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: "test@mail.com",
        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