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

def caesar_cipher(message, key):
    """
    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
    """
    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