New Passphrase class for safer passphrase handling in memory

17 files changed, 81 insertions, 65 deletions

diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CertifyKeyFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CertifyKeyFragment.java
index 9cb4e5f65..a0f89b06a 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CertifyKeyFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CertifyKeyFragment.java
@@ -62,6 +62,7 @@ import org.sufficientlysecure.keychain.ui.util.Notify;
 import org.sufficientlysecure.keychain.ui.widget.CertifyKeySpinner;
 import org.sufficientlysecure.keychain.ui.widget.KeySpinner;
 import org.sufficientlysecure.keychain.util.Log;
+import org.sufficientlysecure.keychain.util.Passphrase;
 import org.sufficientlysecure.keychain.util.Preferences;
 
 import java.lang.reflect.Method;
@@ -318,7 +319,7 @@ public class CertifyKeyFragment extends LoaderFragment
      */
     private void initiateCertifying() {
         // get the user's passphrase for this key (if required)
-        String passphrase;
+        Passphrase passphrase;
         try {
             passphrase = PassphraseCacheService.getCachedPassphrase(getActivity(), mSignMasterKeyId, mSignMasterKeyId);
         } catch (PassphraseCacheService.KeyNotFoundException e) {
@@ -341,7 +342,6 @@ public class CertifyKeyFragment extends LoaderFragment
         switch (requestCode) {
             case REQUEST_CODE_PASSPHRASE: {
                 if (resultCode == Activity.RESULT_OK && data != null) {
-                    String passphrase = data.getStringExtra(PassphraseDialogActivity.MESSAGE_DATA_PASSPHRASE);
                     startCertifying();
                 }
                 return;
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyActivity.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyActivity.java
index 2da5511b8..0eb9e948a 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyActivity.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyActivity.java
@@ -23,11 +23,20 @@ import android.support.v4.app.FragmentTransaction;
 
 import org.sufficientlysecure.keychain.R;
 
+import java.util.ArrayList;
+
 public class CreateKeyActivity extends BaseActivity {
 
     public static final String EXTRA_NAME = "name";
     public static final String EXTRA_EMAIL = "email";
 
+    public class State {
+        String name;
+        String email;
+        ArrayList<String> additionalEmails;
+        char[] passphrase;
+    }
+
     public static enum FragAction {
         START,
         TO_RIGHT,
@@ -44,7 +53,7 @@ public class CreateKeyActivity extends BaseActivity {
                         getIntent().getStringExtra(EXTRA_NAME),
                         getIntent().getStringExtra(EXTRA_EMAIL)
                 );
-        loadFragment(null, frag, FragAction.START);
+        loadFragment(savedInstanceState, frag, FragAction.START);
     }
 
     @Override
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyEmailFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyEmailFragment.java
index 66424e012..6a4dd7a41 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyEmailFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyEmailFragment.java
@@ -85,7 +85,7 @@ public class CreateKeyEmailFragment extends Fragment {
      */
     private static boolean isEditTextNotEmpty(Context context, EditText editText) {
         boolean output = true;
-        if (editText.getText().toString().length() == 0) {
+        if (editText.getText().length() == 0) {
             editText.setError(context.getString(R.string.create_key_empty));
             editText.requestFocus();
             output = false;
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyFinalFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyFinalFragment.java
index 4871b5ae2..5f6bfdb11 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyFinalFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyFinalFragment.java
@@ -45,6 +45,7 @@ import org.sufficientlysecure.keychain.service.SaveKeyringParcel.Algorithm;
 import org.sufficientlysecure.keychain.service.SaveKeyringParcel.ChangeUnlockParcel;
 import org.sufficientlysecure.keychain.ui.CreateKeyActivity.FragAction;
 import org.sufficientlysecure.keychain.util.Log;
+import org.sufficientlysecure.keychain.util.Passphrase;
 import org.sufficientlysecure.keychain.util.Preferences;
 
 import java.util.ArrayList;
@@ -72,7 +73,7 @@ public class CreateKeyFinalFragment extends Fragment {
     String mName;
     String mEmail;
     ArrayList<String> mAdditionalEmails;
-    String mPassphrase;
+    Passphrase mPassphrase;
 
