ja4h

README

JA4H Fingerprint in Go

An implementation of the JA4H hash algorithm in Go.

JA4H_b Issues

Note that this is not a perfect implementation of the algorithm.

The JA4H_b section will not be correct because the fingerprint should be the truncated SHA256 hash of the request headers in the order they appear.

Since Go stores the headers in a map, it does not keep the ordering as they appeared in the request.

This implementation of the JA4H_b section sorts the headers before hashing to make the fingerprint consistent.

Example Middleware

Below is an example of using the library as a middleware. It calculates the JA4H fingerprint and adds it as a new header.

package main

import (
	"fmt"
	"net/http"

	ja4h "github.com/lum8rjack/go-ja4h"
)

func indexPageHandler(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "Index page with a new JA4H header: %s\n", r.Header.Get("JA4H"))
}

func ja4hMiddleware(nextHandler http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		r.Header.Add("JA4H", ja4h.JA4H(r))
		nextHandler.ServeHTTP(w, r)
	})
}

func main() {
	mux := http.NewServeMux()
	mux.Handle("/", ja4hMiddleware(http.HandlerFunc(indexPageHandler)))
	http.ListenAndServe(":8080", mux)
}

After starting the server, you can perform different requests to view the fingerprint.

$ curl http://127.0.0.1:8080
Index page with a new JA4H header: ge11nn020000_a00508f53a24_000000000000_000000000000

$ curl http://127.0.0.1:8080 -H "Accept-Language: en-us"
Index page with a new JA4H header: ge11nn03enus_7cf2b917f4b0_000000000000_000000000000

$ curl http://127.0.0.1:8080 -H "Accept-Language: en-us" -H "Cookie: admin=true" -X POST
Index page with a new JA4H header: po11cn03enus_55e041b6e2b4_8c6976e5b541_8c6976e5b541

References

• JA4+ Network Fingerprinting
• ja4 GitHub

Documentation

Index

• func JA4H(req *http.Request) string
• func JA4H_a(req *http.Request) string
• func JA4H_b(req *http.Request) string
• func JA4H_c(req *http.Request) string
• func JA4H_d(req *http.Request) string

Functions

func JA4H

func JA4H(req *http.Request) string

JA4H：基于每个HTTP请求生成HTTP客户端指纹

func JA4H_a

func JA4H_a(req *http.Request) string

生成JA4H_a部分

func JA4H_b

func JA4H_b(req *http.Request) string

JA4H_b部分：计算请求头的SHA256哈希值，按顺序排列

func JA4H_c

func JA4H_c(req *http.Request) string

JA4H_c部分：计算Cookie字段的哈希值

func JA4H_d

func JA4H_d(req *http.Request) string

JA4H_d部分：计算Cookie字段及其值的哈希值