a/src/Simplex/Chat/Migrations/chat_schema.sql
+++ b/src/Simplex/Chat/Migrations/chat_schema.sql
@@ -258,6 +258,8 @@ CREATE TABLE connections(
   local_alias DEFAULT '' CHECK(local_alias NOT NULL),
   via_group_link INTEGER DEFAULT 0 CHECK(via_group_link NOT NULL),
   group_link_id BLOB,
+  security_code TEXT NULL,
+  security_code_verified_at TEXT NULL,
   FOREIGN KEY(snd_file_id, connection_id)
   REFERENCES snd_files(file_id, connection_id)
   ON DELETE CASCADE
diff --git a/src/Simplex/Chat/Store.hs b/src/Simplex/Chat/Store.hs
index 0d92f443c9..9e26e2e5f5 100644
--- a/src/Simplex/Chat/Store.hs
+++ b/src/Simplex/Chat/Store.hs
@@ -47,6 +47,7 @@ module Simplex.Chat.Store
     updateContactUsed,
     updateContactUnreadChat,
     updateGroupUnreadChat,
+    setConnectionVerified,
     getUserContacts,
     getUserContactProfiles,
     createUserContactLink,
@@ -304,6 +305,7 @@ import Simplex.Chat.Migrations.M20221112_server_password
 import Simplex.Chat.Migrations.M20221115_server_cfg
 import Simplex.Chat.Migrations.M20221129_delete_group_feature_items
 import Simplex.Chat.Migrations.M20221130_delete_item_deleted
+import Simplex.Chat.Migrations.M20221209_verified_connection
 import Simplex.Chat.Protocol
 import Simplex.Chat.Types
 import Simplex.Messaging.Agent.Protocol (ACorrId, AgentMsgId, ConnId, InvitationId, MsgMeta (..))
@@ -354,7 +356,8 @@ schemaMigrations =
     ("20221112_server_password", m20221112_server_password),
     ("20221115_server_cfg", m20221115_server_cfg),
     ("20221129_delete_group_feature_items", m20221129_delete_group_feature_items),
-    ("20221130_delete_item_deleted", m20221130_delete_item_deleted)
+    ("20221130_delete_item_deleted", m20221130_delete_item_deleted),
+    ("20221209_verified_connection", m20221209_verified_connection)
   ]
 
 -- | The list of migrations in ascending order by date
@@ -465,7 +468,7 @@ getConnReqContactXContactId db user@User {userId} cReqHash = do
               ct.contact_id, ct.contact_profile_id, ct.local_display_name, ct.via_group, cp.display_name, cp.full_name, cp.image, cp.local_alias, ct.contact_used, ct.enable_ntfs, cp.preferences, ct.user_preferences, ct.created_at, ct.updated_at,
               -- Connection
               c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id, c.conn_status, c.conn_type, c.local_alias,
-              c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+              c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
             FROM contacts ct
             JOIN contact_profiles cp ON ct.contact_profile_id = cp.contact_profile_id
             JOIN connections c ON c.contact_id = ct.contact_id
@@ -540,7 +543,7 @@ createConnection_ db userId connType entityId acId viaContact viaUserContactLink
         :. (ent ConnContact, ent ConnMember, ent ConnSndFile, ent ConnRcvFile, ent ConnUserContact, currentTs, currentTs)
     )
   connId <- insertedRowId db
-  pure Connection {connId, agentConnId = AgentConnId acId, connType, entityId, viaContact, viaUserContactLink, viaGroupLink, groupLinkId = Nothing, customUserProfileId, connLevel, connStatus = ConnNew, localAlias = "", createdAt = currentTs}
+  pure Connection {connId, agentConnId = AgentConnId acId, connType, entityId, viaContact, viaUserContactLink, viaGroupLink, groupLinkId = Nothing, customUserProfileId, connLevel, connStatus = ConnNew, localAlias = "", createdAt = currentTs, connectionCode = Nothing}
   where
     ent ct = if connType == ct then entityId else Nothing
 
