Rename folder structure from OpenPGP Keychain to OpenKeychain

16 files changed, 1638 insertions, 0 deletions

diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/AlgorithmNames.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/AlgorithmNames.java
new file mode 100644
index 000000000..d2f4cc003
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/AlgorithmNames.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2013 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * 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.util;
+
+import android.annotation.SuppressLint;
+import android.app.Activity;
+import org.spongycastle.bcpg.HashAlgorithmTags;
+import org.spongycastle.openpgp.PGPEncryptedData;
+import org.sufficientlysecure.keychain.Id;
+import org.sufficientlysecure.keychain.R;
+
+import java.util.HashMap;
+
+@SuppressLint("UseSparseArrays")
+public class AlgorithmNames {
+    Activity mActivity;
+
+    HashMap<Integer, String> mEncryptionNames = new HashMap<Integer, String>();
+    HashMap<Integer, String> mHashNames = new HashMap<Integer, String>();
+    HashMap<Integer, String> mCompressionNames = new HashMap<Integer, String>();
+
+    public AlgorithmNames(Activity context) {
+        super();
+        this.mActivity = context;
+
+        mEncryptionNames.put(PGPEncryptedData.AES_128, "AES-128");
+        mEncryptionNames.put(PGPEncryptedData.AES_192, "AES-192");
+        mEncryptionNames.put(PGPEncryptedData.AES_256, "AES-256");
+        mEncryptionNames.put(PGPEncryptedData.BLOWFISH, "Blowfish");
+        mEncryptionNames.put(PGPEncryptedData.TWOFISH, "Twofish");
+        mEncryptionNames.put(PGPEncryptedData.CAST5, "CAST5");
+        mEncryptionNames.put(PGPEncryptedData.DES, "DES");
+        mEncryptionNames.put(PGPEncryptedData.TRIPLE_DES, "Triple DES");
+        mEncryptionNames.put(PGPEncryptedData.IDEA, "IDEA");
+
+        mHashNames.put(HashAlgorithmTags.MD5, "MD5");
+        mHashNames.put(HashAlgorithmTags.RIPEMD160, "RIPEMD-160");
+        mHashNames.put(HashAlgorithmTags.SHA1, "SHA-1");
+        mHashNames.put(HashAlgorithmTags.SHA224, "SHA-224");
+        mHashNames.put(HashAlgorithmTags.SHA256, "SHA-256");
+        mHashNames.put(HashAlgorithmTags.SHA384, "SHA-384");
+        mHashNames.put(HashAlgorithmTags.SHA512, "SHA-512");
+
+        mCompressionNames.put(Id.choice.compression.none, mActivity.getString(R.string.choice_none)
+                + " (" + mActivity.getString(R.string.compression_fast) + ")");
+        mCompressionNames.put(Id.choice.compression.zip,
+                "ZIP (" + mActivity.getString(R.string.compression_fast) + ")");
+        mCompressionNames.put(Id.choice.compression.zlib,
+                "ZLIB (" + mActivity.getString(R.string.compression_fast) + ")");
+        mCompressionNames.put(Id.choice.compression.bzip2,
+                "BZIP2 (" + mActivity.getString(R.string.compression_very_slow) + ")");
+    }
+
+    public HashMap<Integer, String> getEncryptionNames() {
+        return mEncryptionNames;
+    }
+
+    public void setEncryptionNames(HashMap<Integer, String> encryptionNames) {
+        this.mEncryptionNames = encryptionNames;
+    }
+
+    public HashMap<Integer, String> getHashNames() {
+        return mHashNames;
+    }
+
+    public void setHashNames(HashMap<Integer, String> hashNames) {
+        this.mHashNames = hashNames;
+    }
+
+    public HashMap<Integer, String> getCompressionNames() {
+        return mCompressionNames;
+    }
+
+    public void setCompressionNames(HashMap<Integer, String> compressionNames) {
+        this.mCompressionNames = compressionNames;
+    }
+
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/Choice.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/Choice.java
new file mode 100644
index 000000000..1a6184d9c
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/Choice.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2010 Thialfihar <thi@thialfihar.org>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.sufficientlysecure.keychain.util;
+
+public class Choice {
+    private String mName;
+    private int mId;
+
+    public Choice() {
+        mId = -1;
+        mName = "";
+    }
+
+    public Choice(int id, String name) {
+        mId = id;
+        mName = name;
+    }
+
+    public int getId() {
+        return mId;
+    }
+
+    public String getName() {
+        return mName;
+    }
+
+    @Override
+    public String toString() {
+        return mName;
+    }
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/HkpKeyServer.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/HkpKeyServer.java
new file mode 100644
index 000000000..5efc732e4
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/HkpKeyServer.java
@@ -0,0 +1,353 @@
+/*
+ * Copyright (C) 2012-2014 Dominik Schürmann <dominik@dominikschuermann.de>
+ * Copyright (C) 2011 Thialfihar <thi@thialfihar.org>