     SaveKeyringParcel mSaveKeyringParcel;
 
@@ -81,14 +82,14 @@ public class CreateKeyFinalFragment extends Fragment {
      */
     public static CreateKeyFinalFragment newInstance(String name, String email,
                                                      ArrayList<String> additionalEmails,
-                                                     String passphrase) {
+                                                     Passphrase passphrase) {
         CreateKeyFinalFragment frag = new CreateKeyFinalFragment();
 
         Bundle args = new Bundle();
         args.putString(ARG_NAME, name);
         args.putString(ARG_EMAIL, email);
         args.putStringArrayList(ARG_ADDITIONAL_EMAILS, additionalEmails);
-        args.putString(ARG_PASSPHRASE, passphrase);
+        args.putParcelable(ARG_PASSPHRASE, passphrase);
 
         frag.setArguments(args);
 
@@ -111,7 +112,7 @@ public class CreateKeyFinalFragment extends Fragment {
         mName = getArguments().getString(ARG_NAME);
         mEmail = getArguments().getString(ARG_EMAIL);
         mAdditionalEmails = getArguments().getStringArrayList(ARG_ADDITIONAL_EMAILS);
-        mPassphrase = getArguments().getString(ARG_PASSPHRASE);
+        mPassphrase = getArguments().getParcelable(ARG_PASSPHRASE);
 
         // set values
         mNameEdit.setText(mName);
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyNameFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyNameFragment.java
index 50a3bd655..093d427b7 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyNameFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyNameFragment.java
@@ -68,7 +68,7 @@ public class CreateKeyNameFragment extends Fragment {
      */
     private static boolean isEditTextNotEmpty(Context context, EditText editText) {
         boolean output = true;
-        if (editText.getText().toString().length() == 0) {
+        if (editText.getText().length() == 0) {
             editText.setError(context.getString(R.string.create_key_empty));
             editText.requestFocus();
             output = false;
@@ -79,19 +79,6 @@ public class CreateKeyNameFragment extends Fragment {
         return output;
     }
 
-    private static boolean areEditTextsEqual(Context context, EditText editText1, EditText editText2) {
-        boolean output = true;
-        if (!editText1.getText().toString().equals(editText2.getText().toString())) {
-            editText2.setError(context.getString(R.string.create_key_passphrases_not_equal));
-            editText2.requestFocus();
-            output = false;
-        } else {
-            editText2.setError(null);
-        }
-
-        return output;
-    }
-
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         View view = inflater.inflate(R.layout.create_key_name_fragment, container, false);
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyPassphraseFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyPassphraseFragment.java
index 055ea608b..a10c94093 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyPassphraseFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/CreateKeyPassphraseFragment.java
@@ -34,6 +34,7 @@ import android.widget.EditText;
 import org.sufficientlysecure.keychain.R;
 import org.sufficientlysecure.keychain.ui.CreateKeyActivity.FragAction;
 import org.sufficientlysecure.keychain.ui.widget.PassphraseEditText;
+import org.sufficientlysecure.keychain.util.Passphrase;
 
 import java.util.ArrayList;
 