@@ -722,6 +725,11 @@ updateGroupUnreadChat db User {userId} GroupInfo {groupId} unreadChat = do
   updatedAt <- getCurrentTime
   DB.execute db "UPDATE groups SET unread_chat = ?, updated_at = ? WHERE user_id = ? AND group_id = ?" (unreadChat, updatedAt, userId, groupId)
 
+setConnectionVerified :: DB.Connection -> User -> Int64 -> Maybe Text -> IO ()
+setConnectionVerified db User {userId} connId code = do
+  updatedAt <- getCurrentTime
+  DB.execute db "UPDATE connections SET security_code = ?, security_code_verified_at = ?, updated_at = ? WHERE user_id = ? AND connection_id = ?" (code, code $> updatedAt, updatedAt, userId, connId)
+
 updateContactProfile_ :: DB.Connection -> UserId -> ProfileId -> Profile -> IO ()
 updateContactProfile_ db userId profileId profile = do
   currentTs <- getCurrentTime
@@ -821,7 +829,7 @@ getUserAddressConnections db User {userId} = do
           db
           [sql|
             SELECT c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id,
-              c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+              c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
             FROM connections c
             JOIN user_contact_links uc ON c.user_contact_link_id = uc.user_contact_link_id
             WHERE c.user_id = ? AND uc.user_id = ? AND uc.local_display_name = '' AND uc.group_id IS NULL
@@ -835,7 +843,7 @@ getUserContactLinks db User {userId} =
       db
       [sql|
         SELECT c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id,
-          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at,
+          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at,
           uc.user_contact_link_id, uc.conn_req_contact, uc.group_id
         FROM connections c
         JOIN user_contact_links uc ON c.user_contact_link_id = uc.user_contact_link_id
@@ -968,7 +976,7 @@ getGroupLinkConnection db User {userId} groupInfo@GroupInfo {groupId} =
       db
       [sql|
         SELECT c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id,
-          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
         FROM connections c
         JOIN user_contact_links uc ON c.user_contact_link_id = uc.user_contact_link_id
         WHERE c.user_id = ? AND uc.user_id = ? AND uc.group_id = ?
@@ -1071,7 +1079,7 @@ createOrUpdateContactRequest db user@User {userId} userContactLinkId invId Profi
               ct.contact_id, ct.contact_profile_id, ct.local_display_name, ct.via_group, cp.display_name, cp.full_name, cp.image, cp.local_alias, ct.contact_used, ct.enable_ntfs, cp.preferences, ct.user_preferences, ct.created_at, ct.updated_at,
               -- Connection
               c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id, c.conn_status, c.conn_type, c.local_alias,
-              c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+              c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
             FROM contacts ct
             JOIN contact_profiles cp ON ct.contact_profile_id = cp.contact_profile_id
             LEFT JOIN connections c ON c.contact_id = ct.contact_id
@@ -1266,7 +1274,7 @@ getContactConnections db userId Contact {contactId} =
         db
         [sql|
           SELECT c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id,
-            c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+            c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
           FROM connections c
           JOIN contacts ct ON ct.contact_id = c.contact_id
           WHERE c.user_id = ? AND ct.user_id = ? AND ct.contact_id = ?
@@ -1277,14 +1285,15 @@ getContactConnections db userId Contact {contactId} =
 
 type EntityIdsRow = (Maybe Int64, Maybe Int64, Maybe Int64, Maybe Int64, Maybe Int64)
 
-type ConnectionRow = (Int64, ConnId, Int, Maybe Int64, Maybe Int64, Bool, Maybe GroupLinkId, Maybe Int64, ConnStatus, ConnType, LocalAlias) :. EntityIdsRow :. Only UTCTime
+type ConnectionRow = (Int64, ConnId, Int, Maybe Int64, Maybe Int64, Bool, Maybe GroupLinkId, Maybe Int64, ConnStatus, ConnType, LocalAlias) :. EntityIdsRow :. (UTCTime, Maybe Text, Maybe UTCTime)
 
