diff --git a/README.md b/README.md
index 7fc99edf4b..095c6816cf 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ Tachiyomi is a free and open source manga reader for Android.
 ![screenshots of app](./.github/readme-images/theming-screenshots.gif)
 
 ## Newest Release
-[v0.9.2](https://github.com/Jays2Kings/tachiyomi/releases)
+[v0.9.3](https://github.com/Jays2Kings/tachiyomi/releases)
 
 ## Features
 
diff --git a/app/build.gradle b/app/build.gradle
index ab1c627797..efdfa26707 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -38,8 +38,8 @@ android {
         minSdkVersion 21
         targetSdkVersion 29
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
-        versionCode 44
-        versionName '0.9.2'
+        versionCode 45
+        versionName '0.9.3'
 
         buildConfigField "String", "COMMIT_COUNT", "\"${getCommitCount()}\""
         buildConfigField "String", "COMMIT_SHA", "\"${getGitSha()}\""
@@ -115,10 +115,11 @@ dependencies {
     implementation 'androidx.appcompat:appcompat:1.1.0'
     implementation 'androidx.cardview:cardview:1.0.0'
     implementation 'com.google.android.material:material:1.0.0'
-    implementation 'androidx.recyclerview:recyclerview:1.0.0'
+    implementation 'androidx.recyclerview:recyclerview:1.1.0'
     implementation 'androidx.preference:preference:1.1.0'
     implementation 'androidx.annotation:annotation:1.1.0'
     implementation 'androidx.browser:browser:1.0.0'
+    implementation 'androidx.biometric:biometric:1.0.0'
 
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
 
@@ -126,6 +127,10 @@ dependencies {
 
     standardImplementation 'com.google.firebase:firebase-core:17.2.1'
 
+    final lifecycle_version = "2.1.0"
+    implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
+    implementation "androidx.lifecycle:lifecycle-common-java8:$lifecycle_version"
+
     // ReactiveX
     implementation 'io.reactivex:rxandroid:1.2.1'
     implementation 'io.reactivex:rxjava:1.3.8'
@@ -245,7 +250,7 @@ dependencies {
 }
 
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.3.61'
     repositories {
         mavenCentral()
     }
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 3861b81dac..6801ed687b 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -50,6 +50,8 @@
         <activity
             android:name=".ui.manga.info.WebViewActivity"
             android:configChanges="uiMode|orientation|screenSize"/>
+        <activity
+            android:name=".ui.main.BiometricActivity" />
         <activity
             android:name=".widget.CustomLayoutPickerActivity"
             android:label="@string/app_name"
diff --git a/app/src/main/java/eu/kanade/tachiyomi/App.kt b/app/src/main/java/eu/kanade/tachiyomi/App.kt
index 7a2688b924..3a1373558a 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/App.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/App.kt
@@ -3,18 +3,26 @@ package eu.kanade.tachiyomi
 import android.app.Application
 import android.content.Context
 import android.content.res.Configuration
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleObserver
+import androidx.lifecycle.OnLifecycleEvent
+import androidx.lifecycle.ProcessLifecycleOwner
 import androidx.multidex.MultiDex
 import com.evernote.android.job.JobManager
 import eu.kanade.tachiyomi.data.backup.BackupCreatorJob
 import eu.kanade.tachiyomi.data.library.LibraryUpdateJob
 import eu.kanade.tachiyomi.data.notification.Notifications
+import eu.kanade.tachiyomi.data.preference.PreferencesHelper
+import eu.kanade.tachiyomi.data.preference.getOrDefault
 import eu.kanade.tachiyomi.data.updater.UpdaterJob
+import eu.kanade.tachiyomi.ui.main.MainActivity
 import eu.kanade.tachiyomi.util.LocaleHelper
 import org.acra.ACRA
 import org.acra.annotation.ReportsCrashes
 import timber.log.Timber
 import uy.kohesive.injekt.Injekt
 import uy.kohesive.injekt.api.InjektScope
+import uy.kohesive.injekt.injectLazy
 import uy.kohesive.injekt.registry.default.DefaultRegistrar
 
