{StdEncoding, 6, 16},
		{StdEncoding, 10, 16},
		{StdEncoding, 11, 24},
		{rawStdEncoding, 0, 0},
		{rawStdEncoding, 1, 2},
		{rawStdEncoding, 2, 4},
		{rawStdEncoding, 3, 5},
		{rawStdEncoding, 4, 7},
		{rawStdEncoding, 5, 8},
		{rawStdEncoding, 6, 10},
		{rawStdEncoding, 7, 12},
		{rawStdEncoding, 10, 16},
		{rawStdEncoding, 11, 18},
	}
	// check overflow
	switch strconv.IntSize {
	case 32:

	}
	if length < secretKeyMinLen {
		return "", errors.New("auth: secret key length is too short")
	}

	key := make([]byte, base64.RawStdEncoding.DecodedLen(length))
	if _, err := io.ReadFull(random, key); err != nil {
		return "", err
	}

	s := base64.RawStdEncoding.EncodeToString(key)
	return strings.ReplaceAll(s, "/", "+"), nil
}