-type MaybeConnectionRow = (Maybe Int64, Maybe ConnId, Maybe Int, Maybe Int64, Maybe Int64, Maybe Bool, Maybe GroupLinkId, Maybe Int64, Maybe ConnStatus, Maybe ConnType, Maybe LocalAlias) :. EntityIdsRow :. Only (Maybe UTCTime)
+type MaybeConnectionRow = (Maybe Int64, Maybe ConnId, Maybe Int, Maybe Int64, Maybe Int64, Maybe Bool, Maybe GroupLinkId, Maybe Int64, Maybe ConnStatus, Maybe ConnType, Maybe LocalAlias) :. EntityIdsRow :. (Maybe UTCTime, Maybe Text, Maybe UTCTime)
 
 toConnection :: ConnectionRow -> Connection
-toConnection ((connId, acId, connLevel, viaContact, viaUserContactLink, viaGroupLink, groupLinkId, customUserProfileId, connStatus, connType, localAlias) :. (contactId, groupMemberId, sndFileId, rcvFileId, userContactLinkId) :. Only createdAt) =
+toConnection ((connId, acId, connLevel, viaContact, viaUserContactLink, viaGroupLink, groupLinkId, customUserProfileId, connStatus, connType, localAlias) :. (contactId, groupMemberId, sndFileId, rcvFileId, userContactLinkId) :. (createdAt, code_, verifiedAt_)) =
   let entityId = entityId_ connType
-   in Connection {connId, agentConnId = AgentConnId acId, connLevel, viaContact, viaUserContactLink, viaGroupLink, groupLinkId, customUserProfileId, connStatus, connType, localAlias, entityId, createdAt}
+      connectionCode = SecurityCode <$> code_ <*> verifiedAt_
+   in Connection {connId, agentConnId = AgentConnId acId, connLevel, viaContact, viaUserContactLink, viaGroupLink, groupLinkId, customUserProfileId, connStatus, connType, localAlias, entityId, connectionCode, createdAt}
   where
     entityId_ :: ConnType -> Maybe Int64
     entityId_ ConnContact = contactId
@@ -1294,8 +1303,8 @@ toConnection ((connId, acId, connLevel, viaContact, viaUserContactLink, viaGroup
     entityId_ ConnUserContact = userContactLinkId
 
 toMaybeConnection :: MaybeConnectionRow -> Maybe Connection
-toMaybeConnection ((Just connId, Just agentConnId, Just connLevel, viaContact, viaUserContactLink, Just viaGroupLink, groupLinkId, customUserProfileId, Just connStatus, Just connType, Just localAlias) :. (contactId, groupMemberId, sndFileId, rcvFileId, userContactLinkId) :. Only (Just createdAt)) =
-  Just $ toConnection ((connId, agentConnId, connLevel, viaContact, viaUserContactLink, viaGroupLink, groupLinkId, customUserProfileId, connStatus, connType, localAlias) :. (contactId, groupMemberId, sndFileId, rcvFileId, userContactLinkId) :. Only createdAt)
+toMaybeConnection ((Just connId, Just agentConnId, Just connLevel, viaContact, viaUserContactLink, Just viaGroupLink, groupLinkId, customUserProfileId, Just connStatus, Just connType, Just localAlias) :. (contactId, groupMemberId, sndFileId, rcvFileId, userContactLinkId) :. (Just createdAt, code_, verifiedAt_)) =
+  Just $ toConnection ((connId, agentConnId, connLevel, viaContact, viaUserContactLink, viaGroupLink, groupLinkId, customUserProfileId, connStatus, connType, localAlias) :. (contactId, groupMemberId, sndFileId, rcvFileId, userContactLinkId) :. (createdAt, code_, verifiedAt_))
 toMaybeConnection _ = Nothing
 
