diff --git a/apps/ios/Shared/Views/Helpers/StickyScrollView.swift b/apps/ios/Shared/Views/Helpers/StickyScrollView.swift
index 0ba539772f..71bee4f548 100644
--- a/apps/ios/Shared/Views/Helpers/StickyScrollView.swift
+++ b/apps/ios/Shared/Views/Helpers/StickyScrollView.swift
@@ -44,7 +44,7 @@ struct StickyScrollView<Content: View>: UIViewRepresentable {
             withVelocity velocity: CGPoint,
             targetContentOffset: UnsafeMutablePointer<CGPoint>
         ) {
-            if targetContentOffset.pointee.x < 64 {
+            if targetContentOffset.pointee.x < 32 {
                 targetContentOffset.pointee.x = 0
             }
         }
diff --git a/apps/multiplatform/android/src/main/java/chat/simplex/app/SimplexApp.kt b/apps/multiplatform/android/src/main/java/chat/simplex/app/SimplexApp.kt
index 6adaa1d4e0..40e8ffa9bc 100644
--- a/apps/multiplatform/android/src/main/java/chat/simplex/app/SimplexApp.kt
+++ b/apps/multiplatform/android/src/main/java/chat/simplex/app/SimplexApp.kt
@@ -287,13 +287,23 @@ class SimplexApp: Application(), LifecycleEventObserver {
         // Blend status bar color to the animated color
         val colors = CurrentColors.value.colors
         val baseBackgroundColor = if (toolbarOnTop) colors.background.mixWith(colors.onBackground, 0.97f) else colors.background
-        window.statusBarColor = baseBackgroundColor.mixWith(drawerShadingColor.copy(1f), 1 - drawerShadingColor.alpha).toArgb()
-        val navBar = navBarColor.toArgb()
+        var statusBar = baseBackgroundColor.mixWith(drawerShadingColor.copy(1f), 1 - drawerShadingColor.alpha).toArgb()
+        var statusBarLight = isLight
 
+        // SimplexGreen while in call
+        if (window.statusBarColor == SimplexGreen.toArgb()) {
+          statusBarColorAfterCall.intValue = statusBar
+          statusBar = SimplexGreen.toArgb()
+          statusBarLight = false
+        }
+        window.statusBarColor = statusBar
+        val navBar = navBarColor.toArgb()
+        if (windowInsetController?.isAppearanceLightStatusBars != statusBarLight) {
+          windowInsetController?.isAppearanceLightStatusBars = statusBarLight
+        }
         if (window.navigationBarColor != navBar) {
           window.navigationBarColor = navBar
         }
-
         if (windowInsetController?.isAppearanceLightNavigationBars != isLight) {
           windowInsetController?.isAppearanceLightNavigationBars = isLight
         }
@@ -313,11 +323,13 @@ class SimplexApp: Application(), LifecycleEventObserver {
             backgroundColor
           }
         }).toArgb()
+        var statusBarLight = isLight
 
         // SimplexGreen while in call
         if (window.statusBarColor == SimplexGreen.toArgb()) {
           statusBarColorAfterCall.intValue = statusBar
           statusBar = SimplexGreen.toArgb()
+          statusBarLight = false
         }
         val navBar = (if (hasBottom && appPrefs.onboardingStage.get() == OnboardingStage.OnboardingComplete) {
           backgroundColor.mixWith(CurrentColors.value.colors.onBackground, 0.97f)
@@ -327,8 +339,8 @@ class SimplexApp: Application(), LifecycleEventObserver {
         if (window.statusBarColor != statusBar) {
           window.statusBarColor = statusBar
         }
-        if (windowInsetController?.isAppearanceLightStatusBars != isLight) {
-          windowInsetController?.isAppearanceLightStatusBars = isLight
+        if (windowInsetController?.isAppearanceLightStatusBars != statusBarLight) {
+          windowInsetController?.isAppearanceLightStatusBars = statusBarLight
         }
         if (window.navigationBarColor != navBar) {
           window.navigationBarColor = navBar
diff --git a/cabal.project b/cabal.project
index f2a652d721..d5e17ea299 100644
--- a/cabal.project
+++ b/cabal.project
@@ -12,7 +12,7 @@ constraints: zip +disable-bzip2 +disable-zstd
 source-repository-package
     type: git
     location: https://github.com/simplex-chat/simplexmq.git
-    tag: bef11e4cbe0a3776f0910375f2adb60399043835
+    tag: 7dcac19a671f76dedbe769030742714783946bd3
 