+ * Copyright (C) 2011 Senecaso
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.sufficientlysecure.keychain.util;
+
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpResponse;
+import org.apache.http.HttpStatus;
+import org.apache.http.NameValuePair;
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.entity.UrlEncodedFormEntity;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.client.methods.HttpPost;
+import org.apache.http.impl.client.DefaultHttpClient;
+import org.apache.http.message.BasicNameValuePair;
+import org.apache.http.util.EntityUtils;
+
+import org.sufficientlysecure.keychain.Constants;
+import org.sufficientlysecure.keychain.pgp.PgpHelper;
+import org.sufficientlysecure.keychain.ui.adapter.ImportKeysListEntry;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.UnsupportedEncodingException;
+import java.net.HttpURLConnection;
+import java.net.InetAddress;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLDecoder;
+import java.net.URLEncoder;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.GregorianCalendar;
+import java.util.List;
+import java.util.Locale;
+import java.util.TimeZone;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class HkpKeyServer extends KeyServer {
+    private static class HttpError extends Exception {
+        private static final long serialVersionUID = 1718783705229428893L;
+        private int mCode;
+        private String mData;
+
+        public HttpError(int code, String data) {
+            super("" + code + ": " + data);
+            mCode = code;
+            mData = data;
+        }
+
+        public int getCode() {
+            return mCode;
+        }
+
+        public String getData() {
+            return mData;
+        }
+    }
+
+    private String mHost;
+    private short mPort;
+
+    /**
+     * pub:%keyid%:%algo%:%keylen%:%creationdate%:%expirationdate%:%flags%
+     * <ul>
+     * <li>%<b>keyid</b>% = this is either the fingerprint or the key ID of the key.
+     * Either the 16-digit or 8-digit key IDs are acceptable, but obviously the fingerprint is best.
+     * </li>
+     * <li>%<b>algo</b>% = the algorithm number, (i.e. 1==RSA, 17==DSA, etc).
+     * See <a href="http://tools.ietf.org/html/rfc2440#section-9.1">RFC-2440</a></li>
+     * <li>%<b>keylen</b>% = the key length (i.e. 1024, 2048, 4096, etc.)</li>
+     * <li>%<b>creationdate</b>% = creation date of the key in standard
+     * <a href="http://tools.ietf.org/html/rfc2440#section-9.1">RFC-2440</a> form (i.e. number of
+     * seconds since 1/1/1970 UTC time)</li>
+     * <li>%<b>expirationdate</b>% = expiration date of the key in standard
+     * <a href="http://tools.ietf.org/html/rfc2440#section-9.1">RFC-2440</a> form (i.e. number of
+     * seconds since 1/1/1970 UTC time)</li>
+     * <li>%<b>flags</b>% = letter codes to indicate details of the key, if any. Flags may be in any
+     * order. The meaning of "disabled" is implementation-specific. Note that individual flags may
+     * be unimplemented, so the absence of a given flag does not necessarily mean the absence of the
+     * detail.
+     * <ul>
+     * <li>r == revoked</li>
+     * <li>d == disabled</li>
+     * <li>e == expired</li>
+     * </ul>
+     * </li>
+     * </ul>
+     *
+     * @see <a href="http://tools.ietf.org/html/draft-shaw-openpgp-hkp-00#section-5.2">
+     * 5.2. Machine Readable Indexes</a>
+     * in Internet-Draft OpenPGP HTTP Keyserver Protocol Document
+     */
+    public static final Pattern PUB_KEY_LINE = Pattern
+            .compile("pub:([0-9a-fA-F]+):([0-9]+):([0-9]+):([0-9]+):([0-9]*):([rde]*)[ \n\r]*" // pub line
+                    + "(uid:(.*):([0-9]+):([0-9]*):([rde]*))+", // one or more uid lines
+                    Pattern.CASE_INSENSITIVE);
+
+    /**
+     * uid:%escaped uid string%:%creationdate%:%expirationdate%:%flags%
+     * <ul>
+     * <li>%<b>escaped uid string</b>% = the user ID string, with HTTP %-escaping for anything that
+     * isn't 7-bit safe as well as for the ":" character.  Any other characters may be escaped, as
+     * desired.</li>
+     * <li>%<b>creationdate</b>% = creation date of the key in standard
+     * <a href="http://tools.ietf.org/html/rfc2440#section-9.1">RFC-2440</a> form (i.e. number of
+     * seconds since 1/1/1970 UTC time)</li>
+     * <li>%<b>expirationdate</b>% = expiration date of the key in standard
+     * <a href="http://tools.ietf.org/html/rfc2440#section-9.1">RFC-2440</a> form (i.e. number of
+     * seconds since 1/1/1970 UTC time)</li>
+     * <li>%<b>flags</b>% = letter codes to indicate details of the key, if any. Flags may be in any
+     * order. The meaning of "disabled" is implementation-specific. Note that individual flags may
+     * be unimplemented, so the absence of a given flag does not necessarily mean the absence of
+     * the detail.
