diff --git a/src/lib/client/ServerProxy.cpp b/src/lib/client/ServerProxy.cpp
index f973003db..70e761645 100644
--- a/src/lib/client/ServerProxy.cpp
+++ b/src/lib/client/ServerProxy.cpp
@@ -521,12 +521,12 @@ void ServerProxy::setClipboard()
   ClipboardID id;
   uint32_t seq;
 
-  int r = ClipboardChunk::assemble(m_stream, dataCached, id, seq);
+  auto r = ClipboardChunk::assemble(m_stream, dataCached, id, seq);
 
-  if (r == kStart) {
+  if (r == TransferState::Started) {
     size_t size = ClipboardChunk::getExpectedSize();
     LOG((CLOG_DEBUG "receiving clipboard %d size=%d", id, size));
-  } else if (r == kFinish) {
+  } else if (r == TransferState::Finished) {
     LOG((CLOG_DEBUG "received clipboard %d size=%d", id, dataCached.size()));
 
     // forward
diff --git a/src/lib/deskflow/ClipboardChunk.cpp b/src/lib/deskflow/ClipboardChunk.cpp
index 2d3e5d7bd..6f95c751c 100644
--- a/src/lib/deskflow/ClipboardChunk.cpp
+++ b/src/lib/deskflow/ClipboardChunk.cpp
@@ -63,36 +63,38 @@ ClipboardChunk *ClipboardChunk::end(ClipboardID id, uint32_t sequence)
   return end;
 }
 
-int ClipboardChunk::assemble(deskflow::IStream *stream, std::string &dataCached, ClipboardID &id, uint32_t &sequence)
+TransferState
+ClipboardChunk::assemble(deskflow::IStream *stream, std::string &dataCached, ClipboardID &id, uint32_t &sequence)
 {
+  using enum TransferState;
   uint8_t mark;
   std::string data;
 
   if (!ProtocolUtil::readf(stream, kMsgDClipboard + 4, &id, &sequence, &mark, &data)) {
-    return kError;
+    return Error;
   }
 
   if (mark == kDataStart) {
     s_expectedSize = deskflow::string::stringToSizeType(data);
     LOG((CLOG_DEBUG "start receiving clipboard data"));
     dataCached.clear();
-    return kStart;
+    return Started;
   } else if (mark == kDataChunk) {
     dataCached.append(data);
-    return kNotFinish;
+    return InProgress;
   } else if (mark == kDataEnd) {
     // validate
     if (id >= kClipboardEnd) {
-      return kError;
+      return Error;
     } else if (s_expectedSize != dataCached.size()) {
       LOG((CLOG_ERR "corrupted clipboard data, expected size=%d actual size=%d", s_expectedSize, dataCached.size()));
-      return kError;
+      return Error;
     }
-    return kFinish;
+    return Finished;
   }
 
   LOG((CLOG_ERR "clipboard transmission failed: unknown error"));
-  return kError;
+  return Error;
 }
 
 void ClipboardChunk::send(deskflow::IStream *stream, void *data)
diff --git a/src/lib/deskflow/ClipboardChunk.h b/src/lib/deskflow/ClipboardChunk.h
index 92e202ae0..99529ce44 100644
--- a/src/lib/deskflow/ClipboardChunk.h
+++ b/src/lib/deskflow/ClipboardChunk.h
@@ -9,6 +9,7 @@
 #include "common/Common.h"
 #include "deskflow/Chunk.h"
 #include "deskflow/ClipboardTypes.h"
+#include "deskflow/ProtocolTypes.h"
 
 #include <string>
 
@@ -27,7 +28,8 @@ public:
   static ClipboardChunk *data(ClipboardID id, uint32_t sequence, const std::string &data);
   static ClipboardChunk *end(ClipboardID id, uint32_t sequence);
 
-  static int assemble(deskflow::IStream *stream, std::string &dataCached, ClipboardID &id, uint32_t &sequence);
+  static TransferState
+  assemble(deskflow::IStream *stream, std::string &dataCached, ClipboardID &id, uint32_t &sequence);
 
   static void send(deskflow::IStream *stream, void *data);
 
diff --git a/src/lib/deskflow/ProtocolTypes.h b/src/lib/deskflow/ProtocolTypes.h
index 84a364d8c..be187beed 100644
--- a/src/lib/deskflow/ProtocolTypes.h
+++ b/src/lib/deskflow/ProtocolTypes.h
@@ -210,12 +210,12 @@ enum EDataTransfer
  *
  * @since Protocol version 1.5
  */
-enum EDataReceived
+enum class TransferState : uint8_t
 {
-  kStart,     ///< Reception started
-  kNotFinish, ///< Reception in progress
-  kFinish,    ///< Reception completed successfully
-  kError      ///< Reception failed with error
+  Started,    ///< Reception started
+  InProgress, ///< Reception in progress
+  Finished,   ///< Reception completed successfully
+  Error       ///< Reception failed with error
 };
 
 /** @} */ // end of protocol_enums group
diff --git a/src/lib/server/ClientProxy1_6.cpp b/src/lib/server/ClientProxy1_6.cpp
index 173a96961..a5189eaa8 100644
--- a/src/lib/server/ClientProxy1_6.cpp
+++ b/src/lib/server/ClientProxy1_6.cpp
@@ -50,10 +50,10 @@ bool ClientProxy1_6::recvClipboard()
   ClipboardID id;
   uint32_t seq;
 
-  if (int r = ClipboardChunk::assemble(getStream(), dataCached, id, seq); r == kStart) {
+  if (auto r = ClipboardChunk::assemble(getStream(), dataCached, id, seq); r == TransferState::Started) {
     size_t size = ClipboardChunk::getExpectedSize();
     LOG((CLOG_DEBUG "receiving clipboard %d size=%d", id, size));
-  } else if (r == kFinish) {
+  } else if (r == TransferState::Finished) {
     LOG(
         (CLOG_DEBUG "received client \"%s\" clipboard %d seqnum=%d, size=%d", getName().c_str(), id, seq,
          dataCached.size())