go_totp is a Go package for generating Time-based One-Time Passwords (TOTP) conforming to RFC 6238. It supports multiple hash algorithms, including HMAC-SHA1, HMAC-SHA256, and HMAC-SHA512.

• Supports HMAC-SHA1, HMAC-SHA256, and HMAC-SHA512 algorithms.
• Configurable TOTP parameters such as digit length, time step, and initial counter value.
• Easy-to-use interface for generating TOTPs.

To install the package, run:

go get github.com/michaelwp/go_totp

Here's a step-by-step guide on how to use the go_totp library to generate a TOTP.

First, import the package into your Go code:

import "github.com/michaelwp/go-totp"

Create an instance of the Totp struct with the desired configuration. For example, to create a TOTP generator using HMAC-SHA256 with a 8-digit output:

totp := go_totp.Totp{
    Secret:    "rahasia",
    Digits:    8,
    Period:    15,
    Algorithm: go_totp.SHA256,
    T0:        0,
}

The Totp struct contains the following fields:

• Secret: The shared secret key used for generating the TOTP.
• Digits: The number of digits in the TOTP output.
• Period: The time step in seconds (default is 30 seconds).
• Algorithm: The hash algorithm to use (SHA1, SHA256, or SHA512).
• T0: The initial counter value (default is 0).

To generate the TOTP, call the GenerateTOTP method on the Totp instance, passing the current Unix timestamp as the argument. This method returns the generated TOTP as a string.

Here's a complete example demonstrating how to use the go_totp package:

package main

import (
	"fmt"
	"github.com/michaelwp/go-totp"
	"log"
	"time"
)

func main() {
	// Get the current Unix time
	timestamp := time.Now().Unix()

	// define the variables
	totp := go_totp.Totp{
		Secret:    "rahasia",
		Digits:    8,
		Period:    15,
		Algorithm: go_totp.SHA256,
		T0:        0,
	}

	// Generate the TOTP
	pass, err := totp.GenerateTOTP(timestamp)
	if err != nil {
		log.Println("GenerateTOTP error:", err)
	}

	// Print the TOTP
	fmt.Println("TOTP:", pass)
}

To run the example, save it to a file (e.g., main.go), and then run:

go run main.go

This will output a 8-digit TOTP based on the provided user ID and the current Unix time.

This project is licensed under the MIT License. See the LICENSE file for details.

Contributions are welcome! Please open an issue or submit a pull request with your changes.

For any questions or issues, please open an issue on GitHub.