+     * <ul>
+     * <li>r == revoked</li>
+     * <li>d == disabled</li>
+     * <li>e == expired</li>
+     * </ul>
+     * </li>
+     * </ul>
+     */
+    public static final Pattern UID_LINE = Pattern
+            .compile("uid:(.*):([0-9]+):([0-9]*):([rde]*)",
+                    Pattern.CASE_INSENSITIVE);
+
+    private static final short PORT_DEFAULT = 11371;
+
+    /**
+     * @param hostAndPort may be just
+     *                    "<code>hostname</code>" (eg. "<code>pool.sks-keyservers.net</code>"), then it will
+     *                    connect using {@link #PORT_DEFAULT}. However, port may be specified after colon
+     *                    ("<code>hostname:port</code>", eg. "<code>p80.pool.sks-keyservers.net:80</code>").
+     */
+    public HkpKeyServer(String hostAndPort) {
+        String host = hostAndPort;
+        short port = PORT_DEFAULT;
+        final int colonPosition = hostAndPort.lastIndexOf(':');
+        if (colonPosition > 0) {
+            host = hostAndPort.substring(0, colonPosition);
+            final String portStr = hostAndPort.substring(colonPosition + 1);
+            port = Short.decode(portStr);
+        }
+        mHost = host;
+        mPort = port;
+    }
+
+    public HkpKeyServer(String host, short port) {
+        mHost = host;
+        mPort = port;
+    }
+
+    private static String readAll(InputStream in, String encoding) throws IOException {
+        ByteArrayOutputStream raw = new ByteArrayOutputStream();
+
+        byte buffer[] = new byte[1 << 16];
+        int n = 0;
+        while ((n = in.read(buffer)) != -1) {
+            raw.write(buffer, 0, n);
+        }
+
+        if (encoding == null) {
+            encoding = "utf8";
+        }
+        return raw.toString(encoding);
+    }
+
+    private String query(String request) throws QueryException, HttpError {
+        InetAddress ips[];
+        try {
+            ips = InetAddress.getAllByName(mHost);
+        } catch (UnknownHostException e) {
+            throw new QueryException(e.toString());
+        }
+        for (int i = 0; i < ips.length; ++i) {
+            try {
+                String url = "http://" + ips[i].getHostAddress() + ":" + mPort + request;
+                Log.d(Constants.TAG, "hkp keyserver query: " + url);
+                URL realUrl = new URL(url);
+                HttpURLConnection conn = (HttpURLConnection) realUrl.openConnection();
+                conn.setConnectTimeout(5000);
+                conn.setReadTimeout(25000);
+                conn.connect();
+                int response = conn.getResponseCode();
+                if (response >= 200 && response < 300) {
+                    return readAll(conn.getInputStream(), conn.getContentEncoding());
+                } else {
+                    String data = readAll(conn.getErrorStream(), conn.getContentEncoding());
+                    throw new HttpError(response, data);
+                }
+            } catch (MalformedURLException e) {
+                // nothing to do, try next IP
+            } catch (IOException e) {
+                // nothing to do, try next IP
+            }
+        }
+
+        throw new QueryException("querying server(s) for '" + mHost + "' failed");
+    }
+
+    @Override
+    public ArrayList<ImportKeysListEntry> search(String query) throws QueryException, TooManyResponses,
+            InsufficientQuery {
+        ArrayList<ImportKeysListEntry> results = new ArrayList<ImportKeysListEntry>();
+
+        if (query.length() < 3) {
+            throw new InsufficientQuery();
+        }
+
+        String encodedQuery;
+        try {
+            encodedQuery = URLEncoder.encode(query, "utf8");
+        } catch (UnsupportedEncodingException e) {
+            return null;
+        }
+        String request = "/pks/lookup?op=index&options=mr&search=" + encodedQuery;
+
+        String data;
+        try {
+            data = query(request);
+        } catch (HttpError e) {
+            if (e.getCode() == 404) {
+                return results;
+            } else {
+                if (e.getData().toLowerCase(Locale.US).contains("no keys found")) {
+                    return results;
+                } else if (e.getData().toLowerCase(Locale.US).contains("too many")) {
+                    throw new TooManyResponses();
+                } else if (e.getData().toLowerCase(Locale.US).contains("insufficient")) {
+                    throw new InsufficientQuery();
+                }
+            }
+            throw new QueryException("querying server(s) for '" + mHost + "' failed");
+        }
+
