백엔드 전체 구현 완료: 내부 서비스(Auth, Client, Realtime), API 엔드포인트 및 스케줄러 구현

backend/app/core/crypto.py

@@ -0,0 +1,19 @@
+from Crypto.Cipher import AES
+from Crypto.Util.Padding import unpad
+from base64 import b64decode
+
+def aes_cbc_base64_dec(key: str, iv: str, cipher_text: str) -> str:
+    """
+    Decrypts KIS WebSocket data using AES-256-CBC.
+    adapted from KIS official sample.
+    """
+    if not key or not iv:
+        raise ValueError("Key and IV are required for decryption")
+
+    # Key and IV are assumed to be utf-8 strings
+    cipher = AES.new(key.encode("utf-8"), AES.MODE_CBC, iv.encode("utf-8"))
+    
+    # Decrypt and unpad
+    decrypted_bytes = unpad(cipher.decrypt(b64decode(cipher_text)), AES.block_size)
+    
+    return bytes.decode(decrypted_bytes, 'utf-8')