diff --git a/apps/smp-server/Main.hs b/apps/smp-server/Main.hs
index c7cf3db74..aad2f9ead 100644
--- a/apps/smp-server/Main.hs
+++ b/apps/smp-server/Main.hs
@@ -42,8 +42,8 @@ serverConfig =
   ServerConfig
     { tbqSize = 16,
       msgQueueQuota = 256,
-      queueIdBytes = 12,
-      msgIdBytes = 6,
+      queueIdBytes = 24,
+      msgIdBytes = 24, -- must be at least 24 bytes, it is used as 192-bit nonce for XSalsa20
       trnSignAlg = C.SignAlg C.SEd448,
       -- below parameters are set based on ini file /etc/opt/simplex/smp-server.ini
       transports = undefined,
diff --git a/src/Simplex/Messaging/Server/Env/STM.hs b/src/Simplex/Messaging/Server/Env/STM.hs
index 4fa4d6681..a716d0dd3 100644
--- a/src/Simplex/Messaging/Server/Env/STM.hs
+++ b/src/Simplex/Messaging/Server/Env/STM.hs
@@ -27,7 +27,7 @@ data ServerConfig = ServerConfig
     tbqSize :: Natural,
     msgQueueQuota :: Natural,
     queueIdBytes :: Int,
-    msgIdBytes :: Int,
+    msgIdBytes :: Int, -- must be at least 24 bytes, it is used as 192-bit nonce for XSalsa20
     storeLog :: Maybe (StoreLog 'ReadMode),
     blockSize :: Int,
     trnSignAlg :: C.SignAlg,