Key Pinning in #Golang

keyping.go

package main

import (
	"bytes"
	"crypto/sha256"
	"crypto/tls"
	"crypto/x509"
	"log"
	"net"
	"net/http"
)

type Dialer func(network, addr string) (net.Conn, error)

func makeDialer(fingerprint []byte, skipCAVerification bool) Dialer {
	return func(network, addr string) (net.Conn, error) {
		c, err := tls.Dial(network, addr, &tls.Config{InsecureSkipVerify: skipCAVerification})
		if err != nil {
			return c, err
		}
		connstate := c.ConnectionState()
		keyPinValid := false
		for _, peercert := range connstate.PeerCertificates {
			der, err := x509.MarshalPKIXPublicKey(peercert.PublicKey)
			hash := sha256.Sum256(der)
			// log.Println(peercert.Issuer)
			// log.Printf("%#v", hash)
			if err != nil {
				log.Fatal(err)
			}
			if bytes.Compare(hash[0:], fingerprint) == 0 {
				log.Println("Pinned Key found")
				keyPinValid = true
			}
		}
		if keyPinValid == false {
		}
		return c, nil
	}
}
func main() {
	fingerprint := []byte{0x53, 0x8d, 0xe6, 0x6e, 0x1d, 0xaf, 0xf6, 0x25, 0xd6, 0x78, 0xb0, 0xb3, 0x71, 0x4, 0xe5, 0x41, 0xd8, 0xc9, 0x68, 0x1f, 0xa6, 0x6, 0x24, 0x6a, 0xf, 0xf9, 0xea, 0xa0, 0x36, 0x55, 0xdc, 0xc1}
	client := &http.Client{}
	client.Transport = &http.Transport{
		DialTLS: makeDialer(fingerprint, false),
	}
	req, err := http.NewRequest("GET", "https://www.google.com", nil)
	resp, err := client.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	log.Println(resp)
}