diff --git a/OpenKeychain/src/main/AndroidManifest.xml b/OpenKeychain/src/main/AndroidManifest.xml
index 3be9e0aef..7c604611b 100644
--- a/OpenKeychain/src/main/AndroidManifest.xml
+++ b/OpenKeychain/src/main/AndroidManifest.xml
@@ -877,9 +877,6 @@
             android:name=".remote.CryptoInputParcelCacheService"
             android:exported="false"
             android:process=":remote_api" />
-        <service
-            android:name=".service.KeychainService"
-            android:exported="false" />
 
         <provider
             android:name=".provider.KeychainProvider"
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/keysync/KeyserverSyncWorker.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/keysync/KeyserverSyncWorker.java
index 7b638baf3..2d9b2fdb8 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/keysync/KeyserverSyncWorker.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/keysync/KeyserverSyncWorker.java
@@ -1,12 +1,13 @@
 package org.sufficientlysecure.keychain.keysync;
 
 
+import java.util.concurrent.atomic.AtomicBoolean;
+
 import android.app.NotificationManager;
 import android.content.Context;
 import android.support.annotation.NonNull;
 import android.support.v4.app.NotificationCompat;
 import android.support.v4.app.NotificationCompat.Builder;
-import android.support.v4.os.CancellationSignal;
 
 import androidx.work.Worker;
 import org.sufficientlysecure.keychain.Constants.NotificationIds;
@@ -25,7 +26,7 @@ import timber.log.Timber;
 
 
 public class KeyserverSyncWorker extends Worker {
-    private CancellationSignal cancellationSignal = new CancellationSignal();
+    private AtomicBoolean cancellationSignal = new AtomicBoolean(false);
 
     @NonNull
     @Override
@@ -93,17 +94,7 @@ public class KeyserverSyncWorker extends Worker {
 
         return new Progressable() {
             @Override
-            public void setProgress(String message, int current, int total) {
-                setProgress(current, total);
-            }
-
-            @Override
-            public void setProgress(int resourceId, int current, int total) {
-                setProgress(current, total);
-            }
-
-            @Override
-            public void setProgress(int current, int total) {
+            public void setProgress(Integer ignored, int current, int total) {
                 if (total == 0) {
                     notificationManager.cancel(NotificationIds.KEYSERVER_SYNC);
                     return;
@@ -128,6 +119,6 @@ public class KeyserverSyncWorker extends Worker {
     @Override
     public void onStopped() {
         super.onStopped();
-        cancellationSignal.cancel();
+        cancellationSignal.set(true);
     }
 }
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BackupOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BackupOperation.java
index eb613c27c..f3c85fc0a 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BackupOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BackupOperation.java
@@ -27,17 +27,19 @@ import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.List;
 import java.util.Locale;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.regex.Pattern;
 
 import android.content.Context;
 import android.net.Uri;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
-import android.support.v4.os.CancellationSignal;
 
 import org.bouncycastle.bcpg.ArmoredOutputStream;
 import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.R;
+import org.sufficientlysecure.keychain.daos.KeyRepository;
+import org.sufficientlysecure.keychain.daos.KeyRepository.NotFoundException;
 import org.sufficientlysecure.keychain.model.SubKey.UnifiedKeyInfo;
 import org.sufficientlysecure.keychain.operations.results.ExportResult;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.LogType;
@@ -50,8 +52,6 @@ import org.sufficientlysecure.keychain.pgp.PgpSignEncryptOperation;
 import org.sufficientlysecure.keychain.pgp.Progressable;
 import org.sufficientlysecure.keychain.pgp.UncachedKeyRing;
 import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
-import org.sufficientlysecure.keychain.daos.KeyRepository;
-import org.sufficientlysecure.keychain.daos.KeyRepository.NotFoundException;
 import org.sufficientlysecure.keychain.provider.TemporaryFileProvider;
 import org.sufficientlysecure.keychain.service.BackupKeyringParcel;
 import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
@@ -83,7 +83,7 @@ public class BackupOperation extends BaseOperation<BackupKeyringParcel> {
     }
 
     public BackupOperation(Context context, KeyRepository keyRepository,
-                           Progressable progressable, CancellationSignal cancelled) {
+                           Progressable progressable, AtomicBoolean cancelled) {
         super(context, keyRepository, progressable, cancelled);
     }
 
@@ -222,8 +222,7 @@ public class BackupOperation extends BaseOperation<BackupKeyringParcel> {
             }
             int numKeys = unifiedKeyInfos.size();
 
-            updateProgress(mContext.getResources().getQuantityString(R.plurals.progress_exporting_key, numKeys),
-                    0, numKeys);
+            updateProgress(numKeys == 1 ? R.string.progress_exporting_key : R.string.progress_exporting_key, 0, numKeys);
 
             // For each public masterKey id
             for (UnifiedKeyInfo keyInfo : unifiedKeyInfos) {
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BaseOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BaseOperation.java
index f757eb6dd..a5cc4602d 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BaseOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BaseOperation.java
@@ -18,17 +18,18 @@
 package org.sufficientlysecure.keychain.operations;
 
 
+import java.util.concurrent.atomic.AtomicBoolean;
+
 import android.content.Context;
 import android.os.Parcelable;
 import android.support.annotation.NonNull;
 import android.support.annotation.StringRes;
-import android.support.v4.os.CancellationSignal;
 
 import org.sufficientlysecure.keychain.Constants.key;
+import org.sufficientlysecure.keychain.daos.KeyRepository;
 import org.sufficientlysecure.keychain.operations.results.OperationResult;
 import org.sufficientlysecure.keychain.pgp.PassphraseCacheInterface;
 import org.sufficientlysecure.keychain.pgp.Progressable;
-import org.sufficientlysecure.keychain.daos.KeyRepository;
 import org.sufficientlysecure.keychain.service.PassphraseCacheService;
 import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
 import org.sufficientlysecure.keychain.util.Passphrase;
@@ -37,7 +38,7 @@ public abstract class BaseOperation<T extends Parcelable> implements PassphraseC
 
     final public Context mContext;
     final public Progressable mProgressable;
-    final public CancellationSignal mCancelled;
+    final public AtomicBoolean mCancelled;
 
     final public KeyRepository mKeyRepository;
 
@@ -71,7 +72,7 @@ public abstract class BaseOperation<T extends Parcelable> implements PassphraseC
     }
 
     public BaseOperation(Context context, KeyRepository keyRepository,
-            Progressable progressable, CancellationSignal cancelled) {
+            Progressable progressable, AtomicBoolean cancelled) {
         mContext = context;
         mProgressable = progressable;
         mKeyRepository = keyRepository;
@@ -87,12 +88,6 @@ public abstract class BaseOperation<T extends Parcelable> implements PassphraseC
         }
     }
 
-    public void updateProgress(String message, int current, int total) {
-        if (mProgressable != null) {
-            mProgressable.setProgress(message, current, total);
-        }
-    }
-
     public void updateProgress(int current, int total) {
         if (mProgressable != null) {
             mProgressable.setProgress(current, total);
@@ -100,7 +95,7 @@ public abstract class BaseOperation<T extends Parcelable> implements PassphraseC
     }
 
     protected boolean checkCancelled() {
-        return mCancelled != null && mCancelled.isCanceled();
+        return mCancelled != null && mCancelled.get();
     }
 
     protected void setPreventCancel () {
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BaseReadWriteOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BaseReadWriteOperation.java
index 43df20fb1..ec90c9158 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BaseReadWriteOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BaseReadWriteOperation.java
@@ -18,12 +18,13 @@
 package org.sufficientlysecure.keychain.operations;
 
 
+import java.util.concurrent.atomic.AtomicBoolean;
+
 import android.content.Context;
 import android.os.Parcelable;
-import android.support.v4.os.CancellationSignal;
 