@@ -83,7 +84,7 @@ public class CreateKeyPassphraseFragment extends Fragment {
      */
     private static boolean isEditTextNotEmpty(Context context, EditText editText) {
         boolean output = true;
-        if (editText.getText().toString().length() == 0) {
+        if (editText.getText().length() == 0) {
             editText.setError(context.getString(R.string.create_key_empty));
             editText.requestFocus();
             output = false;
@@ -95,11 +96,13 @@ public class CreateKeyPassphraseFragment extends Fragment {
     }
 
     private static boolean areEditTextsEqual(Context context, EditText editText1, EditText editText2) {
-        boolean output = true;
-        if (!editText1.getText().toString().equals(editText2.getText().toString())) {
+        Passphrase p1 = new Passphrase(editText1);
+        Passphrase p2 = new Passphrase(editText2);
+        boolean output = (p1.equals(p2));
+
+        if (!output) {
             editText2.setError(context.getString(R.string.create_key_passphrases_not_equal));
             editText2.requestFocus();
-            output = false;
         } else {
             editText2.setError(null);
         }
@@ -171,7 +174,7 @@ public class CreateKeyPassphraseFragment extends Fragment {
                             mName,
                             mEmail,
                             mAdditionalEmails,
-                            mPassphraseEdit.getText().toString()
+                            new Passphrase(mPassphraseEdit.getText())
                     );
 
             hideKeyboard();
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptFilesFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptFilesFragment.java
index 7e33843ea..71832daa5 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptFilesFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptFilesFragment.java
@@ -191,7 +191,7 @@ public class DecryptFilesFragment extends DecryptFragment {
         data.putInt(KeychainIntentService.TARGET, IOType.URI.ordinal());
         data.putParcelable(KeychainIntentService.ENCRYPT_DECRYPT_OUTPUT_URI, mOutputUri);
 
-        data.putString(KeychainIntentService.DECRYPT_PASSPHRASE, mPassphrase);
+        data.putParcelable(KeychainIntentService.DECRYPT_PASSPHRASE, mPassphrase);
         data.putByteArray(KeychainIntentService.DECRYPT_NFC_DECRYPTED_SESSION_KEY, mNfcDecryptedSessionKey);
 
         intent.putExtra(KeychainIntentService.EXTRA_DATA, data);
@@ -265,7 +265,7 @@ public class DecryptFilesFragment extends DecryptFragment {
         data.putInt(KeychainIntentService.TARGET, IOType.URI.ordinal());
         data.putParcelable(KeychainIntentService.ENCRYPT_DECRYPT_OUTPUT_URI, mOutputUri);
 
-        data.putString(KeychainIntentService.DECRYPT_PASSPHRASE, mPassphrase);
+        data.putParcelable(KeychainIntentService.DECRYPT_PASSPHRASE, mPassphrase);
         data.putByteArray(KeychainIntentService.DECRYPT_NFC_DECRYPTED_SESSION_KEY, mNfcDecryptedSessionKey);
 
         intent.putExtra(KeychainIntentService.EXTRA_DATA, data);
@@ -341,7 +341,7 @@ public class DecryptFilesFragment extends DecryptFragment {
         switch (requestCode) {
             case REQUEST_CODE_PASSPHRASE: {
                 if (resultCode == Activity.RESULT_OK && data != null) {
-                    mPassphrase = data.getStringExtra(PassphraseDialogActivity.MESSAGE_DATA_PASSPHRASE);
+                    mPassphrase = data.getParcelableExtra(PassphraseDialogActivity.MESSAGE_DATA_PASSPHRASE);
                     decryptOriginalFilename();
                 }
                 return;
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptFragment.java
index 513300cc5..63508e530 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptFragment.java
@@ -32,6 +32,7 @@ import org.sufficientlysecure.keychain.pgp.KeyRing;
 import org.sufficientlysecure.keychain.provider.KeychainContract;
 import org.sufficientlysecure.keychain.ui.util.KeyFormattingUtils;
 import org.sufficientlysecure.keychain.ui.util.KeyFormattingUtils.State;
+import org.sufficientlysecure.keychain.util.Passphrase;
 
 public abstract class DecryptFragment extends Fragment {
     private static final int RESULT_CODE_LOOKUP_KEY = 0x00007006;
@@ -57,7 +58,7 @@ public abstract class DecryptFragment extends Fragment {
 
