diff --git a/.idea/misc.xml b/.idea/misc.xml
index fb8c126a..7631aec3 100644
--- a/.idea/misc.xml
+++ b/.idea/misc.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" project-jdk-name="1.8 (2)" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" project-jdk-name="1.8" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/classes" />
   </component>
 </project>
\ No newline at end of file
diff --git a/app/build.gradle b/app/build.gradle
index 46f2ce9b..97cb1eb5 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -7,13 +7,13 @@ apply plugin: 'io.fabric'
 apply plugin: 'com.google.firebase.firebase-perf'
 
 android {
-    compileSdkVersion 28
+    compileSdkVersion 29
     defaultConfig {
         applicationId "xyz.quaver.pupil"
         minSdkVersion 16
-        targetSdkVersion 28
-        versionCode 16
-        versionName "2.9"
+        targetSdkVersion 29
+        versionCode 17
+        versionName "2.10-alpha"
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         multiDexEnabled true
     }
@@ -42,17 +42,21 @@ dependencies {
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
     implementation 'androidx.preference:preference:1.1.0-beta01'
     implementation 'com.google.android.material:material:1.0.0'
-    implementation 'com.google.firebase:firebase-core:16.0.9'
-    implementation 'com.google.firebase:firebase-perf:17.0.2'
+    implementation 'com.google.firebase:firebase-core:17.0.0'
+    implementation 'com.google.firebase:firebase-perf:18.0.1'
     implementation 'com.crashlytics.sdk.android:crashlytics:2.10.1'
     implementation 'com.github.arimorty:floatingsearchview:2.1.1'
-    implementation 'com.github.deano2390:MaterialShowcaseView:1.3.4'
+    implementation 'com.andrognito.patternlockview:patternlockview:1.0.0'
     implementation 'androidx.appcompat:appcompat:1.0.2'
     implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
     implementation "ru.noties.markwon:core:${markwonVersion}"
     implementation 'com.github.clans:fab:1.6.4'
+    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
+    implementation 'androidx.lifecycle:lifecycle-extensions:2.0.0'
+    implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.0.0'
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'androidx.test.ext:junit:1.1.1'
+    androidTestImplementation 'androidx.test:rules:1.2.0'
     androidTestImplementation 'androidx.test:runner:1.2.0'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
     implementation project(path: ':libpupil')
diff --git a/app/proguard-rules.pro b/app/proguard-rules.pro
index efb4fd24..481bb434 100644
--- a/app/proguard-rules.pro
+++ b/app/proguard-rules.pro
@@ -18,11 +18,4 @@
 
 # If you keep the line number information, uncomment this to
 # hide the original source file name.
-#-renamesourcefileattribute SourceFile
--keep class com.finotes.android.finotescore.* { *; }
-
--keepclassmembers class * {
-    @com.finotes.android.finotescore.annotation.Observe *;
-}
-
--keepattributes SourceFile,LineNumberTable
\ No newline at end of file
+#-renamesourcefileattribute SourceFile
\ No newline at end of file
diff --git a/app/release/output.json b/app/release/output.json
index 0cc69cca..f084575a 100644
--- a/app/release/output.json
+++ b/app/release/output.json
@@ -1 +1 @@
-[{"outputType":{"type":"APK"},"apkData":{"type":"MAIN","splits":[],"versionCode":16,"versionName":"2.9","enabled":true,"outputFile":"app-release.apk","fullName":"release","baseName":"release"},"path":"app-release.apk","properties":{}}]
\ No newline at end of file
+[{"outputType":{"type":"APK"},"apkData":{"type":"MAIN","splits":[],"versionCode":17,"versionName":"2.9.1","enabled":true,"outputFile":"app-release.apk","fullName":"release","baseName":"release"},"path":"app-release.apk","properties":{}}]
\ No newline at end of file
diff --git a/app/src/androidTest/java/xyz/quaver/pupil/ExampleInstrumentedTest.kt b/app/src/androidTest/java/xyz/quaver/pupil/ExampleInstrumentedTest.kt
index 79db10d2..facb9b50 100644
--- a/app/src/androidTest/java/xyz/quaver/pupil/ExampleInstrumentedTest.kt
+++ b/app/src/androidTest/java/xyz/quaver/pupil/ExampleInstrumentedTest.kt
@@ -1,16 +1,18 @@
 package xyz.quaver.pupil
 
-import android.graphics.BitmapFactory
+import android.content.Intent
 import android.util.Log
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.rule.ActivityTestRule
 import org.junit.Assert.assertEquals
+import org.junit.Rule
 import org.junit.Test
 import org.junit.runner.RunWith
 import xyz.quaver.hiyobi.cookie
 import xyz.quaver.hiyobi.getReader
 import xyz.quaver.hiyobi.user_agent
-import java.io.File
+import xyz.quaver.pupil.ui.LockActivity
 import java.net.URL
 import javax.net.ssl.HttpsURLConnection
 
@@ -21,6 +23,7 @@ import javax.net.ssl.HttpsURLConnection
  */
 @RunWith(AndroidJUnit4::class)
 class ExampleInstrumentedTest {
+
     @Test
     fun useAppContext() {
         // Context of the app under test.
@@ -30,12 +33,12 @@ class ExampleInstrumentedTest {
 
     @Test
     fun checkCacheDir() {
+        val activityTestRule = ActivityTestRule<LockActivity>(LockActivity::class.java)
         val appContext = InstrumentationRegistry.getInstrumentation().targetContext
-        val file = File(appContext.cacheDir, "imageCache/1412251/01.jpg.webp")
 
-        val bitmap = BitmapFactory.decodeFile(file.absolutePath)
+        activityTestRule.launchActivity(Intent())
 
-        Log.d("Pupil", bitmap.byteCount.toString())
+        while(true);
     }
 
     @Test
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 294d57a0..c3e6686f 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -6,20 +6,19 @@
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 
     <application
+        android:name=".ui.Pupil"
         android:allowBackup="true"
         android:fullBackupContent="true"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
-        android:theme="@style/AppTheme"
-        android:name=".Pupil">
-
+        android:theme="@style/AppTheme">
+        <activity android:name=".ui.LockActivity"/>
         <activity
-            android:name=".ReaderActivity"
-            android:parentActivityName=".MainActivity"
-            android:configChanges="keyboardHidden|orientation|screenSize">
-
+            android:name=".ui.ReaderActivity"
+            android:configChanges="keyboardHidden|orientation|screenSize"
+            android:parentActivityName=".ui.MainActivity">
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />
 
@@ -27,9 +26,9 @@
                 <category android:name="android.intent.category.BROWSABLE" />
 
                 <data
-                    android:scheme="https"
                     android:host="hitomi.la"
-                    android:pathPrefix="/galleries" />
+                    android:pathPrefix="/galleries"
+                    android:scheme="https" />
             </intent-filter>
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />
@@ -38,9 +37,9 @@
                 <category android:name="android.intent.category.BROWSABLE" />
 
                 <data
-                    android:scheme="https"
                     android:host="히요비.asia"
-                    android:pathPrefix="/reader" />
+                    android:pathPrefix="/reader"
+                    android:scheme="https" />
             </intent-filter>
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />
@@ -49,9 +48,9 @@
                 <category android:name="android.intent.category.BROWSABLE" />
 
                 <data
-                    android:scheme="https"
                     android:host="xn--9w3b15m8vo.asia"
-                    android:pathPrefix="/reader" />
+                    android:pathPrefix="/reader"
+                    android:scheme="https" />
             </intent-filter>
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />
@@ -60,9 +59,9 @@
                 <category android:name="android.intent.category.BROWSABLE" />
 
                 <data
-                    android:scheme="https"
                     android:host="e-hentai.org"
-                    android:pathPrefix="/g" />
+                    android:pathPrefix="/g"
+                    android:scheme="https" />
             </intent-filter>
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />
@@ -71,9 +70,9 @@
                 <category android:name="android.intent.category.BROWSABLE" />
 
                 <data
-                    android:scheme="http"
                     android:host="hitomi.la"
-                    android:pathPrefix="/galleries" />
+                    android:pathPrefix="/galleries"
+                    android:scheme="http" />
             </intent-filter>
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />
@@ -82,9 +81,9 @@
                 <category android:name="android.intent.category.BROWSABLE" />
 
                 <data
-                    android:scheme="http"
                     android:host="히요비.asia"
-                    android:pathPrefix="/reader" />
+                    android:pathPrefix="/reader"
+                    android:scheme="http" />
             </intent-filter>
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />
@@ -93,9 +92,9 @@
                 <category android:name="android.intent.category.BROWSABLE" />
 
