text: #!/usr/local/bin/python
  
  
  import binascii
  from Crypto.Cipher import AES
  
  blocksize = 16
  key = b'YELLOW SUBMARINE'
  
  cipher = AES.new(key, AES.MODE_ECB)
  
  
  with open("./7.txt") as f:
      ciphertext = binascii.a2b_base64(f.read())
  
  assert len(ciphertext) > blocksize - 1
  print cipher.decrypt(ciphertext)
  