 source-repository-package
     type: git
diff --git a/scripts/nix/sha256map.nix b/scripts/nix/sha256map.nix
index 730a0f9501..91e5e8866f 100644
--- a/scripts/nix/sha256map.nix
+++ b/scripts/nix/sha256map.nix
@@ -1,5 +1,5 @@
 {
-  "https://github.com/simplex-chat/simplexmq.git"."bef11e4cbe0a3776f0910375f2adb60399043835" = "195hir9crv51iyli8yjk8sivk7wagxxjfmhzq6ahydvbkrpd3258";
+  "https://github.com/simplex-chat/simplexmq.git"."7dcac19a671f76dedbe769030742714783946bd3" = "0c1jygir4c1s8g4hdz7b6vw69bvcrknbih9rq8y8rv3d8zl32qpq";
   "https://github.com/simplex-chat/hs-socks.git"."a30cc7a79a08d8108316094f8f2f82a0c5e1ac51" = "0yasvnr7g91k76mjkamvzab2kvlb1g5pspjyjn2fr6v83swjhj38";
   "https://github.com/simplex-chat/direct-sqlcipher.git"."f814ee68b16a9447fbb467ccc8f29bdd3546bfd9" = "1ql13f4kfwkbaq7nygkxgw84213i0zm7c1a8hwvramayxl38dq5d";
   "https://github.com/simplex-chat/sqlcipher-simple.git"."a46bd361a19376c5211f1058908fc0ae6bf42446" = "1z0r78d8f0812kxbgsm735qf6xx8lvaz27k1a0b4a2m0sshpd5gl";
diff --git a/src/Simplex/Chat/Remote.hs b/src/Simplex/Chat/Remote.hs
index 76d3754f17..0d39951b90 100644
--- a/src/Simplex/Chat/Remote.hs
+++ b/src/Simplex/Chat/Remote.hs
@@ -54,6 +54,7 @@ import Simplex.Chat.Util (encryptFile, liftIOEither)
 import Simplex.FileTransfer.Description (FileDigest (..))
 import Simplex.Messaging.Agent
 import Simplex.Messaging.Agent.Protocol (AgentErrorType (RCP))
+import qualified Simplex.Messaging.Crypto as C
 import Simplex.Messaging.Crypto.File (CryptoFile (..), CryptoFileArgs (..))
 import qualified Simplex.Messaging.Crypto.File as CF
 import Simplex.Messaging.Encoding.String (StrEncoding (..))
@@ -497,31 +498,32 @@ handleRemoteCommand :: (ByteString -> CM' ChatResponse) -> RemoteCrypto -> TBQue
 handleRemoteCommand execChatCommand encryption remoteOutputQ HTTP2Request {request, reqBody, sendResponse} = do
   logDebug "handleRemoteCommand"
   liftIO (tryRemoteError' parseRequest) >>= \case
-    Right (getNext, rc) -> do
+    Right (rfKN, getNext, rc) -> do
       chatReadVar' currentUser >>= \case
         Nothing -> replyError $ ChatError CENoActiveUser
-        Just user -> processCommand user getNext rc `catchChatError'` replyError
+        Just user -> processCommand user rfKN getNext rc `catchChatError'` replyError
     Left e -> reply $ RRProtocolError e
   where
-    parseRequest :: ExceptT RemoteProtocolError IO (GetChunk, RemoteCommand)
+    parseRequest :: ExceptT RemoteProtocolError IO (C.SbKeyNonce, GetChunk, RemoteCommand)
     parseRequest = do
-      (header, getNext) <- parseDecryptHTTP2Body encryption request reqBody
-      (getNext,) <$> liftEitherWith RPEInvalidJSON (J.eitherDecode header)
+      (rfKN, header, getNext) <- parseDecryptHTTP2Body encryption request reqBody
+      (rfKN,getNext,) <$> liftEitherWith RPEInvalidJSON (J.eitherDecode header)
     replyError = reply . RRChatResponse . CRChatCmdError Nothing
-    processCommand :: User -> GetChunk -> RemoteCommand -> CM ()
-    processCommand user getNext = \case
+    processCommand :: User -> C.SbKeyNonce -> GetChunk -> RemoteCommand -> CM ()
+    processCommand user rfKN getNext = \case
       RCSend {command} -> lift $ handleSend execChatCommand command >>= reply
       RCRecv {wait = time} -> lift $ liftIO (handleRecv time remoteOutputQ) >>= reply
-      RCStoreFile {fileName, fileSize, fileDigest} -> lift $ handleStoreFile encryption fileName fileSize fileDigest getNext >>= reply
-      RCGetFile {file} -> handleGetFile encryption user file replyWith
+      RCStoreFile {fileName, fileSize, fileDigest} -> lift $ handleStoreFile rfKN fileName fileSize fileDigest getNext >>= reply
+      RCGetFile {file} -> handleGetFile user file replyWith
     reply :: RemoteResponse -> CM' ()
-    reply = (`replyWith` \_ -> pure ())
+    reply = (`replyWith` \_ _ -> pure ())
     replyWith :: Respond
-    replyWith rr attach =
-      liftIO (tryRemoteError' . encryptEncodeHTTP2Body encryption $ J.encode rr) >>= \case
+    replyWith rr attach = do
+      (corrId, cmdKN, sfKN) <- atomically $ getRemoteSndKeys encryption
+      liftIO (tryRemoteError' . encryptEncodeHTTP2Body corrId cmdKN encryption $ J.encode rr) >>= \case
         Right resp -> liftIO . sendResponse . responseStreaming N.status200 [] $ \send flush -> do
           send resp
-          attach send
+          attach sfKN send
           flush
         Left e -> toView' . CRChatError Nothing . ChatErrorRemoteCtrl $ RCEProtocolError e
 