 getMatchingContacts :: DB.Connection -> User -> Contact -> IO [Contact]
@@ -1466,7 +1475,7 @@ getConnectionEntity db user@User {userId, userContactId} agentConnId = do
           db
           [sql|
             SELECT connection_id, agent_conn_id, conn_level, via_contact, via_user_contact_link, via_group_link, group_link_id, custom_user_profile_id,
-              conn_status, conn_type, local_alias, contact_id, group_member_id, snd_file_id, rcv_file_id, user_contact_link_id, created_at
+              conn_status, conn_type, local_alias, contact_id, group_member_id, snd_file_id, rcv_file_id, user_contact_link_id, created_at, security_code, security_code_verified_at
             FROM connections
             WHERE user_id = ? AND agent_conn_id = ?
           |]
@@ -1564,7 +1573,7 @@ getConnectionById db User {userId} connId = ExceptT $ do
       db
       [sql|
         SELECT connection_id, agent_conn_id, conn_level, via_contact, via_user_contact_link, via_group_link, group_link_id, custom_user_profile_id,
-          conn_status, conn_type, local_alias, contact_id, group_member_id, snd_file_id, rcv_file_id, user_contact_link_id, created_at
+          conn_status, conn_type, local_alias, contact_id, group_member_id, snd_file_id, rcv_file_id, user_contact_link_id, created_at, security_code, security_code_verified_at
         FROM connections
         WHERE user_id = ? AND connection_id = ?
       |]
@@ -1609,7 +1618,7 @@ getGroupAndMember db User {userId, userContactId} groupMemberId =
           m.group_member_id, m.group_id, m.member_id, m.member_role, m.member_category, m.member_status,
           m.invited_by, m.local_display_name, m.contact_id, m.contact_profile_id, p.contact_profile_id, p.display_name, p.full_name, p.image, p.local_alias, p.preferences,
           c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id,
-          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
         FROM group_members m
         JOIN contact_profiles p ON p.contact_profile_id = COALESCE(m.member_profile_id, m.contact_profile_id)
         JOIN groups g ON g.group_id = m.group_id
@@ -1891,7 +1900,7 @@ getGroupMember db user@User {userId} groupId groupMemberId =
           m.group_member_id, m.group_id, m.member_id, m.member_role, m.member_category, m.member_status,
           m.invited_by, m.local_display_name, m.contact_id, m.contact_profile_id, p.contact_profile_id, p.display_name, p.full_name, p.image, p.local_alias, p.preferences,
           c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id,
-          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
         FROM group_members m
         JOIN contact_profiles p ON p.contact_profile_id = COALESCE(m.member_profile_id, m.contact_profile_id)
         LEFT JOIN connections c ON c.connection_id = (
@@ -1913,7 +1922,7 @@ getGroupMembers db user@User {userId, userContactId} GroupInfo {groupId} = do
           m.group_member_id, m.group_id, m.member_id, m.member_role, m.member_category, m.member_status,
           m.invited_by, m.local_display_name, m.contact_id, m.contact_profile_id, p.contact_profile_id, p.display_name, p.full_name, p.image, p.local_alias, p.preferences,
           c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id,
-          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
         FROM group_members m
         JOIN contact_profiles p ON p.contact_profile_id = COALESCE(m.member_profile_id, m.contact_profile_id)
         LEFT JOIN connections c ON c.connection_id = (
@@ -1935,7 +1944,7 @@ getGroupMembersForExpiration db user@User {userId, userContactId} GroupInfo {gro
           m.group_member_id, m.group_id, m.member_id, m.member_role, m.member_category, m.member_status,
           m.invited_by, m.local_display_name, m.contact_id, m.contact_profile_id, p.contact_profile_id, p.display_name, p.full_name, p.image, p.local_alias,
           c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id,
-          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
         FROM group_members m
         JOIN contact_profiles p ON p.contact_profile_id = COALESCE(m.member_profile_id, m.contact_profile_id)