 @ReportsCrashes(
@@ -24,7 +32,7 @@ import uy.kohesive.injekt.registry.default.DefaultRegistrar
         buildConfigClass = BuildConfig::class,
         excludeMatchingSharedPreferencesKeys = arrayOf(".*username.*", ".*password.*", ".*token.*")
 )
-open class App : Application() {
+open class App : Application(), LifecycleObserver {
 
     override fun onCreate() {
         super.onCreate()
@@ -38,6 +46,16 @@ open class App : Application() {
         setupNotificationChannels()
 
         LocaleHelper.updateConfiguration(this, resources.configuration)
+        ProcessLifecycleOwner.get().lifecycle.addObserver(this)
+    }
+
+    @OnLifecycleEvent(Lifecycle.Event.ON_STOP)
+    fun onAppBackgrounded() {
+        //App in background
+        val preferences: PreferencesHelper by injectLazy()
+        if (preferences.lockAfter().getOrDefault() >= 0) {
+            MainActivity.unlocked = false
+        }
     }
 
     override fun attachBaseContext(base: Context) {
diff --git a/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferenceKeys.kt b/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferenceKeys.kt
index b9a2744741..4668ac1972 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferenceKeys.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferenceKeys.kt
@@ -117,6 +117,12 @@ object PreferenceKeys {
 
     const val downloadBadge = "display_download_badge"
 
+    const val useBiometrics = "use_biometrics"
+
+    const val lockAfter = "lock_after"
+
+    const val lastUnlock = "last_unlock"
+
     @Deprecated("Use the preferences of the source")
     fun sourceUsername(sourceId: Long) = "pref_source_username_$sourceId"
 
diff --git a/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt b/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt
index 17cbc29e0e..79f16009fe 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt
@@ -176,6 +176,12 @@ class PreferencesHelper(val context: Context) {
 
     fun skipRead() = prefs.getBoolean(Keys.skipRead, false)
 
+    fun useBiometrics() = rxPrefs.getBoolean(Keys.useBiometrics, false)
+
+    fun lockAfter() = rxPrefs.getInteger(Keys.lockAfter, 0)
+
+    fun lastUnlock() = rxPrefs.getLong(Keys.lastUnlock, 0)
+
     fun migrateFlags() = rxPrefs.getInteger("migrate_flags", Int.MAX_VALUE)
 
     fun trustedSignatures() = rxPrefs.getStringSet("trusted_signatures", emptySet())
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/main/BiometricActivity.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/main/BiometricActivity.kt
new file mode 100644
index 0000000000..1b18e44c16
--- /dev/null
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/main/BiometricActivity.kt
@@ -0,0 +1,47 @@
+package eu.kanade.tachiyomi.ui.main
+
+import android.os.Bundle
+import androidx.biometric.BiometricPrompt
+import eu.kanade.tachiyomi.R
+import eu.kanade.tachiyomi.data.preference.PreferencesHelper
+import eu.kanade.tachiyomi.ui.base.activity.BaseActivity
+import uy.kohesive.injekt.injectLazy
+import java.util.Date
+import java.util.concurrent.Executors
+
+class BiometricActivity : BaseActivity() {
+    val executor = Executors.newSingleThreadExecutor()
+
+    val preferences: PreferencesHelper by injectLazy()
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        val biometricPrompt = BiometricPrompt(this, executor, object : BiometricPrompt
+        .AuthenticationCallback() {
+
+            override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
+                super.onAuthenticationError(errorCode, errString)
+                finishAffinity()
+            }
+
+            override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
+                super.onAuthenticationSucceeded(result)
+                MainActivity.unlocked = true
+                preferences.lastUnlock().set(Date().time)
+                finish()
+            }
+
+            override fun onAuthenticationFailed() {
+                super.onAuthenticationFailed()
+                //  TODO("Called when a biometric is valid but not recognized.")
+            }
+        })
+
+        val promptInfo = BiometricPrompt.PromptInfo.Builder()
+            .setTitle(getString(R.string.unlock_library))
+            .setNegativeButtonText(getString(android.R.string.cancel))
+            .build()
+
+        biometricPrompt.authenticate(promptInfo)
+    }
+
+}
\ No newline at end of file
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/main/MainActivity.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/main/MainActivity.kt
index 37318f2901..95c4e10647 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/main/MainActivity.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/main/MainActivity.kt
@@ -16,6 +16,7 @@ import android.view.View
 import android.view.ViewGroup
 import android.widget.FrameLayout
 import android.widget.LinearLayout
+import androidx.biometric.BiometricManager
 import androidx.core.graphics.ColorUtils
 import com.bluelinelabs.conductor.*
 import com.google.android.material.snackbar.Snackbar
@@ -23,6 +24,7 @@ import eu.kanade.tachiyomi.Migrations
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.notification.NotificationReceiver
 import eu.kanade.tachiyomi.data.preference.PreferencesHelper
+import eu.kanade.tachiyomi.data.preference.getOrDefault
 import eu.kanade.tachiyomi.ui.base.activity.BaseActivity
 import eu.kanade.tachiyomi.ui.base.controller.*
 import eu.kanade.tachiyomi.ui.catalogue.CatalogueController
@@ -46,6 +48,7 @@ import eu.kanade.tachiyomi.util.updatePaddingRelative
 import kotlinx.android.synthetic.main.main_activity.*
 import kotlinx.coroutines.delay
 import uy.kohesive.injekt.injectLazy
+import java.util.Date
 