                 <data
-                    android:scheme="http"
                     android:host="xn--9w3b15m8vo.asia"
-                    android:pathPrefix="/reader" />
+                    android:pathPrefix="/reader"
+                    android:scheme="http" />
             </intent-filter>
             <intent-filter>
                 <action android:name="android.intent.action.VIEW" />
@@ -104,16 +103,16 @@
                 <category android:name="android.intent.category.BROWSABLE" />
 
                 <data
-                    android:scheme="http"
                     android:host="e-hentai.org"
-                    android:pathPrefix="/g" />
+                    android:pathPrefix="/g"
+                    android:scheme="http" />
             </intent-filter>
         </activity>
         <activity
-            android:name=".SettingsActivity"
+            android:name=".ui.SettingsActivity"
             android:label="@string/settings_title" />
         <activity
-            android:name=".MainActivity"
+            android:name=".ui.MainActivity"
             android:configChanges="keyboardHidden|orientation|screenSize"
             android:theme="@style/NoActionBarAppTheme">
             <intent-filter>
diff --git a/app/src/main/java/xyz/quaver/pupil/adapters/GalleryBlockAdapter.kt b/app/src/main/java/xyz/quaver/pupil/adapters/GalleryBlockAdapter.kt
index 12080356..9cf73343 100644
--- a/app/src/main/java/xyz/quaver/pupil/adapters/GalleryBlockAdapter.kt
+++ b/app/src/main/java/xyz/quaver/pupil/adapters/GalleryBlockAdapter.kt
@@ -24,7 +24,7 @@ import kotlinx.serialization.json.JsonConfiguration
 import kotlinx.serialization.list
 import xyz.quaver.hitomi.GalleryBlock
 import xyz.quaver.hitomi.ReaderItem
-import xyz.quaver.pupil.Pupil
+import xyz.quaver.pupil.ui.Pupil
 import xyz.quaver.pupil.R
 import xyz.quaver.pupil.types.Tag
 import xyz.quaver.pupil.util.Histories
diff --git a/app/src/main/java/xyz/quaver/pupil/adapters/ReaderAdapter.kt b/app/src/main/java/xyz/quaver/pupil/adapters/ReaderAdapter.kt
index f4f33a09..e75617c4 100644
--- a/app/src/main/java/xyz/quaver/pupil/adapters/ReaderAdapter.kt
+++ b/app/src/main/java/xyz/quaver/pupil/adapters/ReaderAdapter.kt
@@ -6,9 +6,6 @@ import android.view.View
 import android.view.ViewGroup
 import android.widget.ImageView
 import androidx.recyclerview.widget.RecyclerView
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.launch
 import xyz.quaver.pupil.R
 
 class ReaderAdapter(private val images: List<String>) : RecyclerView.Adapter<ReaderAdapter.ViewHolder>() {
diff --git a/app/src/main/java/xyz/quaver/pupil/ui/LockActivity.kt b/app/src/main/java/xyz/quaver/pupil/ui/LockActivity.kt
new file mode 100644
index 00000000..d8eee511
--- /dev/null
+++ b/app/src/main/java/xyz/quaver/pupil/ui/LockActivity.kt
@@ -0,0 +1,85 @@
+package xyz.quaver.pupil.ui
+
+import android.app.Activity
+import androidx.appcompat.app.AppCompatActivity
+import android.os.Bundle
+import android.widget.Toast
+import com.andrognito.patternlockview.PatternLockView
+import com.google.android.material.snackbar.Snackbar
+import kotlinx.android.synthetic.main.activity_lock.*
+import kotlinx.android.synthetic.main.fragment_pattern_lock.*
+import kotlinx.android.synthetic.main.settings_activity.*
+import xyz.quaver.pupil.R
+import xyz.quaver.pupil.util.Lock
+import xyz.quaver.pupil.util.LockManager
+
+class LockActivity : AppCompatActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_lock)
+
+        val lockManager = LockManager(this)
+
+        val mode = intent.getStringExtra("mode")
+
+        lock_pattern.isEnabled = false
+        lock_pin.isEnabled = false
+        lock_fingerprint.isEnabled = false
+        lock_password.isEnabled = false
+
+        when(mode) {
+            null -> {
+                if (lockManager.empty()) {
+                    setResult(RESULT_OK)
+                    finish()
+                }
+            }
+            "add_lock" -> {
+                when(intent.getStringExtra("type")!!) {
+                    "pattern" -> {
+
+                    }
+                }
+            }
+        }
+
+        supportFragmentManager.beginTransaction().add(
+            R.id.lock_content,
+            PatternLockFragment().apply {
+                var lastPass = ""
+                onPatternDrawn = {
+                    when(mode) {
+                        null -> {
+                            val result = lockManager.check(it)
+
+                            if (result == true) {
+                                setResult(Activity.RESULT_OK)
+                                finish()
+                            } else
+                                lock_pattern_view.setViewMode(PatternLockView.PatternViewMode.WRONG)
+                        }
+                        "add_lock" -> {
+                            if (lastPass.isEmpty()) {
+                                lastPass = it
+
+                                Snackbar.make(view!!, R.string.settings_lock_confirm, Snackbar.LENGTH_LONG).show()
+                            } else {
+                                if (lastPass == it) {
+                                    LockManager(context!!).add(Lock.generate(Lock.Type.PATTERN, it))
+                                    finish()
+                                } else {
+                                    lock_pattern_view.setViewMode(PatternLockView.PatternViewMode.WRONG)
+                                    lastPass = ""
+
+                                    Snackbar.make(view!!, R.string.settings_lock_wrong_confirm, Snackbar.LENGTH_LONG).show()
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        ).commit()
+    }
+
+}
diff --git a/app/src/main/java/xyz/quaver/pupil/MainActivity.kt b/app/src/main/java/xyz/quaver/pupil/ui/MainActivity.kt
similarity index 96%
rename from app/src/main/java/xyz/quaver/pupil/MainActivity.kt
rename to app/src/main/java/xyz/quaver/pupil/ui/MainActivity.kt
index 1933c54e..8b59da1c 100644
--- a/app/src/main/java/xyz/quaver/pupil/MainActivity.kt
+++ b/app/src/main/java/xyz/quaver/pupil/ui/MainActivity.kt
@@ -1,12 +1,12 @@
-package xyz.quaver.pupil
+package xyz.quaver.pupil.ui
 
 import android.Manifest
+import android.app.Activity
 import android.content.Intent
 import android.content.pm.PackageManager
 import android.graphics.drawable.Animatable
 import android.net.Uri
 import android.os.Bundle
-import android.preference.PreferenceManager
 import android.text.*
 import android.text.style.AlignmentSpan
 import android.view.*
@@ -21,6 +21,7 @@ import androidx.core.app.ActivityCompat
 import androidx.core.content.ContextCompat
 import androidx.core.content.res.ResourcesCompat
 import androidx.core.view.GravityCompat
+import androidx.preference.PreferenceManager
 import androidx.vectordrawable.graphics.drawable.AnimatedVectorDrawableCompat
 import com.arlib.floatingsearchview.FloatingSearchView
 import com.arlib.floatingsearchview.suggestions.model.SearchSuggestion
@@ -40,6 +41,8 @@ import kotlinx.serialization.list
 import kotlinx.serialization.stringify
 import ru.noties.markwon.Markwon
 import xyz.quaver.hitomi.*
+import xyz.quaver.pupil.BuildConfig
+import xyz.quaver.pupil.R
 import xyz.quaver.pupil.adapters.GalleryBlockAdapter
 import xyz.quaver.pupil.types.Tag
 import xyz.quaver.pupil.types.TagSuggestion
@@ -51,6 +54,7 @@ import java.net.URL
 import java.util.*
 import javax.net.ssl.HttpsURLConnection
 import kotlin.collections.ArrayList
+import kotlin.math.min
 import kotlin.math.roundToInt
 
 class MainActivity : AppCompatActivity() {
@@ -65,9 +69,16 @@ class MainActivity : AppCompatActivity() {
     private val galleries = ArrayList<Pair<GalleryBlock, Deferred<String>>>()
 
     private var query = ""
+    set(value) {
+        field = value
+        findViewById<SearchInputView>(R.id.search_bar_text)
+            .setText(query, TextView.BufferType.EDITABLE)
+    }
+
     private var mode = Mode.SEARCH
 