         LEFT JOIN connections c ON c.connection_id = (
@@ -2060,7 +2069,7 @@ getContactViaMember db user@User {userId} GroupMember {groupMemberId} =
           ct.contact_id, ct.contact_profile_id, ct.local_display_name, ct.via_group, cp.display_name, cp.full_name, cp.image, cp.local_alias, ct.contact_used, ct.enable_ntfs, cp.preferences, ct.user_preferences, ct.created_at, ct.updated_at,
           -- Connection
           c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id, c.conn_status, c.conn_type, c.local_alias,
-          c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+          c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
         FROM contacts ct
         JOIN contact_profiles cp ON cp.contact_profile_id = ct.contact_profile_id
         JOIN connections c ON c.connection_id = (
@@ -2365,7 +2374,7 @@ getViaGroupMember db User {userId, userContactId} Contact {contactId} =
           m.group_member_id, m.group_id, m.member_id, m.member_role, m.member_category, m.member_status,
           m.invited_by, m.local_display_name, m.contact_id, m.contact_profile_id, p.contact_profile_id, p.display_name, p.full_name, p.image, p.local_alias, p.preferences,
           c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id,
-          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
         FROM group_members m
         JOIN contacts ct ON ct.contact_id = m.contact_id
         JOIN contact_profiles p ON p.contact_profile_id = COALESCE(m.member_profile_id, m.contact_profile_id)
@@ -2397,7 +2406,7 @@ getViaGroupContact db user@User {userId} GroupMember {groupMemberId} =
         SELECT
           ct.contact_id, ct.contact_profile_id, ct.local_display_name, p.display_name, p.full_name, p.image, p.local_alias, ct.via_group, ct.contact_used, ct.enable_ntfs, p.preferences, ct.user_preferences, ct.created_at, ct.updated_at,
           c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id,
-          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+          c.conn_status, c.conn_type, c.local_alias, c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
         FROM contacts ct
         JOIN contact_profiles p ON ct.contact_profile_id = p.contact_profile_id
         JOIN connections c ON c.connection_id = (
@@ -3276,7 +3285,7 @@ getDirectChatPreviews_ db user@User {userId} = do
           ct.contact_id, ct.contact_profile_id, ct.local_display_name, ct.via_group, cp.display_name, cp.full_name, cp.image, cp.local_alias, ct.contact_used, ct.enable_ntfs, cp.preferences, ct.user_preferences, ct.created_at, ct.updated_at,
           -- Connection
           c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id, c.conn_status, c.conn_type, c.local_alias,
-          c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at,
+          c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at,
           -- ChatStats
           COALESCE(ChatStats.UnreadCount, 0), COALESCE(ChatStats.MinUnread, 0), ct.unread_chat,
           -- ChatItem
@@ -3598,7 +3607,7 @@ getContact db user@User {userId} contactId =
           ct.contact_id, ct.contact_profile_id, ct.local_display_name, ct.via_group, cp.display_name, cp.full_name, cp.image, cp.local_alias, ct.contact_used, ct.enable_ntfs, cp.preferences, ct.user_preferences, ct.created_at, ct.updated_at,
           -- Connection
           c.connection_id, c.agent_conn_id, c.conn_level, c.via_contact, c.via_user_contact_link, c.via_group_link, c.group_link_id, c.custom_user_profile_id, c.conn_status, c.conn_type, c.local_alias,
-          c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at
+          c.contact_id, c.group_member_id, c.snd_file_id, c.rcv_file_id, c.user_contact_link_id, c.created_at, c.security_code, c.security_code_verified_at
         FROM contacts ct
         JOIN contact_profiles cp ON ct.contact_profile_id = cp.contact_profile_id
         LEFT JOIN connections c ON c.contact_id = ct.contact_id
diff --git a/src/Simplex/Chat/Types.hs b/src/Simplex/Chat/Types.hs
index 2c54be0c1c..f03b3d5c63 100644
--- a/src/Simplex/Chat/Types.hs
+++ b/src/Simplex/Chat/Types.hs
@@ -20,6 +20,7 @@
 module Simplex.Chat.Types where
 