 class MainActivity : BaseActivity() {
 
@@ -60,7 +63,6 @@ class MainActivity : BaseActivity() {
     private var snackBar:Snackbar? = null
     var extraViewForUndo:View? = null
     private var canDismissSnackBar = false
-
     fun setUndoSnackBar(snackBar: Snackbar?, extraViewToCheck: View? = null) {
         this.snackBar = snackBar
         canDismissSnackBar = false
@@ -248,6 +250,22 @@ class MainActivity : BaseActivity() {
         }
     }
 
+    override fun onResume() {
+        super.onResume()
+        val useBiometrics = preferences.useBiometrics().getOrDefault()
+        if (useBiometrics && BiometricManager.from(this)
+                .canAuthenticate() == BiometricManager.BIOMETRIC_SUCCESS) {
+            if (!unlocked && (preferences.lockAfter().getOrDefault() <= 0 || Date().time >=
+                    preferences.lastUnlock().getOrDefault() + 60 * 1000 * preferences.lockAfter().getOrDefault())) {
+                val intent = Intent(this, BiometricActivity::class.java)
+                startActivity(intent)
+                this.overridePendingTransition(0, 0)
+            }
+        }
+        else if (useBiometrics)
+            preferences.useBiometrics().set(false)
+    }
+
     override fun onNewIntent(intent: Intent) {
         if (!handleIntentAction(intent)) {
             super.onNewIntent(intent)
@@ -314,6 +332,7 @@ class MainActivity : BaseActivity() {
         } else if (backstackSize == 1 && router.getControllerWithTag("$startScreenId") == null) {
             setSelectedDrawerItem(startScreenId)
         } else if (backstackSize == 1 || !router.handleBack()) {
+            unlocked = false
             super.onBackPressed()
         }
     }
@@ -412,6 +431,8 @@ class MainActivity : BaseActivity() {
         const val INTENT_SEARCH_FILTER = "filter"
 
         private const val URL_HELP = "https://tachiyomi.org/help/"
+
+        var unlocked = false
     }
 