@@ -532,7 +534,7 @@ type GetChunk = Int -> IO ByteString
 
 type SendChunk = Builder -> IO ()
 
-type Respond = RemoteResponse -> (SendChunk -> IO ()) -> CM' ()
+type Respond = RemoteResponse -> (C.SbKeyNonce -> SendChunk -> IO ()) -> CM' ()
 
 liftRC :: ExceptT RemoteProtocolError IO a -> CM a
 liftRC = liftError (ChatErrorRemoteCtrl . RCEProtocolError)
@@ -559,8 +561,8 @@ handleRecv time events = do
 
 -- TODO this command could remember stored files and return IDs to allow removing files that are not needed.
 -- Also, there should be some process removing unused files uploaded to remote host (possibly, all unused files).
-handleStoreFile :: RemoteCrypto -> FilePath -> Word32 -> FileDigest -> GetChunk -> CM' RemoteResponse
-handleStoreFile encryption fileName fileSize fileDigest getChunk =
+handleStoreFile :: C.SbKeyNonce -> FilePath -> Word32 -> FileDigest -> GetChunk -> CM' RemoteResponse
+handleStoreFile rfKN fileName fileSize fileDigest getChunk =
   either RRProtocolError RRFileStored <$> (chatReadVar' filesFolder >>= storeFile)
   where
     storeFile :: Maybe FilePath -> CM' (Either RemoteProtocolError FilePath)
@@ -570,11 +572,11 @@ handleStoreFile encryption fileName fileSize fileDigest getChunk =
     storeFileTo :: FilePath -> CM' (Either RemoteProtocolError FilePath)
     storeFileTo dir = liftIO . tryRemoteError' $ do
       filePath <- liftIO $ dir `uniqueCombine` fileName
-      receiveEncryptedFile encryption getChunk fileSize fileDigest filePath
+      receiveEncryptedFile rfKN getChunk fileSize fileDigest filePath
       pure filePath
 