 
     // State
-    protected String mPassphrase;
+    protected Passphrase mPassphrase;
     protected byte[] mNfcDecryptedSessionKey;
 
     @Override
@@ -100,7 +101,7 @@ public abstract class DecryptFragment extends Fragment {
         startActivityForResult(intent, REQUEST_CODE_PASSPHRASE);
     }
 
-    protected void startNfcDecrypt(long subKeyId, String pin, byte[] encryptedSessionKey) {
+    protected void startNfcDecrypt(long subKeyId, Passphrase pin, byte[] encryptedSessionKey) {
         // build PendingIntent for Yubikey NFC operations
         Intent intent = new Intent(getActivity(), NfcActivity.class);
         intent.setAction(NfcActivity.ACTION_DECRYPT_SESSION_KEY);
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptTextFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptTextFragment.java
index 1b34f6bf0..30cf739fc 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptTextFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptTextFragment.java
@@ -161,7 +161,7 @@ public class DecryptTextFragment extends DecryptFragment {
         // data
         data.putInt(KeychainIntentService.TARGET, IOType.BYTES.ordinal());
         data.putByteArray(KeychainIntentService.DECRYPT_CIPHERTEXT_BYTES, mCiphertext.getBytes());
-        data.putString(KeychainIntentService.DECRYPT_PASSPHRASE, mPassphrase);
+        data.putParcelable(KeychainIntentService.DECRYPT_PASSPHRASE, mPassphrase);
         data.putByteArray(KeychainIntentService.DECRYPT_NFC_DECRYPTED_SESSION_KEY, mNfcDecryptedSessionKey);
 
         intent.putExtra(KeychainIntentService.EXTRA_DATA, data);
@@ -247,7 +247,7 @@ public class DecryptTextFragment extends DecryptFragment {
 
             case REQUEST_CODE_PASSPHRASE: {
                 if (resultCode == Activity.RESULT_OK && data != null) {
-                    mPassphrase = data.getStringExtra(PassphraseDialogActivity.MESSAGE_DATA_PASSPHRASE);
+                    mPassphrase = data.getParcelableExtra(PassphraseDialogActivity.MESSAGE_DATA_PASSPHRASE);
                     decryptStart();
                 } else {
                     getActivity().finish();
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EditKeyFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EditKeyFragment.java
index 8d16fe47e..d2c1ab74c 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EditKeyFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EditKeyFragment.java
@@ -67,6 +67,7 @@ import org.sufficientlysecure.keychain.ui.dialog.EditUserIdDialogFragment;
 import org.sufficientlysecure.keychain.ui.dialog.SetPassphraseDialogFragment;
 import org.sufficientlysecure.keychain.ui.util.Notify;
 import org.sufficientlysecure.keychain.util.Log;
+import org.sufficientlysecure.keychain.util.Passphrase;
 
 public class EditKeyFragment extends LoaderFragment implements
         LoaderManager.LoaderCallbacks<Cursor> {
@@ -100,7 +101,7 @@ public class EditKeyFragment extends LoaderFragment implements
     private SaveKeyringParcel mSaveKeyringParcel;
 
     private String mPrimaryUserId;
-    private String mCurrentPassphrase;
+    private Passphrase mCurrentPassphrase;
 
     /**
      * Creates new instance of this fragment
@@ -267,7 +268,7 @@ public class EditKeyFragment extends LoaderFragment implements
         switch (requestCode) {
             case REQUEST_CODE_PASSPHRASE: {
                 if (resultCode == Activity.RESULT_OK && data != null) {
-                    mCurrentPassphrase = data.getStringExtra(PassphraseDialogActivity.MESSAGE_DATA_PASSPHRASE);
+                    mCurrentPassphrase = data.getParcelableExtra(PassphraseDialogActivity.MESSAGE_DATA_PASSPHRASE);
                     // Prepare the loaders. Either re-connect with an existing ones,
                     // or start new ones.
                     getLoaderManager().initLoader(LOADER_ID_USER_IDS, null, EditKeyFragment.this);
@@ -386,7 +387,7 @@ public class EditKeyFragment extends LoaderFragment implements
 