 }
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt
index 6b644f3895..56f128d56e 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderActivity.kt
@@ -11,15 +11,19 @@ import android.graphics.Bitmap
 import android.graphics.Color
 import android.os.Build
 import android.os.Bundle
-import com.google.android.material.bottomsheet.BottomSheetDialog
-import android.view.*
+import android.view.KeyEvent
+import android.view.Menu
+import android.view.MenuItem
+import android.view.MotionEvent
+import android.view.View
+import android.view.WindowManager
 import android.view.animation.Animation
 import android.view.animation.AnimationUtils
-import android.widget.LinearLayout
 import android.widget.SeekBar
+import androidx.biometric.BiometricManager
 import com.davemorrissey.labs.subscaleview.SubsamplingScaleImageView
+import com.google.android.material.bottomsheet.BottomSheetDialog
 import eu.kanade.tachiyomi.R
-import eu.kanade.tachiyomi.data.database.DatabaseHelper
 import eu.kanade.tachiyomi.data.database.models.Chapter
 import eu.kanade.tachiyomi.data.database.models.Manga
 import eu.kanade.tachiyomi.data.notification.NotificationReceiver
@@ -27,6 +31,8 @@ import eu.kanade.tachiyomi.data.notification.Notifications
 import eu.kanade.tachiyomi.data.preference.PreferencesHelper
 import eu.kanade.tachiyomi.data.preference.getOrDefault
 import eu.kanade.tachiyomi.ui.base.activity.BaseRxActivity
+import eu.kanade.tachiyomi.ui.main.BiometricActivity
+import eu.kanade.tachiyomi.ui.main.MainActivity
 import eu.kanade.tachiyomi.ui.reader.ReaderPresenter.SetAsCoverResult.AddToLibraryFirst
 import eu.kanade.tachiyomi.ui.reader.ReaderPresenter.SetAsCoverResult.Error
 import eu.kanade.tachiyomi.ui.reader.ReaderPresenter.SetAsCoverResult.Success
@@ -38,12 +44,17 @@ import eu.kanade.tachiyomi.ui.reader.viewer.pager.L2RPagerViewer
 import eu.kanade.tachiyomi.ui.reader.viewer.pager.R2LPagerViewer
 import eu.kanade.tachiyomi.ui.reader.viewer.pager.VerticalPagerViewer
 import eu.kanade.tachiyomi.ui.reader.viewer.webtoon.WebtoonViewer
-import eu.kanade.tachiyomi.util.*
+import eu.kanade.tachiyomi.util.GLUtil
+import eu.kanade.tachiyomi.util.getResourceColor
+import eu.kanade.tachiyomi.util.getUriCompat
+import eu.kanade.tachiyomi.util.gone
+import eu.kanade.tachiyomi.util.launchUI
+import eu.kanade.tachiyomi.util.plusAssign
+import eu.kanade.tachiyomi.util.toast
+import eu.kanade.tachiyomi.util.visible
 import eu.kanade.tachiyomi.widget.SimpleAnimationListener
 import eu.kanade.tachiyomi.widget.SimpleSeekBarListener
 import kotlinx.android.synthetic.main.reader_activity.*
-import kotlinx.android.synthetic.main.reader_activity.toolbar
-import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
 import me.zhanghai.android.systemuihelper.SystemUiHelper
@@ -55,6 +66,7 @@ import rx.subscriptions.CompositeSubscription
 import timber.log.Timber
 import uy.kohesive.injekt.injectLazy
 import java.io.File
+import java.util.Date
 import java.util.concurrent.TimeUnit
 
 /**
@@ -506,6 +518,23 @@ class ReaderActivity : BaseRxActivity<ReaderPresenter>(),
         presenter.shareImage(page)
     }
 
+    override fun onResume() {
+        super.onResume()
+        val useBiometrics = preferences.useBiometrics().getOrDefault()
+        if (useBiometrics && BiometricManager.from(this)
+                .canAuthenticate() == BiometricManager.BIOMETRIC_SUCCESS) {
+            if (!MainActivity.unlocked && (preferences.lockAfter().getOrDefault() <= 0 || Date()
+                    .time >=
+                    preferences.lastUnlock().getOrDefault() + 60 * 1000 * preferences.lockAfter().getOrDefault())) {
+                val intent = Intent(this, BiometricActivity::class.java)
+                startActivity(intent)
+                this.overridePendingTransition(0, 0)
+            }
+        }
+        else if (useBiometrics)
+            preferences.useBiometrics().set(false)
+    }
+
     /**
      * Called from the presenter when a page is ready to be shared. It shows Android's default
      * sharing tool.
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsGeneralController.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsGeneralController.kt
index e93a95f4c6..a3828bb25f 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsGeneralController.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsGeneralController.kt
@@ -1,12 +1,11 @@
 package eu.kanade.tachiyomi.ui.setting
 
