OTP Generated by Google Authenticator not validated by the Library's OTP

[Cprime50]

I am using this library to generate a QR code that I connect to Google Authenticator. However, the OTP generated by Google Authenticator doesn't get validated by the library.

version of package

github.com/pquerna/otp v1.4.0

go version

go version go1.22.4 linux/amd64

code:

package main

import (
	"fmt"
	"image/png"
	"log"
	"os"

	"github.com/pquerna/otp"
	"github.com/pquerna/otp/totp"
)

func main() {
	key, err := totp.Generate(totp.GenerateOpts{
		Issuer:      "localhost:8000",
		AccountName: "[email protected]",
		SecretSize:  32,
	})
	if err != nil {
		log.Fatalf("Failed to generate OTP: %v", err)
	}

	qrImage, err := key.Image(256, 256)
	if err != nil {
		log.Fatalf("Failed to generate QR code image: %v", err)
	}
	file, err := os.Create("otp_qrcode.png")
	if err != nil {
		log.Fatalf("Failed to create file for QR code: %v", err)
	}
	defer file.Close()
	if err := png.Encode(file, qrImage); err != nil {
		log.Fatalf("Failed to save QR code image: %v", err)
	}
	fmt.Println("QR code generated and saved as otp_qrcode.png")

	fmt.Print("Enter the OTP code from your authenticator app: ")
	var otpCode string
	fmt.Scanln(&otpCode)

	valid := totp.Validate(otpCode, key.Secret())
	if valid {
		fmt.Println("OTP verified successfully!")
	} else {
		fmt.Println("Invalid OTP code.")
	}
}

to reproduce:
Run the code provided above.
Scan the generated QR code using Google Authenticator.
Enter the OTP code displayed in Google Authenticator into the terminal.

[KEINOS]

I can not reproduce in my environment and all the authenticator apps below returns as success, "OTP verified successfully!"

• Authenticators
  • Android 9 (Kernel 4.9.148)
    • Google Authenticator 6.0 ... OK
    • Microsoft Authenticator 6.2407.5108 ... OK
  • iPhone (iOS 17.6.1)
    • Google Authenticator 4.2.1 ... OK
    • Microsoft Authenticator 6.8.14 ... OK
• Code executed via macOS, Linux (Alpine, Ubuntu via Docker) @ go1.23.0
• Package: github.com/pquerna/otp v1.4.0

In my experience, the time zone and/or NTP are not set correctly in such cases.

[the-real-i9]

Hi, @Cprime50. I reproduced your code and it worked for me.

Go version (Latest)

go version go1.23.0 linux/amd64

I don't think this issue has anything to do with Go's version.

Package version

github.com/pquerna/otp v1.4.0