 import Control.Applicative ((<|>))
+import Crypto.Number.Serialize (os2ip)
 import Data.Aeson (FromJSON, ToJSON)
 import qualified Data.Aeson as J
 import qualified Data.Aeson.Encoding as JE
@@ -126,6 +127,9 @@ directContact Contact {contactUsed, activeConn = Connection {connLevel, viaGroup
 anyDirectContact :: Contact -> Bool
 anyDirectContact Contact {contactUsed, activeConn = Connection {connLevel}} = connLevel == 0 || contactUsed
 
+contactSecurityCode :: Contact -> Maybe SecurityCode
+contactSecurityCode Contact {activeConn} = connectionCode activeConn
+
 data ContactRef = ContactRef
   { contactId :: ContactId,
     localDisplayName :: ContactName
@@ -866,6 +870,9 @@ groupMemberId' GroupMember {groupMemberId} = groupMemberId
 memberIncognito :: GroupMember -> Bool
 memberIncognito GroupMember {memberProfile, memberContactProfileId} = localProfileId memberProfile /= memberContactProfileId
 
+memberSecurityCode :: GroupMember -> Maybe SecurityCode
+memberSecurityCode GroupMember {activeConn} = connectionCode =<< activeConn
+
 data NewGroupMember = NewGroupMember
   { memInfo :: MemberInfo,
     memCategory :: GroupMemberCategory,
@@ -1302,10 +1309,29 @@ data Connection = Connection
     connStatus :: ConnStatus,
     localAlias :: Text,
     entityId :: Maybe Int64, -- contact, group member, file ID or user contact ID
+    connectionCode :: Maybe SecurityCode,
     createdAt :: UTCTime
   }
   deriving (Eq, Show, Generic)
 
+data SecurityCode = SecurityCode {securityCode :: Text, verifiedAt :: UTCTime}
+  deriving (Eq, Show, Generic)
+
+instance ToJSON SecurityCode where
+  toJSON = J.genericToJSON J.defaultOptions {J.omitNothingFields = True}
+  toEncoding = J.genericToEncoding J.defaultOptions {J.omitNothingFields = True}
+
+verificationCode :: ByteString -> Text
+verificationCode = T.pack . unwords . chunks 5 . show . os2ip
+  where
+    chunks _ [] = []
+    chunks n xs = let (h, t) = splitAt n xs in h : chunks n t
+
+sameVerificationCode :: Text -> Text -> Bool
+sameVerificationCode c1 c2 = noSpaces c1 == noSpaces c2
+  where
+    noSpaces = T.filter (/= ' ')
+
 aConnId :: Connection -> ConnId
 aConnId Connection {agentConnId = AgentConnId cId} = cId
 
diff --git a/src/Simplex/Chat/View.hs b/src/Simplex/Chat/View.hs
index 3c4382eb81..b12053f2af 100644
--- a/src/Simplex/Chat/View.hs
+++ b/src/Simplex/Chat/View.hs
@@ -74,6 +74,9 @@ responseToView user_ testView ts = \case
   CRGroupMemberInfo g m cStats -> viewGroupMemberInfo g m cStats
   CRContactSwitch ct progress -> viewContactSwitch ct progress
   CRGroupMemberSwitch g m progress -> viewGroupMemberSwitch g m progress
+  CRCodeVerification verified code -> [plain $ if verified then "connection verified" else "error: current connection code is " <> code]
+  CRContactCode ct code -> viewContactCode ct code testView
+  CRGroupMemberCode g m code -> viewGroupMemberCode g m code testView
   CRNewChatItem (AChatItem _ _ chat item) -> unmuted chat item $ viewChatItem chat item False ts
   CRLastMessages chatItems -> concatMap (\(AChatItem _ _ chat item) -> viewChatItem chat item True ts) chatItems
   CRChatItemStatusUpdated _ -> []
@@ -497,8 +500,8 @@ viewCannotResendInvitation GroupInfo {localDisplayName = gn} c =
   ]
 
 viewDirectMessagesProhibited :: MsgDirection -> Contact -> [StyledString]
-viewDirectMessagesProhibited MDSnd c = [ "direct messages to indirect contact " <> ttyContact' c <> " are prohibited"]
-viewDirectMessagesProhibited MDRcv c = [ "received prohibited direct message from indirect contact " <> ttyContact' c <> " (discarded)"]
+viewDirectMessagesProhibited MDSnd c = ["direct messages to indirect contact " <> ttyContact' c <> " are prohibited"]
+viewDirectMessagesProhibited MDRcv c = ["received prohibited direct message from indirect contact " <> ttyContact' c <> " (discarded)"]
 
 viewUserJoinedGroup :: GroupInfo -> [StyledString]
 viewUserJoinedGroup g@GroupInfo {membership = membership@GroupMember {memberProfile}} =
@@ -681,21 +684,27 @@ viewNetworkConfig NetworkConfig {socksProxy, tcpTimeout} =
   ]
 