 import android.app.Dialog
-import android.os.Build
 import android.os.Bundle
 import android.os.Handler
-import androidx.appcompat.app.AppCompatDelegate
-import androidx.preference.PreferenceScreen
 import android.view.View
+import androidx.biometric.BiometricManager
+import androidx.preference.PreferenceScreen
 import com.afollestad.materialdialogs.MaterialDialog
 import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.database.DatabaseHelper
@@ -16,6 +15,7 @@ import eu.kanade.tachiyomi.data.preference.PreferencesHelper
 import eu.kanade.tachiyomi.data.preference.getOrDefault
 import eu.kanade.tachiyomi.ui.base.controller.DialogController
 import eu.kanade.tachiyomi.util.LocaleHelper
+import eu.kanade.tachiyomi.widget.preference.IntListPreference
 import kotlinx.android.synthetic.main.pref_library_columns.view.*
 import rx.Observable
 import uy.kohesive.injekt.Injekt
@@ -199,6 +199,36 @@ class SettingsGeneralController : SettingsController() {
                 true
             }
         }
+        val biometricManager = BiometricManager.from(context)
+        if (biometricManager.canAuthenticate() == BiometricManager.BIOMETRIC_SUCCESS) {
+            var preference:IntListPreference? = null
+            switchPreference {
+                key = Keys.useBiometrics
+                titleRes = R.string.lock_with_biometrics
+                defaultValue = false
+
+                onChange {
+                    preference?.isVisible = it as Boolean
+                    true
+                }
+            }
+            preference = intListPreference {
+                key = Keys.lockAfter
+                titleRes = R.string.lock_when_idle
+                isVisible = preferences.useBiometrics().getOrDefault()
+                val values = arrayOf("0", "2", "5", "10", "20", "30", "60", "90", "120", "-1")
+                entries = values.map {
+                    when (it) {
+                        "0" -> context.getString(R.string.lock_always)
+                        "-1" -> context.getString(R.string.lock_never)
+                        else -> context.getString(R.string.lock_after_mins, it)
+                    }
+                }.toTypedArray()
+                entryValues = values
+                defaultValue = "0"
+                summary = "%s"
+            }
+        }
     }
 
     class LibraryColumnsDialog : DialogController() {
diff --git a/app/src/main/res/raw/changelog_release.xml b/app/src/main/res/raw/changelog_release.xml
index 699959e4da..44fa174c6a 100644
--- a/app/src/main/res/raw/changelog_release.xml
+++ b/app/src/main/res/raw/changelog_release.xml
@@ -1,5 +1,12 @@
 <?xml version="1.0" encoding="utf-8"?>
 <changelog bulletedList="true">
+	<changelogversion versionName="v0.9.3" changeDate="">
+        <changelogtext>Lock Tachiyomi using your fingerprint/Biometrics</changelogtext>
+        <changelogtext>Added search/sorting/mass enable/disable to catalouge sources</changelogtext>
+        <changelogtext>Extensions are now filtered to your locale, with an option to show other languages</changelogtext>
+        <changelogtext>Fixed AMOLED theme not having dark snackbar</changelogtext>
+    </changelogversion>
+	
     <changelogversion versionName="v0.9.2" changeDate="">
         <changelogtext>Fixes notification text when there are multiple chapters</changelogtext>
         <changelogtext>Simplified errors now show after restoring a backup on the popup dialog</changelogtext>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index a6003a8ed5..ce9c5a058b 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -27,6 +27,7 @@
     <string name="label_extensions">Extensions</string>
     <string name="label_extension_info">Extension info</string>
     <string name="label_help">Help</string>
+    <string name="unlock_library">Unlock to access Library</string>
 
 
     <!-- Actions -->
@@ -161,6 +162,11 @@
     <string name="system_default">System default</string>
     <string name="default_category">Default category</string>
     <string name="default_category_summary">Always ask</string>
+    <string name="lock_with_biometrics">Lock with biometrics</string>
+    <string name="lock_when_idle">Lock when idle</string>
+    <string name="lock_always">Always</string>
+    <string name="lock_never">Never</string>
+    <string name="lock_after_mins">After %1$s minutes</string>
 
     <!-- Extension section -->
     <string name="all_lang">All</string>