-import org.sufficientlysecure.keychain.pgp.Progressable;
 import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
+import org.sufficientlysecure.keychain.pgp.Progressable;
 
 public abstract class BaseReadWriteOperation<T extends Parcelable> extends BaseOperation<T> {
     protected final KeyWritableRepository mKeyWritableRepository;
@@ -37,7 +38,7 @@ public abstract class BaseReadWriteOperation<T extends Parcelable> extends BaseO
     }
 
     protected BaseReadWriteOperation(Context context, KeyWritableRepository databaseInteractor,
-            Progressable progressable, CancellationSignal cancelled) {
+            Progressable progressable, AtomicBoolean cancelled) {
         super(context, databaseInteractor, progressable, cancelled);
 
         mKeyWritableRepository = databaseInteractor;
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/CertifyOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/CertifyOperation.java
index b9a657cd8..87eaccd8f 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/CertifyOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/CertifyOperation.java
@@ -19,11 +19,14 @@ package org.sufficientlysecure.keychain.operations;
 
 
 import java.util.ArrayList;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import android.content.Context;
 import android.support.annotation.NonNull;
-import android.support.v4.os.CancellationSignal;
 
+import org.sufficientlysecure.keychain.daos.KeyMetadataDao;
+import org.sufficientlysecure.keychain.daos.KeyRepository.NotFoundException;
+import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.operations.results.CertifyResult;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.LogType;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.OperationLog;
@@ -38,9 +41,6 @@ import org.sufficientlysecure.keychain.pgp.PgpCertifyOperation.PgpCertifyResult;
 import org.sufficientlysecure.keychain.pgp.Progressable;
 import org.sufficientlysecure.keychain.pgp.UncachedKeyRing;
 import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
-import org.sufficientlysecure.keychain.daos.KeyMetadataDao;
-import org.sufficientlysecure.keychain.daos.KeyRepository.NotFoundException;
-import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.service.CertifyActionsParcel;
 import org.sufficientlysecure.keychain.service.CertifyActionsParcel.CertifyAction;
 import org.sufficientlysecure.keychain.service.ContactSyncAdapterService;
@@ -63,8 +63,8 @@ import org.sufficientlysecure.keychain.util.Passphrase;
 public class CertifyOperation extends BaseReadWriteOperation<CertifyActionsParcel> {
     private final KeyMetadataDao keyMetadataDao;
 
-    public CertifyOperation(Context context, KeyWritableRepository keyWritableRepository, Progressable progressable, CancellationSignal
-            cancelled) {
+    public CertifyOperation(Context context, KeyWritableRepository keyWritableRepository, Progressable progressable,
+            AtomicBoolean cancelled) {
         super(context, keyWritableRepository, progressable, cancelled);
 
         this.keyMetadataDao = KeyMetadataDao.create(context);
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/EditKeyOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/EditKeyOperation.java
index f0d10c7b5..053ca87b0 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/EditKeyOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/EditKeyOperation.java
@@ -19,12 +19,15 @@ package org.sufficientlysecure.keychain.operations;
 
 
 import java.io.IOException;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import android.content.Context;
 import android.support.annotation.NonNull;
-import android.support.v4.os.CancellationSignal;
 
 import org.sufficientlysecure.keychain.R;
+import org.sufficientlysecure.keychain.daos.KeyMetadataDao;
+import org.sufficientlysecure.keychain.daos.KeyRepository.NotFoundException;
+import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.operations.results.EditKeyResult;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.LogType;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.OperationLog;
@@ -35,9 +38,6 @@ import org.sufficientlysecure.keychain.pgp.CanonicalizedSecretKeyRing;
 import org.sufficientlysecure.keychain.pgp.PgpKeyOperation;
 import org.sufficientlysecure.keychain.pgp.Progressable;
 import org.sufficientlysecure.keychain.pgp.UncachedKeyRing;
-import org.sufficientlysecure.keychain.daos.KeyMetadataDao;
-import org.sufficientlysecure.keychain.daos.KeyRepository.NotFoundException;
-import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.service.ContactSyncAdapterService;
 import org.sufficientlysecure.keychain.service.SaveKeyringParcel;
 import org.sufficientlysecure.keychain.service.UploadKeyringParcel;
@@ -61,7 +61,7 @@ public class EditKeyOperation extends BaseReadWriteOperation<SaveKeyringParcel>
 
 
     public EditKeyOperation(Context context, KeyWritableRepository databaseInteractor,
-                            Progressable progressable, CancellationSignal cancelled) {
+                            Progressable progressable, AtomicBoolean cancelled) {
         super(context, databaseInteractor, progressable, cancelled);
 
         this.keyMetadataDao = KeyMetadataDao.create(context);
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/ImportOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/ImportOperation.java
index 189d596fd..452990673 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/ImportOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/ImportOperation.java
@@ -29,13 +29,15 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import android.content.Context;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
-import android.support.v4.os.CancellationSignal;
 
 import org.sufficientlysecure.keychain.R;
+import org.sufficientlysecure.keychain.daos.KeyMetadataDao;
+import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.keyimport.FacebookKeyserverClient;
 import org.sufficientlysecure.keychain.keyimport.HkpKeyserverAddress;
 import org.sufficientlysecure.keychain.keyimport.HkpKeyserverClient;
@@ -54,8 +56,6 @@ import org.sufficientlysecure.keychain.pgp.CanonicalizedKeyRing;
 import org.sufficientlysecure.keychain.pgp.Progressable;
 import org.sufficientlysecure.keychain.pgp.UncachedKeyRing;
 import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
-import org.sufficientlysecure.keychain.daos.KeyMetadataDao;
-import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.service.ContactSyncAdapterService;
 import org.sufficientlysecure.keychain.service.ImportKeyringParcel;
 import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
@@ -102,7 +102,7 @@ public class ImportOperation extends BaseReadWriteOperation<ImportKeyringParcel>
     }
 
     public ImportOperation(Context context, KeyWritableRepository databaseInteractor,
-                           Progressable progressable, CancellationSignal cancelled) {
+                           Progressable progressable, AtomicBoolean cancelled) {
         super(context, databaseInteractor, progressable, cancelled);
 
         this.keyMetadataDao = KeyMetadataDao.create(context);
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/KeySyncOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/KeySyncOperation.java
index ba4f5d79e..e97a31bf4 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/KeySyncOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/KeySyncOperation.java
@@ -5,18 +5,18 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Random;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import android.content.Context;
 import android.support.annotation.NonNull;
-import android.support.v4.os.CancellationSignal;
 
 import org.sufficientlysecure.keychain.Constants;
+import org.sufficientlysecure.keychain.daos.KeyMetadataDao;
+import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.keyimport.ParcelableKeyRing;
 import org.sufficientlysecure.keychain.operations.results.ImportKeyResult;
 import org.sufficientlysecure.keychain.operations.results.OperationResult;
 import org.sufficientlysecure.keychain.pgp.Progressable;
-import org.sufficientlysecure.keychain.daos.KeyMetadataDao;
-import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.service.ImportKeyringParcel;
 import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
 import org.sufficientlysecure.keychain.ui.util.KeyFormattingUtils;
@@ -36,7 +36,7 @@ public class KeySyncOperation extends BaseReadWriteOperation<KeySyncParcel> {
     private final Preferences preferences;
 
     public KeySyncOperation(Context context, KeyWritableRepository databaseInteractor,
-            Progressable progressable, CancellationSignal cancellationSignal) {
+            Progressable progressable, AtomicBoolean cancellationSignal) {
         super(context, databaseInteractor, progressable, cancellationSignal);
 
         keyMetadataDao = KeyMetadataDao.create(context);
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/PromoteKeyOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/PromoteKeyOperation.java
index fb4f350b2..b1126cf2f 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/PromoteKeyOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/PromoteKeyOperation.java
@@ -20,12 +20,14 @@ package org.sufficientlysecure.keychain.operations;
 
 import java.util.Arrays;
 import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import android.content.Context;
 import android.support.annotation.NonNull;
-import android.support.v4.os.CancellationSignal;
 
 import org.sufficientlysecure.keychain.R;
+import org.sufficientlysecure.keychain.daos.KeyRepository.NotFoundException;
+import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.LogType;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.OperationLog;
 import org.sufficientlysecure.keychain.operations.results.PgpEditKeyResult;
@@ -35,8 +37,6 @@ import org.sufficientlysecure.keychain.pgp.CanonicalizedPublicKey;
 import org.sufficientlysecure.keychain.pgp.CanonicalizedPublicKeyRing;
 import org.sufficientlysecure.keychain.pgp.Progressable;
 import org.sufficientlysecure.keychain.pgp.UncachedKeyRing;
-import org.sufficientlysecure.keychain.daos.KeyRepository.NotFoundException;
-import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.service.PromoteKeyringParcel;
 import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
 import org.sufficientlysecure.keychain.ui.util.KeyFormattingUtils;
@@ -50,7 +50,7 @@ import org.sufficientlysecure.keychain.ui.util.KeyFormattingUtils;
  */
 public class PromoteKeyOperation extends BaseReadWriteOperation<PromoteKeyringParcel> {
     public PromoteKeyOperation(Context context, KeyWritableRepository databaseInteractor,
-                               Progressable progressable, CancellationSignal cancelled) {
+                               Progressable progressable, AtomicBoolean cancelled) {
         super(context, databaseInteractor, progressable, cancelled);
     }
 