+        final Matcher matcher = PUB_KEY_LINE.matcher(data);
+        while (matcher.find()) {
+            final ImportKeysListEntry entry = new ImportKeysListEntry();
+
+            entry.setBitStrength(Integer.parseInt(matcher.group(3)));
+
+            final int algorithmId = Integer.decode(matcher.group(2));
+            entry.setAlgorithm(ImportKeysListEntry.getAlgorithmFromId(algorithmId));
+
+            // group 1 contains the full fingerprint (v4) or the long key id if available
+            // see http://bit.ly/1d4bxbk and http://bit.ly/1gD1wwr
+            String fingerprintOrKeyId = matcher.group(1);
+            if (fingerprintOrKeyId.length() > 16) {
+                entry.setFingerPrintHex(fingerprintOrKeyId.toLowerCase(Locale.US));
+                entry.setKeyIdHex("0x" + fingerprintOrKeyId.substring(fingerprintOrKeyId.length()
+                        - 16, fingerprintOrKeyId.length()));
+            } else {
+                // set key id only
+                entry.setKeyIdHex("0x" + fingerprintOrKeyId);
+            }
+
+            final long creationDate = Long.parseLong(matcher.group(4));
+            final GregorianCalendar tmpGreg = new GregorianCalendar(TimeZone.getTimeZone("UTC"));
+            tmpGreg.setTimeInMillis(creationDate * 1000);
+            entry.setDate(tmpGreg.getTime());
+
+            entry.setRevoked(matcher.group(6).contains("r"));
+
+            ArrayList<String> userIds = new ArrayList<String>();
+            final String uidLines = matcher.group(7);
+            final Matcher uidMatcher = UID_LINE.matcher(uidLines);
+            while (uidMatcher.find()) {
+                String tmp = uidMatcher.group(1).trim();
+                if (tmp.contains("%")) {
+                    try {
+                        // converts Strings like "Universit%C3%A4t" to a proper encoding form "Universität".
+                        tmp = (URLDecoder.decode(tmp, "UTF8"));
+                    } catch (UnsupportedEncodingException ignored) {
+                        // will never happen, because "UTF8" is supported
+                    }
+                }
+                userIds.add(tmp);
+            }
+            entry.setUserIds(userIds);
+
+            results.add(entry);
+        }
+        return results;
+    }
+
+    @Override
+    public String get(String keyIdHex) throws QueryException {
+        HttpClient client = new DefaultHttpClient();
+        try {
+            String query = "http://" + mHost + ":" + mPort +
+                    "/pks/lookup?op=get&options=mr&search=" + keyIdHex;
+            Log.d(Constants.TAG, "hkp keyserver get: " + query);
+            HttpGet get = new HttpGet(query);
+            HttpResponse response = client.execute(get);
+            if (response.getStatusLine().getStatusCode() != HttpStatus.SC_OK) {
+                throw new QueryException("not found");
+            }
+
+            HttpEntity entity = response.getEntity();
+            InputStream is = entity.getContent();
+            String data = readAll(is, EntityUtils.getContentCharSet(entity));
+            Matcher matcher = PgpHelper.PGP_PUBLIC_KEY.matcher(data);
+            if (matcher.find()) {
+                return matcher.group(1);
+            }
+        } catch (IOException e) {
+            // nothing to do, better luck on the next keyserver
+        } finally {
+            client.getConnectionManager().shutdown();
+        }
+
+        return null;
+    }
+
+    @Override
+    public void add(String armoredKey) throws AddKeyException {
+        HttpClient client = new DefaultHttpClient();
+        try {
+            String query = "http://" + mHost + ":" + mPort + "/pks/add";
+            HttpPost post = new HttpPost(query);
+            Log.d(Constants.TAG, "hkp keyserver add: " + query);
+            List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
+            nameValuePairs.add(new BasicNameValuePair("keytext", armoredKey));
+            post.setEntity(new UrlEncodedFormEntity(nameValuePairs));
+
+            HttpResponse response = client.execute(post);
+            if (response.getStatusLine().getStatusCode() != HttpStatus.SC_OK) {
+                throw new AddKeyException();
+            }
+        } catch (IOException e) {
+            // nothing to do, better luck on the next keyserver
+        } finally {
+            client.getConnectionManager().shutdown();
+        }
+    }
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/InputData.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/InputData.java
new file mode 100644
index 000000000..28cfa11f2
