https://github.com/jonfriesen/otp

A Go implementation of RFC 4226 HOTP: An HMAC-Based One-Time Password Algorithm and RFC 6238: TOTP: Time-Based One-Time Password Algorithm
https://github.com/jonfriesen/otp

2-factor 2fa hacktoberfest hmac-sha1 hotp otp password-algorithm rfc-4226 rfc-6238 totp

Last synced: 2 months ago
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A Go implementation of RFC 4226 HOTP: An HMAC-Based One-Time Password Algorithm and RFC 6238: TOTP: Time-Based One-Time Password Algorithm

• Host: GitHub
• URL: https://github.com/jonfriesen/otp
• Owner: jonfriesen
• License: mit
• Created: 2017-11-17T16:54:25.000Z (about 7 years ago)
• Default Branch: master
• Last Pushed: 2023-11-09T20:41:18.000Z (about 1 year ago)
• Last Synced: 2024-06-20T12:39:12.790Z (6 months ago)
• Topics: 2-factor, 2fa, hacktoberfest, hmac-sha1, hotp, otp, password-algorithm, rfc-4226, rfc-6238, totp
• Language: Go
• Homepage:
• Size: 354 KB
• Stars: 9
• Watchers: 4
• Forks: 5
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# ![OneTimePasswords](media/otp_logo.png)

![Build Status](https://github.com/jonfriesen/otp/workflows/build/badge.svg)

This package is an implementation of [RFC 4226: HOTP: An HMAC-Based One-Time Password Algorithm](https://tools.ietf.org/html/rfc4226) and [RFC 6238: TOTP: Time-Based One-Time Password Algorithm](https://tools.ietf.org/html/rfc6238) with slight deviations from the RFC based on the algorithmic reference implementation and tested using the RFC test values to ensure comaptibility with other HOTP and TOTP systems. 

## Installation

Clone this repository into your Go src directory or pull it automatically with:

```

$ go get github.com/jonfriesen/otp

```

## Usage

```

import "github.com/jonfriesen/otp"

...

// To generate and checking a Time base OTP

totpToken := NewTOTP("secret", Time, 8, 30, 2, sha1.New)

totp := totpToken.Generate()

isValid := totp == totpToken.Check("12345678")

...

// To generate and checking a HMAC OTP 

hotpToken := NewHOTP("secret", 0, 6, 5, sha1.New)

hotp := hotpToken.Generate()

isValid := hotp == hotpToken.Check("123456")

```

## Considerations and Variations from RFC

### Checksum

The checksum option is not included in this implementation as I feel most real world implementations don't use it or account for it. 

### Truncation Offset

The truncation offset is intended to give the entire hash digest the opportunity to contribute to the truncated portion of the hash. Removing this section does not make the algorithm more or less secure.

## Motivation

The OTP package was created to offer a simple, close implementation of RFC 4226 and RFC 6238 for easy consumption in Go.

## Contributions

Pull Requests are welcome, please include tests covering your contributions. 

[MIT License Copyright (c) 2022 Jonathan Friesen](./LICENSE)