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/SignEncryptOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/SignEncryptOperation.java
index 306003b6e..20bcd19e8 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/SignEncryptOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/SignEncryptOperation.java
@@ -20,12 +20,13 @@ package org.sufficientlysecure.keychain.operations;
 
 import java.util.ArrayDeque;
 import java.util.ArrayList;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import android.content.Context;
 import android.net.Uri;
 import android.support.annotation.NonNull;
-import android.support.v4.os.CancellationSignal;
 
+import org.sufficientlysecure.keychain.daos.KeyRepository;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.LogType;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.OperationLog;
 import org.sufficientlysecure.keychain.operations.results.PgpSignEncryptResult;
@@ -34,7 +35,6 @@ import org.sufficientlysecure.keychain.pgp.PgpSignEncryptInputParcel;
 import org.sufficientlysecure.keychain.pgp.PgpSignEncryptOperation;
 import org.sufficientlysecure.keychain.pgp.Progressable;
 import org.sufficientlysecure.keychain.pgp.SignEncryptParcel;
-import org.sufficientlysecure.keychain.daos.KeyRepository;
 import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
 import org.sufficientlysecure.keychain.service.input.RequiredInputParcel;
 import org.sufficientlysecure.keychain.service.input.RequiredInputParcel.RequiredInputType;
@@ -52,7 +52,7 @@ import org.sufficientlysecure.keychain.util.ProgressScaler;
 public class SignEncryptOperation extends BaseOperation<SignEncryptParcel> {
 
     public SignEncryptOperation(Context context, KeyRepository keyRepository,
-                                Progressable progressable, CancellationSignal cancelled) {
+                                Progressable progressable, AtomicBoolean cancelled) {
         super(context, keyRepository, progressable, cancelled);
     }
 
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/UploadOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/UploadOperation.java
index 221d7af64..f7c70e671 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/UploadOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/UploadOperation.java
@@ -21,11 +21,11 @@ package org.sufficientlysecure.keychain.operations;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.net.Proxy;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import android.content.Context;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
-import android.support.v4.os.CancellationSignal;
 
 import org.bouncycastle.bcpg.ArmoredOutputStream;
 import org.sufficientlysecure.keychain.R;
@@ -60,7 +60,7 @@ public class UploadOperation extends BaseOperation<UploadKeyringParcel> {
     private KeyMetadataDao keyMetadataDao;
 
     public UploadOperation(Context context, KeyRepository keyRepository,
-            Progressable progressable, CancellationSignal cancelled) {
+            Progressable progressable, AtomicBoolean cancelled) {
         super(context, keyRepository, progressable, cancelled);
 
         keyMetadataDao = KeyMetadataDao.create(mContext);
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
index 8fd9867cf..47fdd57fa 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpKeyOperation.java
@@ -33,8 +33,7 @@ import java.util.Date;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Stack;
-
-import android.support.v4.os.CancellationSignal;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.bouncycastle.asn1.ASN1ObjectIdentifier;
 import org.bouncycastle.asn1.nist.NISTNamedCurves;
@@ -109,7 +108,7 @@ import timber.log.Timber;
 public class PgpKeyOperation {
 
     private Stack<Progressable> mProgress;
-    private CancellationSignal mCancelled;
+    private AtomicBoolean mCancelled;
 
     public PgpKeyOperation(Progressable progress) {
         super();
@@ -119,13 +118,13 @@ public class PgpKeyOperation {
         }
     }
 
-    public PgpKeyOperation(Progressable progress, CancellationSignal cancelled) {
+    public PgpKeyOperation(Progressable progress, AtomicBoolean cancelled) {
         this(progress);
         mCancelled = cancelled;
     }
 
     private boolean checkCancelled() {
-        return mCancelled != null && mCancelled.isCanceled();
+        return mCancelled != null && mCancelled.get();
     }
 
     private void subProgressPush(int from, int to) {
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpSignEncryptOperation.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpSignEncryptOperation.java
index 9d071fc4b..038cbf01a 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpSignEncryptOperation.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpSignEncryptOperation.java
@@ -33,11 +33,11 @@ import java.security.SignatureException;
 import java.util.Collection;
 import java.util.Date;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import android.content.Context;
 import android.net.Uri;
 import android.support.annotation.NonNull;
-import android.support.v4.os.CancellationSignal;
 
 import org.bouncycastle.bcpg.ArmoredOutputStream;
 import org.bouncycastle.bcpg.BCPGOutputStream;
@@ -54,6 +54,9 @@ import org.bouncycastle.openpgp.operator.jcajce.NfcSyncPGPContentSignerBuilder;
 import org.bouncycastle.openpgp.operator.jcajce.PGPUtil;
 import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.R;
+import org.sufficientlysecure.keychain.daos.KeyRepository;
+import org.sufficientlysecure.keychain.daos.KeyRepository.NotFoundException;
+import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.operations.BaseOperation;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.LogType;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.OperationLog;
@@ -63,9 +66,6 @@ import org.sufficientlysecure.keychain.pgp.PgpSecurityConstants.OpenKeychainComp
 import org.sufficientlysecure.keychain.pgp.PgpSecurityConstants.OpenKeychainHashAlgorithmTags;
 import org.sufficientlysecure.keychain.pgp.PgpSecurityConstants.OpenKeychainSymmetricKeyAlgorithmTags;
 import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException;
-import org.sufficientlysecure.keychain.daos.KeyRepository;
-import org.sufficientlysecure.keychain.daos.KeyRepository.NotFoundException;
-import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
 import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
 import org.sufficientlysecure.keychain.service.input.RequiredInputParcel;
 import org.sufficientlysecure.keychain.ui.util.KeyFormattingUtils;
@@ -104,7 +104,7 @@ public class PgpSignEncryptOperation extends BaseOperation<PgpSignEncryptInputPa
         }
     }
 
-    public PgpSignEncryptOperation(Context context, KeyRepository keyRepository, Progressable progressable, CancellationSignal cancelled) {
+    public PgpSignEncryptOperation(Context context, KeyRepository keyRepository, Progressable progressable, AtomicBoolean cancelled) {
         super(context, keyRepository, progressable, cancelled);
     }
 
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/Progressable.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/Progressable.java
index 4a5381bca..cdce4875c 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/Progressable.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/Progressable.java
@@ -18,11 +18,9 @@
 package org.sufficientlysecure.keychain.pgp;
 