                     // cache new returned passphrase!
                     mSaveKeyringParcel.mNewUnlock = new ChangeUnlockParcel(
-                            data.getString(SetPassphraseDialogFragment.MESSAGE_NEW_PASSPHRASE),
+                            (Passphrase) data.getParcelable(SetPassphraseDialogFragment.MESSAGE_NEW_PASSPHRASE),
                             null
                     );
                 }
@@ -593,7 +594,7 @@ public class EditKeyFragment extends LoaderFragment implements
         getActivity().finish();
     }
 
-    private void saveInDatabase(String passphrase) {
+    private void saveInDatabase(Passphrase passphrase) {
         Log.d(Constants.TAG, "mSaveKeyringParcel:\n" + mSaveKeyringParcel.toString());
 
         KeychainIntentServiceHandler saveHandler = new KeychainIntentServiceHandler(
@@ -640,7 +641,7 @@ public class EditKeyFragment extends LoaderFragment implements
 
         // fill values for this action
         Bundle data = new Bundle();
-        data.putString(KeychainIntentService.EDIT_KEYRING_PASSPHRASE, passphrase);
+        data.putParcelable(KeychainIntentService.EDIT_KEYRING_PASSPHRASE, passphrase);
         data.putParcelable(KeychainIntentService.EDIT_KEYRING_PARCEL, mSaveKeyringParcel);
         intent.putExtra(KeychainIntentService.EXTRA_DATA, data);
 
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptActivity.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptActivity.java
index 35dfcb87c..5438f667c 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptActivity.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptActivity.java
@@ -32,6 +32,7 @@ import org.sufficientlysecure.keychain.operations.results.SignEncryptResult;
 import org.sufficientlysecure.keychain.pgp.SignEncryptParcel;
 import org.sufficientlysecure.keychain.service.KeychainIntentService;
 import org.sufficientlysecure.keychain.service.KeychainIntentServiceHandler;
+import org.sufficientlysecure.keychain.util.Passphrase;
 
 import java.util.Date;
 
@@ -41,7 +42,7 @@ public abstract class EncryptActivity extends BaseActivity {
     public static final int REQUEST_CODE_NFC = 0x00008002;
 
     // For NFC data
-    protected String mSigningKeyPassphrase = null;
+    protected Passphrase mSigningKeyPassphrase = null;
     protected Date mNfcTimestamp = null;
     protected byte[] mNfcHash = null;
 
@@ -64,7 +65,7 @@ public abstract class EncryptActivity extends BaseActivity {
         startActivityForResult(intent, REQUEST_CODE_PASSPHRASE);
     }
 
-    protected void startNfcSign(long keyId, String pin, byte[] hashToSign, int hashAlgo) {
+    protected void startNfcSign(long keyId, Passphrase pin, byte[] hashToSign, int hashAlgo) {
         // build PendingIntent for Yubikey NFC operations
         Intent intent = new Intent(this, NfcActivity.class);
         intent.setAction(NfcActivity.ACTION_SIGN_HASH);
@@ -84,7 +85,7 @@ public abstract class EncryptActivity extends BaseActivity {
         switch (requestCode) {
             case REQUEST_CODE_PASSPHRASE: {
                 if (resultCode == RESULT_OK && data != null) {
-                    mSigningKeyPassphrase = data.getStringExtra(PassphraseDialogActivity.MESSAGE_DATA_PASSPHRASE);
+                    mSigningKeyPassphrase = data.getParcelableExtra(PassphraseDialogActivity.MESSAGE_DATA_PASSPHRASE);
                     startEncrypt();
                     return;
                 }
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptActivityInterface.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptActivityInterface.java
index c89707c34..2a102c6c4 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptActivityInterface.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptActivityInterface.java
@@ -19,6 +19,8 @@ package org.sufficientlysecure.keychain.ui;
 
 import android.net.Uri;
 
