diff --git a/addon/nonce_check.py b/addon/nonce_check.py
index a020ce4..723436c 100644
--- a/addon/nonce_check.py
+++ b/addon/nonce_check.py
@@ -40,14 +40,13 @@ class NonceChecker:
         """
         res = flow.response
         # 1. JSON 응답에 id_token 있음
-        try:
-            if "application/json" in res.headers.get("content-type", ""):
+        if "application/json" in res.headers.get("content-type", ""):
+            try:
                 data = res.json()
                 return data.get("id_token")
-            else:
-                return None
-        except Exception:
-            pass
+            except Exception:
+                pass
+
 
         # 2. Location 헤더에서 id_token 파싱 (예: #id_token=...&access_token=...)
         location = res.headers.get("location", "")
@@ -66,7 +65,7 @@ class NonceChecker:
 
     def decode_id_token(self, flow) -> dict:
         res = flow.response
-        id_token = self.extract_id_token(res)
+        id_token = self.extract_id_token(flow)
         if not id_token:
             return {}
         try:
@@ -85,12 +84,12 @@ class NonceChecker:
         parsed = urlparse(url)
         fragment_params = parse_qs(parsed.fragment)
 
-        if "id token" in fragment_params:
+        if "id_token" in fragment_params:
             # id_token이 fragment에 있는 경우
-            id_token = fragment_params["id token"][0]
+            id_token = fragment_params["id_token"][0]
             return True
 
-        id_token = self.extract_id_token(res)
+        id_token = self.extract_id_token(flow)
         decoded = self.decode_id_token(id_token)
         nonce = decoded.get("nonce")