 public interface Progressable {
-    void setProgress(String message, int current, int total);
-
-    void setProgress(int resourceId, int current, int total);
-
-    void setProgress(int current, int total);
-
+    void setProgress(Integer resourceId, int current, int total);
+    default void setProgress(int current, int total) {
+        setProgress(null, current, total);
+    }
     void setPreventCancel();
 }
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/remote/OpenPgpService.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/remote/OpenPgpService.java
index b173e65bc..39e405a7b 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/remote/OpenPgpService.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/remote/OpenPgpService.java
@@ -1095,17 +1095,7 @@ public class OpenPgpService extends Service {
         return new Progressable() {
             boolean errorState = false;
             @Override
-            public void setProgress(String message, int current, int total) {
-                setProgress(current, total);
-            }
-
-            @Override
-            public void setProgress(int resourceId, int current, int total) {
-                setProgress(current, total);
-            }
-
-            @Override
-            public void setProgress(int current, int total) {
+            public void setProgress(Integer ignored, int current, int total) {
                 if (errorState) {
                     return;
                 }
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/KeychainService.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/KeychainService.java
deleted file mode 100644
index bdaee7166..000000000
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/KeychainService.java
+++ /dev/null
@@ -1,228 +0,0 @@
-/*
- * Copyright (C) 2017 Schürmann & Breitmoser GbR
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-package org.sufficientlysecure.keychain.service;
-
-
-import android.app.Service;
-import android.content.Intent;
-import android.os.Bundle;
-import android.os.IBinder;
-import android.os.Message;
-import android.os.Messenger;
-import android.os.Parcelable;
-import android.os.RemoteException;
-import android.support.v4.os.CancellationSignal;
-
-import org.sufficientlysecure.keychain.operations.KeySyncOperation;
-import org.sufficientlysecure.keychain.operations.KeySyncParcel;
-import org.sufficientlysecure.keychain.operations.BackupOperation;
-import org.sufficientlysecure.keychain.operations.BaseOperation;
-import org.sufficientlysecure.keychain.operations.BenchmarkOperation;
-import org.sufficientlysecure.keychain.operations.CertifyOperation;
-import org.sufficientlysecure.keychain.operations.ChangeUnlockOperation;
-import org.sufficientlysecure.keychain.operations.DeleteOperation;
-import org.sufficientlysecure.keychain.operations.EditKeyOperation;
-import org.sufficientlysecure.keychain.operations.ImportOperation;
-import org.sufficientlysecure.keychain.operations.InputDataOperation;
-import org.sufficientlysecure.keychain.operations.KeybaseVerificationOperation;
-import org.sufficientlysecure.keychain.operations.PromoteKeyOperation;
-import org.sufficientlysecure.keychain.operations.RevokeOperation;
-import org.sufficientlysecure.keychain.operations.SignEncryptOperation;
-import org.sufficientlysecure.keychain.operations.UploadOperation;
-import org.sufficientlysecure.keychain.operations.results.OperationResult;
-import org.sufficientlysecure.keychain.pgp.PgpDecryptVerifyInputParcel;
-import org.sufficientlysecure.keychain.pgp.PgpDecryptVerifyOperation;
-import org.sufficientlysecure.keychain.pgp.Progressable;
-import org.sufficientlysecure.keychain.pgp.SignEncryptParcel;
-import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
-import org.sufficientlysecure.keychain.service.ServiceProgressHandler.MessageStatus;
-import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
-import timber.log.Timber;
-
-
-/**
- * This Service contains all important long lasting operations for OpenKeychain. It receives Intents with
- * data from the activities or other apps, executes them, and stops itself after doing them.
- */
-public class KeychainService extends Service implements Progressable {
-
-    // messenger for communication (hack)
-    public static final String EXTRA_MESSENGER = "messenger";
-
-    // extras for operation
-    public static final String EXTRA_OPERATION_INPUT = "op_input";
-    public static final String EXTRA_CRYPTO_INPUT = "crypto_input";
-
-    public static final String ACTION_CANCEL = "action_cancel";
-
-    // this attribute can possibly merged with the one above? not sure...
-    private CancellationSignal mActionCanceled;
-
-    ThreadLocal<Messenger> mMessenger = new ThreadLocal<>();
-
-    @Override
-    public IBinder onBind(Intent intent) {
-        return null;
-    }
-
-    /**
-     * This is run on the main thread, we need to spawn a runnable which runs on another thread for the actual operation
-     */
-    @Override
-    public int onStartCommand(final Intent intent, int flags, int startId) {
-
-        if (intent.getAction() != null && intent.getAction().equals(ACTION_CANCEL)) {
-            if (mActionCanceled != null) {
-                mActionCanceled.cancel();
-            }
-            return START_NOT_STICKY;
-        }
-
-        mActionCanceled = new CancellationSignal();
-
-        Runnable actionRunnable = new Runnable() {
-            @Override
-            public void run() {
-                Bundle extras = intent.getExtras();
-
-                // Set messenger for communication (for this particular thread)
-                mMessenger.set(extras.getParcelable(EXTRA_MESSENGER));
-
-                // Input
-                Parcelable inputParcel = extras.getParcelable(EXTRA_OPERATION_INPUT);
-                CryptoInputParcel cryptoInput = extras.getParcelable(EXTRA_CRYPTO_INPUT);
-
-                // Operation
-                BaseOperation op;
-
-                // just for brevity
-                KeychainService outerThis = KeychainService.this;
-                KeyWritableRepository databaseInteractor =
-                        KeyWritableRepository.create(outerThis);
-                if (inputParcel instanceof SignEncryptParcel) {
-                    op = new SignEncryptOperation(outerThis, databaseInteractor, outerThis, mActionCanceled);
-                } else if (inputParcel instanceof PgpDecryptVerifyInputParcel) {
-                    op = new PgpDecryptVerifyOperation(outerThis, databaseInteractor, outerThis);
-                } else if (inputParcel instanceof SaveKeyringParcel) {
-                    op = new EditKeyOperation(outerThis, databaseInteractor, outerThis, mActionCanceled);
-                } else if (inputParcel instanceof  ChangeUnlockParcel) {
-                    op = new ChangeUnlockOperation(outerThis, databaseInteractor, outerThis);
-                } else if (inputParcel instanceof RevokeKeyringParcel) {
-                    op = new RevokeOperation(outerThis, databaseInteractor, outerThis);
-                } else if (inputParcel instanceof CertifyActionsParcel) {
-                    op = new CertifyOperation(outerThis, databaseInteractor, outerThis, mActionCanceled);
-                } else if (inputParcel instanceof DeleteKeyringParcel) {
-                    op = new DeleteOperation(outerThis, databaseInteractor, outerThis);
-                } else if (inputParcel instanceof PromoteKeyringParcel) {
-                    op = new PromoteKeyOperation(outerThis, databaseInteractor, outerThis, mActionCanceled);
-                } else if (inputParcel instanceof ImportKeyringParcel) {
-                    op = new ImportOperation(outerThis, databaseInteractor, outerThis, mActionCanceled);
-                } else if (inputParcel instanceof BackupKeyringParcel) {
-                    op = new BackupOperation(outerThis, databaseInteractor, outerThis, mActionCanceled);
-                } else if (inputParcel instanceof UploadKeyringParcel) {
-                    op = new UploadOperation(outerThis, databaseInteractor, outerThis, mActionCanceled);
-                } else if (inputParcel instanceof KeybaseVerificationParcel) {
-                    op = new KeybaseVerificationOperation(outerThis, databaseInteractor, outerThis);
-                } else if (inputParcel instanceof InputDataParcel) {
-                    op = new InputDataOperation(outerThis, databaseInteractor, outerThis);
-                } else if (inputParcel instanceof BenchmarkInputParcel) {
-                    op = new BenchmarkOperation(outerThis, databaseInteractor, outerThis);
-                } else if (inputParcel instanceof KeySyncParcel) {
-                    op = new KeySyncOperation(outerThis, databaseInteractor, outerThis, mActionCanceled);
-                } else {
-                    throw new AssertionError("Unrecognized input parcel in KeychainService!");
-                }
-
-                @SuppressWarnings("unchecked") // this is unchecked, we make sure it's the correct op above!
-                OperationResult result = op.execute(inputParcel, cryptoInput);
-                sendMessageToHandler(MessageStatus.OKAY, result);
-
-            }
-        };
-
-        Thread actionThread = new Thread(actionRunnable);
-        actionThread.start();
-
-        return START_NOT_STICKY;
-    }
-
-    private void sendMessageToHandler(MessageStatus status, Integer arg2, Bundle data) {
-
-        Message msg = Message.obtain();
-        assert msg != null;
-        msg.arg1 = status.ordinal();
-        if (arg2 != null) {
-            msg.arg2 = arg2;
-        }
-        if (data != null) {
-            msg.setData(data);
-        }
-
-        try {
-            mMessenger.get().send(msg);
-        } catch (RemoteException e) {
-            Timber.w(e, "Exception sending message, Is handler present?");
-        } catch (NullPointerException e) {
-            Timber.w(e, "Messenger is null!");
-        }
-    }
-
-    private void sendMessageToHandler(MessageStatus status, OperationResult data) {
-        Bundle bundle = new Bundle();
-        bundle.putParcelable(OperationResult.EXTRA_RESULT, data);