-    private val SETTINGS = 45162
+    private val REQUEST_SETTINGS = 45162
+    private val REQUEST_LOCK = 561
 
     private var galleryIDs: Deferred<List<Int>>? = null
     private var totalItems = 0
@@ -81,6 +92,8 @@ class MainActivity : AppCompatActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
+        startActivityForResult(Intent(this, LockActivity::class.java), REQUEST_LOCK)
+
         checkPermissions()
 
         val preference = PreferenceManager.getDefaultSharedPreferences(this)
@@ -110,19 +123,11 @@ class MainActivity : AppCompatActivity() {
         initView()
     }
 
-    override fun onDestroy() {
-        super.onDestroy()
-
-        if (cacheDir.exists())
-            cacheDir.deleteRecursively()
-    }
-
     override fun onBackPressed() {
         when {
             main_drawer_layout.isDrawerOpen(GravityCompat.START) -> main_drawer_layout.closeDrawer(GravityCompat.START)
             query.isNotEmpty() -> runOnUiThread {
                 query = ""
-                findViewById<SearchInputView>(R.id.search_bar_text).setText(query, TextView.BufferType.EDITABLE)
 
                 cancelFetch()
                 clearGalleries()
@@ -142,6 +147,7 @@ class MainActivity : AppCompatActivity() {
                 WindowManager.LayoutParams.FLAG_SECURE)
         else
             window.clearFlags(WindowManager.LayoutParams.FLAG_SECURE)
+
         super.onResume()
     }
 
@@ -186,7 +192,7 @@ class MainActivity : AppCompatActivity() {
     override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
         super.onActivityResult(requestCode, resultCode, data)
         when(requestCode) {
-            SETTINGS -> {
+            REQUEST_SETTINGS -> {
                 runOnUiThread {
                     cancelFetch()
                     clearGalleries()
@@ -194,6 +200,10 @@ class MainActivity : AppCompatActivity() {
                     loadBlocks()
                 }
             }
+            REQUEST_LOCK -> {
+                if (resultCode != Activity.RESULT_OK)
+                    finish()
+            }
         }
     }
 
@@ -352,8 +362,7 @@ class MainActivity : AppCompatActivity() {
                 onChipClickedHandler.add {
                     runOnUiThread {
                         query = it.toQuery()
-                        this@MainActivity.findViewById<SearchInputView>(R.id.search_bar_text)
-                            .setText(query, TextView.BufferType.EDITABLE)
+                        currentPage = 0
 
                         cancelFetch()
                         clearGalleries()
@@ -679,7 +688,7 @@ class MainActivity : AppCompatActivity() {
 
             setOnMenuItemClickListener {
                 when(it.itemId) {
-                    R.id.main_menu_settings -> startActivityForResult(Intent(this@MainActivity, SettingsActivity::class.java), SETTINGS)
+                    R.id.main_menu_settings -> startActivityForResult(Intent(this@MainActivity, SettingsActivity::class.java), REQUEST_SETTINGS)
                     R.id.main_menu_jump -> {
                         val preference = PreferenceManager.getDefaultSharedPreferences(context)
                         val perPage = preference.getString("per_page", "25")!!.toInt()
@@ -726,7 +735,8 @@ class MainActivity : AppCompatActivity() {
 
                                         startActivity(intent)
                                     } catch (e: Exception) {
-                                        Snackbar.make(main_layout, R.string.main_open_gallery_by_id_error, Snackbar.LENGTH_LONG).show()
+                                        Snackbar.make(main_layout,
+                                            R.string.main_open_gallery_by_id_error, Snackbar.LENGTH_LONG).show()
                                     }
                                 }
                             }
@@ -804,7 +814,9 @@ class MainActivity : AppCompatActivity() {
                             favorites.remove(tag)
                         }
                         else {
-                            setImageDrawable(AnimatedVectorDrawableCompat.create(context, R.drawable.avd_star))
+                            setImageDrawable(AnimatedVectorDrawableCompat.create(context,
+                                R.drawable.avd_star
+                            ))
                             (drawable as Animatable).start()
 
                             favorites.add(tag)
@@ -880,10 +892,8 @@ class MainActivity : AppCompatActivity() {
     }
 
     private fun cancelFetch() {
-        runBlocking {
-            galleryIDs?.cancelAndJoin()
-            loadingJob?.cancelAndJoin()
-        }
+        galleryIDs?.cancel()
+        loadingJob?.cancel()
     }
 
     private fun clearGalleries() {
@@ -992,7 +1002,7 @@ class MainActivity : AppCompatActivity() {
                 query.isEmpty() and defaultQuery.isEmpty() and (mode == Mode.SEARCH) ->
                     galleryIDs
                 else ->
-                    galleryIDs.slice(currentPage*perPage until Math.min(currentPage*perPage+perPage, galleryIDs.size))
+                    galleryIDs.slice(currentPage*perPage until min(currentPage*perPage+perPage, galleryIDs.size))
             }.chunked(5).let { chunks ->
                 for (chunk in chunks)
                     chunk.map { galleryID ->
@@ -1009,8 +1019,8 @@ class MainActivity : AppCompatActivity() {
                                                 getGalleryBlock(galleryID).apply {
                                                     this ?: return@apply
 
-                                                    if (!cache.parentFile.exists())
-                                                        cache.parentFile.mkdirs()
+                                                    if (cache.parentFile?.exists() == false)
+                                                        cache.parentFile!!.mkdirs()
 
                                                     cache.writeText(json.stringify(serializer, this))
                                                 }
@@ -1024,8 +1034,8 @@ class MainActivity : AppCompatActivity() {
                                         if (!exists())
                                             try {
                                                 with(URL(galleryBlock.thumbnails[0]).openConnection() as HttpsURLConnection) {
-                                                    if (!this@apply.parentFile.exists())
-                                                        this@apply.parentFile.mkdirs()
+                                                    if (this@apply.parentFile?.exists() == false)
+                                                        this@apply.parentFile!!.mkdirs()
 
                                                     inputStream.copyTo(FileOutputStream(this@apply))
                                                 }
diff --git a/app/src/main/java/xyz/quaver/pupil/ui/PatternLockFragment.kt b/app/src/main/java/xyz/quaver/pupil/ui/PatternLockFragment.kt
new file mode 100644
index 00000000..11d8a53b
--- /dev/null
+++ b/app/src/main/java/xyz/quaver/pupil/ui/PatternLockFragment.kt
@@ -0,0 +1,47 @@
+package xyz.quaver.pupil.ui
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import com.andrognito.patternlockview.PatternLockView
+import com.andrognito.patternlockview.listener.PatternLockViewListener
+import com.andrognito.patternlockview.utils.PatternLockUtils
+import kotlinx.android.synthetic.main.fragment_pattern_lock.*
+import kotlinx.android.synthetic.main.fragment_pattern_lock.view.*
+import xyz.quaver.pupil.R
+import xyz.quaver.pupil.util.hash
+import xyz.quaver.pupil.util.hashWithSalt
+
+class PatternLockFragment : Fragment(), PatternLockViewListener {
+
+    var onPatternDrawn: ((String) -> Unit)? = null
+
+    override fun onCreateView(
+        inflater: LayoutInflater, container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View? {
+        return inflater.inflate(R.layout.fragment_pattern_lock, container, false).apply {
+            lock_pattern_view.addPatternLockListener(this@PatternLockFragment)
+        }
+    }
+
+    override fun onCleared() {
+
+    }
+
+    override fun onComplete(pattern: MutableList<PatternLockView.Dot>?) {
+        val password = PatternLockUtils.patternToMD5(lock_pattern_view, pattern)
+        onPatternDrawn?.invoke(password)
+    }
+
+    override fun onProgress(progressPattern: MutableList<PatternLockView.Dot>?) {
+
+    }
+
+    override fun onStarted() {
+
+    }
+
+}
diff --git a/app/src/main/java/xyz/quaver/pupil/Pupil.kt b/app/src/main/java/xyz/quaver/pupil/ui/Pupil.kt
similarity index 94%
rename from app/src/main/java/xyz/quaver/pupil/Pupil.kt
rename to app/src/main/java/xyz/quaver/pupil/ui/Pupil.kt
index add8d659..c1859fe3 100644
--- a/app/src/main/java/xyz/quaver/pupil/Pupil.kt
+++ b/app/src/main/java/xyz/quaver/pupil/ui/Pupil.kt
@@ -1,14 +1,14 @@
-package xyz.quaver.pupil
+package xyz.quaver.pupil.ui
 