-handleGetFile :: RemoteCrypto -> User -> RemoteFile -> Respond -> CM ()
-handleGetFile encryption User {userId} RemoteFile {userId = commandUserId, fileId, sent, fileSource = cf'@CryptoFile {filePath}} reply = do
+handleGetFile :: User -> RemoteFile -> Respond -> CM ()
+handleGetFile User {userId} RemoteFile {userId = commandUserId, fileId, sent, fileSource = cf'@CryptoFile {filePath}} reply = do
   logDebug $ "GetFile: " <> tshow filePath
   unless (userId == commandUserId) $ throwChatError $ CEDifferentActiveUser {commandUserId, activeUserId = userId}
   path <- maybe filePath (</> filePath) <$> chatReadVar filesFolder
@@ -582,11 +584,12 @@ handleGetFile encryption User {userId} RemoteFile {userId = commandUserId, fileI
     cf <- getLocalCryptoFile db commandUserId fileId sent
     unless (cf == cf') $ throwError $ SEFileNotFound fileId
   liftRC (tryRemoteError $ getFileInfo path) >>= \case
-    Left e -> lift $ reply (RRProtocolError e) $ \_ -> pure ()
+    Left e -> lift $ reply (RRProtocolError e) $ \_ _ -> pure ()
     Right (fileSize, fileDigest) ->
-      ExceptT . withFile path ReadMode $ \h -> runExceptT $ do
-        encFile <- liftRC $ prepareEncryptedFile encryption (h, fileSize)
-        lift $ reply RRFile {fileSize, fileDigest} $ sendEncryptedFile encFile
+      lift . withFile path ReadMode $ \h -> do
+        reply RRFile {fileSize, fileDigest} $ \sfKN send -> void . runExceptT $ do
+          encFile <- prepareEncryptedFile sfKN (h, fileSize)
+          liftIO $ sendEncryptedFile encFile send
 
 listRemoteCtrls :: CM [RemoteCtrlInfo]
 listRemoteCtrls = do
diff --git a/src/Simplex/Chat/Remote/Protocol.hs b/src/Simplex/Chat/Remote/Protocol.hs
index fe07a940ae..00fc56f897 100644
--- a/src/Simplex/Chat/Remote/Protocol.hs
+++ b/src/Simplex/Chat/Remote/Protocol.hs
@@ -43,6 +43,8 @@ import Simplex.Messaging.Crypto.File (CryptoFile (..))
 import Simplex.Messaging.Crypto.Lazy (LazyByteString)
 import Simplex.Messaging.Encoding
 import Simplex.Messaging.Parsers (dropPrefix, taggedObjectJSON, pattern SingleFieldJSONTag, pattern TaggedObjectJSONData, pattern TaggedObjectJSONTag)
+import qualified Simplex.Messaging.TMap as TM
+import Simplex.Messaging.Transport (TSbChainKeys)
 import Simplex.Messaging.Transport.Buffer (getBuffered)
 import Simplex.Messaging.Transport.HTTP2 (HTTP2Body (..), HTTP2BodyChunk, getBodyChunk)
 import Simplex.Messaging.Transport.HTTP2.Client (HTTP2Client, HTTP2Response (..), closeHTTP2Client, sendRequestDirect)
@@ -77,11 +79,9 @@ $(deriveJSON (taggedObjectJSON $ dropPrefix "RR") ''RemoteResponse)
 
 mkRemoteHostClient :: HTTP2Client -> HostSessKeys -> SessionCode -> FilePath -> HostAppInfo -> CM RemoteHostClient
 mkRemoteHostClient httpClient sessionKeys sessionCode storePath HostAppInfo {encoding, deviceName, encryptFiles} = do
-  drg <- asks random
-  counter <- newTVarIO 1
-  let HostSessKeys {hybridKey, idPrivKey, sessPrivKey} = sessionKeys
+  let HostSessKeys {chainKeys, idPrivKey, sessPrivKey} = sessionKeys
       signatures = RSSign {idPrivKey, sessPrivKey}
-      encryption = RemoteCrypto {drg, counter, sessionCode, hybridKey, signatures}
+  encryption <- liftIO $ mkRemoteCrypto sessionCode chainKeys signatures
   pure
     RemoteHostClient
       { hostEncoding = encoding,
@@ -93,11 +93,16 @@ mkRemoteHostClient httpClient sessionKeys sessionCode storePath HostAppInfo {enc
       }
 
 mkCtrlRemoteCrypto :: CtrlSessKeys -> SessionCode -> CM RemoteCrypto
-mkCtrlRemoteCrypto CtrlSessKeys {hybridKey, idPubKey, sessPubKey} sessionCode = do
-  drg <- asks random
-  counter <- newTVarIO 1
+mkCtrlRemoteCrypto CtrlSessKeys {chainKeys, idPubKey, sessPubKey} sessionCode =
   let signatures = RSVerify {idPubKey, sessPubKey}
-  pure RemoteCrypto {drg, counter, sessionCode, hybridKey, signatures}
+   in liftIO $ mkRemoteCrypto sessionCode chainKeys signatures
+
+mkRemoteCrypto :: SessionCode -> TSbChainKeys -> RemoteSignatures -> IO RemoteCrypto
+mkRemoteCrypto sessionCode chainKeys signatures = do
+  sndCounter <- newTVarIO 0
+  rcvCounter <- newTVarIO 0
+  skippedKeys <- liftIO TM.emptyIO
+  pure RemoteCrypto {sessionCode, sndCounter, rcvCounter, chainKeys, skippedKeys, signatures}
 
