diff --git a/src/AIHub/Controllers/AudioTranscriptionController.cs b/src/AIHub/Controllers/AudioTranscriptionController.cs
index ee8ff40..d71ef17 100644
--- a/src/AIHub/Controllers/AudioTranscriptionController.cs
+++ b/src/AIHub/Controllers/AudioTranscriptionController.cs
@@ -1,13 +1,4 @@
 namespace MVCWeb.Controllers;
-using System;
-using System.Net.Http;
-using System.Net.Http.Headers;
-using System.Threading.Tasks;
-using Newtonsoft.Json;
-using Microsoft.AspNetCore.Mvc;
-using System.Net;
-using Newtonsoft.Json.Linq;
-using Microsoft.VisualBasic;
 
 public class AudioTranscriptionController : Controller
 {
diff --git a/src/AIHub/Controllers/BrandAnalyzerController.cs b/src/AIHub/Controllers/BrandAnalyzerController.cs
index e1b745b..8d2cca4 100644
--- a/src/AIHub/Controllers/BrandAnalyzerController.cs
+++ b/src/AIHub/Controllers/BrandAnalyzerController.cs
@@ -83,9 +83,19 @@ public async Task<IActionResult> AnalyzeCompany()
         try
         {
 
-            OpenAIClient client_oai = new OpenAIClient(
-             new Uri(AOAIendpoint),
-             new AzureKeyCredential(AOAIsubscriptionKey));
+            OpenAIClient client_oai = null;
+            if (string.IsNullOrEmpty(AOAIsubscriptionKey))
+            {
+                client_oai = new OpenAIClient(
+                    new Uri(AOAIendpoint),
+                    new DefaultAzureCredential());
+            }
+            else
+            {
+                client_oai = new OpenAIClient(
+                    new Uri(AOAIendpoint),
+                    new AzureKeyCredential(AOAIsubscriptionKey));
+            }
 
             // ### If streaming is not selected
             Response<ChatCompletions> responseWithoutStream = await client_oai.GetChatCompletionsAsync(
diff --git a/src/AIHub/Controllers/CallCenterController.cs b/src/AIHub/Controllers/CallCenterController.cs
index 4257957..52340a8 100644
--- a/src/AIHub/Controllers/CallCenterController.cs
+++ b/src/AIHub/Controllers/CallCenterController.cs
@@ -37,10 +37,19 @@ public async Task<IActionResult> AnalyzeCall()
         }
         try
         {
-
-            OpenAIClient client_oai = new OpenAIClient(
-             new Uri(endpoint),
-             new AzureKeyCredential(subscriptionKey));
+            OpenAIClient client_oai = null;
+            if (string.IsNullOrEmpty(subscriptionKey))
+            {
+                client_oai = new OpenAIClient(
+                    new Uri(endpoint),
+                    new DefaultAzureCredential());
+            }
+            else
+            {
+                client_oai = new OpenAIClient(
+                    new Uri(endpoint),
+                    new AzureKeyCredential(subscriptionKey));
+            }
 
             // ### If streaming is not selected
             Response<ChatCompletions> responseWithoutStream = await client_oai.GetChatCompletionsAsync(
diff --git a/src/AIHub/Controllers/FormAnalyzerController.cs b/src/AIHub/Controllers/FormAnalyzerController.cs
index 709e277..83043dc 100644
--- a/src/AIHub/Controllers/FormAnalyzerController.cs
+++ b/src/AIHub/Controllers/FormAnalyzerController.cs
@@ -120,10 +120,19 @@ public async Task<IActionResult> AnalyzeForm(string image_url, string prompt)
 
         try
         {
-
-            OpenAIClient client_oai = new OpenAIClient(
-             new Uri(AOAIendpoint),
-             new AzureKeyCredential(AOAIsubscriptionKey));
+            OpenAIClient client_oai = null;
+            if (string.IsNullOrEmpty(AOAIsubscriptionKey))
+            {
+                client_oai = new OpenAIClient(
+                    new Uri(AOAIendpoint),
+                    new DefaultAzureCredential());
+            }
+            else
+            {
+                client_oai = new OpenAIClient(
+                    new Uri(AOAIendpoint),
+                    new AzureKeyCredential(AOAIsubscriptionKey));
+            }
 
             // ### If streaming is not selected
             Response<ChatCompletions> responseWithoutStream = await client_oai.GetChatCompletionsAsync(
diff --git a/src/AIHub/Controllers/ImageAnalyzerController.cs b/src/AIHub/Controllers/ImageAnalyzerController.cs
index 7a80c44..64004ae 100644
--- a/src/AIHub/Controllers/ImageAnalyzerController.cs
+++ b/src/AIHub/Controllers/ImageAnalyzerController.cs
@@ -163,10 +163,19 @@ public async Task<IActionResult> DenseCaptionImage(string image_url)
         //7. Describe Image GPT4
         try
         {
-
-            OpenAIClient client_oai = new OpenAIClient(
-             new Uri(AOAIendpoint),
-             new AzureKeyCredential(AOAIsubscriptionKey));
+            OpenAIClient client_oai = null;
+            if (string.IsNullOrEmpty(AOAIsubscriptionKey))
+            {
+                client_oai = new OpenAIClient(
+                    new Uri(AOAIendpoint),
+                    new DefaultAzureCredential());
+            }
+            else
+            {
+                client_oai = new OpenAIClient(
+                    new Uri(AOAIendpoint),
+                    new AzureKeyCredential(AOAIsubscriptionKey));
+            }
 
             // ### If streaming is not selected
             Response<ChatCompletions> responseWithoutStream = await client_oai.GetChatCompletionsAsync(
diff --git a/src/AIHub/GlobalUsings.cs b/src/AIHub/GlobalUsings.cs
index 4951a6e..e3d4be4 100644
--- a/src/AIHub/GlobalUsings.cs
+++ b/src/AIHub/GlobalUsings.cs
@@ -3,11 +3,13 @@
 global using MVCWeb.Models;
 global using Azure.AI.ContentSafety;
 global using Azure;
+global using Azure.Identity;
 global using Azure.Storage.Blobs;
 global using Azure.Storage.Blobs.Models;
 global using Azure.AI.OpenAI;
 global using System.Net.Http.Headers;
 global using Newtonsoft.Json;
+global using Newtonsoft.Json.Linq;
 global using System.Text;
 global using System.Text.Json;
 global using System.Text.Json.Serialization;