diff --git a/auth/utils.py b/auth/utils.py
index 4bded89..c9ee6a5 100644
--- a/auth/utils.py
+++ b/auth/utils.py
@@ -1,5 +1,6 @@
 import bcrypt
 import jwt
+import logging
 import os
 import secrets
 from datetime import datetime, timedelta
@@ -10,6 +11,8 @@
 from cache_db.models import User, RefreshToken
 from typing import Tuple, Optional
 
+logger = logging.getLogger(__name__)
+
 
 class PasswordUtils:
     """Password hashing and verification utilities"""
@@ -129,7 +132,8 @@ def decorated_function(*args, **kwargs):
             g.user = user_data
             return f(*args, **kwargs)
         except Exception as e:
-            return jsonify({'error': 'Unauthorized', 'details': str(e)}), 401
+            logger.warning("Authentication failed: %s", e)
+            return jsonify({'error': 'Unauthorized'}), 401
     return decorated_function
 
 
diff --git a/tests/test_auth.py b/tests/test_auth.py
new file mode 100644
index 0000000..5e7d21d
--- /dev/null
+++ b/tests/test_auth.py
@@ -0,0 +1,55 @@
+import sys
+import unittest
+from unittest.mock import MagicMock, patch
+
+# Mock cache_db modules prior to importing auth.utils
+cache_db_mock = MagicMock()
+sys.modules['cache_db'] = cache_db_mock
+sys.modules['cache_db.redis_client'] = cache_db_mock
+sys.modules['cache_db.models'] = cache_db_mock
+
+from flask import Flask, jsonify
+from auth.utils import login_required, PasswordUtils, JWTUtils
+
+
+class TestAuthUtils(unittest.TestCase):
+
+    def setUp(self):
+        self.app = Flask(__name__)
+        self.app.config['SECRET_KEY'] = 'test-secret'
+
+        @self.app.route('/protected')
+        @login_required
+        def protected_route():
+            return jsonify({'message': 'success'})
+
+        self.client = self.app.test_client()
+
+    @patch('auth.utils.verify_jwt_in_request')
+    def test_login_required_unauthorized_does_not_leak_details(self, mock_verify):
+        mock_verify.side_effect = Exception("Internal DB error: connection timeout at 10.0.0.5:5432")
+
+        response = self.client.get('/protected')
+        self.assertEqual(response.status_code, 401)
+        data = response.get_json()
+
+        self.assertEqual(data, {'error': 'Unauthorized'})
+        self.assertNotIn('details', data)
+        self.assertNotIn('10.0.0.5', str(data))
+
+    def test_password_utils_hash_and_verify(self):
+        password = "securePassword123!"
+        hashed = PasswordUtils.hash_password(password)
+        self.assertTrue(PasswordUtils.verify_password(password, hashed))
+        self.assertFalse(PasswordUtils.verify_password("wrongPassword", hashed))
+
+    def test_jwt_utils_create_and_decode(self):
+        access_token, refresh_token = JWTUtils.create_tokens("user123", "alice")
+        decoded = JWTUtils.decode_token(access_token)
+        self.assertIsNotNone(decoded)
+        self.assertEqual(decoded.get("user_id"), "user123")
+        self.assertEqual(decoded.get("username"), "alice")
+
+
+if __name__ == '__main__':
+    unittest.main()