Just a Kotlin library that validates secrets and generates one-time passwords for Yandex two-factor authentication.

Inspired by:

• https://github.com/norblik/KeeYaOtp (original source of algorithms)
• https://github.com/beemdevelopment/Aegis

To use it with Gradle insert the following code in your build.gradle:

repositories {
    mavenCentral()
}

dependencies {
    implementation("ru.mihailpro.lib:yandexotp:1.0")
}

To use it with Maven insert the following code in your pom.xml file:

<dependency>
  <groupId>ru.mihailpro.lib</groupId>
  <artifactId>yandexotp</artifactId>
  <version>1.0</version>
</dependency>

1. The process of generating a one-time code is quite simple:

import ru.mihailpro.lib.yandexotp.YandexOTPGenerator

// Get a secret from QR code or provided directly by passport.yandex
val secretHash = "LA2V6KMCGYMWWVEW64RNP3JA3IAAAAAAHTSG4HRZPI"
// Get a PIN code, which user decided to use before QR generation
val pin = "7586"
// Call method
val result = YandexOTPGenerator.getCode(secretHash, pin)
// Example output: oactmacq

2. If you want to make sure in advance that you can process a given secret, there is a special method for checking its checksum. This is useful when the user enters the secret manually and might accidentally make a mistake when typing

import ru.mihailpro.lib.yandexotp.utils.YandexOTPValidator

// Output: true - if everything is OK, false - if not
val result = YandexOTPValidator.validateSecret(secretHash)

3. You can also use a special class YandexSecret to interact with the generator and store the secret obtained from the QR code or manual input by using the following method:

import ru.mihailpro.lib.yandexotp.utils.YandexOTPParser

// If you obtained secret string from QR code use:
val resultQR = YandexOTPParser.parseQRSecret(secretHash)

// If you obtained secret string from user manual input
val resultManual = YandexOTPParser.parseManualSecret(secretHash)

4. If you don't want to process URI from QR code by yourself please use our method:

Example URL from QR:

otpauth://yaotp/test-user?secret=LA2V6KMCGYMWWVEW64RNP3JA3I&name=test.user&track_id=7d60d52842566939afbb08637e160a514f&uid=1544094177&pin_length=16

Contains:
- <yaotp>: means that this string contains data for Yandex.2FA
- <test-user>: unique user name, usually you may see it in email: test-user@ya.ru

Query params:
- secret: used by another yandexotp methods,
- name: user chosen name, can be configured in Yandex.Passport
- pin_length: user-defined PIN length

Method:

val yandexSecret = YandexOTPParser.parseQRUri(uri)

This project is licensed under the GNU General Public License v3.0. See the LICENSE file for details.