+import org.sufficientlysecure.keychain.util.Passphrase;
+
 import java.util.ArrayList;
 
 public interface EncryptActivityInterface {
@@ -39,7 +41,7 @@ public interface EncryptActivityInterface {
     public void setEncryptionKeys(long[] encryptionKeys);
     public void setEncryptionUsers(String[] encryptionUsers);
 
-    public void setPassphrase(String passphrase);
+    public void setPassphrase(Passphrase passphrase);
 
     // ArrayList on purpose as only those are parcelable
     public ArrayList<Uri> getInputUris();
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptFilesActivity.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptFilesActivity.java
index f1784fab3..0dd672c90 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptFilesActivity.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptFilesActivity.java
@@ -36,6 +36,7 @@ import org.sufficientlysecure.keychain.pgp.SignEncryptParcel;
 import org.sufficientlysecure.keychain.ui.dialog.DeleteFileDialogFragment;
 import org.sufficientlysecure.keychain.ui.util.Notify;
 import org.sufficientlysecure.keychain.util.Log;
+import org.sufficientlysecure.keychain.util.Passphrase;
 import org.sufficientlysecure.keychain.util.ShareHelper;
 
 import java.util.ArrayList;
@@ -72,7 +73,7 @@ public class EncryptFilesActivity extends EncryptActivity implements EncryptActi
     private long mEncryptionKeyIds[] = null;
     private String mEncryptionUserIds[] = null;
     private long mSigningKeyId = Constants.key.none;
-    private String mPassphrase = "";
+    private Passphrase mPassphrase = new Passphrase();
 
     private ArrayList<Uri> mInputUris;
     private ArrayList<Uri> mOutputUris;
@@ -136,7 +137,7 @@ public class EncryptFilesActivity extends EncryptActivity implements EncryptActi
     }
 
     @Override
-    public void setPassphrase(String passphrase) {
+    public void setPassphrase(Passphrase passphrase) {
         mPassphrase = passphrase;
     }
 
@@ -243,8 +244,8 @@ public class EncryptFilesActivity extends EncryptActivity implements EncryptActi
 
         if (isModeSymmetric()) {
             Log.d(Constants.TAG, "Symmetric encryption enabled!");
-            String passphrase = mPassphrase;
-            if (passphrase.length() == 0) {
+            Passphrase passphrase = mPassphrase;
+            if (passphrase.isEmpty()) {
                 passphrase = null;
             }
             data.setSymmetricPassphrase(passphrase);
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptSymmetricFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptSymmetricFragment.java
index 86731b162..36b3c08f9 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptSymmetricFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptSymmetricFragment.java
@@ -28,6 +28,7 @@ import android.view.ViewGroup;
 import android.widget.EditText;
 
 import org.sufficientlysecure.keychain.R;
+import org.sufficientlysecure.keychain.util.Passphrase;
 
 public class EncryptSymmetricFragment extends Fragment implements EncryptActivityInterface.UpdateListener {
 
@@ -67,8 +68,13 @@ public class EncryptSymmetricFragment extends Fragment implements EncryptActivit
             @Override
             public void afterTextChanged(Editable s) {
                 // update passphrase in EncryptActivity
-                if (mPassphrase.getText().toString().equals(mPassphraseAgain.getText().toString())) {
-                    mEncryptInterface.setPassphrase(s.toString());
+                Passphrase p1 = new Passphrase(mPassphrase.getText());
+                Passphrase p2 = new Passphrase(mPassphraseAgain.getText());
+                boolean passesEquals = (p1.equals(p2));
+                p1.removeFromMemory();
+                p2.removeFromMemory();
+                if (passesEquals) {
+                    mEncryptInterface.setPassphrase(new Passphrase(mPassphrase.getText()));
                 } else {
                     mEncryptInterface.setPassphrase(null);
                 }
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptTextActivity.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptTextActivity.java
index 14f2c492d..847f745d7 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptTextActivity.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptTextActivity.java
@@ -36,6 +36,7 @@ import org.sufficientlysecure.keychain.pgp.PgpConstants;
 import org.sufficientlysecure.keychain.pgp.SignEncryptParcel;
 import org.sufficientlysecure.keychain.ui.util.Notify;
 import org.sufficientlysecure.keychain.util.Log;
+import org.sufficientlysecure.keychain.util.Passphrase;
 import org.sufficientlysecure.keychain.util.ShareHelper;
 