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/InputData.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2010-2014 Thialfihar <thi@thialfihar.org>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.sufficientlysecure.keychain.util;
+
+import java.io.InputStream;
+
+public class InputData {
+    private PositionAwareInputStream mInputStream;
+    private long mSize;
+
+    public InputData(InputStream inputStream, long size) {
+        mInputStream = new PositionAwareInputStream(inputStream);
+        mSize = size;
+    }
+
+    public InputStream getInputStream() {
+        return mInputStream;
+    }
+
+    public long getSize() {
+        return mSize;
+    }
+
+    public long getStreamPosition() {
+        return mInputStream.position();
+    }
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/IntentIntegratorSupportV4.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/IntentIntegratorSupportV4.java
new file mode 100644
index 000000000..ae87deb31
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/IntentIntegratorSupportV4.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012 ZXing authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.sufficientlysecure.keychain.util;
+
+import com.google.zxing.integration.android.IntentIntegrator;
+
+import android.content.Intent;
+import android.support.v4.app.Fragment;
+
+/**
+ * IntentIntegrator for the V4 Android compatibility package.
+ *
+ * @author Lachezar Dobrev
+ */
+public final class IntentIntegratorSupportV4 extends IntentIntegrator {
+
+    private final Fragment mFragment;
+
+    /**
+     * @param fragment Fragment to handle activity response.
+     */
+    public IntentIntegratorSupportV4(Fragment fragment) {
+        super(fragment.getActivity());
+        this.mFragment = fragment;
+    }
+
+    @Override
+    protected void startActivityForResult(Intent intent, int code) {
+        mFragment.startActivityForResult(intent, code);
+    }
+
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/IterableIterator.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/IterableIterator.java
new file mode 100644
index 000000000..3af674526
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/IterableIterator.java
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2010 Thialfihar <thi@thialfihar.org>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.sufficientlysecure.keychain.util;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+
+public class IterableIterator<T> implements Iterable<T> {
+    private Iterator<T> mIter;
+
+    public IterableIterator(Iterator<T> iter, boolean failsafe) {
+        mIter = iter;
+        if (failsafe && mIter == null) {
+            // is there a better way?
+            mIter = new ArrayList<T>().iterator();
+        }
+    }
+    public IterableIterator(Iterator<T> iter) {
+        this(iter, false);
+    }
+
+    public Iterator<T> iterator() {
+        return mIter;
+    }
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/KeyServer.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/KeyServer.java
new file mode 100644
index 000000000..7f70867a5
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/KeyServer.java
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2012-2014 Dominik Schürmann <dominik@dominikschuermann.de>
+ * Copyright (C) 2011 Thialfihar <thi@thialfihar.org>
+ * Copyright (C) 2011 Senecaso
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.sufficientlysecure.keychain.util;
+
+import org.sufficientlysecure.keychain.ui.adapter.ImportKeysListEntry;
+
+import java.util.List;
+
+public abstract class KeyServer {
+    public static class QueryException extends Exception {
+        private static final long serialVersionUID = 2703768928624654512L;
+
+        public QueryException(String message) {
+            super(message);
+        }
+    }
+
+    public static class TooManyResponses extends Exception {
+        private static final long serialVersionUID = 2703768928624654513L;
+    }
+
+    public static class InsufficientQuery extends Exception {
+        private static final long serialVersionUID = 2703768928624654514L;
+    }
+
+    public static class AddKeyException extends Exception {
+        private static final long serialVersionUID = -507574859137295530L;
+    }
+
+    abstract List<ImportKeysListEntry> search(String query) throws QueryException, TooManyResponses,
+            InsufficientQuery;
+
+    abstract String get(String keyIdHex) throws QueryException;
+
+    abstract void add(String armoredKey) throws AddKeyException;
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/KeychainServiceListener.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/KeychainServiceListener.java
