Implement Rust-owned Android Keystore secure storage (#93)

android/app/src/main/AndroidManifest.xml

@@ -1,4 +1,5 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <uses-permission android:name="android.permission.USE_BIOMETRIC" />
     <application
         android:name=".IronStorageApplication"
         android:allowBackup="false"

android/app/src/main/kotlin/de/rfc1437/ironstorage/MainActivity.kt

@@ -1,24 +1,33 @@
 package de.rfc1437.ironstorage
 
 import android.os.Bundle
-import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.activity.viewModels
 import androidx.compose.material3.MaterialTheme
+import androidx.fragment.app.FragmentActivity
 import dagger.hilt.android.AndroidEntryPoint
 import de.rfc1437.ironstorage.core.ShellRepository
 import de.rfc1437.ironstorage.features.ShellViewModel
+import de.rfc1437.ironstorage.platform.AndroidKeystoreAdapter
 import javax.inject.Inject
 
 @AndroidEntryPoint
-class MainActivity : ComponentActivity() {
+class MainActivity : FragmentActivity() {
+    @Inject lateinit var keystore: AndroidKeystoreAdapter
+
     @Inject lateinit var repository: ShellRepository
 
     private val viewModel: ShellViewModel by viewModels()
 
+    override fun onDestroy() {
+        keystore.detach(this)
+        super.onDestroy()
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
+        keystore.attach(this)
         enableEdgeToEdge()
         setContent {
             MaterialTheme {

android/app/src/main/kotlin/de/rfc1437/ironstorage/ShellModule.kt

@@ -8,6 +8,7 @@ import dagger.hilt.android.qualifiers.ApplicationContext
 import dagger.hilt.components.SingletonComponent
 import de.rfc1437.ironstorage.core.NativeFixtureShellRepository
 import de.rfc1437.ironstorage.core.ShellRepository
+import de.rfc1437.ironstorage.platform.AndroidKeystoreAdapter
 import de.rfc1437.ironstorage.platform.privateDirectories
 import javax.inject.Singleton
 import kotlinx.coroutines.CoroutineScope
@@ -19,10 +20,18 @@ import kotlinx.coroutines.SupervisorJob
 object ShellModule {
     @Provides
     @Singleton
-    fun shellRepository(@ApplicationContext context: Context): ShellRepository =
-        NativeFixtureShellRepository(
-            context,
-            CoroutineScope(SupervisorJob() + Dispatchers.Main.immediate),
-            { privateDirectories(context) }
-        )
+    fun keystore(@ApplicationContext context: Context): AndroidKeystoreAdapter =
+        AndroidKeystoreAdapter(context)
+
+    @Provides
+    @Singleton
+    fun shellRepository(
+        @ApplicationContext context: Context,
+        keystore: AndroidKeystoreAdapter
+    ): ShellRepository = NativeFixtureShellRepository(
+        context,
+        CoroutineScope(SupervisorJob() + Dispatchers.Main.immediate),
+        { privateDirectories(context) },
+        keystore
+    )
 }