보안 강화: DB 자격증명(AppKey, Secret) 및 세션토큰(Access Token) 암호화 저장 구현 (AES-GCM/CBC), .env 정리

backend/.env.example

@@ -4,11 +4,10 @@ HOST=0.0.0.0
 
 # Security
 ALLOWED_HOSTS=["kis.tindevil.com", "localhost", "127.0.0.1"]
-SECRET_KEY=change_this_to_a_secure_random_string
+SECRET_KEY=dlrjtdmsQlalfzlfksmsep@wkf!wkf!ahfmrpTdj$#
 
 # Database
 DATABASE_URL=sqlite+aiosqlite:///./kis_stock.db
 
-# KIS API (Optional here, managed in DB mostly)
-# KIS_APP_KEY=
-# KIS_APP_SECRET=
+# Security
+SECRET_KEY=change_this_to_a_secure_random_string_min_32_chars