diff --git a/sender/sender.py b/sender/sender.py
index 4f02093..71b5142 100644
--- a/sender/sender.py
+++ b/sender/sender.py
@@ -6,12 +6,11 @@ import os
 
 
 from entity.Letter import Letter
-from itsdangerous import base64_encode
 from tool import PriKeyHelper
 from tool.PriKeyHelper import getUserKey
 from tool.asymmetric import RSA
 from tool.symmetric.AES import AESUtils
-from tool.symmetric.SM4 import encrypt_ecb, decrypt_cbc_with_iv, encrypt_cbc_with_iv
+from tool.symmetric.SM4 import encrypt_ecb, encrypt_cbc_with_iv
 from Crypto.Random import get_random_bytes
 
 
@@ -43,7 +42,7 @@ def main():
     letter.fileName = getFileName(path)
     letter.recvPubKey = getRecvPubKey()
     letter.senderPubKey = getSenderPubKey()
-    letter.fileBase64, akey = SymEncryption(base64_encode(data).decode("utf-8"),letterSymKey)
+    letter.fileBase64, akey = SymEncryption(base64.b64encode(data).decode("utf-8"),letterSymKey)
     letter.encryptKey = getEncryptKey()
     letter.encryptType = getEncryptType()