 viewContactInfo :: Contact -> ConnectionStats -> Maybe Profile -> [StyledString]
-viewContactInfo Contact {contactId, profile = LocalProfile {localAlias}} stats incognitoProfile =
+viewContactInfo ct@Contact {contactId, profile = LocalProfile {localAlias}} stats incognitoProfile =
   ["contact ID: " <> sShow contactId] <> viewConnectionStats stats
     <> maybe
       ["you've shared main profile with this contact"]
       (\p -> ["you've shared incognito profile with this contact: " <> incognitoProfile' p])
       incognitoProfile
-    <> if localAlias /= "" then ["alias: " <> plain localAlias] else ["alias not set"]
+    <> ["alias: " <> plain localAlias | localAlias /= ""]
+    <> [viewConnectionVerified (contactSecurityCode ct)]
 
 viewGroupMemberInfo :: GroupInfo -> GroupMember -> Maybe ConnectionStats -> [StyledString]
-viewGroupMemberInfo GroupInfo {groupId} GroupMember {groupMemberId, memberProfile = LocalProfile {localAlias}} stats =
+viewGroupMemberInfo GroupInfo {groupId} m@GroupMember {groupMemberId, memberProfile = LocalProfile {localAlias}} stats =
   [ "group ID: " <> sShow groupId,
     "member ID: " <> sShow groupMemberId
   ]
     <> maybe ["member not connected"] viewConnectionStats stats
-    <> if localAlias /= "" then ["alias: " <> plain localAlias] else ["no alias for contact"]
+    <> ["alias: " <> plain localAlias | localAlias /= ""]
+    <> [viewConnectionVerified (memberSecurityCode m) | isJust stats]
+
+viewConnectionVerified :: Maybe SecurityCode -> StyledString
+viewConnectionVerified (Just _) = "connection verified" -- TODO show verification time?
+viewConnectionVerified _ = "connection not verified, use " <> highlight' "/code" <> " command to see security code"
 
 viewConnectionStats :: ConnectionStats -> [StyledString]
 viewConnectionStats ConnectionStats {rcvServers, sndServers} =
@@ -720,6 +729,17 @@ viewGroupMemberSwitch g m (SwitchProgress qd phase _) = case qd of
   QDRcv -> [ttyGroup' g <> ": you " <> viewSwitchPhase phase <> " for " <> ttyMember m]
   QDSnd -> [ttyGroup' g <> ": " <> ttyMember m <> " " <> viewSwitchPhase phase <> " for you"]
 