 closeRemoteHostClient :: RemoteHostClient -> IO ()
 closeRemoteHostClient RemoteHostClient {httpClient} = closeHTTP2Client httpClient
@@ -125,26 +130,30 @@ remoteStoreFile c localPath fileName = do
     r -> badResponse r
 
 remoteGetFile :: RemoteHostClient -> FilePath -> RemoteFile -> ExceptT RemoteProtocolError IO ()
-remoteGetFile c@RemoteHostClient {encryption} destDir rf@RemoteFile {fileSource = CryptoFile {filePath}} =
+remoteGetFile c destDir rf@RemoteFile {fileSource = CryptoFile {filePath}} =
   sendRemoteCommand c Nothing RCGetFile {file = rf} >>= \case
-    (getChunk, RRFile {fileSize, fileDigest}) -> do
+    (rfKN, getChunk, RRFile {fileSize, fileDigest}) -> do
       -- TODO we could optimize by checking size and hash before receiving the file
       let localPath = destDir </> takeFileName filePath
-      receiveEncryptedFile encryption getChunk fileSize fileDigest localPath
-    (_, r) -> badResponse r
+      receiveEncryptedFile rfKN getChunk fileSize fileDigest localPath
+    (_, _, r) -> badResponse r
 
 -- TODO validate there is no attachment in response
 sendRemoteCommand' :: RemoteHostClient -> Maybe (Handle, Word32) -> RemoteCommand -> ExceptT RemoteProtocolError IO RemoteResponse
-sendRemoteCommand' c attachment_ rc = snd <$> sendRemoteCommand c attachment_ rc
+sendRemoteCommand' c attachment_ rc = do
+  (_, _, r) <- sendRemoteCommand c attachment_ rc
+  pure r
 
-sendRemoteCommand :: RemoteHostClient -> Maybe (Handle, Word32) -> RemoteCommand -> ExceptT RemoteProtocolError IO (Int -> IO ByteString, RemoteResponse)
+sendRemoteCommand :: RemoteHostClient -> Maybe (Handle, Word32) -> RemoteCommand -> ExceptT RemoteProtocolError IO (C.SbKeyNonce, Int -> IO ByteString, RemoteResponse)
 sendRemoteCommand RemoteHostClient {httpClient, hostEncoding, encryption} file_ cmd = do
-  encFile_ <- mapM (prepareEncryptedFile encryption) file_
-  req <- httpRequest encFile_ <$> encryptEncodeHTTP2Body encryption (J.encode cmd)
+  (corrId, cmdKN, sfKN) <- atomically $ getRemoteSndKeys encryption
+  encCmd <- encryptEncodeHTTP2Body corrId cmdKN encryption $ J.encode cmd
+  encFile_ <- mapM (prepareEncryptedFile sfKN) file_
+  let req = httpRequest encFile_ encCmd
   HTTP2Response {response, respBody} <- liftError' (RPEHTTP2 . tshow) $ sendRequestDirect httpClient req Nothing
-  (header, getNext) <- parseDecryptHTTP2Body encryption response respBody
+  (rfKN, header, getNext) <- parseDecryptHTTP2Body encryption response respBody
   rr <- liftEitherWith (RPEInvalidJSON . fromString) $ J.eitherDecode header >>= JT.parseEither J.parseJSON . convertJSON hostEncoding localEncoding
-  pure (getNext, rr)
+  pure (rfKN, getNext, rr)
   where
     httpRequest encFile_ cmdBld = H.requestStreaming N.methodPost "/" mempty $ \send flush -> do
       send cmdBld
@@ -213,13 +222,11 @@ pattern OwsfTag = (SingleFieldJSONTag, J.Bool True)
 
 -- See https://github.com/simplex-chat/simplexmq/blob/master/rfcs/2023-10-25-remote-control.md for encoding
 