 import java.util.ArrayList;
@@ -70,7 +71,7 @@ public class EncryptTextActivity extends EncryptActivity implements EncryptActiv
     private String mEncryptionUserIds[] = null;
     // TODO Constants.key.none? What's wrong with a null value?
     private long mSigningKeyId = Constants.key.none;
-    private String mPassphrase = "";
+    private Passphrase mPassphrase = new Passphrase();
 
     private ArrayList<Uri> mInputUris;
     private ArrayList<Uri> mOutputUris;
@@ -134,7 +135,8 @@ public class EncryptTextActivity extends EncryptActivity implements EncryptActiv
     }
 
     @Override
-    public void setPassphrase(String passphrase) {
+    public void setPassphrase(Passphrase passphrase) {
+        mPassphrase.removeFromMemory();
         mPassphrase = passphrase;
     }
 
@@ -223,8 +225,8 @@ public class EncryptTextActivity extends EncryptActivity implements EncryptActiv
 
         if (isModeSymmetric()) {
             Log.d(Constants.TAG, "Symmetric encryption enabled!");
-            String passphrase = mPassphrase;
-            if (passphrase.length() == 0) {
+            Passphrase passphrase = mPassphrase;
+            if (passphrase.isEmpty()) {
                 passphrase = null;
             }
             data.setSymmetricPassphrase(passphrase);
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/PassphraseDialogActivity.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/PassphraseDialogActivity.java
index 48509710a..360d30c82 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/PassphraseDialogActivity.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/PassphraseDialogActivity.java
@@ -55,6 +55,7 @@ import org.sufficientlysecure.keychain.provider.ProviderHelper;
 import org.sufficientlysecure.keychain.service.PassphraseCacheService;
 import org.sufficientlysecure.keychain.ui.dialog.CustomAlertDialogBuilder;
 import org.sufficientlysecure.keychain.util.Log;
+import org.sufficientlysecure.keychain.util.Passphrase;
 import org.sufficientlysecure.keychain.util.Preferences;
 
 /**
@@ -318,7 +319,7 @@ public class PassphraseDialogActivity extends FragmentActivity {
             positive.setOnClickListener(new View.OnClickListener() {
                 @Override
                 public void onClick(View v) {
-                    final String passphrase = mPassphraseEditText.getText().toString();
+                    final Passphrase passphrase = new Passphrase(mPassphraseEditText);
 
                     // Early breakout if we are dealing with a symmetric key
                     if (mSecretRing == null) {
@@ -395,7 +396,7 @@ public class PassphraseDialogActivity extends FragmentActivity {
             });
         }
 