new file mode 100644
index 000000000..b205bd556
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/KeychainServiceListener.java
@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2014 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * 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.util;
+
+public interface KeychainServiceListener {
+    boolean hasServiceStopped();
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/Log.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/Log.java
new file mode 100644
index 000000000..f58f1757a
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/Log.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2012-2013 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * 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.util;
+
+import org.sufficientlysecure.keychain.Constants;
+
+/**
+ * Wraps Android Logging to enable or disable debug output using Constants
+ */
+public final class Log {
+
+    public static void v(String tag, String msg) {
+        if (Constants.DEBUG) {
+            android.util.Log.v(tag, msg);
+        }
+    }
+
+    public static void v(String tag, String msg, Throwable tr) {
+        if (Constants.DEBUG) {
+            android.util.Log.v(tag, msg, tr);
+        }
+    }
+
+    public static void d(String tag, String msg) {
+        if (Constants.DEBUG) {
+            android.util.Log.d(tag, msg);
+        }
+    }
+
+    public static void d(String tag, String msg, Throwable tr) {
+        if (Constants.DEBUG) {
+            android.util.Log.d(tag, msg, tr);
+        }
+    }
+
+    public static void i(String tag, String msg) {
+        if (Constants.DEBUG) {
+            android.util.Log.i(tag, msg);
+        }
+    }
+
+    public static void i(String tag, String msg, Throwable tr) {
+        if (Constants.DEBUG) {
+            android.util.Log.i(tag, msg, tr);
+        }
+    }
+
+    public static void w(String tag, String msg) {
+        android.util.Log.w(tag, msg);
+    }
+
+    public static void w(String tag, String msg, Throwable tr) {
+        android.util.Log.w(tag, msg, tr);
+    }
+
+    public static void w(String tag, Throwable tr) {
+        android.util.Log.w(tag, tr);
+    }
+
+    public static void e(String tag, String msg) {
+        android.util.Log.e(tag, msg);
+    }
+
+    public static void e(String tag, String msg, Throwable tr) {
+        android.util.Log.e(tag, msg, tr);
+    }
+
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/PRNGFixes.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/PRNGFixes.java
new file mode 100644
index 000000000..2d8fbcd81
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/PRNGFixes.java
@@ -0,0 +1,352 @@
+/*
+ * This software is provided 'as-is', without any express or implied
+ * warranty.  In no event will Google be held liable for any damages
+ * arising from the use of this software.
+ *
+ * Permission is granted to anyone to use this software for any purpose,
+ * including commercial applications, and to alter it and redistribute it
+ * freely, as long as the origin is not misrepresented.
+ */
+
+package org.sufficientlysecure.keychain.util;
+
+import android.os.Build;
+import android.os.Process;
+import android.util.Log;
+
+import java.io.*;
+import java.security.*;
+
+/**
+ * Fixes for the output of the default PRNG having low entropy.
+ * <p/>
+ * The fixes need to be applied via {@link #apply()} before any use of Java Cryptography
+ * Architecture primitives. A good place to invoke them is in the application's {@code onCreate}.
+ * <p/>
+ * copied from http://android-developers.blogspot.de/2013/08/some-securerandom-thoughts.html
+ * <p/>
+ * <p/>
+ * More information on these Android bugs:
+ * http://blog.k3170makan.com/2013/08/more-details-on-android-jca-prng-flaw.html
+ * Paper: "Randomly failed! Weaknesses in Java Pseudo Random Number Generators (PRNGs)"
+ * <p/>
+ * <p/>
+ * Sep 15, 2013:
+ * On some devices /dev/urandom is non-writable!
+ * No need to seed /dev/urandom. urandom should have enough seeds from the OS and kernel.
+ * Only OpenSSL seeds are broken. See http://emboss.github.io/blog/2013/08/21/openssl-prng-is-not-really-fork-safe
+ * <p/>
+ * see also:
+ * https://github.com/k9mail/k-9/commit/dda8f64276d4d29c43f86237cd77819c28f22f21
+ * In addition to a couple of custom ROMs linking /dev/urandom to a non-writable
+ * random version, now Samsung's SELinux policy also prevents apps from opening
+ * /dev/urandom for writing. Since we shouldn't need to write to /dev/urandom anyway
+ * we now simply don't.
