code: def transposition_cipher(key, message):
      
      ciphertext = [''] * key
      ml = len(message)
      for col in range(key):
          pointer = col
          while pointer < ml:
              ciphertext[col] += message[pointer]
              pointer += key
  
      return ''.join(ciphertext)
docs: 换位加密法
      :param key: 数字Key
      :param message: 待加密字符串
      :return: 被加密数据