# otp-kt

`otp-kt` is a Kotlin Multiplatform library that provides common one-time password implementations.

Supported implementations:
- HOTP
- TOTP

## Targets

| Target           | Status        |
|------------------|---------------|
| JVM              | Supported     |
| JavaScript       | Supported     |
| Native (Linux)   | Supported     |
| Native (Windows) | Not Supported |

## Installation

Add the following to your `build.gradle.kts`.

```kotlin
repositories {
    maven("https://git.infendro.com/api/packages/Infendro/maven")
}

dependencies {
    implementation("com.infendro:otp:1.2.2")
}
```

## Usage

```kotlin
import com.infendro.hash.sha1.SHA1
import com.infendro.otp.SecretGenerator
import com.infendro.otp.TOTP
import com.infendro.random.csprng.CSPRNG
import kotlin.time.Clock.System.now
import kotlin.time.Duration.Companion.seconds

fun main() {
    // create a SecretGenerator and TOTP instance
    val generator = SecretGenerator(CSPRNG.HMAC(SHA1))
    val totp = TOTP(
        function = SHA1,
        length = 6,
        period = 30.seconds,
    )

    // generate a secret using SHA1
    val secret = generator.generate()

    // generate an OTP
    val otp = totp.generate(secret, now())

    // verify an OTP
    totp.verify(secret, now(), otp)
}
```