+ * <p/>
+ * <p/>
+ * Sep 17, 2013:
+ * Updated from official blogpost:
+ * Update: the original code sample below crashed on a small fraction of Android
+ * devices due to /dev/urandom not being writable. We have now updated the code sample to handle this case gracefully.
+ */
+public final class PRNGFixes {
+
+    private static final int VERSION_CODE_JELLY_BEAN = 16;
+    private static final int VERSION_CODE_JELLY_BEAN_MR2 = 18;
+    private static final byte[] BUILD_FINGERPRINT_AND_DEVICE_SERIAL =
+            getBuildFingerprintAndDeviceSerial();
+
+    /**
+     * Hidden constructor to prevent instantiation.
+     */
+    private PRNGFixes() {
+    }
+
+    /**
+     * Applies all fixes.
+     *
+     * @throws SecurityException if a fix is needed but could not be applied.
+     */
+    public static void apply() {
+        applyOpenSSLFix();
+        installLinuxPRNGSecureRandom();
+    }
+
+    /**
+     * Applies the fix for OpenSSL PRNG having low entropy. Does nothing if the
+     * fix is not needed.
+     *
+     * @throws SecurityException if the fix is needed but could not be applied.
+     */
+    private static void applyOpenSSLFix() throws SecurityException {
+        if ((Build.VERSION.SDK_INT < VERSION_CODE_JELLY_BEAN)
+                || (Build.VERSION.SDK_INT > VERSION_CODE_JELLY_BEAN_MR2)) {
+            // No need to apply the fix
+            return;
+        }
+
+        try {
+            // Mix in the device- and invocation-specific seed.
+            Class.forName("org.apache.harmony.xnet.provider.jsse.NativeCrypto")
+                    .getMethod("RAND_seed", byte[].class)
+                    .invoke(null, generateSeed());
+
+            // Mix output of Linux PRNG into OpenSSL's PRNG
+            int bytesRead = (Integer) Class.forName(
+                    "org.apache.harmony.xnet.provider.jsse.NativeCrypto")
+                    .getMethod("RAND_load_file", String.class, long.class)
+                    .invoke(null, "/dev/urandom", 1024);
+            if (bytesRead != 1024) {
+                throw new IOException(
+                        "Unexpected number of bytes read from Linux PRNG: "
+                                + bytesRead);
+            }
+        } catch (Exception e) {
+            throw new SecurityException("Failed to seed OpenSSL PRNG", e);
+        }
+    }
+
+    /**
+     * Installs a Linux PRNG-backed {@code SecureRandom} implementation as the
+     * default. Does nothing if the implementation is already the default or if
+     * there is not need to install the implementation.
+     *
+     * @throws SecurityException if the fix is needed but could not be applied.
+     */
+    private static void installLinuxPRNGSecureRandom()
+            throws SecurityException {
+        if (Build.VERSION.SDK_INT > VERSION_CODE_JELLY_BEAN_MR2) {
+            // No need to apply the fix
+            return;
+        }
+
+        // Install a Linux PRNG-based SecureRandom implementation as the
+        // default, if not yet installed.
+        Provider[] secureRandomProviders =
+                Security.getProviders("SecureRandom.SHA1PRNG");
+        if ((secureRandomProviders == null)
+                || (secureRandomProviders.length < 1)
+                || (!LinuxPRNGSecureRandomProvider.class.equals(
+                secureRandomProviders[0].getClass()))) {
+            Security.insertProviderAt(new LinuxPRNGSecureRandomProvider(), 1);
+        }
+
+        // Assert that new SecureRandom() and
+        // SecureRandom.getInstance("SHA1PRNG") return a SecureRandom backed
+        // by the Linux PRNG-based SecureRandom implementation.
+        SecureRandom rng1 = new SecureRandom();
+        if (!LinuxPRNGSecureRandomProvider.class.equals(
+                rng1.getProvider().getClass())) {
+            throw new SecurityException(
+                    "new SecureRandom() backed by wrong Provider: "
+                            + rng1.getProvider().getClass());
+        }
+
+        SecureRandom rng2;
+        try {
+            rng2 = SecureRandom.getInstance("SHA1PRNG");
+        } catch (NoSuchAlgorithmException e) {
+            throw new SecurityException("SHA1PRNG not available", e);
+        }
+        if (!LinuxPRNGSecureRandomProvider.class.equals(
+                rng2.getProvider().getClass())) {
+            throw new SecurityException(
+                    "SecureRandom.getInstance(\"SHA1PRNG\") backed by wrong"
+                            + " Provider: " + rng2.getProvider().getClass());
+        }
+    }
+
+    /**
+     * {@code Provider} of {@code SecureRandom} engines which pass through
+     * all requests to the Linux PRNG.
