code: def caesar_cipher(message, key):
      
      LEFTERS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
      translated = ''
      message = message.upper()
      for symbol in message:
          if symbol in LEFTERS:
              num = LEFTERS.find(symbol)
              num = num + key
  
              if num >= len(LEFTERS):
                  num = num - len(LEFTERS)
              elif num < 0:
                  num = num + len(LEFTERS)
  
              translated = translated + LEFTERS[num]
          else:
              translated = translated + symbol
  
      return translated
docs: 凯特加密法
      :param message: 待加密数据
      :param key: 加密向量
      :return: 被加密的字符串