Authentication and biometric support for Kotlin Multiplatform.

• A common biometric API with availability checks and detailed authentication results.
• Platform biometric implementations:
  • Android Biometric Prompt.
  • Windows Hello on JVM and Kotlin/Native.
  • Touch ID on macOS ARM64 and JVM on macOS ARM64.
  • fprintd on Linux JVM.
• PIN authentication with pluggable hashing and storage providers.
• A responsive Compose Multiplatform PIN and biometric authentication screen.

Choose the highest-level module that your application needs. auth-compose exposes auth, and auth exposes biometric.

kotlin {
    sourceSets {
        commonMain.dependencies {
            implementation("com.ucasoft.koncierge:biometric:0.2.0")
            // Or:
            // implementation("com.ucasoft.koncierge:auth:0.2.0")
            // implementation("com.ucasoft.koncierge:auth-compose:0.2.0")
        }
    }
}

On JVM, macOS ARM64, and mingwX64:

val koncierge = Koncierge()

On Android, pass a FragmentActivity as the context:

val koncierge = Koncierge(activity)

Create the platform instance at the application boundary and pass it to common code.

when (val result = koncierge.authenticate("Confirm your identity")) {
    BiometricResults.AuthenticationSuccessful -> {
        // Continue to protected content.
    }
    BiometricResults.AuthenticationCancelled -> {
        // The request was cancelled.
    }
    else -> {
        // Handle unavailable hardware, missing enrollment, lockout, or failure.
    }
}

Use koncierge.isBiometricAvailable() when you only need an availability check.

val authenticator = Authenticator(koncierge)

authenticator.storePinCode("1234")

if (authenticator.verifyPinCode("1234")) {
    // PIN verified.
}

By default, Authenticator hashes the PIN with SHA-256 and stores the result with Multiplatform Settings. Implement PinCodeHashProvider or PinCodeStoreProvider to use hashing and storage appropriate for your application's security requirements.

@Composable
fun LoginScreen(
    authenticator: Authenticator,
    onAuthorized: () -> Unit,
) {
    AuthScreen(
        authenticator = authenticator,
        title = { Text("Koncierge") },
        description = { Text("Authenticate to continue") },
        onAuthorizationFailed = { method ->
            // Handle a failed PIN or biometric attempt.
        },
        onAuthorized = onAuthorized,
    )
}

Biometric authentication is requested automatically when it is available. Set autoRequestBiometry = false to wait for the user to tap the biometric button.

• Android requires API 26 or newer. Pass a FragmentActivity to Koncierge.
• JVM applications require Java 17 or newer.
• Linux JVM biometric authentication requires fprintd-list and fprintd-verify on PATH, with a fingerprint already enrolled.
• The packaged macOS JVM native library currently supports ARM64.
• The packaged Windows JVM native library supports x86-64.

Koncierge is currently at version 0.2.0 and is under active development.

Koncierge is licensed under the Apache License 2.0.