-        private void finishCaching(String passphrase) {
+        private void finishCaching(Passphrase passphrase) {
             // any indication this isn't needed anymore, don't do it.
             if (mIsCancelled || getActivity() == null) {
                 return;
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/dialog/SetPassphraseDialogFragment.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/dialog/SetPassphraseDialogFragment.java
index b34dc2edc..947c316e0 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/dialog/SetPassphraseDialogFragment.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/dialog/SetPassphraseDialogFragment.java
@@ -45,6 +45,7 @@ import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.R;
 import org.sufficientlysecure.keychain.ui.widget.PassphraseEditText;
 import org.sufficientlysecure.keychain.util.Log;
+import org.sufficientlysecure.keychain.util.Passphrase;
 
 public class SetPassphraseDialogFragment extends DialogFragment implements OnEditorActionListener {
     private static final String ARG_MESSENGER = "messenger";
@@ -67,12 +68,12 @@ public class SetPassphraseDialogFragment extends DialogFragment implements OnEdi
      * @param messenger to communicate back after setting the passphrase
      * @return
      */
-    public static SetPassphraseDialogFragment newInstance(Messenger messenger, String oldPassphrase, int title) {
+    public static SetPassphraseDialogFragment newInstance(Messenger messenger, Passphrase oldPassphrase, int title) {
         SetPassphraseDialogFragment frag = new SetPassphraseDialogFragment();
         Bundle args = new Bundle();
         args.putInt(ARG_TITLE, title);
         args.putParcelable(ARG_MESSENGER, messenger);
-        args.putString(ARG_OLD_PASSPHRASE, oldPassphrase);
+        args.putParcelable(ARG_OLD_PASSPHRASE, oldPassphrase);
 
         frag.setArguments(args);
 
@@ -88,7 +89,7 @@ public class SetPassphraseDialogFragment extends DialogFragment implements OnEdi
 
         int title = getArguments().getInt(ARG_TITLE);
         mMessenger = getArguments().getParcelable(ARG_MESSENGER);
-        String oldPassphrase = getArguments().getString(ARG_OLD_PASSPHRASE);
+        Passphrase oldPassphrase = getArguments().getParcelable(ARG_OLD_PASSPHRASE);
 
         CustomAlertDialogBuilder alert = new CustomAlertDialogBuilder(activity);
 
@@ -103,7 +104,7 @@ public class SetPassphraseDialogFragment extends DialogFragment implements OnEdi
         mNoPassphraseCheckBox = (CheckBox) view.findViewById(R.id.passphrase_no_passphrase);
 
 
-        if (TextUtils.isEmpty(oldPassphrase)) {
+        if (oldPassphrase.isEmpty()) {
             mNoPassphraseCheckBox.setChecked(true);
             mPassphraseEditText.setEnabled(false);
             mPassphraseAgainEditText.setEnabled(false);
@@ -123,12 +124,12 @@ public class SetPassphraseDialogFragment extends DialogFragment implements OnEdi
             public void onClick(DialogInterface dialog, int id) {
                 dismiss();
 
-                String passphrase1;
+                Passphrase passphrase1 = new Passphrase();
                 if (mNoPassphraseCheckBox.isChecked()) {
-                    passphrase1 = "";
+                    passphrase1.setEmpty();
                 } else {
-                    passphrase1 = mPassphraseEditText.getText().toString();
-                    String passphrase2 = mPassphraseAgainEditText.getText().toString();
+                    passphrase1 = new Passphrase(mPassphraseEditText);
+                    Passphrase passphrase2 = new Passphrase(mPassphraseAgainEditText);
                     if (!passphrase1.equals(passphrase2)) {
                         Toast.makeText(
                                 activity,
@@ -139,7 +140,7 @@ public class SetPassphraseDialogFragment extends DialogFragment implements OnEdi
                         return;
                     }
 
-                    if (passphrase1.equals("")) {
+                    if (passphrase1.isEmpty()) {
                         Toast.makeText(
                                 activity,
                                 getString(R.string.error_message,
@@ -152,7 +153,7 @@ public class SetPassphraseDialogFragment extends DialogFragment implements OnEdi
 
                 // return resulting data back to activity
                 Bundle data = new Bundle();
-                data.putString(MESSAGE_NEW_PASSPHRASE, passphrase1);
+                data.putParcelable(MESSAGE_NEW_PASSPHRASE, passphrase1);
 
                 sendMessageToHandler(MESSAGE_OKAY, data);
             }