XTLS/Xray-core · error

first padding length must not be smaller than 35

Error message

first padding length must not be smaller than 35

What it means

Error "first padding length must not be smaller than 35" thrown in XTLS/Xray-core.

Source

Thrown at proxy/vless/encryption/common.go:244

	}
	maxLen := 0
	for i, s := range strings.Split(padding, ".") {
		x := strings.Split(s, "-")
		if len(x) < 3 || x[0] == "" || x[1] == "" || x[2] == "" {
			return errors.New("invalid padding lenth/gap parameter: " + s)
		}
		y := [3]int{}
		if y[0], err = strconv.Atoi(x[0]); err != nil {
			return
		}
		if y[1], err = strconv.Atoi(x[1]); err != nil {
			return
		}
		if y[2], err = strconv.Atoi(x[2]); err != nil {
			return
		}
		if i == 0 && (y[0] < 100 || y[1] < 18+17 || y[2] < 18+17) {
			return errors.New("first padding length must not be smaller than 35")
		}
		if i%2 == 0 {
			*paddingLens = append(*paddingLens, y)
			maxLen += max(y[1], y[2])
		} else {
			*paddingGaps = append(*paddingGaps, y)
		}
	}
	if maxLen > 18+65535 {
		return errors.New("total padding length must not be larger than 65553")
	}
	return
}

func CreatPadding(paddingLens, paddingGaps [][3]int) (length int, lens []int, gaps []time.Duration) {
	if len(paddingLens) == 0 {
		paddingLens = [][3]int{{100, 111, 1111}, {50, 0, 3333}}
		paddingGaps = [][3]int{{75, 0, 111}}

View on GitHub (pinned to 7d214f8b09)

When it happens

Trigger: Thrown at proxy/vless/encryption/common.go:244 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/6ce3930149c5e0ca. Report an issue: GitHub.