README
¶
TOTP (Time-based One Time Password)
This package provides a convenient way of generarting Time-based One-Time Passwords in accordance with IETF's RFC6238.
Hash-based One-Time Password Algorithm(HOTP)uses a counter as a moving factor while generating the OTP. This counter is hashed using an HMAC hashing algorithms (HAMC-SHA1, HMAC-SHA256 or HMAC-512). TOTP builds on on HOTP by deriving the moving factor from UNIX time instead of a counter.
TOTP can be used to create OTPs containing more than 6 digits. Users can choose between the HMAC-SHA1, HMAC-SHA256 and HMAC-SHA512 for generating TOTPs.
Example
package main
import (
"github.com/kelsier27/totp"
"fmt"
)
func main() {
var sharedSecret = "3132333435363738393031323334353637383930"
otpgen := totp.NewDefaultTOTP(sharedSecret)
totp := otpgen.GenerateTOTP("1970-01-01T00:00:59Z")
fmt.Println(totp) // output - 94287082
}
Install
TOTP can be installed using go get
go get github.com/kelsier27/totp
Usage
- Obtain TOTPConfig object
Before generating the OTP, we need to obtain a TOTPConfig object. The default objects generate a 8-digit TOTP using T0 as Epoch time 1970-01-01T00:00:00Z and Time Step X as 30s. To get the default TOTPConfig, use one of the following functions depending on the choice of HMAC algorithm
- NewDefaultSHA1
- NewDefaultSHA256
- NewDefaultSHA512
- Generate TOTP
Once we obtain a config object, we can call the GenerateTOTP method. This method takes a time string as the input and returns a TOTP string.
Documentation
¶
Overview ¶
Package totp generates a Timed One Time Password conforming to RFC6238
Index ¶
Constants ¶
const ( DefaultT0 = "1970-01-01T00:00:00Z" DefaultX = 30 DefaultCodeDigits = 10 CryptoSHA1 = "HMACSHA1" CryptoSHA256 = "HMACSHA256" CryptoSHA512 = "HMACSHA512" )
Variables ¶
var (
DIGIT_POWERS = []int64{1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000, 10000000000, 100000000000}
)
Functions ¶
This section is empty.
Types ¶
type TOTPConfig ¶
type TOTPConfig struct {
// Epoc time in standard format
// eg: "1970-01-01T00:00:00Z"
T0 string
// Time step
// eg 30.0
X int64
// shared secret K
SecretK string
// number of digits in OTP
CodeDigits int
// HMAC algorithm
// enum{'HMACSHA1', 'HMACSHA256', 'HMACSHA512'}
Crypto string
}
func DefaultConfig ¶
func DefaultConfig(seed string) *TOTPConfig
Returns TOTP config object with defaults
func NewDefaultSHA1 ¶
func NewDefaultSHA1(seed string) *TOTPConfig
* Returns a TOTP config object that uses SHA1 for HMAC hashing and default values for `T0`, `X`, and `CodeDigits`.
The secret key still needs supplied by the user.
func NewDefaultSHA256 ¶
func NewDefaultSHA256(seed string) *TOTPConfig
* Returns a TOTP config object that uses SHA256 for HMAC hashing and default values for `T0`, `X`, and `CodeDigits`.
The secret key still needs supplied by the user.
func NewDefaultSHA512 ¶
func NewDefaultSHA512(seed string) *TOTPConfig
* Returns a TOTP config object that uses SHA512 for HMAC hashing and default values for `T0`, `X`, and `CodeDigits`.
The secret key still needs supplied by the user.
func (*TOTPConfig) GenerateTOTP ¶
func (otpConf *TOTPConfig) GenerateTOTP(date string) (string, error)
Source Files