+viewContactCode :: Contact -> Text -> Bool -> [StyledString]
+viewContactCode ct@Contact {localDisplayName = c} = viewSecurityCode (ttyContact' ct) ("/verify " <> c <> " <code from your contact>")
+
+viewGroupMemberCode :: GroupInfo -> GroupMember -> Text -> Bool -> [StyledString]
+viewGroupMemberCode g m@GroupMember {localDisplayName = n} = viewSecurityCode (ttyGroup' g <> " " <> ttyMember m) ("/verify #" <> groupName' g <> " " <> n <> " <code from your contact>")
+
+viewSecurityCode :: StyledString -> Text -> Text -> Bool -> [StyledString]
+viewSecurityCode name cmd code testView
+  | testView = [plain code]
+  | otherwise = [name <> " security code:", plain code, "pass this code to your contact and use " <> highlight cmd <> " to verify"]
+
 viewSwitchPhase :: SwitchPhase -> StyledString
 viewSwitchPhase SPCompleted = "changed address"
 viewSwitchPhase phase = plain (strEncode phase) <> " changing address"
diff --git a/stack.yaml b/stack.yaml
index ca7450fedf..3685176bae 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -49,7 +49,7 @@ extra-deps:
   # - simplexmq-1.0.0@sha256:34b2004728ae396e3ae449cd090ba7410781e2b3cefc59259915f4ca5daa9ea8,8561
   # - ../simplexmq
   - github: simplex-chat/simplexmq
-    commit: e4842f4f47fb60ef8843dbce6fd43dec96f157d2
+    commit: fb21d9836e07706c7498baa967f932cb11b818e5
   # - ../direct-sqlcipher
   - github: simplex-chat/direct-sqlcipher
     commit: 34309410eb2069b029b8fc1872deb1e0db123294
diff --git a/tests/ChatTests.hs b/tests/ChatTests.hs
index 4eb9159f55..b3faefbef8 100644
--- a/tests/ChatTests.hs
+++ b/tests/ChatTests.hs
@@ -27,6 +27,7 @@ import Simplex.Chat.Options (ChatOpts (..))
 import Simplex.Chat.Store (getUserContactProfiles)
 import Simplex.Chat.Types
 import Simplex.Messaging.Agent.Store.SQLite (withTransaction)
+import qualified Simplex.Messaging.Crypto as C
 import Simplex.Messaging.Encoding.String
 import Simplex.Messaging.Util (unlessM)
 import System.Directory (copyFile, createDirectoryIfMissing, doesDirectoryExist, doesFileExist)
@@ -168,6 +169,13 @@ chatTests = do
   describe "queue rotation" $ do
     it "switch contact to a different queue" testSwitchContact
     it "switch group member to a different queue" testSwitchGroupMember
+  describe "connection verification code" $ do
+    it "verificationCode function converts ByteString to series of digits" $
+      verificationCode (C.sha256Hash "abcd") `shouldBe` "61889 38426 63934 09576 96390 79389 84124 85253 63658 69469 70853 37788 95900 68296 20156 25"
+    it "sameVerificationCode function should ignore spaces" $
+      sameVerificationCode "123 456 789" "12345 6789" `shouldBe` True
+    it "mark contact verified" testMarkContactVerified
+    it "mark group member verified" testMarkGroupMemberVerified
 
 versionTestMatrix2 :: (TestCC -> TestCC -> IO ()) -> Spec
 versionTestMatrix2 runTest = do
@@ -4551,6 +4559,58 @@ testSwitchGroupMember =
       bob #> "#team hi"
       alice <# "#team bob> hi"
 
+testMarkContactVerified :: IO ()
+testMarkContactVerified =
+  testChat2 aliceProfile bobProfile $ \alice bob -> do
+    connectUsers alice bob
+    alice ##> "/i bob"
+    bobInfo alice
+    alice <## "connection not verified, use /code command to see security code"
+    alice ##> "/code bob"
+    bCode <- getTermLine alice
+    bob ##> "/code alice"
+    aCode <- getTermLine bob
+    bCode `shouldBe` aCode
+    alice ##> "/verify bob 123"
+    alice <##. "error: current connection code is "
+    alice ##> ("/verify bob " <> aCode)
+    alice <## "connection verified"
+    alice ##> "/i bob"
+    bobInfo alice
+    alice <## "connection verified"
+  where
+    bobInfo alice = do
+      alice <## "contact ID: 2"
+      alice <## "receiving messages via: localhost"
+      alice <## "sending messages via: localhost"
+      alice <## "you've shared main profile with this contact"
+
+testMarkGroupMemberVerified :: IO ()
+testMarkGroupMemberVerified =
+  testChat2 aliceProfile bobProfile $ \alice bob -> do
+    createGroup2 "team" alice bob
+    alice ##> "/i #team bob"
+    bobInfo alice
+    alice <## "connection not verified, use /code command to see security code"
+    alice ##> "/code #team bob"
+    bCode <- getTermLine alice
+    bob ##> "/code #team alice"
+    aCode <- getTermLine bob
+    bCode `shouldBe` aCode
+    alice ##> "/verify #team bob 123"
+    alice <##. "error: current connection code is "
+    alice ##> ("/verify #team bob " <> aCode)
+    alice <## "connection verified"
+    alice ##> "/i #team bob"
+    bobInfo alice
+    alice <## "connection verified"
+  where
+    bobInfo alice = do
+      alice <## "group ID: 1"
+      alice <## "member ID: 2"
+      alice <## "receiving messages via: localhost"
+      alice <## "sending messages via: localhost"
+
 withTestChatContactConnected :: String -> (TestCC -> IO a) -> IO a
 withTestChatContactConnected dbPrefix action =
   withTestChat dbPrefix $ \cc -> do