-encryptEncodeHTTP2Body :: RemoteCrypto -> LazyByteString -> ExceptT RemoteProtocolError IO Builder
-encryptEncodeHTTP2Body RemoteCrypto {drg, counter, sessionCode, hybridKey, signatures} s = do
-  corrId <- atomically $ stateTVar counter $ \c -> (c, c + 1)
-  let pfx = smpEncode (sessionCode, corrId)
-  (nonce, ct) <- liftError PRERemoteControl $ RC.rcEncryptBody drg hybridKey $ LB.fromStrict pfx <> s
+encryptEncodeHTTP2Body :: Word32 -> C.SbKeyNonce -> RemoteCrypto -> LazyByteString -> ExceptT RemoteProtocolError IO Builder
+encryptEncodeHTTP2Body corrId cmdKN RemoteCrypto {sessionCode, signatures} s = do
+  ct <- liftError PRERemoteControl $ RC.rcEncryptBody cmdKN $ LB.fromStrict (smpEncode sessionCode) <> s
   let ctLen = encodeWord32 (fromIntegral $ LB.length ct)
-      signed = LB.fromStrict (smpEncode nonce <> ctLen) <> ct
+      signed = LB.fromStrict (encodeWord32 corrId <> ctLen) <> ct
   sigs <- bodySignatures signed
   pure $ lazyByteString signed <> sigs
   where
@@ -235,24 +242,25 @@ encryptEncodeHTTP2Body RemoteCrypto {drg, counter, sessionCode, hybridKey, signa
     sign k = C.signatureBytes . C.sign' k . BA.convert . CH.hashFinalize
 
 -- | Parse and decrypt HTTP2 request/response
-parseDecryptHTTP2Body :: HTTP2BodyChunk a => RemoteCrypto -> a -> HTTP2Body -> ExceptT RemoteProtocolError IO (LazyByteString, Int -> IO ByteString)
-parseDecryptHTTP2Body RemoteCrypto {hybridKey, sessionCode, signatures} hr HTTP2Body {bodyBuffer} = do
-  (nonce, ct) <- getBody
-  s <- liftError PRERemoteControl $ RC.rcDecryptBody hybridKey nonce ct
-  (,getNext) <$> parseBody s
+parseDecryptHTTP2Body :: HTTP2BodyChunk a => RemoteCrypto -> a -> HTTP2Body -> ExceptT RemoteProtocolError IO (C.SbKeyNonce, LazyByteString, Int -> IO ByteString)
+parseDecryptHTTP2Body rc@RemoteCrypto {sessionCode, signatures} hr HTTP2Body {bodyBuffer} = do
+  (corrId, ct) <- getBody
+  (cmdKN, rfKN) <- ExceptT $ atomically $ getRemoteRcvKeys rc corrId
+  s <- liftError PRERemoteControl $ RC.rcDecryptBody cmdKN ct
+  s' <- parseBody s
+  pure (rfKN, s', getNext)
   where
-    getBody :: ExceptT RemoteProtocolError IO (C.CbNonce, LazyByteString)
+    getBody :: ExceptT RemoteProtocolError IO (Word32, LazyByteString)
     getBody = do
-      nonceStr <- liftIO $ getNext 24
-      nonce <- liftEitherWith RPEInvalidBody $ smpDecode nonceStr
+      corrIdStr <- liftIO $ getNext 4
       ctLenStr <- liftIO $ getNext 4
       let ctLen = decodeWord32 ctLenStr
       when (ctLen > fromIntegral (maxBound :: Int)) $ throwError RPEInvalidSize
       chunks <- liftIO $ getLazy $ fromIntegral ctLen
-      let hc = CH.hashUpdates (CH.hashInit @SHA512) [nonceStr, ctLenStr]
+      let hc = CH.hashUpdates (CH.hashInit @SHA512) [corrIdStr, ctLenStr]
           hc' = CH.hashUpdates hc chunks
       verifySignatures hc'
-      pure (nonce, LB.fromChunks chunks)
+      pure (decodeWord32 corrIdStr, LB.fromChunks chunks)
     getLazy :: Int -> IO [ByteString]
     getLazy 0 = pure []
     getLazy n = do
@@ -279,9 +287,8 @@ parseDecryptHTTP2Body RemoteCrypto {hybridKey, sessionCode, signatures} hr HTTP2
     parseBody s = case LB.uncons s of
       Nothing -> throwError $ RPEInvalidBody "empty body"
       Just (scLen, rest) -> do
-        (sessCode', rest') <- takeBytes (fromIntegral scLen) rest
+        (sessCode', s') <- takeBytes (fromIntegral scLen) rest
         unless (sessCode' == sessionCode) $ throwError PRESessionCode
-        (_corrId, s') <- takeBytes 8 rest'
         pure s'
       where
         takeBytes n s' = do
diff --git a/src/Simplex/Chat/Remote/Transport.hs b/src/Simplex/Chat/Remote/Transport.hs
index 774aeccda2..933936aa4d 100644
--- a/src/Simplex/Chat/Remote/Transport.hs
+++ b/src/Simplex/Chat/Remote/Transport.hs
@@ -1,5 +1,6 @@
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 module Simplex.Chat.Remote.Transport where
 
