diff --git a/apps/common/utils/crypto.py b/apps/common/utils/crypto.py
index 994c0f087..1407c7d7d 100644
--- a/apps/common/utils/crypto.py
+++ b/apps/common/utils/crypto.py
@@ -83,7 +83,7 @@ class PiicoSM4EcbCrypto(BaseCrypto):
 
     def _decrypt(self, data: bytes) -> bytes:
         bs = self.cipher.decrypt(data)
-        return bs[:bs.index(0)]
+        return bs.rstrip(b'\0')
 
 
 class AESCrypto: