crypto: Add configuration flag to enable invisible crypto

libraries/featureflag/api/src/main/kotlin/io/element/android/libraries/featureflag/api/FeatureFlags.kt

@@ -123,4 +123,13 @@ enum class FeatureFlags(
         defaultValue = { true },
         isFinished = false,
     ),
+    InvisibleCrypto(
+        key = "feature.invisibleCrypto",
+        title = "Invisible Crypto",
+        description = "This setting controls how end-to-end encryption (E2E) keys are shared." +
+            " Enabling it will prevent the inclusion of devices that have not been explicitly verified by their owners." +
+            " You'll have to stop and re-open the app manually for that setting to take effect.",
+        defaultValue = { false },
+        isFinished = false,
+    ),
 }

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/RustMatrixClientFactory.kt

@@ -10,6 +10,8 @@ package io.element.android.libraries.matrix.impl
 import io.element.android.appconfig.AuthenticationConfig
 import io.element.android.libraries.core.coroutine.CoroutineDispatchers
 import io.element.android.libraries.di.CacheDirectory
+import io.element.android.libraries.featureflag.api.FeatureFlagService
+import io.element.android.libraries.featureflag.api.FeatureFlags
 import io.element.android.libraries.matrix.impl.analytics.UtdTracker
 import io.element.android.libraries.matrix.impl.certificates.UserCertificatesProvider
 import io.element.android.libraries.matrix.impl.paths.SessionPaths
@@ -30,6 +32,7 @@ import org.matrix.rustcomponents.sdk.SlidingSyncVersion
 import org.matrix.rustcomponents.sdk.SlidingSyncVersionBuilder
 import org.matrix.rustcomponents.sdk.use
 import timber.log.Timber
+import uniffi.matrix_sdk_crypto.CollectStrategy
 import java.io.File
 import javax.inject.Inject
 
@@ -45,6 +48,7 @@ class RustMatrixClientFactory @Inject constructor(
     private val clock: SystemClock,
     private val utdTracker: UtdTracker,
     private val appPreferencesStore: AppPreferencesStore,
+    private val featureFlagService: FeatureFlagService,
 ) {
     suspend fun create(sessionData: SessionData): RustMatrixClient = withContext(coroutineDispatchers.io) {
         val sessionDelegate = RustClientSessionDelegate(sessionStore, appCoroutineScope, coroutineDispatchers)
@@ -104,6 +108,13 @@ class RustMatrixClientFactory @Inject constructor(
             .addRootCertificates(userCertificatesProvider.provides())
             .autoEnableBackups(true)
             .autoEnableCrossSigning(true)
+            .roomKeyRecipientStrategy(
+                strategy = if (featureFlagService.isFeatureEnabled(FeatureFlags.InvisibleCrypto)) {
+                    CollectStrategy.IdentityBasedStrategy
+                } else {
+                    CollectStrategy.DeviceBasedStrategy(onlyAllowTrustedDevices = false, errorOnVerifiedUserProblem = false)
+                }
+            )
             .run {
                 // Apply sliding sync version settings
                 when (slidingSync) {

samples/minimal/src/main/kotlin/io/element/android/samples/minimal/AlwaysEnabledFeatureFlagService.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2024 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ * Please see LICENSE in the repository root for full details.
+ */
+
+package io.element.android.samples.minimal
+
+import io.element.android.libraries.featureflag.api.Feature
+import io.element.android.libraries.featureflag.api.FeatureFlagService
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flowOf
+
+class AlwaysEnabledFeatureFlagService : FeatureFlagService {
+    override fun isFeatureEnabledFlow(feature: Feature): Flow<Boolean> {
+        return flowOf(true)
+    }
+
+    override suspend fun setFeatureEnabled(feature: Feature, enabled: Boolean): Boolean {
+        return true
+    }
+}

samples/minimal/src/main/kotlin/io/element/android/samples/minimal/MainActivity.kt

@@ -56,6 +56,7 @@ class MainActivity : ComponentActivity() {
                 clock = DefaultSystemClock(),
                 utdTracker = UtdTracker(NoopAnalyticsService()),
                 appPreferencesStore = InMemoryAppPreferencesStore(),
+                featureFlagService = AlwaysEnabledFeatureFlagService(),
             ),
             passphraseGenerator = NullPassphraseGenerator(),
             oidcConfigurationProvider = OidcConfigurationProvider(baseDirectory),

samples/minimal/src/main/kotlin/io/element/android/samples/minimal/RoomListScreen.kt

@@ -25,8 +25,6 @@ import io.element.android.features.roomlist.impl.filters.selection.DefaultFilter
 import io.element.android.features.roomlist.impl.search.RoomListSearchDataSource
 import io.element.android.features.roomlist.impl.search.RoomListSearchPresenter
 import io.element.android.libraries.core.coroutine.CoroutineDispatchers
-import io.element.android.libraries.core.meta.BuildMeta
-import io.element.android.libraries.core.meta.BuildType
 import io.element.android.libraries.dateformatter.impl.DateFormatters
 import io.element.android.libraries.dateformatter.impl.DefaultLastMessageTimestampFormatter
 import io.element.android.libraries.dateformatter.impl.LocalDateTimeProvider
@@ -35,8 +33,6 @@ import io.element.android.libraries.eventformatter.impl.DefaultRoomLastMessageFo
 import io.element.android.libraries.eventformatter.impl.ProfileChangeContentFormatter
 import io.element.android.libraries.eventformatter.impl.RoomMembershipContentFormatter
 import io.element.android.libraries.eventformatter.impl.StateContentFormatter
-import io.element.android.libraries.featureflag.impl.DefaultFeatureFlagService
-import io.element.android.libraries.featureflag.impl.PreferencesFeatureFlagProvider
 import io.element.android.libraries.fullscreenintent.api.FullScreenIntentPermissionsPresenter
 import io.element.android.libraries.fullscreenintent.api.FullScreenIntentPermissionsState
 import io.element.android.libraries.indicator.impl.DefaultIndicatorService
@@ -70,13 +66,7 @@ class RoomListScreen(
     private val sessionVerificationService = matrixClient.sessionVerificationService()
     private val encryptionService = matrixClient.encryptionService()
     private val stringProvider = AndroidStringProvider(context.resources)
-    private val buildMeta = getBuildMeta(context)
-    private val featureFlagService = DefaultFeatureFlagService(
-        providers = setOf(
-            PreferencesFeatureFlagProvider(context = context, buildMeta = buildMeta)
-        ),
-        buildMeta = buildMeta,
-    )
+    private val featureFlagService = AlwaysEnabledFeatureFlagService()
     private val roomListRoomSummaryFactory = RoomListRoomSummaryFactory(
         lastMessageTimestampFormatter = DefaultLastMessageTimestampFormatter(
             localDateTimeProvider = dateTimeProvider,
@@ -191,25 +181,4 @@ class RoomListScreen(
             }
         }
     }
-
-    private fun getBuildMeta(context: Context): BuildMeta {
-        val buildType = BuildType.valueOf(BuildConfig.BUILD_TYPE.uppercase())
-        val name = context.getString(R.string.app_name)
-        return BuildMeta(
-            isDebuggable = BuildConfig.DEBUG,
-            buildType = buildType,
-            applicationName = name,
-            productionApplicationName = name,
-            desktopApplicationName = name,
-            applicationId = BuildConfig.APPLICATION_ID,
-            lowPrivacyLoggingEnabled = false,
-            versionName = BuildConfig.VERSION_NAME,
-            versionCode = BuildConfig.VERSION_CODE.toLong(),
-            gitRevision = "",
-            gitBranchName = "",
-            flavorDescription = "",
-            flavorShortDescription = "",
-            isEnterpriseBuild = false,
-        )
-    }
 }