-import android.app.Application
 import android.app.Notification
 import android.app.NotificationChannel
 import android.app.NotificationManager
 import android.content.Context
 import android.os.Build
-import android.preference.PreferenceManager
 import androidx.core.content.ContextCompat
 import androidx.multidex.MultiDexApplication
+import androidx.preference.PreferenceManager
+import xyz.quaver.pupil.R
 import xyz.quaver.pupil.util.Histories
 import java.io.File
 
diff --git a/app/src/main/java/xyz/quaver/pupil/ReaderActivity.kt b/app/src/main/java/xyz/quaver/pupil/ui/ReaderActivity.kt
similarity index 97%
rename from app/src/main/java/xyz/quaver/pupil/ReaderActivity.kt
rename to app/src/main/java/xyz/quaver/pupil/ui/ReaderActivity.kt
index 49fa1f33..990f7b50 100644
--- a/app/src/main/java/xyz/quaver/pupil/ReaderActivity.kt
+++ b/app/src/main/java/xyz/quaver/pupil/ui/ReaderActivity.kt
@@ -1,4 +1,4 @@
-package xyz.quaver.pupil
+package xyz.quaver.pupil.ui
 
 import android.content.Intent
 import android.graphics.drawable.Animatable
@@ -11,9 +11,9 @@ import androidx.preference.PreferenceManager
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.PagerSnapHelper
 import androidx.recyclerview.widget.RecyclerView
-import androidx.recyclerview.widget.SimpleItemAnimator
 import androidx.vectordrawable.graphics.drawable.Animatable2Compat
 import androidx.vectordrawable.graphics.drawable.AnimatedVectorDrawableCompat
+import com.crashlytics.android.Crashlytics
 import com.google.android.material.snackbar.Snackbar
 import kotlinx.android.synthetic.main.activity_reader.*
 import kotlinx.android.synthetic.main.activity_reader.view.*
@@ -28,6 +28,7 @@ import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.JsonConfiguration
 import xyz.quaver.hitomi.GalleryBlock
 import xyz.quaver.hitomi.getGalleryBlock
+import xyz.quaver.pupil.R
 import xyz.quaver.pupil.adapters.ReaderAdapter
 import xyz.quaver.pupil.util.GalleryDownloader
 import xyz.quaver.pupil.util.Histories
@@ -72,6 +73,8 @@ class ReaderActivity : AppCompatActivity() {
 
         handleIntent(intent)
 
+        Crashlytics.setInt("GalleryID", galleryBlock.id)
+
         if (!::galleryBlock.isInitialized) {
             onBackPressed()
             return
@@ -117,7 +120,7 @@ class ReaderActivity : AppCompatActivity() {
         } else {
             galleryBlock = Json(JsonConfiguration.Stable).parse(
                 GalleryBlock.serializer(),
-                intent.getStringExtra("galleryblock")
+                intent.getStringExtra("galleryblock")!!
             )
         }
     }
@@ -372,10 +375,7 @@ class ReaderActivity : AppCompatActivity() {
             reader_recyclerview.layoutManager = LinearLayoutManager(this)
         } else {
             snapHelper.attachToRecyclerView(reader_recyclerview)
-            reader_recyclerview.layoutManager = LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false).apply {
-                isItemPrefetchEnabled = true
-                initialPrefetchItemCount = 4
-            }
+            reader_recyclerview.layoutManager = LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false)
         }
 
         (reader_recyclerview.layoutManager as LinearLayoutManager).scrollToPositionWithOffset(currentPage-1, 0)
diff --git a/app/src/main/java/xyz/quaver/pupil/SettingsActivity.kt b/app/src/main/java/xyz/quaver/pupil/ui/SettingsActivity.kt
similarity index 58%
rename from app/src/main/java/xyz/quaver/pupil/SettingsActivity.kt
rename to app/src/main/java/xyz/quaver/pupil/ui/SettingsActivity.kt
index e93b0166..1f995222 100644
--- a/app/src/main/java/xyz/quaver/pupil/SettingsActivity.kt
+++ b/app/src/main/java/xyz/quaver/pupil/ui/SettingsActivity.kt
@@ -1,8 +1,8 @@
-package xyz.quaver.pupil
+package xyz.quaver.pupil.ui
 
+import android.app.Activity
+import android.content.Intent
 import android.os.Bundle
-import android.os.Environment
-import android.preference.PreferenceManager
 import android.text.Editable
 import android.text.TextWatcher
 import android.view.LayoutInflater
@@ -15,12 +15,18 @@ import androidx.appcompat.app.AlertDialog
 import androidx.appcompat.app.AppCompatActivity
 import androidx.preference.Preference
 import androidx.preference.PreferenceFragmentCompat
+import androidx.preference.PreferenceManager
 import kotlinx.android.synthetic.main.dialog_default_query.view.*
+import xyz.quaver.pupil.R
 import xyz.quaver.pupil.types.Tags
+import xyz.quaver.pupil.util.Lock
+import xyz.quaver.pupil.util.LockManager
 import java.io.File
 
 class SettingsActivity : AppCompatActivity() {
 
+    val REQUEST_LOCK = 38238
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
@@ -58,7 +64,25 @@ class SettingsActivity : AppCompatActivity() {
             "TB" //really?
         )
 
-        private fun getCacheSize(dir: File) : String {
+        override fun onResume() {
+            super.onResume()
+
+            val lockManager = LockManager(context!!)
+
+            findPreference<Preference>("app_lock")?.summary = if (lockManager.locks.isNullOrEmpty()) {
+                getString(R.string.settings_lock_none)
+            } else {
+                lockManager.locks?.joinToString(", ") {
+                    when(it.type) {
+                        Lock.Type.PATTERN -> getString(R.string.settings_lock_pattern)
+                        Lock.Type.PIN -> getString(R.string.settings_lock_pin)
+                        Lock.Type.PASSWORD -> getString(R.string.settings_lock_password)
+                    }
+                }
+            }
+        }
+
+        private fun getDirSize(dir: File) : String {
             var size = dir.walk().map { it.length() }.sum()
             var suffixIndex = 0
 
@@ -67,20 +91,53 @@ class SettingsActivity : AppCompatActivity() {
                 suffixIndex++
             }
 
-            return getString(R.string.settings_clear_downloads_summary, size, suffix[suffixIndex])
+            return getString(R.string.settings_clear_summary, size, suffix[suffixIndex])
         }
 
         override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
             setPreferencesFromResource(R.xml.root_preferences, rootKey)
 
+            with(findPreference<Preference>("app_version")) {
+                this!!
+
+                val manager = context.packageManager
+                val info = manager.getPackageInfo(context.packageName, 0)
+
+                summary = info.versionName
+            }
+
+            with(findPreference<Preference>("delete_cache")) {
+                this!!
+
+                val dir = File(context.cacheDir, "imageCache")
+
+                summary = getDirSize(dir)
+
+                onPreferenceClickListener = Preference.OnPreferenceClickListener {
+                    AlertDialog.Builder(context).apply {
+                        setTitle(R.string.warning)
+                        setMessage(R.string.settings_clear_cache_alert_message)
+                        setPositiveButton(android.R.string.yes) { _, _ ->
+                            if (dir.exists())
+                                dir.deleteRecursively()
+
+                            summary = getDirSize(dir)
+                        }
+                        setNegativeButton(android.R.string.no) { _, _ -> }
+                    }.show()
+
+                    true
+                }
+            }
+
             with(findPreference<Preference>("delete_downloads")) {
-                this ?: return@with
+                this!!
 
-                val dir = File(Environment.getExternalStorageDirectory(), "Pupil")
+                val dir = context.getExternalFilesDir("Pupil") ?: return@with
 
-                summary = getCacheSize(dir)
+                summary = getDirSize(dir)
 
-                setOnPreferenceClickListener {
+                onPreferenceClickListener = Preference.OnPreferenceClickListener {
                     AlertDialog.Builder(context).apply {
                         setTitle(R.string.warning)
                         setMessage(R.string.settings_clear_downloads_alert_message)
@@ -92,7 +149,7 @@ class SettingsActivity : AppCompatActivity() {
 
                             downloads.clear()
 
-                            summary = getCacheSize(dir)
+                            summary = getDirSize(dir)
                         }
                         setNegativeButton(android.R.string.no) { _, _ -> }
                     }.show()
@@ -101,13 +158,13 @@ class SettingsActivity : AppCompatActivity() {
                 }
             }
             with(findPreference<Preference>("clear_history")) {
-                this ?: return@with
+                this!!
 
                 val histories = (activity!!.application as Pupil).histories
 
                 summary = getString(R.string.settings_clear_history_summary, histories.size)
 
-                setOnPreferenceClickListener {
+                onPreferenceClickListener = Preference.OnPreferenceClickListener {
                     AlertDialog.Builder(context).apply {
                         setTitle(R.string.warning)
                         setMessage(R.string.settings_clear_history_alert_message)
@@ -123,7 +180,7 @@ class SettingsActivity : AppCompatActivity() {
             }
 
             with(findPreference<Preference>("default_query")) {
-                this ?: return@with
+                this!!
 