@@ -20,27 +21,25 @@ import Simplex.RemoteControl.Types (RCErrorType (..))
 import UnliftIO
 import UnliftIO.Directory (getFileSize)
 
-type EncryptedFile = ((Handle, Word32), C.CbNonce, LC.SbState)
+type EncryptedFile = ((Handle, Word32), LC.SbState)
 
-prepareEncryptedFile :: RemoteCrypto -> (Handle, Word32) -> ExceptT RemoteProtocolError IO EncryptedFile
-prepareEncryptedFile RemoteCrypto {drg, hybridKey} f = do
-  nonce <- atomically $ C.randomCbNonce drg
-  sbState <- liftEitherWith (const $ PRERemoteControl RCEEncrypt) $ LC.kcbInit hybridKey nonce
-  pure (f, nonce, sbState)
+prepareEncryptedFile :: C.SbKeyNonce -> (Handle, Word32) -> ExceptT RemoteProtocolError IO EncryptedFile
+prepareEncryptedFile (sk, nonce) f = do
+  sbState <- liftEitherWith (const $ PRERemoteControl RCEEncrypt) $ LC.sbInit sk nonce
+  pure (f, sbState)
 
 sendEncryptedFile :: EncryptedFile -> (Builder -> IO ()) -> IO ()
-sendEncryptedFile ((h, sz), nonce, sbState) send = do
-  send $ byteString $ smpEncode ('\x01', nonce, sz + fromIntegral C.authTagSize)
+sendEncryptedFile ((h, sz), sbState) send = do
+  send $ byteString $ smpEncode ('\x01', sz + fromIntegral C.authTagSize)
   sendEncFile h send sbState sz
 
-receiveEncryptedFile :: RemoteCrypto -> (Int -> IO ByteString) -> Word32 -> FileDigest -> FilePath -> ExceptT RemoteProtocolError IO ()
-receiveEncryptedFile RemoteCrypto {hybridKey} getChunk fileSize fileDigest toPath = do
+receiveEncryptedFile :: C.SbKeyNonce -> (Int -> IO ByteString) -> Word32 -> FileDigest -> FilePath -> ExceptT RemoteProtocolError IO ()
+receiveEncryptedFile (sk, nonce) getChunk fileSize fileDigest toPath = do
   c <- liftIO $ getChunk 1
   unless (c == "\x01") $ throwError RPENoFile
-  nonce <- liftError' RPEInvalidBody $ smpDecode <$> getChunk 24
   size <- liftError' RPEInvalidBody $ smpDecode <$> getChunk 4
   unless (size == fileSize + fromIntegral C.authTagSize) $ throwError RPEFileSize
-  sbState <- liftEitherWith (const $ PRERemoteControl RCEDecrypt) $ LC.kcbInit hybridKey nonce
+  sbState <- liftEitherWith (const $ PRERemoteControl RCEDecrypt) $ LC.sbInit sk nonce
   liftError' fErr $ withFile toPath WriteMode $ \h -> receiveSbFile getChunk h sbState fileSize
   digest <- liftIO $ LC.sha512Hash <$> LB.readFile toPath
   unless (FileDigest digest == fileDigest) $ throwError RPEFileDigest
diff --git a/src/Simplex/Chat/Remote/Types.hs b/src/Simplex/Chat/Remote/Types.hs
index d85dde9e87..a5396e7945 100644
--- a/src/Simplex/Chat/Remote/Types.hs
+++ b/src/Simplex/Chat/Remote/Types.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE BangPatterns #-}
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DeriveAnyClass #-}
@@ -11,22 +12,22 @@
 module Simplex.Chat.Remote.Types where
 
