def rsa_encrypt(msg):
    """
    RSA加密
    :param pub_key_str:公鑰
    :param msg:待加密信息
    :return:
    """
    msg = msg.encode('utf-8')
    length = len(msg)
    default_length = 117
    # 公鑰加密
    public_keystr = '-----BEGIN RSA PUBLIC KEY-----\n' + get_public_key() + '\n-----END RSA PUBLIC KEY-----'
    pubobj = Cipher_pkcs1_v1_5.new(RSA.importKey(public_keystr))
    # 長度不用分段
    if length < default_length:
        return base64.b64encode(pubobj.encrypt(msg))
    # 需要分段
    offset = 0
    res = []
    while length - offset > 0:
        if length - offset > default_length:
            res.append(pubobj.encrypt(msg[offset:offset + default_length]))
        else:
            res.append(pubobj.encrypt(msg[offset:]))
        offset += default_length
    byte_data = b''.join(res)
    return base64.b64encode(byte_data)