                 val preferences = PreferenceManager.getDefaultSharedPreferences(context)
 
@@ -139,7 +196,7 @@ class SettingsActivity : AppCompatActivity() {
                 val excludeBL = "-male:yaoi"
                 val excludeGuro = listOf("-female:guro", "-male:guro")
 
-                setOnPreferenceClickListener {
+                onPreferenceClickListener = Preference.OnPreferenceClickListener {
                     val dialogView = LayoutInflater.from(context).inflate(
                         R.layout.dialog_default_query,
                         LinearLayout(context),
@@ -154,7 +211,7 @@ class SettingsActivity : AppCompatActivity() {
 
                     with(dialogView.default_query_dialog_language_selector) {
                         adapter =
-                            ArrayAdapter<String>(
+                            ArrayAdapter(
                                 context,
                                 android.R.layout.simple_spinner_dropdown_item,
                                 arrayListOf(
@@ -234,6 +291,82 @@ class SettingsActivity : AppCompatActivity() {
 
                     dialog.show()
 
+                    true
+                }
+            }
+            with(findPreference<Preference>("app_lock")) {
+                this!!
+
+                val lockManager = LockManager(context)
+
+                summary = if (lockManager.locks.isNullOrEmpty()) {
+                    getString(R.string.settings_lock_none)
+                } else {
+                    lockManager.locks?.joinToString(", ") {
+                        when(it.type) {
+                            Lock.Type.PATTERN -> getString(R.string.settings_lock_pattern)
+                            Lock.Type.PIN -> getString(R.string.settings_lock_pin)
+                            Lock.Type.PASSWORD -> getString(R.string.settings_lock_password)
+                        }
+                    }
+                }
+
+                onPreferenceClickListener = Preference.OnPreferenceClickListener {
+                    val intent = Intent(context, LockActivity::class.java)
+                    activity?.startActivityForResult(intent, (activity as SettingsActivity).REQUEST_LOCK)
+
+                    true
+                }
+            }
+        }
+    }
+
+    class LockFragment : PreferenceFragmentCompat() {
+
+        override fun onResume() {
+            super.onResume()
+
+            val lockManager = LockManager(context!!)
+
+            findPreference<Preference>("lock_pattern")?.summary =
+                if (lockManager.contains(Lock.Type.PATTERN))
+                    getString(R.string.settings_lock_enabled)
+                else
+                    ""
+        }
+
+        override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
+            setPreferencesFromResource(R.xml.lock_preferences, rootKey)
+
+            with(findPreference<Preference>("lock_pattern")) {
+                this!!
+
+                if (LockManager(context!!).contains(Lock.Type.PATTERN))
+                    summary = getString(R.string.settings_lock_enabled)
+
+                onPreferenceClickListener = Preference.OnPreferenceClickListener {
+                    val lockManager = LockManager(context!!)
+
+                    if (lockManager.contains(Lock.Type.PATTERN)) {
+                        AlertDialog.Builder(context).apply {
+                            setTitle(R.string.warning)
+                            setMessage(R.string.settings_lock_remove_message)
+
+                            setPositiveButton(android.R.string.yes) { _, _ ->
+                                lockManager.remove(Lock.Type.PATTERN)
+                                onResume()
+                            }
+                            setNegativeButton(android.R.string.no) { _, _ -> }
+                        }.show()
+                    } else {
+                        val intent = Intent(context, LockActivity::class.java).apply {
+                            putExtra("mode", "add_lock")
+                            putExtra("type", "pattern")
+                        }
+
+                        startActivity(intent)
+                    }
+
                     true
                 }
             }
@@ -247,4 +380,19 @@ class SettingsActivity : AppCompatActivity() {
 
         return true
     }
+
+    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
+        when(requestCode) {
+            REQUEST_LOCK -> {
+                if (resultCode == Activity.RESULT_OK) {
+                    supportFragmentManager
+                        .beginTransaction()
+                        .replace(R.id.settings, LockFragment())
+                        .addToBackStack("Lock")
+                        .commitAllowingStateLoss()
+                }
+            }
+            else -> super.onActivityResult(requestCode, resultCode, data)
+        }
+    }
 }
\ No newline at end of file
diff --git a/app/src/main/java/xyz/quaver/pupil/util/GalleryDownloader.kt b/app/src/main/java/xyz/quaver/pupil/util/GalleryDownloader.kt
index f4e08369..fda31db8 100644
--- a/app/src/main/java/xyz/quaver/pupil/util/GalleryDownloader.kt
+++ b/app/src/main/java/xyz/quaver/pupil/util/GalleryDownloader.kt
@@ -4,7 +4,7 @@ import android.app.PendingIntent
 import android.content.Context
 import android.content.ContextWrapper
 import android.content.Intent
-import android.os.Environment
+import android.util.Log
 import android.util.SparseArray
 import androidx.core.app.NotificationCompat
 import androidx.core.app.NotificationManagerCompat
@@ -18,9 +18,9 @@ import kotlinx.serialization.list
 import xyz.quaver.hitomi.*
 import xyz.quaver.hiyobi.cookie
 import xyz.quaver.hiyobi.user_agent
-import xyz.quaver.pupil.Pupil
+import xyz.quaver.pupil.ui.Pupil
 import xyz.quaver.pupil.R
-import xyz.quaver.pupil.ReaderActivity
+import xyz.quaver.pupil.ui.ReaderActivity
 import java.io.File
 import java.io.FileOutputStream
 import java.net.URL
@@ -52,7 +52,7 @@ class GalleryDownloader(
                     cache.deleteRecursively()
                 }
 
-                if (!reader.isActive && downloadJob?.isActive != true)
+                if (reader?.isActive == false && downloadJob?.isActive != true)
                     field = false
 
                 downloads.add(galleryBlock.id)
@@ -63,7 +63,7 @@ class GalleryDownloader(
             onNotifyChangedHandler?.invoke(value)
         }
 
-    private val reader: Deferred<Reader>
+    private val reader: Deferred<Reader>?
     private var downloadJob: Job? = null
 
     private lateinit var notificationBuilder: NotificationCompat.Builder
@@ -126,8 +126,8 @@ class GalleryDownloader(
 
             if (reader.isNotEmpty()) {
                 //Save cache
-                if (!cache.parentFile.exists())
-                    cache.parentFile.mkdirs()
+                if (cache.parentFile?.exists() == false)
+                    cache.parentFile!!.mkdirs()
 
                 cache.writeText(json.stringify(serializer, reader))
             }
@@ -140,7 +140,7 @@ class GalleryDownloader(
 
     fun start() {
         downloadJob = CoroutineScope(Dispatchers.Default).launch {
-            val reader = reader.await()
+            val reader = reader!!.await()
 
             if (reader.isEmpty())
                 onErrorHandler?.invoke(IOException("Couldn't retrieve Reader"))
@@ -183,8 +183,8 @@ class GalleryDownloader(
                                     } else
                                         setRequestProperty("Referer", getReferer(galleryBlock.id))
 
-                                    if (!cache.parentFile.exists())
-                                        cache.parentFile.mkdirs()
+                                    if (cache.parentFile?.exists() == false)
+                                        cache.parentFile!!.mkdirs()
 
                                     inputStream.copyTo(FileOutputStream(cache))
                                 }
@@ -209,8 +209,6 @@ class GalleryDownloader(
                 }
             }
 
-            onCompleteHandler?.invoke()
-
             Timer(false).schedule(1000) {
                 notificationBuilder
                     .setContentTitle(galleryBlock.title)
@@ -220,7 +218,7 @@ class GalleryDownloader(
                 if (download) {
                     File(cacheDir, "imageCache/${galleryBlock.id}").let {
                         if (it.exists()) {
-                            val target = File(Environment.getExternalStorageDirectory(), "Pupil/${galleryBlock.id}")
+                            val target = File(getExternalFilesDir("Pupil"), galleryBlock.id.toString())
 
                             if (!target.exists())
                                 target.mkdirs()
@@ -231,9 +229,11 @@ class GalleryDownloader(
                     }
 
                     notificationManager.notify(galleryBlock.id, notificationBuilder.build())
-                }
 