-        sendMessageToHandler(status, null, bundle);
-    }
-
-    private void sendMessageToHandler(MessageStatus status) {
-        sendMessageToHandler(status, null, null);
-    }
-
-    /**
-     * Set progress of ProgressDialog by sending message to handler on UI thread
-     */
-    @Override
-    public void setProgress(String message, int progress, int max) {
-        Timber.d("Send message by setProgress with progress=" + progress + ", max="
-                + max);
-
-        Bundle data = new Bundle();
-        if (message != null) {
-            data.putString(ServiceProgressHandler.DATA_MESSAGE, message);
-        }
-        data.putInt(ServiceProgressHandler.DATA_PROGRESS, progress);
-        data.putInt(ServiceProgressHandler.DATA_PROGRESS_MAX, max);
-
-        sendMessageToHandler(MessageStatus.UPDATE_PROGRESS, null, data);
-    }
-
-    @Override
-    public void setProgress(int resourceId, int progress, int max) {
-        setProgress(getString(resourceId), progress, max);
-    }
-
-    @Override
-    public void setProgress(int progress, int max) {
-        setProgress(null, progress, max);
-    }
-
-    @Override
-    public void setPreventCancel() {
-        sendMessageToHandler(MessageStatus.PREVENT_CANCEL);
-    }
-
-}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/KeychainServiceTask.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/KeychainServiceTask.java
new file mode 100644
index 000000000..305a566a1
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/KeychainServiceTask.java
@@ -0,0 +1,183 @@
+/*
+ * Copyright (C) 2017 Schürmann & Breitmoser GbR
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sufficientlysecure.keychain.service;
+
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import android.annotation.SuppressLint;
+import android.content.Context;
+import android.os.AsyncTask;
+import android.os.Parcelable;
+import android.support.v4.os.CancellationSignal;
+
+import org.sufficientlysecure.keychain.daos.KeyWritableRepository;
+import org.sufficientlysecure.keychain.operations.BackupOperation;
+import org.sufficientlysecure.keychain.operations.BaseOperation;
+import org.sufficientlysecure.keychain.operations.BenchmarkOperation;
+import org.sufficientlysecure.keychain.operations.CertifyOperation;
+import org.sufficientlysecure.keychain.operations.ChangeUnlockOperation;
+import org.sufficientlysecure.keychain.operations.DeleteOperation;
+import org.sufficientlysecure.keychain.operations.EditKeyOperation;
+import org.sufficientlysecure.keychain.operations.ImportOperation;
+import org.sufficientlysecure.keychain.operations.InputDataOperation;
+import org.sufficientlysecure.keychain.operations.KeySyncOperation;
+import org.sufficientlysecure.keychain.operations.KeySyncParcel;
+import org.sufficientlysecure.keychain.operations.KeybaseVerificationOperation;
+import org.sufficientlysecure.keychain.operations.PromoteKeyOperation;
+import org.sufficientlysecure.keychain.operations.RevokeOperation;
+import org.sufficientlysecure.keychain.operations.SignEncryptOperation;
+import org.sufficientlysecure.keychain.operations.UploadOperation;
+import org.sufficientlysecure.keychain.operations.results.OperationResult;
+import org.sufficientlysecure.keychain.pgp.PgpDecryptVerifyInputParcel;
+import org.sufficientlysecure.keychain.pgp.PgpDecryptVerifyOperation;
+import org.sufficientlysecure.keychain.pgp.Progressable;
+import org.sufficientlysecure.keychain.pgp.SignEncryptParcel;
+import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
+
+
+public class KeychainServiceTask {
+    public static KeychainServiceTask create(Context context) {
+        return new KeychainServiceTask(context.getApplicationContext());
+    }
+
+    private KeychainServiceTask(Context context) {
+        this.context = context;
+        this.keyRepository = KeyWritableRepository.create(context);
+    }
+
+    private final Context context;
+    private final KeyWritableRepository keyRepository;
+
+    @SuppressLint("StaticFieldLeak")
+    public CancellationSignal startOperationInBackground(
+            Parcelable inputParcel, CryptoInputParcel cryptoInput, OperationCallback operationCallback) {
+        AtomicBoolean operationCancelledBoolean = new AtomicBoolean(false);
+
+        AsyncTask<Void, ProgressUpdate, OperationResult> asyncTask =
+                new AsyncTask<Void, ProgressUpdate, OperationResult>() {
+                    @Override
+                    protected OperationResult doInBackground(Void... voids) {
+                        BaseOperation op;
+
+                        if (inputParcel instanceof SignEncryptParcel) {
+                            op = new SignEncryptOperation(context, keyRepository, asyncProgressable,
+                                    operationCancelledBoolean);
+                        } else if (inputParcel instanceof PgpDecryptVerifyInputParcel) {
+                            op = new PgpDecryptVerifyOperation(context, keyRepository, asyncProgressable);
+                        } else if (inputParcel instanceof SaveKeyringParcel) {
+                            op = new EditKeyOperation(context, keyRepository, asyncProgressable,
+                                    operationCancelledBoolean);
+                        } else if (inputParcel instanceof ChangeUnlockParcel) {
+                            op = new ChangeUnlockOperation(context, keyRepository, asyncProgressable);
+                        } else if (inputParcel instanceof RevokeKeyringParcel) {
+                            op = new RevokeOperation(context, keyRepository, asyncProgressable);
+                        } else if (inputParcel instanceof CertifyActionsParcel) {
+                            op = new CertifyOperation(context, keyRepository, asyncProgressable,
+                                    operationCancelledBoolean);
+                        } else if (inputParcel instanceof DeleteKeyringParcel) {
+                            op = new DeleteOperation(context, keyRepository, asyncProgressable);
+                        } else if (inputParcel instanceof PromoteKeyringParcel) {
+                            op = new PromoteKeyOperation(context, keyRepository, asyncProgressable,
+                                    operationCancelledBoolean);
+                        } else if (inputParcel instanceof ImportKeyringParcel) {
+                            op = new ImportOperation(context, keyRepository, asyncProgressable,
+                                    operationCancelledBoolean);
+                        } else if (inputParcel instanceof BackupKeyringParcel) {
+                            op = new BackupOperation(context, keyRepository, asyncProgressable,
+                                    operationCancelledBoolean);
+                        } else if (inputParcel instanceof UploadKeyringParcel) {
+                            op = new UploadOperation(context, keyRepository, asyncProgressable,
+                                    operationCancelledBoolean);
+                        } else if (inputParcel instanceof KeybaseVerificationParcel) {
+                            op = new KeybaseVerificationOperation(context, keyRepository, asyncProgressable);
+                        } else if (inputParcel instanceof InputDataParcel) {
+                            op = new InputDataOperation(context, keyRepository, asyncProgressable);
+                        } else if (inputParcel instanceof BenchmarkInputParcel) {
+                            op = new BenchmarkOperation(context, keyRepository, asyncProgressable);
+                        } else if (inputParcel instanceof KeySyncParcel) {
+                            op = new KeySyncOperation(context, keyRepository, asyncProgressable,
+                                    operationCancelledBoolean);
+                        } else {
+                            throw new AssertionError("Unrecognized input parcel in KeychainService!");
+                        }
+
+                        if (isCancelled()) {
+                            return null;
+                        }
+
+                        // noinspection unchecked, we make sure it's the correct op above
+                        return op.execute(inputParcel, cryptoInput);
+                    }
+
+                    Progressable asyncProgressable = new Progressable() {
+                        @Override
+                        public void setPreventCancel() {
+                            publishProgress((ProgressUpdate) null);
+                        }
+
+                        @Override
+                        public void setProgress(Integer resourceId, int current, int total) {
+                            publishProgress(new ProgressUpdate(resourceId, current, total));
+                        }
+                    };
+
+                    @Override
+                    protected void onProgressUpdate(ProgressUpdate... values) {
+                        ProgressUpdate progressUpdate = values[0];
+                        if (progressUpdate == null) {
+                            operationCallback.setPreventCancel();
+                        } else {
+                            operationCallback.setProgress(progressUpdate.resourceId, progressUpdate.current,
+                                    progressUpdate.total);
+                        }
+                    }
+
+                    @Override
+                    protected void onPostExecute(OperationResult result) {
+                        operationCallback.operationFinished(result);
+                    }
+                };
+        asyncTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
+
+        CancellationSignal cancellationSignal = new CancellationSignal();
+        cancellationSignal.setOnCancelListener(() -> {
+            operationCancelledBoolean.set(true);
+        });
+        return cancellationSignal;
+    }
+
+    public interface OperationCallback {
+        void setProgress(Integer message, int current, int total);
+        void setPreventCancel();
+        void operationFinished(OperationResult data);
+    }
+
+    private static class ProgressUpdate {
