README
¶
otp
One Time Password package for Go/Golang developers
Contents
What is OTP
A one-time password (OTP) is an automatically generated numeric string that authenticates a user for a single transaction or login session.
The most important advantage addressed by OTPs is that, in contrast to static passwords, they are not vulnerable to replay attacks.
There are two kinds of OTP which are HOTP and TOTP. The vast majority of OTP today is TOTP. Very few people still use HTOP.
By the way, the TOTP RFC document has a mistake. More details can be found here if you are interested.
How to Use
Before using this package, you need to install Go and set your Go workspace first.
- Use the below Go command to install the package.
$ go get -u github.com/lucasbbb/otp
- Import it in your code.
import "github.com/lucasbbb/otp"
- Generate a Key and show it's QR code.
func main() {
http.HandleFunc("/image", QRImage)
_ = http.ListenAndServe(":6789", nil)
}
func QRImage(w http.ResponseWriter, req *http.Request) {
secret, _ := base32.StdEncoding.WithPadding(base32.NoPadding).DecodeString("INEECT2TEBEVGICBEBGECRCEIVJA")
key := otp.Key{
Issuer: "example",
Account: "foo",
Typ: "totp",
Secret: secret,
}
image, _ := key.QRImage(256)
_, _ = w.Write(image)
}
- User scan the QR code with Google Authenticator or other apps.
- Compare the code with the sever generated code.
func VerifyOTP(accountName, code string) {
now := time.Now()
// Get user's secret from DATABASE or other repository.
// SELECT secret FORM user WHERE `account_name` = accountName
secret, _ := base32.StdEncoding.WithPadding(base32.NoPadding).DecodeString("INEECT2TEBEVGICBEBGECRCEIVJA")
res := otp.NewTOTP(secret).Validate(now, code)
if res {
// Continue your business logic.
} else {
// Abort.
}
}
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( ErrInvalidType = fmt.Errorf("valid type must be hotp or totp") ErrSecretRequired = fmt.Errorf("the secret is required") ErrInvalidSecret = fmt.Errorf("the secret must be a base32 encoded string") ErrInvalidDigits = fmt.Errorf("parse digits to int failed") ErrCounterRequired = fmt.Errorf("the counter is required for hotp") ErrInvalidCounter = fmt.Errorf("parse counter to uint failed") ErrInvalidPeriod = fmt.Errorf("parse period to uint failed") )
Functions ¶
This section is empty.
Types ¶
type HOTP ¶
type HOTP struct {
Key []byte
}
func (HOTP) Generate ¶
Generate https://datatracker.ietf.org/doc/html/rfc4226#section-5.3
type Key ¶
type Key struct {
Typ string
Issuer string
Account string
Secret []byte
Period int
Counter uint64
Digits int
Algorithm string
// contains filtered or unexported fields
}
func ParseFromURL ¶
ParseFromURL https://github.com/google/google-authenticator/wiki/Key-Uri-Format
type Option ¶
type Option func(*Options)
func WithHashFunc ¶
WithHashFunc The default hash func is sha1.New You can use other hash func such as: sha256.New, sha512.New, md5.New
func WithStartTime ¶
WithStartTime The default start time = 0 The UNIX time to start counting time steps
type Options ¶
func NewOptions ¶
func NewOptions() *Options
Source Files
Directories