-                download = false
+                    onCompleteHandler?.invoke()
+
+                    download = false
+                }
             }
 
             remove(galleryBlock.id)
@@ -254,7 +254,7 @@ class GalleryDownloader(
 
     fun invokeOnReaderLoaded() {
         CoroutineScope(Dispatchers.Default).launch {
-            onReaderLoadedHandler?.invoke(reader.await())
+            onReaderLoadedHandler?.invoke(reader?.await() ?: return@launch)
         }
     }
 
diff --git a/app/src/main/java/xyz/quaver/pupil/util/file.kt b/app/src/main/java/xyz/quaver/pupil/util/file.kt
index 7e085650..f351dcd2 100644
--- a/app/src/main/java/xyz/quaver/pupil/util/file.kt
+++ b/app/src/main/java/xyz/quaver/pupil/util/file.kt
@@ -2,10 +2,11 @@ package xyz.quaver.pupil.util
 
 import android.content.Context
 import android.os.Environment
+import android.provider.MediaStore
 import java.io.File
 
 fun getCachedGallery(context: Context, galleryID: Int): File {
-    return File(Environment.getExternalStorageDirectory(), "Pupil/$galleryID").let {
+    return File(context.getExternalFilesDir("Pupil"), galleryID.toString()).let {
         when {
             it.exists() -> it
             else -> File(context.cacheDir, "imageCache/$galleryID")
diff --git a/app/src/main/java/xyz/quaver/pupil/util/lock.kt b/app/src/main/java/xyz/quaver/pupil/util/lock.kt
new file mode 100644
index 00000000..13f87003
--- /dev/null
+++ b/app/src/main/java/xyz/quaver/pupil/util/lock.kt
@@ -0,0 +1,105 @@
+package xyz.quaver.pupil.util
+
+import android.content.Context
+import android.content.ContextWrapper
+import androidx.core.content.ContextCompat
+import kotlinx.serialization.*
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonConfiguration
+import java.io.File
+import java.security.MessageDigest
+
+fun hash(password: String): String {
+    val bytes = password.toByteArray()
+    val md = MessageDigest.getInstance("SHA-256")
+
+    return md.digest(bytes).fold("") { str, it -> str + "%02x".format(it) }
+}
+
+// Ret1: SHA-256 Hash
+// Ret2: Hash salt
+fun hashWithSalt(password: String): Pair<String, String> {
+    val salt = (0 until 12).map { source.random() }.joinToString()
+
+    return Pair(hash(password+salt), salt)
+}
+
+val source = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+
+@Serializable
+data class Lock(val type: Type, val hash: String, val salt: String) {
+
+    enum class Type {
+        PATTERN,
+        PIN,
+        PASSWORD
+    }
+
+    companion object {
+        fun generate(type: Type, password: String): Lock {
+            val (hash, salt) = hashWithSalt(password)
+            return Lock(type, hash, salt)
+        }
+    }
+
+    fun match(password: String): Boolean {
+        return hash(password+salt) == hash
+    }
+}
+
+class LockManager(base: Context): ContextWrapper(base) {
+
+    var locks: ArrayList<Lock>? = null
+
+    init {
+        load()
+    }
+
+    @UseExperimental(ImplicitReflectionSerializer::class)
+    private fun load() {
+        val lock = File(ContextCompat.getDataDir(this), "lock.json")
+
+        if (!lock.exists()) {
+            lock.createNewFile()
+            lock.writeText("[]")
+        }
+
+        locks = ArrayList(Json(JsonConfiguration.Stable).parseList(lock.readText()))
+    }
+
+    @UseExperimental(ImplicitReflectionSerializer::class)
+    private fun save() {
+        val lock = File(ContextCompat.getDataDir(this), "lock.json")
+
+        if (!lock.exists())
+            lock.createNewFile()
+
+        lock.writeText(Json(JsonConfiguration.Stable).stringify(locks?.toList() ?: listOf()))
+    }
+
+    fun add(lock: Lock) {
+        remove(lock.type)
+        locks?.add(lock)
+        save()
+    }
+
+    fun remove(type: Lock.Type) {
+        locks?.removeAll { it.type == type }
+        save()
+    }
+
+    fun check(password: String): Boolean? {
+        return locks?.any {
+            it.match(password)
+        }
+    }
+
+    fun empty(): Boolean {
+        return locks.isNullOrEmpty()
+    }
+
+    fun contains(type: Lock.Type): Boolean {
+        return locks?.any { it.type == type } ?: false
+    }
+
+}
\ No newline at end of file
diff --git a/app/src/main/java/xyz/quaver/pupil/util/update.kt b/app/src/main/java/xyz/quaver/pupil/util/update.kt
index 2c951cbe..1461f75c 100644
--- a/app/src/main/java/xyz/quaver/pupil/util/update.kt
+++ b/app/src/main/java/xyz/quaver/pupil/util/update.kt
@@ -1,5 +1,6 @@
 package xyz.quaver.pupil.util
 
+import android.util.Log
 import kotlinx.serialization.json.*
 import java.net.URL
 
@@ -19,8 +20,20 @@ fun checkUpdate(url: String, currentVersion: String) : JsonObject? {
     if (releases.isEmpty())
         return null
 
-    if (currentVersion != releases[0].jsonObject["tag_name"]?.content)
-        return releases[0].jsonObject
+    val latestVersion = releases[0].jsonObject["tag_name"]?.content
 