+        public final Integer resourceId;
+        public final int current;
+        public final int total;
+
+        ProgressUpdate(Integer resourceId, int current, int total) {
+            this.resourceId = resourceId;
+            this.current = current;
+            this.total = total;
+        }
+    }
+
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/ProgressDialogManager.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/ProgressDialogManager.java
new file mode 100644
index 000000000..d5086a4ba
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/ProgressDialogManager.java
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2017 Schürmann & Breitmoser GbR
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.sufficientlysecure.keychain.service;
+
+
+import android.app.ProgressDialog;
+import android.os.Handler;
+import android.support.v4.app.FragmentActivity;
+import android.support.v4.app.FragmentManager;
+import android.support.v4.os.CancellationSignal;
+
+import org.sufficientlysecure.keychain.ui.dialog.ProgressDialogFragment;
+
+
+public class ProgressDialogManager {
+    public static final String TAG_PROGRESS_DIALOG = "progressDialog";
+
+    private FragmentActivity activity;
+
+    public ProgressDialogManager(FragmentActivity activity) {
+        this.activity = activity;
+    }
+
+    public void showProgressDialog() {
+        showProgressDialog("", ProgressDialog.STYLE_SPINNER, null);
+    }
+
+    public void showProgressDialog(
+            String progressDialogMessage, int progressDialogStyle, CancellationSignal cancellationSignal) {
+
+        final ProgressDialogFragment frag = ProgressDialogFragment.newInstance(
+                progressDialogMessage, progressDialogStyle, cancellationSignal != null);
+
+        frag.setCancellationSignal(cancellationSignal);
+
+        // TODO: This is a hack!, see
+        // http://stackoverflow.com/questions/10114324/show-dialogfragment-from-onactivityresult
+        final FragmentManager manager = activity.getSupportFragmentManager();
+        Handler handler = new Handler();
+        handler.post(() -> frag.show(manager, TAG_PROGRESS_DIALOG));
+
+    }
+
+    public void setPreventCancel() {
+        ProgressDialogFragment progressDialogFragment =
+                (ProgressDialogFragment) activity.getSupportFragmentManager()
+                        .findFragmentByTag(TAG_PROGRESS_DIALOG);
+
+        if (progressDialogFragment == null) {
+            return;
+        }
+
+        progressDialogFragment.setPreventCancel();
+    }
+
+    public void dismissAllowingStateLoss() {
+        ProgressDialogFragment progressDialogFragment =
+                (ProgressDialogFragment) activity.getSupportFragmentManager()
+                        .findFragmentByTag(TAG_PROGRESS_DIALOG);
+
+        if (progressDialogFragment == null) {
+            return;
+        }
+
+        progressDialogFragment.dismissAllowingStateLoss();
+    }
+
+    public void onSetProgress(Integer resourceInt, int progress, int max) {
+        ProgressDialogFragment progressDialogFragment =
+                (ProgressDialogFragment) activity.getSupportFragmentManager()
+                        .findFragmentByTag(TAG_PROGRESS_DIALOG);
+
+        if (progressDialogFragment == null) {
+            return;
+        }
+
+        if (resourceInt != null) {
+            progressDialogFragment.setProgress(resourceInt, progress, max);
+        } else {
+            progressDialogFragment.setProgress(progress, max);
+        }
+    }
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/ServiceProgressHandler.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/ServiceProgressHandler.java
deleted file mode 100644
index 544d2e77c..000000000
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/service/ServiceProgressHandler.java
+++ /dev/null
@@ -1,195 +0,0 @@
-/*
- * Copyright (C) 2017 Schürmann & Breitmoser GbR
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-package org.sufficientlysecure.keychain.service;
-
-
-import android.app.ProgressDialog;
-import android.os.Bundle;
-import android.os.Handler;
-import android.os.Message;
-import android.support.v4.app.FragmentActivity;
-import android.support.v4.app.FragmentManager;
-
-import org.sufficientlysecure.keychain.R;
-import org.sufficientlysecure.keychain.ui.dialog.ProgressDialogFragment;
-import org.sufficientlysecure.keychain.ui.util.Notify;
-import timber.log.Timber;
-
-
-public class ServiceProgressHandler extends Handler {
-
-    // possible messages sent from this service to handler on ui
-    public enum MessageStatus {
-        UNKNOWN,
-        OKAY,
-        EXCEPTION,
-        UPDATE_PROGRESS,
-        PREVENT_CANCEL;
-
-        private static final MessageStatus[] values = values();
-
-        public static MessageStatus fromInt(int n) {
-            if (n < 0 || n >= values.length) {
-                return UNKNOWN;
-            } else {
-                return values[n];
-            }
-        }
-    }
-
-    // possible data keys for messages
-    public static final String DATA_ERROR = "error";
-    public static final String DATA_PROGRESS = "progress";
-    public static final String DATA_PROGRESS_MAX = "max";
-    public static final String DATA_MESSAGE = "message";
-    public static final String DATA_MESSAGE_ID = "message_id";
-
-    // keybase proof specific
-    public static final String KEYBASE_PROOF_URL = "keybase_proof_url";
-    public static final String KEYBASE_PRESENCE_URL = "keybase_presence_url";
-    public static final String KEYBASE_PRESENCE_LABEL = "keybase_presence_label";
-
-    public static final String TAG_PROGRESS_DIALOG = "progressDialog";
-
-    FragmentActivity mActivity;
-
-    public ServiceProgressHandler(FragmentActivity activity) {
-        mActivity = activity;
-    }
-
-    public void showProgressDialog() {
-        showProgressDialog("", ProgressDialog.STYLE_SPINNER, false);
-    }
-
-    public void showProgressDialog(
-            String progressDialogMessage, int progressDialogStyle, boolean cancelable) {
-
-        final ProgressDialogFragment frag = ProgressDialogFragment.newInstance(
-                progressDialogMessage,
-                progressDialogStyle,
-                cancelable);
-
-        // TODO: This is a hack!, see
-        // http://stackoverflow.com/questions/10114324/show-dialogfragment-from-onactivityresult
-        final FragmentManager manager = mActivity.getSupportFragmentManager();
-        Handler handler = new Handler();
-        handler.post(new Runnable() {
-            public void run() {
-                frag.show(manager, TAG_PROGRESS_DIALOG);
-            }
-        });
-
-    }
-
-    @Override
-    public void handleMessage(Message message) {
-        Bundle data = message.getData();
-
-        MessageStatus status = MessageStatus.fromInt(message.arg1);
-        switch (status) {
-            case OKAY:
-                dismissAllowingStateLoss();
-
-                break;
-
-            case EXCEPTION:
-                dismissAllowingStateLoss();
-
-                // show error from service
-                if (data.containsKey(DATA_ERROR)) {
-                    Notify.create(mActivity,
-                            mActivity.getString(R.string.error_message, data.getString(DATA_ERROR)),
-                            Notify.Style.ERROR).show();
-                }
-
-                break;
-
-            case UPDATE_PROGRESS:
-                if (data.containsKey(DATA_PROGRESS) && data.containsKey(DATA_PROGRESS_MAX)) {
-
-                    String msg = null;
-                    int progress = data.getInt(DATA_PROGRESS);
-                    int max = data.getInt(DATA_PROGRESS_MAX);
-
-                    // update progress from service
-                    if (data.containsKey(DATA_MESSAGE)) {
-                        msg = data.getString(DATA_MESSAGE);
-                    } else if (data.containsKey(DATA_MESSAGE_ID)) {
-                        msg = mActivity.getString(data.getInt(DATA_MESSAGE_ID));
-                    }
-
-                    onSetProgress(msg, progress, max);
-
-                }
-
-                break;
-
-            case PREVENT_CANCEL:
-                setPreventCancel(true);
-                break;
-
-            default:
-                Timber.e("unknown handler message!");
-                break;
-        }
-    }
-
-    private void setPreventCancel(boolean preventCancel) {
-        ProgressDialogFragment progressDialogFragment =
-                (ProgressDialogFragment) mActivity.getSupportFragmentManager()
-                        .findFragmentByTag("progressDialog");
-
-        if (progressDialogFragment == null) {
-            return;
-        }
-
-        progressDialogFragment.setPreventCancel(preventCancel);
-    }
-
-    protected void dismissAllowingStateLoss() {
-        ProgressDialogFragment progressDialogFragment =
-                (ProgressDialogFragment) mActivity.getSupportFragmentManager()
-                        .findFragmentByTag("progressDialog");
-
-        if (progressDialogFragment == null) {
-            return;
-        }
-
-        progressDialogFragment.dismissAllowingStateLoss();
-    }
-
-
-    protected void onSetProgress(String msg, int progress, int max) {
-
-        ProgressDialogFragment progressDialogFragment =
-                (ProgressDialogFragment) mActivity.getSupportFragmentManager()
-                        .findFragmentByTag("progressDialog");
-
-        if (progressDialogFragment == null) {
-            return;
-        }
-
-        if (msg != null) {
-            progressDialogFragment.setProgress(msg, progress, max);
-        } else {
-            progressDialogFragment.setProgress(progress, max);
-        }
-
-    }
-
-}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/CryptoOperationFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/CryptoOperationFragment.java
index 13b62752e..92aaeda39 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/CryptoOperationFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/CryptoOperationFragment.java
@@ -29,7 +29,6 @@ import android.view.inputmethod.InputMethodManager;
 
