Golang Authenticator Time Based (you can use it with Authenticator App. Eg: Google Authenticator)

main.go

package main

import (
	"encoding/base64"
	"fmt"
	"time"

	"github.com/skip2/go-qrcode"
	"github.com/xlzd/gotp"
)

const STATIC_SECRET = "X3BZLQW56LDBDZTW"

func main() {

	data, secret, err := GenerateTOTPWithSecret("GolangCool", "[email protected]")
	if err != nil {
		fmt.Println(err)
		return
	}

	fmt.Println(secret)
	fmt.Println(data)
	//VerifyOTP(secret)
}

func ToDataURI(base64EncodedQr string) string {
	return fmt.Sprintf("data:image/png;base64,%s", base64EncodedQr)
}

func GenerateTOTPWithSecret(applicationName, userID string) (string, string, error) {
	secret := gotp.RandomSecret(10)
	uri := gotp.NewDefaultTOTP(secret).ProvisioningUri(userID, applicationName)
	fmt.Println("Secret Key URI:", uri)

	png, err := qrcode.Encode(uri, qrcode.Medium, 256)
	if err != nil {
		return "", "", err
	}
	encoded := base64.StdEncoding.EncodeToString(png)
	return ToDataURI(encoded), secret, nil
}

func VerifyOTP(secret string, otp string) {
	totp := gotp.NewDefaultTOTP(secret)

	if totp.Verify(otp, time.Now().Unix()) {
		fmt.Println("Authentication successful! Access granted.")
	} else {
		fmt.Println("Authentication failed! Invalid OTP.")
	}
}