-    return null
+    return when {
+        currentVersion.split('-').size == 1 -> {
+            when {
+                currentVersion != latestVersion -> releases[0].jsonObject
+                else -> null
+            }
+        }
+        else -> {
+            when {
+                (currentVersion.split('-')[0] == latestVersion) -> releases[0].jsonObject
+                else -> null
+            }
+        }
+    }
 }
\ No newline at end of file
diff --git a/app/src/main/res/drawable/fingerprint.xml b/app/src/main/res/drawable/fingerprint.xml
new file mode 100644
index 00000000..ffa8a34b
--- /dev/null
+++ b/app/src/main/res/drawable/fingerprint.xml
@@ -0,0 +1,8 @@
+<!-- drawable/fingerprint.xml -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:height="24dp"
+    android:width="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path android:fillColor="#000" android:pathData="M17.81,4.47C17.73,4.47 17.65,4.45 17.58,4.41C15.66,3.42 14,3 12,3C10.03,3 8.15,3.47 6.44,4.41C6.2,4.54 5.9,4.45 5.76,4.21C5.63,3.97 5.72,3.66 5.96,3.53C7.82,2.5 9.86,2 12,2C14.14,2 16,2.47 18.04,3.5C18.29,3.65 18.38,3.95 18.25,4.19C18.16,4.37 18,4.47 17.81,4.47M3.5,9.72C3.4,9.72 3.3,9.69 3.21,9.63C3,9.47 2.93,9.16 3.09,8.93C4.08,7.53 5.34,6.43 6.84,5.66C10,4.04 14,4.03 17.15,5.65C18.65,6.42 19.91,7.5 20.9,8.9C21.06,9.12 21,9.44 20.78,9.6C20.55,9.76 20.24,9.71 20.08,9.5C19.18,8.22 18.04,7.23 16.69,6.54C13.82,5.07 10.15,5.07 7.29,6.55C5.93,7.25 4.79,8.25 3.89,9.5C3.81,9.65 3.66,9.72 3.5,9.72M9.75,21.79C9.62,21.79 9.5,21.74 9.4,21.64C8.53,20.77 8.06,20.21 7.39,19C6.7,17.77 6.34,16.27 6.34,14.66C6.34,11.69 8.88,9.27 12,9.27C15.12,9.27 17.66,11.69 17.66,14.66A0.5,0.5 0 0,1 17.16,15.16A0.5,0.5 0 0,1 16.66,14.66C16.66,12.24 14.57,10.27 12,10.27C9.43,10.27 7.34,12.24 7.34,14.66C7.34,16.1 7.66,17.43 8.27,18.5C8.91,19.66 9.35,20.15 10.12,20.93C10.31,21.13 10.31,21.44 10.12,21.64C10,21.74 9.88,21.79 9.75,21.79M16.92,19.94C15.73,19.94 14.68,19.64 13.82,19.05C12.33,18.04 11.44,16.4 11.44,14.66A0.5,0.5 0 0,1 11.94,14.16A0.5,0.5 0 0,1 12.44,14.66C12.44,16.07 13.16,17.4 14.38,18.22C15.09,18.7 15.92,18.93 16.92,18.93C17.16,18.93 17.56,18.9 17.96,18.83C18.23,18.78 18.5,18.96 18.54,19.24C18.59,19.5 18.41,19.77 18.13,19.82C17.56,19.93 17.06,19.94 16.92,19.94M14.91,22C14.87,22 14.82,22 14.78,22C13.19,21.54 12.15,20.95 11.06,19.88C9.66,18.5 8.89,16.64 8.89,14.66C8.89,13.04 10.27,11.72 11.97,11.72C13.67,11.72 15.05,13.04 15.05,14.66C15.05,15.73 16,16.6 17.13,16.6C18.28,16.6 19.21,15.73 19.21,14.66C19.21,10.89 15.96,7.83 11.96,7.83C9.12,7.83 6.5,9.41 5.35,11.86C4.96,12.67 4.76,13.62 4.76,14.66C4.76,15.44 4.83,16.67 5.43,18.27C5.53,18.53 5.4,18.82 5.14,18.91C4.88,19 4.59,18.87 4.5,18.62C4,17.31 3.77,16 3.77,14.66C3.77,13.46 4,12.37 4.45,11.42C5.78,8.63 8.73,6.82 11.96,6.82C16.5,6.82 20.21,10.33 20.21,14.65C20.21,16.27 18.83,17.59 17.13,17.59C15.43,17.59 14.05,16.27 14.05,14.65C14.05,13.58 13.12,12.71 11.97,12.71C10.82,12.71 9.89,13.58 9.89,14.65C9.89,16.36 10.55,17.96 11.76,19.16C12.71,20.1 13.62,20.62 15.03,21C15.3,21.08 15.45,21.36 15.38,21.62C15.33,21.85 15.12,22 14.91,22Z" />
+</vector>
\ No newline at end of file
diff --git a/app/src/main/res/drawable/lastpass.xml b/app/src/main/res/drawable/lastpass.xml
new file mode 100644
index 00000000..9dbf638b
--- /dev/null
+++ b/app/src/main/res/drawable/lastpass.xml
@@ -0,0 +1,8 @@
+<!-- drawable/lastpass.xml -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:height="24dp"
+    android:width="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path android:fillColor="#000" android:pathData="M14,12A2,2 0 0,1 16,10A2,2 0 0,1 18,12A2,2 0 0,1 16,14A2,2 0 0,1 14,12M8,12A2,2 0 0,1 10,10A2,2 0 0,1 12,12A2,2 0 0,1 10,14A2,2 0 0,1 8,12M2,12A2,2 0 0,1 4,10A2,2 0 0,1 6,12A2,2 0 0,1 4,14A2,2 0 0,1 2,12M22,5H20V19H22V5Z" />
+</vector>
\ No newline at end of file
diff --git a/app/src/main/res/drawable/lock_pattern.xml b/app/src/main/res/drawable/lock_pattern.xml
new file mode 100644
index 00000000..f1be51c2
--- /dev/null
+++ b/app/src/main/res/drawable/lock_pattern.xml
@@ -0,0 +1,8 @@
+<!-- drawable/lock_pattern.xml -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:height="24dp"
+    android:width="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path android:fillColor="#000" android:pathData="M7,3A4,4 0 0,1 11,7C11,8.86 9.73,10.43 8,10.87V13.13C8.37,13.22 8.72,13.37 9.04,13.56L13.56,9.04C13.2,8.44 13,7.75 13,7A4,4 0 0,1 17,3A4,4 0 0,1 21,7A4,4 0 0,1 17,11C16.26,11 15.57,10.8 15,10.45L10.45,15C10.8,15.57 11,16.26 11,17A4,4 0 0,1 7,21A4,4 0 0,1 3,17C3,15.14 4.27,13.57 6,13.13V10.87C4.27,10.43 3,8.86 3,7A4,4 0 0,1 7,3M17,13A4,4 0 0,1 21,17A4,4 0 0,1 17,21A4,4 0 0,1 13,17A4,4 0 0,1 17,13M17,15A2,2 0 0,0 15,17A2,2 0 0,0 17,19A2,2 0 0,0 19,17A2,2 0 0,0 17,15Z" />
+</vector>
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_lock.xml b/app/src/main/res/layout/activity_lock.xml
new file mode 100644
index 00000000..e4632044
--- /dev/null
+++ b/app/src/main/res/layout/activity_lock.xml
@@ -0,0 +1,64 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".ui.LockActivity">
+
+    <FrameLayout
+        android:id="@+id/lock_content"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        app:layout_constraintTop_toTopOf="parent"
+        app:layout_constraintBottom_toTopOf="@id/lock_button_layout"/>
+
+    <LinearLayout
+        android:id="@+id/lock_button_layout"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginTop="16dp"
+        android:layout_marginBottom="32dp"
+        app:layout_constraintTop_toBottomOf="@id/lock_content"
+        app:layout_constraintBottom_toBottomOf="parent"
+        android:gravity="center">
+
+        <com.google.android.material.floatingactionbutton.FloatingActionButton
+            android:id="@+id/lock_pattern"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:src="@drawable/lock_pattern"
+            app:backgroundTint="@color/colorPrimary"
+            app:fabSize="mini"/>
+
+        <com.google.android.material.floatingactionbutton.FloatingActionButton
+            android:id="@+id/lock_pin"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:src="@drawable/numeric"
+            android:layout_marginLeft="8dp"
+            android:layout_marginRight="8dp"
+            app:backgroundTint="@color/dark_gray"
+            app:fabSize="mini"/>
+
+        <com.google.android.material.floatingactionbutton.FloatingActionButton
+            android:id="@+id/lock_fingerprint"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:src="@drawable/fingerprint"
+            android:layout_marginLeft="8dp"
+            android:layout_marginRight="8dp"
+            app:backgroundTint="@color/dark_gray"
+            app:fabSize="mini"/>
+
+        <com.google.android.material.floatingactionbutton.FloatingActionButton
+            android:id="@+id/lock_password"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:src="@drawable/lastpass"
+            app:backgroundTint="@color/dark_gray"
+            app:fabSize="mini"/>
+
+    </LinearLayout>
+
+</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_main_content.xml b/app/src/main/res/layout/activity_main_content.xml
index a5b3b266..bde8ddf4 100644
--- a/app/src/main/res/layout/activity_main_content.xml
+++ b/app/src/main/res/layout/activity_main_content.xml
@@ -6,7 +6,7 @@
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    tools:context=".MainActivity">
+    tools:context=".ui.MainActivity">
 
     <androidx.coordinatorlayout.widget.CoordinatorLayout
         android:layout_width="match_parent"
diff --git a/app/src/main/res/layout/activity_reader.xml b/app/src/main/res/layout/activity_reader.xml
index ea646156..b1cd6c1d 100644
--- a/app/src/main/res/layout/activity_reader.xml
+++ b/app/src/main/res/layout/activity_reader.xml
@@ -6,7 +6,7 @@
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:background="@color/dark_gray"
-    tools:context=".ReaderActivity">
+    tools:context=".ui.ReaderActivity">
 