 import org.sufficientlysecure.keychain.R;
 import org.sufficientlysecure.keychain.operations.results.OperationResult;
-import org.sufficientlysecure.keychain.service.KeychainService;
 import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
 
 /** This is a base class for fragments which implement a cryptoOperation.
@@ -47,8 +46,6 @@ import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
  * must override at least onCryptoOperationSuccess to proceed after a
  * successful operation.
  *
- * @see KeychainService
- *
  */
 public abstract class CryptoOperationFragment<T extends Parcelable, S extends OperationResult>
         extends Fragment implements CryptoOperationHelper.Callback<T, S> {
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/CryptoOperationHelper.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/CryptoOperationHelper.java
index 06dc54345..16737121a 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/CryptoOperationHelper.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/CryptoOperationHelper.java
@@ -17,32 +17,31 @@
 
 package org.sufficientlysecure.keychain.ui.base;
 
+
 import java.util.Date;
 
 import android.app.Activity;
 import android.app.ProgressDialog;
 import android.content.Intent;
-import android.os.Bundle;
 import android.os.Handler;
-import android.os.Message;
-import android.os.Messenger;
 import android.os.Parcelable;
 import android.os.SystemClock;
+import android.support.annotation.UiThread;
 import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentActivity;
-import android.support.v4.app.FragmentManager;
+import android.support.v4.os.CancellationSignal;
 
 import org.sufficientlysecure.keychain.operations.results.InputPendingResult;
 import org.sufficientlysecure.keychain.operations.results.OperationResult;
-import org.sufficientlysecure.keychain.service.KeychainService;
-import org.sufficientlysecure.keychain.service.ServiceProgressHandler;
+import org.sufficientlysecure.keychain.service.KeychainServiceTask;
+import org.sufficientlysecure.keychain.service.KeychainServiceTask.OperationCallback;
+import org.sufficientlysecure.keychain.service.ProgressDialogManager;
 import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
 import org.sufficientlysecure.keychain.service.input.RequiredInputParcel;
-import org.sufficientlysecure.keychain.ui.SecurityTokenOperationActivity;
 import org.sufficientlysecure.keychain.ui.OrbotRequiredDialogActivity;
 import org.sufficientlysecure.keychain.ui.PassphraseDialogActivity;
 import org.sufficientlysecure.keychain.ui.RetryUploadDialogActivity;
-import org.sufficientlysecure.keychain.ui.dialog.ProgressDialogFragment;
+import org.sufficientlysecure.keychain.ui.SecurityTokenOperationActivity;
 import timber.log.Timber;
 
 
@@ -91,12 +90,12 @@ public class CryptoOperationHelper<T extends Parcelable, S extends OperationResu
     // summands are stored in the mHelperId for easy operation.
     private final int mHelperId;
     // bitmask for helperId is everything except the least 8 bits
-    public static final int HELPER_ID_BITMASK = ~0xff;
+    private static final int HELPER_ID_BITMASK = ~0xff;
 
-    public static final int REQUEST_CODE_PASSPHRASE = 1;
-    public static final int REQUEST_CODE_NFC = 2;
-    public static final int REQUEST_CODE_ENABLE_ORBOT = 3;
-    public static final int REQUEST_CODE_RETRY_UPLOAD = 4;
+    private static final int REQUEST_CODE_PASSPHRASE = 1;
+    private static final int REQUEST_CODE_NFC = 2;
+    private static final int REQUEST_CODE_ENABLE_ORBOT = 3;
+    private static final int REQUEST_CODE_RETRY_UPLOAD = 4;
 
     private Integer mProgressMessageResource;
     private boolean mCancellable = false;
@@ -264,84 +263,60 @@ public class CryptoOperationHelper<T extends Parcelable, S extends OperationResu
         return true;
     }
 
-    protected void dismissProgress() {
-        FragmentManager fragmentManager =
-                mUseFragment ? mFragment.getFragmentManager() :
-                        mActivity.getSupportFragmentManager();
-
-        if (fragmentManager == null) { // the fragment holding us has died
-            // fragmentManager was null when used with DialogFragments. (they close on click?)
-            return;
-        }
-
-        ProgressDialogFragment progressDialogFragment =
-                (ProgressDialogFragment) fragmentManager.findFragmentByTag(
-                        ServiceProgressHandler.TAG_PROGRESS_DIALOG);
-
-        if (progressDialogFragment == null) {
-            return;
-        }
-
-        progressDialogFragment.dismissAllowingStateLoss();
-
-    }
-
     public void cryptoOperation(final CryptoInputParcel cryptoInput) {
-
-        FragmentActivity activity = mUseFragment ? mFragment.getActivity() : mActivity;
-
         T operationInput = mCallback.createOperationInput();
         if (operationInput == null) {
             return;
         }
 
-        // Send all information needed to service to edit key in other thread
-        Intent intent = new Intent(activity, KeychainService.class);
+        FragmentActivity activity = mUseFragment ? mFragment.getActivity() : mActivity;
+        if (activity == null) {
+            throw new NullPointerException();
+        }
 
-        intent.putExtra(KeychainService.EXTRA_OPERATION_INPUT, operationInput);
-        intent.putExtra(KeychainService.EXTRA_CRYPTO_INPUT, cryptoInput);
+        ProgressDialogManager progressDialogManager;
+        if (mProgressMessageResource != null) {
+            progressDialogManager = new ProgressDialogManager(activity);
+        } else {
+            progressDialogManager = null;
+        }
 
-        ServiceProgressHandler saveHandler = new ServiceProgressHandler(activity) {
+        KeychainServiceTask keychainServiceTask = KeychainServiceTask.create(activity);
+        OperationCallback operationCallback = new OperationCallback() {
             @Override
-            public void handleMessage(Message message) {
-                // handle messages by standard KeychainIntentServiceHandler first
-                super.handleMessage(message);
+            public void operationFinished(OperationResult result) {
+                if (progressDialogManager != null) {
+                    progressDialogManager.dismissAllowingStateLoss();
+                }
+                onHandleResult(result);
+            }
 
-                if (message.arg1 == MessageStatus.OKAY.ordinal()) {
-
-                    // get returned data bundle
-                    Bundle returnData = message.getData();
-                    if (returnData == null) {
-                        return;
-                    }
-
-                    final OperationResult result =
-                            returnData.getParcelable(OperationResult.EXTRA_RESULT);
-
-                    onHandleResult(result);
+            @Override
+            public void setProgress(Integer resourceId, int current, int total) {
+                String msgString = resourceId != null ? activity.getString(resourceId) : null;
+                if (mCallback.onCryptoSetProgress(msgString, current, total)) {
+                    return;
+                }
+                if (progressDialogManager != null) {
+                    progressDialogManager.onSetProgress(resourceId, current, total);
                 }
             }
 
             @Override
-            protected void onSetProgress(String msg, int progress, int max) {
-                // allow handling of progress in fragment, or delegate upwards
-                if (!mCallback.onCryptoSetProgress(msg, progress, max)) {
-                    super.onSetProgress(msg, progress, max);
+            public void setPreventCancel() {
+                if (progressDialogManager != null) {
+                    progressDialogManager.setPreventCancel();
                 }
             }
         };
 
-        // Create a new Messenger for the communication back
-        Messenger messenger = new Messenger(saveHandler);
-        intent.putExtra(KeychainService.EXTRA_MESSENGER, messenger);
+        CancellationSignal cancellationSignal =
+                keychainServiceTask.startOperationInBackground(operationInput, cryptoInput, operationCallback);
 