 import Control.Concurrent.Async (Async)
-import Control.Concurrent.STM (TVar)
+import Control.Concurrent.STM
 import Control.Exception (Exception)
-import Crypto.Random (ChaChaDRG)
+import Control.Monad (when)
 import qualified Data.Aeson.TH as J
 import Data.ByteString (ByteString)
 import Data.Int (Int64)
 import Data.Text (Text)
-import Data.Word (Word16)
+import Data.Word (Word16, Word32)
 import Simplex.Chat.Remote.AppVersion
 import Simplex.Chat.Types (verificationCode)
 import qualified Simplex.Messaging.Crypto as C
 import Simplex.Messaging.Crypto.File (CryptoFile)
-import Simplex.Messaging.Crypto.SNTRUP761 (KEMHybridSecret)
 import Simplex.Messaging.Parsers (defaultJSON, dropPrefix, enumJSON, sumTypeJSON)
-import Simplex.Messaging.Transport (TLS (..))
+import Simplex.Messaging.Transport (TLS (..), TSbChainKeys (..))
 import Simplex.Messaging.Transport.HTTP2.Client (HTTP2Client)
+import qualified Simplex.Messaging.TMap as TM
 import Simplex.RemoteControl.Client
 import Simplex.RemoteControl.Types
 
@@ -40,13 +41,45 @@ data RemoteHostClient = RemoteHostClient
   }
 
 data RemoteCrypto = RemoteCrypto
-  { drg :: TVar ChaChaDRG,
-    counter :: TVar Int64,
-    sessionCode :: ByteString,
-    hybridKey :: KEMHybridSecret,
+  { sessionCode :: ByteString,
+    sndCounter :: TVar Word32,
+    rcvCounter :: TVar Word32,
+    chainKeys :: TSbChainKeys,
+    skippedKeys :: TM.TMap Word32 (C.SbKeyNonce, C.SbKeyNonce),
     signatures :: RemoteSignatures
   }
 
+getRemoteSndKeys :: RemoteCrypto -> STM (Word32, C.SbKeyNonce, C.SbKeyNonce)
+getRemoteSndKeys RemoteCrypto {sndCounter, chainKeys = TSbChainKeys {sndKey}} = do
+  corrId <- stateTVar sndCounter $ \c -> let !c' = c + 1 in (c', c')
+  cmdKN <- stateTVar sndKey C.sbcHkdf
+  fileKN <- stateTVar sndKey C.sbcHkdf
+  pure (corrId, cmdKN, fileKN)
+
+getRemoteRcvKeys :: RemoteCrypto -> Word32 -> STM (Either RemoteProtocolError (C.SbKeyNonce, C.SbKeyNonce))
+getRemoteRcvKeys RemoteCrypto {rcvCounter, chainKeys = TSbChainKeys {rcvKey}, skippedKeys} !corrId =
+  readTVar rcvCounter >>= getRcvKeys
+  where
+    getRcvKeys prevCorrId
+      | prevCorrId > corrId =
+          let err = PREEarlierId $ prevCorrId - corrId
+           in maybe (Left err) Right <$> TM.lookupDelete corrId skippedKeys
+      | prevCorrId == corrId =
+          pure $ Left PREDuplicateId
+      | prevCorrId + maxSkip < corrId =
+          pure $ Left $ RPEManySkippedIds (corrId - prevCorrId)
+      | otherwise = do -- prevCorrId < corrId
+          writeTVar rcvCounter corrId
+          skipKeys (prevCorrId + 1)
+          Right <$> getKeys
+    maxSkip = 256
+    getKeys = (,) <$> stateTVar rcvKey C.sbcHkdf <*> stateTVar rcvKey C.sbcHkdf
+    skipKeys !cId =
+      when (cId < corrId) $ do
+        keys <- getKeys
+        TM.insert cId keys skippedKeys
+        skipKeys (cId + 1)
+
 data RemoteSignatures
   = RSSign
       { idPrivKey :: C.PrivateKeyEd25519,
@@ -110,6 +143,9 @@ data RemoteProtocolError
   | RPENoFile
   | RPEFileSize
   | RPEFileDigest
+  | RPEManySkippedIds Word32
+  | PREEarlierId Word32
+  | PREDuplicateId
   | -- | Wrong response received for the command sent
     RPEUnexpectedResponse {response :: Text}
   | -- | A file already exists in the destination position