     <LinearLayout
         android:layout_width="match_parent"
diff --git a/app/src/main/res/layout/fragment_pattern_lock.xml b/app/src/main/res/layout/fragment_pattern_lock.xml
new file mode 100644
index 00000000..6ed146b3
--- /dev/null
+++ b/app/src/main/res/layout/fragment_pattern_lock.xml
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    tools:context=".ui.PatternLockFragment">
+
+    <com.andrognito.patternlockview.PatternLockView
+        android:id="@+id/lock_pattern_view"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_gravity="center"
+        app:aspectRatioEnabled="true"
+        app:normalStateColor="@color/colorPrimary"
+        app:correctStateColor="@color/colorPrimaryDark"
+        app:wrongStateColor="@color/colorAccent"/>
+
+</FrameLayout>
\ No newline at end of file
diff --git a/app/src/main/res/values-ja/strings.xml b/app/src/main/res/values-ja/strings.xml
index 8e7dd7d0..bdab1daf 100644
--- a/app/src/main/res/values-ja/strings.xml
+++ b/app/src/main/res/values-ja/strings.xml
@@ -8,7 +8,8 @@
     <string name="search_hint">ギャラリー検索</string>
     <string name="search_hint_with_page">ギャラリー検索</string>
     <string name="settings_clear_image_cache">イメージキャッシュクリア</string>
-    <string name="settings_clear_downloads_summary">サイズ: %1$d%2$s</string>
+    <string name="settings_clear_cache_alert_message">キャッシュをクリアするとイメージのロード速度に影響を与えます。実行しますか？</string>
+    <string name="settings_clear_summary">サイズ: %1$d%2$s</string>
     <string name="settings_default_query">デフォルトキーワード</string>
     <string name="settings_galleries_per_page">一回にロードするギャラリー数</string>
     <string name="settings_search_title">検索設定</string>
@@ -66,4 +67,16 @@
     <string name="main_open_gallery_by_id_error">エラーが発生しました</string>
     <string name="settings_storage">ストレージ</string>
     <string name="main_drawer_grouop_contact_kakaotalk">カカオトーク</string>
+    <string name="settings_app_lock">アプリロック</string>
+    <string name="settings_app_lock_type">アップロックの種類</string>
+    <string name="settings_app_version_title">バージョン</string>
+    <string name="settings_lock_biomatrics">生体認識</string>
+    <string name="settings_lock_confirm">ロック確認のためもう一回入力してください。</string>
+    <string name="settings_lock_enabled">有効</string>
+    <string name="settings_lock_fingerprint">指紋</string>
+    <string name="settings_lock_password">パスワード</string>
+    <string name="settings_lock_pattern">パターン</string>
+    <string name="settings_lock_wrong_confirm">ロックが一致しません。やり直してください。</string>
+    <string name="settings_lock_none">なし</string>
+    <string name="settings_lock_remove_message">ロックを無効にしますか？</string>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values-ko/strings.xml b/app/src/main/res/values-ko/strings.xml
index 0b99f608..d7c7956d 100644
--- a/app/src/main/res/values-ko/strings.xml
+++ b/app/src/main/res/values-ko/strings.xml
@@ -7,7 +7,8 @@
     <string name="search_hint_with_page">갤러리 검색</string>
     <string name="settings_default_query">기본 검색어</string>
     <string name="settings_clear_image_cache">이미지 캐시 정리하기</string>
-    <string name="settings_clear_downloads_summary">사용량: %1$d%2$s</string>
+    <string name="settings_clear_cache_alert_message">캐시를 정리하면 이미지 로딩속도가 느려질 수 있습니다. 계속하시겠습니까?</string>
+    <string name="settings_clear_summary">사용량: %1$d%2$s</string>
     <string name="settings_galleries_per_page">한 번에 로드할 갤러리 수</string>
     <string name="settings_search_title">검색 설정</string>
     <string name="settings_title">설정</string>
@@ -66,4 +67,16 @@
     <string name="main_open_gallery_by_id_error">갤러리를 찾지 못했습니다</string>
     <string name="settings_storage">저장 공간</string>
     <string name="main_drawer_grouop_contact_kakaotalk">카카오톡 오픈채팅방</string>
+    <string name="settings_app_lock">앱 잠금</string>
+    <string name="settings_app_lock_type">앱 잠금 종류</string>
+    <string name="settings_app_version_title">앱 버전</string>
+    <string name="settings_lock_biomatrics">생체 인식</string>
+    <string name="settings_lock_confirm">잠금 확인을 위해 한번 더 입력해주세요</string>
+    <string name="settings_lock_enabled">사용 중</string>
+    <string name="settings_lock_fingerprint">지문</string>
+    <string name="settings_lock_password">비밀번호</string>
+    <string name="settings_lock_pattern">패턴</string>
+    <string name="settings_lock_wrong_confirm">잠금이 일치하지 않습니다. 다시 시도하세요.</string>
+    <string name="settings_lock_none">없음</string>
+    <string name="settings_lock_remove_message">잠금을 해제할까요?</string>
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 2cc8d514..c8ef231d 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -80,23 +80,38 @@
     <string name="reader_notification_error">Download error</string>
 
     <string name="settings_title">Settings</string>
+    <string name="settings_app_version_title">App version</string>
     <string name="settings_search_title">Search Settings</string>
     <string name="settings_galleries_per_page">Galleries per page</string>
     <string name="settings_default_query">Default query</string>
     <string name="settings_storage">Storage</string>
     <string name="settings_clear_image_cache">Clear image cache</string>
-    <string name="settings_clear_downloads_summary">Currently using %1$d%2$s</string>
+    <string name="settings_clear_cache_alert_message">Deleting cache can affect image loading speed. Do you want to continue?</string>
+    <string name="settings_clear_summary">Currently using %1$d%2$s</string>
     <string name="settings_clear_downloads">Clear downloads</string>
     <string name="settings_clear_downloads_alert_message">Delete all downloaded galleries.\nDo you want to continue?</string>
     <string name="settings_clear_history">Clear history</string>
     <string name="settings_clear_history_alert_message">Do you want to clear histories?</string>
     <string name="settings_clear_history_summary">%1$d histories saved</string>
+    <string name="settings_app_lock">App lock</string>
+    <string name="settings_app_lock_type">App lock type</string>
     <string name="settings_miscellaneous_title">Miscellaneous</string>
     <string name="settings_use_hiyobi_title">Use hiyobi.me</string>
     <string name="settings_use_hiyobi_summary">Load images from hiyobi.me to improve loading speed (if available)</string>
     <string name="settings_security_mode_title">Enable security mode</string>
     <string name="settings_security_mode_summary">Enable security mode to make the screen invisible on recent app window</string>
 
+    <string name="settings_lock_none">None</string>
+    <string name="settings_lock_pattern">Pattern</string>
+    <string name="settings_lock_pin" translatable="false">PIN</string>
+    <string name="settings_lock_password">Password</string>
+    <string name="settings_lock_biomatrics">Biomatrics</string>
+    <string name="settings_lock_fingerprint">Fingerprint</string>
+    <string name="settings_lock_enabled">Enabled</string>
+    <string name="settings_lock_confirm">Input same lock once more to confirm Lock</string>
+    <string name="settings_lock_remove_message">Do you want to remove lock?</string>
+    <string name="settings_lock_wrong_confirm">Lock is different from last one. Please try again.</string>
+
     <string name="default_query_dialog_title">Set default query</string>
     <string name="default_query_dialog_language">Language: </string>
     <string name="default_query_dialog_filter_BL">Filter BL</string>
diff --git a/app/src/main/res/xml/lock_preferences.xml b/app/src/main/res/xml/lock_preferences.xml
new file mode 100644
index 00000000..9fed9fba
--- /dev/null
+++ b/app/src/main/res/xml/lock_preferences.xml
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.preference.PreferenceScreen
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+
+    <Preference
+        app:title="@string/settings_lock_pattern"
+        app:key="lock_pattern"/>
+
+    <Preference
+        app:title="@string/settings_lock_pin"
+        app:key="lock_pin"/>
+
+    <Preference
+        app:title="@string/settings_lock_password"
+        app:key="lock_password"/>
+
+    <PreferenceCategory
+        app:title="@string/settings_lock_biomatrics">
+
+        <Preference
+            app:title="@string/settings_lock_fingerprint"
+            app:key="lock_fingerprint"/>
+
+    </PreferenceCategory>
+
+</androidx.preference.PreferenceScreen>
\ No newline at end of file
diff --git a/app/src/main/res/xml/root_preferences.xml b/app/src/main/res/xml/root_preferences.xml
index 0ccfbbb2..5a802f27 100644
--- a/app/src/main/res/xml/root_preferences.xml
+++ b/app/src/main/res/xml/root_preferences.xml
@@ -2,6 +2,10 @@
 <androidx.preference.PreferenceScreen
     xmlns:app="http://schemas.android.com/apk/res-auto">
 
+    <Preference
+        app:title="@string/settings_app_version_title"
+        app:key="app_version"/>
+
     <PreferenceCategory
         app:title="@string/settings_search_title">
 
@@ -24,6 +28,10 @@
     <PreferenceCategory
         app:title="@string/settings_storage">
 
+        <Preference
+            app:title="Clear cache"
+            app:key="delete_cache"/>
+
         <Preference
             app:title="@string/settings_clear_downloads"
             app:key="delete_downloads"/>
@@ -34,6 +42,15 @@
 
     </PreferenceCategory>
 
+    <PreferenceCategory
+        app:title="@string/settings_app_lock">
+
+        <Preference
+            app:title="@string/settings_app_lock_type"
+            app:key="app_lock"/>
+
+    </PreferenceCategory>
+
     <PreferenceCategory
         app:title="@string/settings_miscellaneous_title">
 
diff --git a/libpupil/src/test/java/xyz/quaver/hitomi/UnitTest.kt b/libpupil/src/test/java/xyz/quaver/hitomi/UnitTest.kt
index bc7c0d78..1b864d91 100644
--- a/libpupil/src/test/java/xyz/quaver/hitomi/UnitTest.kt
+++ b/libpupil/src/test/java/xyz/quaver/hitomi/UnitTest.kt
@@ -1,15 +1,24 @@
 package xyz.quaver.hitomi
 
 import org.junit.Test
-import java.io.File
-import java.net.URL
+import java.net.InetAddress
+import java.net.UnknownHostException
+
 
 class UnitTest {
     @Test
     fun test() {
-        val galleries = getGalleryIDsForQuery("series:touhou_project")
 
-        println(galleries.size)
+    }
+
+    private fun getByIp(host: String): InetAddress {
+        try {
+            return InetAddress.getByName(host)
+        } catch (e: UnknownHostException) {
+            // unlikely
+            throw RuntimeException(e)
+        }
+
     }
 
     @Test