go get "github.com/KEINOS/go-totp"

import (
    "fmt"
    "log"

    "github.com/KEINOS/go-totp/totp"
)

func Example() {
    // Generate a new secret key
    Issuer := "Example.com"
    AccountName := "[email protected]"

    key, err := totp.GenerateKey(Issuer, AccountName)
    if err != nil {
        log.Fatal(err)
    }

    // Generate 6 digits passcode (valid for 30 seconds)
    passcode, err := key.PassCode()
    if err != nil {
        log.Fatal(err)
    }

    // Validate the passcode
    valid, err := key.Validate(passcode)
    if err != nil {
        log.Fatal(err)
    }

    if valid {
        fmt.Println("Passcode is valid")
    }

    // Output: Passcode is valid
}

// --------------------------------------------------
//  Basic methods of totp.Key object
// --------------------------------------------------

// Generate the current passcode. Which is a string of
// 6 digit numbers and valid for 30 seconds.
passcode, err := key.PassCode()

// Validate the received passcode.
ok := key.Validate(passcode)

// Get 100x100 px image of QR code as PNG byte data.
// FixLevelDefault is the 15% of error correction.
qrCodeObj, err := key.QRCode(totp.FixLevelDefault)
pngBytes, err := qrCodeObj.PNG(100, 100)

// Get the secret key in PEM format text.
pemKey, err := key.PEM()

// Get the secret key in TOTP URI format string.
uriKey := key.URI()

// Get the secret value in Base32 format string.
base32Key := key.Secret.Base32()

// Get the secret value in Base62 format string.
base62Key := key.Secret.Base62()