diff --git a/cluster/bootstrap.go b/cluster/bootstrap.go
index 18c5e09..314ec88 100644
--- a/cluster/bootstrap.go
+++ b/cluster/bootstrap.go
@@ -82,10 +82,19 @@ func (s *BootstrapService) attemptJoin(seedAddr string) bool {
 		return false
 	}
 
-	client := &http.Client{Timeout: 10 * time.Second}
-	url := fmt.Sprintf("http://%s/members/join", seedAddr)
+	client := NewAuthenticatedHTTPClient(s.config, 10*time.Second)
+	protocol := GetProtocol(s.config)
+	url := fmt.Sprintf("%s://%s/members/join", protocol, seedAddr)
 
-	resp, err := client.Post(url, "application/json", bytes.NewBuffer(jsonData))
+	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonData))
+	if err != nil {
+		s.logger.WithError(err).Error("Failed to create join request")
+		return false
+	}
+	req.Header.Set("Content-Type", "application/json")
+	AddClusterAuthHeaders(req, s.config)
+
+	resp, err := client.Do(req)
 	if err != nil {
 		s.logger.WithFields(logrus.Fields{
 			"seed":  seedAddr,
diff --git a/integration_test.sh b/integration_test.sh
index e209cf3..af6d3b6 100755
--- a/integration_test.sh
+++ b/integration_test.sh
@@ -124,7 +124,10 @@ EOF
 # Test 3: Cluster formation
 test_cluster_formation() {
     test_start "2-node cluster formation and Merkle Tree replication"
-    
+
+    # Shared cluster secret for authentication (Issue #13)
+    local CLUSTER_SECRET="test-cluster-secret-12345678901234567890"
+
     # Node 1 config
     cat > cluster1.yaml <<EOF
 node_id: "cluster-1"
@@ -138,8 +141,9 @@ gossip_interval_max: 10
 sync_interval: 10
 allow_anonymous_read: true
 allow_anonymous_write: true
+cluster_secret: "$CLUSTER_SECRET"
 EOF
-    
+
     # Node 2 config
     cat > cluster2.yaml <<EOF
 node_id: "cluster-2"
@@ -153,6 +157,7 @@ gossip_interval_max: 10
 sync_interval: 10
 allow_anonymous_read: true
 allow_anonymous_write: true
+cluster_secret: "$CLUSTER_SECRET"
 EOF
     
     # Start nodes
@@ -230,15 +235,18 @@ EOF
 # but same path. The Merkle tree sync should then trigger conflict resolution.
 test_conflict_resolution() {
     test_start "Conflict resolution test (Merkle Tree based)"
-    
+
     # Create conflicting data using our utility
     rm -rf conflict1_data conflict2_data 2>/dev/null || true
     mkdir -p conflict1_data conflict2_data
-    
+
     cd "$SCRIPT_DIR"
     if go run test_conflict.go "$TEST_DIR/conflict1_data" "$TEST_DIR/conflict2_data"; then
         cd "$TEST_DIR"
-        
+
+        # Shared cluster secret for authentication (Issue #13)
+        local CLUSTER_SECRET="conflict-cluster-secret-1234567890123"
+
         # Create configs
         cat > conflict1.yaml <<EOF
 node_id: "conflict-1"
@@ -250,8 +258,9 @@ log_level: "info"
 sync_interval: 3
 allow_anonymous_read: true
 allow_anonymous_write: true
+cluster_secret: "$CLUSTER_SECRET"
 EOF
-        
+
         cat > conflict2.yaml <<EOF
 node_id: "conflict-2"
 bind_address: "127.0.0.1"
@@ -262,6 +271,7 @@ log_level: "info"
 sync_interval: 3
 allow_anonymous_read: true
 allow_anonymous_write: true
+cluster_secret: "$CLUSTER_SECRET"
 EOF
         
         # Start nodes
diff --git a/server/routes.go b/server/routes.go
index 297e647..c05547f 100644
--- a/server/routes.go
+++ b/server/routes.go
@@ -43,9 +43,11 @@ func (s *Server) setupRoutes() *mux.Router {
 
 	// Member endpoints (available when clustering is enabled)
 	if s.config.ClusteringEnabled {
-		// Apply cluster authentication middleware if cluster secret is configured
+		// GET /members/ is unprotected for monitoring/inspection
+		router.HandleFunc("/members/", s.getMembersHandler).Methods("GET")
+
+		// Apply cluster authentication middleware to all cluster communication endpoints
 		if s.clusterAuthService != nil {
-			router.Handle("/members/", s.clusterAuthService.Middleware(http.HandlerFunc(s.getMembersHandler))).Methods("GET")
 			router.Handle("/members/join", s.clusterAuthService.Middleware(http.HandlerFunc(s.joinMemberHandler))).Methods("POST")
 			router.Handle("/members/leave", s.clusterAuthService.Middleware(http.HandlerFunc(s.leaveMemberHandler))).Methods("DELETE")
 			router.Handle("/members/gossip", s.clusterAuthService.Middleware(http.HandlerFunc(s.gossipHandler))).Methods("POST")
@@ -57,7 +59,6 @@ func (s *Server) setupRoutes() *mux.Router {
 			router.Handle("/kv_range", s.clusterAuthService.Middleware(http.HandlerFunc(s.getKVRangeHandler))).Methods("POST")
 		} else {
 			// Fallback to unprotected endpoints (for backwards compatibility)
-			router.HandleFunc("/members/", s.getMembersHandler).Methods("GET")
 			router.HandleFunc("/members/join", s.joinMemberHandler).Methods("POST")
 			router.HandleFunc("/members/leave", s.leaveMemberHandler).Methods("DELETE")
 			router.HandleFunc("/members/gossip", s.gossipHandler).Methods("POST")