-        if (mProgressMessageResource != null) {
-            saveHandler.showProgressDialog(
-                    activity.getString(mProgressMessageResource),
-                    ProgressDialog.STYLE_HORIZONTAL, mCancellable);
+        if (progressDialogManager != null) {
+            progressDialogManager.showProgressDialog(activity.getString(mProgressMessageResource),
+                    ProgressDialog.STYLE_HORIZONTAL, mCancellable ? cancellationSignal : null);
         }
-
-        activity.startService(intent);
     }
 
     public void cryptoOperation() {
@@ -349,8 +324,9 @@ public class CryptoOperationHelper<T extends Parcelable, S extends OperationResu
         cryptoOperation(CryptoInputParcel.createCryptoInputParcel(new Date()));
     }
 
-    private void onHandleResult(final OperationResult result) {
-        Timber.d("Handling result in OperationHelper success: " + result.success());
+    @UiThread
+    private void onHandleResult(OperationResult result) {
+        Timber.d("Handling result in OperationHelper success: %s", result.success());
 
         if (result instanceof InputPendingResult) {
             InputPendingResult pendingResult = (InputPendingResult) result;
@@ -361,20 +337,14 @@ public class CryptoOperationHelper<T extends Parcelable, S extends OperationResu
             }
         }
 
-        dismissProgress();
-
         long elapsedTime = SystemClock.elapsedRealtime() - operationStartTime;
         if (minimumOperationDelay == null || elapsedTime > minimumOperationDelay) {
             returnResultToCallback(result);
             return;
         }
 
-        new Handler().postDelayed(new Runnable() {
-            @Override
-            public void run() {
-                returnResultToCallback(result);
-            }
-        }, minimumOperationDelay - elapsedTime);
+        long artificialDelay = minimumOperationDelay - elapsedTime;
+        new Handler().postDelayed(() -> returnResultToCallback(result), artificialDelay);
     }
 
     private void returnResultToCallback(OperationResult result) {
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/dialog/ProgressDialogFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/dialog/ProgressDialogFragment.java
index 5d48b7b09..3132dce00 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/dialog/ProgressDialogFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/dialog/ProgressDialogFragment.java
@@ -17,16 +17,17 @@
 
 package org.sufficientlysecure.keychain.ui.dialog;
 
+
 import android.app.Activity;
 import android.app.Dialog;
 import android.app.ProgressDialog;
 import android.content.DialogInterface;
 import android.content.DialogInterface.OnKeyListener;
-import android.content.Intent;
 import android.graphics.Color;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.support.v4.app.DialogFragment;
+import android.support.v4.os.CancellationSignal;
 import android.view.ContextThemeWrapper;
 import android.view.KeyEvent;
 import android.view.View;
@@ -34,7 +35,6 @@ import android.view.View.OnClickListener;
 import android.widget.Button;
 
 import org.sufficientlysecure.keychain.R;
-import org.sufficientlysecure.keychain.service.KeychainService;
 import org.sufficientlysecure.keychain.ui.util.ThemeChanger;
 
 /**
@@ -44,15 +44,18 @@ public class ProgressDialogFragment extends DialogFragment {
     private static final String ARG_MESSAGE = "message";
     private static final String ARG_STYLE = "style";
     private static final String ARG_CANCELABLE = "cancelable";
-    private static final String ARG_SERVICE_TYPE = "service_class";
 
     boolean mCanCancel = false, mPreventCancel = false, mIsCancelled = false;
+    private CancellationSignal cancellationSignal;
 
     /**
      * creates a new instance of this fragment
-     * @param message the message to be displayed initially above the progress bar
-     * @param style the progress bar style, as defined in ProgressDialog (horizontal or spinner)
-     * @param cancelable should we let the user cancel this operation
+     *
+     * @param message
+     *         the message to be displayed initially above the progress bar
+     * @param style
+     *         the progress bar style, as defined in ProgressDialog (horizontal or spinner)
+     *
      * @return
      */
     public static ProgressDialogFragment newInstance(String message, int style, boolean cancelable) {
@@ -141,20 +144,24 @@ public class ProgressDialogFragment extends DialogFragment {
         return dialog;
     }
 
-    public void setPreventCancel(boolean preventCancel) {
+    public void setPreventCancel() {
         // Don't care if we can't cancel anymore either way!
         if (mIsCancelled || ! mCanCancel) {
             return;
         }
 
-        mPreventCancel = preventCancel;
+        mPreventCancel = true;
         ProgressDialog dialog = (ProgressDialog) getDialog();
         if (dialog == null) {
             return;
         }
 
         final Button negative = dialog.getButton(DialogInterface.BUTTON_NEGATIVE);
-        negative.setEnabled(mIsCancelled && !preventCancel);
+        negative.setEnabled(false);
+    }
+
+    public void setCancellationSignal(CancellationSignal cancellationSignal) {
+        this.cancellationSignal = cancellationSignal;
     }
 
     @Override
@@ -167,7 +174,7 @@ public class ProgressDialogFragment extends DialogFragment {
             @Override
             public void onClick(View v) {
                 // nvm if we are already cancelled, or weren't able to begin with
-                if (mIsCancelled || ! mCanCancel) {
+                if (mIsCancelled || !mCanCancel || cancellationSignal == null) {
                     return;
                 }
 
@@ -176,13 +183,7 @@ public class ProgressDialogFragment extends DialogFragment {
                 negative.setClickable(false);
                 negative.setTextColor(Color.GRAY);
 
-                // send a cancel message. note that this message will be handled by
-                // KeychainService.onStartCommand, which runs in this thread,
-                // not the service one, and will not queue up a command.
-                Intent serviceIntent = new Intent(getActivity(), KeychainService.class);
-
-                serviceIntent.setAction(KeychainService.ACTION_CANCEL);
-                getActivity().startService(serviceIntent);
+                cancellationSignal.cancel();
 
                 // Set the progress bar accordingly
                 ProgressDialog dialog = (ProgressDialog) getDialog();
@@ -192,11 +193,8 @@ public class ProgressDialogFragment extends DialogFragment {
 
                 dialog.setIndeterminate(true);
                 dialog.setMessage(getString(R.string.progress_cancelling));
-
-
             }
         });
 
     }
-
 }
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ProgressScaler.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ProgressScaler.java
index cc20cc0de..48908b1dc 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ProgressScaler.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ProgressScaler.java
@@ -39,27 +39,12 @@ public class ProgressScaler implements Progressable {
         this.mMax = max;
     }
 
-    /**
-     * Set progress of ProgressDialog by sending message to handler on UI thread
-     */
-    public void setProgress(String message, int progress, int max) {
-        if (mWrapped != null) {
-            mWrapped.setProgress(message, mFrom + progress * (mTo - mFrom) / max, mMax);
-        }
-    }
-
-    public void setProgress(int resourceId, int progress, int max) {
+    public void setProgress(Integer resourceId, int progress, int max) {
         if (mWrapped != null) {
             mWrapped.setProgress(resourceId, mFrom + progress * (mTo - mFrom) / max, mMax);
         }
     }
 
-    public void setProgress(int progress, int max) {
-        if (mWrapped != null) {
-            mWrapped.setProgress(mFrom + progress * (mTo - mFrom) / max, mMax);
-        }
-    }
-
     @Override
     public void setPreventCancel() {
         if (mWrapped != null) {
diff --git a/OpenKeychain/src/main/res/values/strings.xml b/OpenKeychain/src/main/res/values/strings.xml
index 6ff54cc39..5a7d2ac92 100644
--- a/OpenKeychain/src/main/res/values/strings.xml
+++ b/OpenKeychain/src/main/res/values/strings.xml
@@ -477,10 +477,8 @@
     <string name="progress_modify_pin">"changing PIN…"</string>
     <string name="progress_modify_admin_pin">"changing Admin PIN…"</string>
 
-    <plurals name="progress_exporting_key">
-        <item quantity="one">"exporting key…"</item>
-        <item quantity="other">"exporting keys…"</item>
-    </plurals>
+    <string name="progress_exporting_key">"exporting key…"</string>
+    <string name="progress_exporting_keys">"exporting keys…"</string>
 
     <string name="progress_start">"preparing operation…"</string>
     <string name="progress_extracting_signature_key">"extracting signature key…"</string>