Exemple of signign an AWS Access Token - Unfixed

SigningToken.go

package main

import (
	"crypto/rsa"
	"encoding/base64"
	"encoding/binary"
	"encoding/json"
	"fmt"
	"github.com/dgrijalva/jwt-go"
	"io/ioutil"
	"log"
	"math/big"
	"net/http")

type AccessToken struct {
	Exp      uint32 `json:"exp"`
	TokenUse string `json:"token_use"`
	Iss      string `json:"iss"`
	ClientId string `json:"client_id"`
	Username string `json:"username"`
	Kid      string `json:"kid"`
	Alg      string `json:"alg"`
	jwt.StandardClaims
}

func main() {
	//Access Token returned from AWS
	tokenString := "eyJraWQiOiJqRb2pKdEZCNE5jSEdQZnFcaDNIcjZidVdYQjRXOTFFN3ltY2NRE33TT0iLCJhbGciOiJSUzI1NFiJ9.eyJzdWIiOGGFWMwNmExOS1iMTgj4LTQ0YzAtOD4NmNy04N1jY1NmNjNGYy4MzE0iLCJ0b2tlbl91c2UiOiJhY2Nlc53MiLC3JzY29wZSI61ImF3cy5jb2duaXRvLnNpZ25pbi51gc52V3yLmbFkbWiX34IjoiaHR0cHM6XC9cL2NvZ25pdG8taWRwLnVzLWVhc3QtMS5hbWF6b25hd3MuY29tXC91cy1lYXN0LTFfR3U4WWFUaDcyIiwiZXhwIjoxNDcwMjc4MzExLCJpYXQiOjE0NzAyNzQ3MTEsImp0aSI6IjhmNTBiZmU4LWVlNGUtNGFkZi04MDQxLWU5MGM4YWJkZDExZCIsImNsaWVudF9pZCI6IjRwNzNuYjhra3NsbHJrbTlzMzdzYXZr4FjiwidXNlcm5hbWUiOiJtYXRlbyJ9.GYZQKv7o8_o9E4ktVKZngYD4BS5QluOMwE-MRcJB432CmNimQm6JbvT3H48ECThe4f3sZ1KyVbgDJbyUnlkaAwMEBjMnlV7AUaZb-ifveM7kHM30BS5LCV_SCiCk-PvmWjeIHu9bR3EwG8azJCceD5Are03LmhAtPN94gRy-opXJPAnaCba00AwKBd_pN3UH7LYu4u4EQ29eIfn4k4RCLuR31jr7ad3dvvjhhy658dQSHzSuPZGcN1-CRVSlrd0nk0Ba2t8W33LtjxM6wzPThWgh0fpy2XEDosGU_9FiXdEjUKisE3VHxroygQ8ekVWKHssa2eu3rCx8OthWzaGag0w1"
	
	//JWKS.json from AWS User Pool
	rawN := "rdTmzrh7tw0i_YreN0MDLejnS0jrewIFoSzRfFEbqf-bwGre3zGAk9HGZreG6B5gg1D40Jsz1upo4E70VS0raGfSBPrePO7ZAJ2VCUUeblr9X_aWK4f294v4Cf3n8jZyFcGK9qhgcqy3DlHqqDANtjamWVtEhTRTFc-qoz1ScvHmPupsXlj1FsAEFEbVhP4705ez5gW3uQOoidrm38sPFwCN7g7xhA9CyzF04Zsjky55OfMCyWlIt7nljLx7ZRG3dVRD3vdEBI99qtxf43qMCWSPUk7Whn11Wf_u0xDrWhtGR9k599rKBBRWuqcujYYnFuOp80BeQIL25cePPK8lxw"
	rawE := "AQAB"

	decodedE, err := base64.RawURLEncoding.DecodeString(rawE)
	if err != nil {
		panic(err)
	}
	if len(decodedE) < 4 {
		ndata := make([]byte, 4)
		copy(ndata[4-len(decodedE):], decodedE)
		decodedE = ndata
	}
	pubKey := &rsa.PublicKey{
		N: &big.Int{},
		E: int(binary.BigEndian.Uint32(decodedE[:])),
	}
	decodedN, err := base64.RawURLEncoding.DecodeString(rawN)
	if err != nil {
		panic(err)
	}
	pubKey.N.SetBytes(decodedN)
	fmt.Println(decodedN)
	fmt.Println(decodedE)
	fmt.Printf("%#v\n", *pubKey)

	token, err := jwt.ParseWithClaims(tokenString, &AccessToken{}, func(token *jwt.Token) (verifykey interface{}, err error) {
		return pubKey, nil
	})
	
	if err != nil {
		fmt.Println(err)	
	} else {
		fmt.Println(token.Valid)	
	}
}