+     */
+    private static class LinuxPRNGSecureRandomProvider extends Provider {
+
+        public LinuxPRNGSecureRandomProvider() {
+            super("LinuxPRNG",
+                    1.0,
+                    "A Linux-specific random number provider that uses"
+                            + " /dev/urandom");
+            // Although /dev/urandom is not a SHA-1 PRNG, some apps
+            // explicitly request a SHA1PRNG SecureRandom and we thus need to
+            // prevent them from getting the default implementation whose output
+            // may have low entropy.
+            put("SecureRandom.SHA1PRNG", LinuxPRNGSecureRandom.class.getName());
+            put("SecureRandom.SHA1PRNG ImplementedIn", "Software");
+        }
+    }
+
+    /**
+     * {@link SecureRandomSpi} which passes all requests to the Linux PRNG
+     * ({@code /dev/urandom}).
+     */
+    public static class LinuxPRNGSecureRandom extends SecureRandomSpi {
+
+        /*
+         * IMPLEMENTATION NOTE: Requests to generate bytes and to mix in a seed
+         * are passed through to the Linux PRNG (/dev/urandom). Instances of
+         * this class seed themselves by mixing in the current time, PID, UID,
+         * build fingerprint, and hardware serial number (where available) into
+         * Linux PRNG.
+         *
+         * Concurrency: Read requests to the underlying Linux PRNG are
+         * serialized (on sLock) to ensure that multiple threads do not get
+         * duplicated PRNG output.
+         */
+
+        private static final File URANDOM_FILE = new File("/dev/urandom");
+
+        private static final Object sLock = new Object();
+
+        /**
+         * Input stream for reading from Linux PRNG or {@code null} if not yet
+         * opened.
+         *
+         * @GuardedBy("sLock")
+         */
+        private static DataInputStream sUrandomIn;
+
+        /**
+         * Output stream for writing to Linux PRNG or {@code null} if not yet
+         * opened.
+         *
+         * @GuardedBy("sLock")
+         */
+        private static OutputStream sUrandomOut;
+
+        /**
+         * Whether this engine instance has been seeded. This is needed because
+         * each instance needs to seed itself if the client does not explicitly
+         * seed it.
+         */
+        private boolean mSeeded;
+
+        @Override
+        protected void engineSetSeed(byte[] bytes) {
+            try {
+                OutputStream out;
+                synchronized (sLock) {
+                    out = getUrandomOutputStream();
+                }
+                out.write(bytes);
+                out.flush();
+            } catch (IOException e) {
+                // On a small fraction of devices /dev/urandom is not writable.
+                // Log and ignore.
+                Log.w(PRNGFixes.class.getSimpleName(),
+                        "Failed to mix seed into " + URANDOM_FILE);
+            } finally {
+                mSeeded = true;
+            }
+        }
+
+        @Override
+        protected void engineNextBytes(byte[] bytes) {
+            if (!mSeeded) {
+                // Mix in the device- and invocation-specific seed.
+                engineSetSeed(generateSeed());
+            }
+
+            try {
+                DataInputStream in;
+                synchronized (sLock) {
+                    in = getUrandomInputStream();
+                }
+                synchronized (in) {
+                    in.readFully(bytes);
+                }
+            } catch (IOException e) {
+                throw new SecurityException(
+                        "Failed to read from " + URANDOM_FILE, e);
+            }
+        }
+
+        @Override
+        protected byte[] engineGenerateSeed(int size) {
+            byte[] seed = new byte[size];
+            engineNextBytes(seed);
+            return seed;
+        }
+
+        private DataInputStream getUrandomInputStream() {
+            synchronized (sLock) {
+                if (sUrandomIn == null) {
+                    // NOTE: Consider inserting a BufferedInputStream between
+                    // DataInputStream and FileInputStream if you need higher
+                    // PRNG output performance and can live with future PRNG
+                    // output being pulled into this process prematurely.
+                    try {
+                        sUrandomIn = new DataInputStream(
+                                new FileInputStream(URANDOM_FILE));
+                    } catch (IOException e) {
+                        throw new SecurityException("Failed to open "
+                                + URANDOM_FILE + " for reading", e);
+                    }
+                }
+                return sUrandomIn;
+            }
+        }
+
+        private OutputStream getUrandomOutputStream() throws IOException {
+            synchronized (sLock) {
+                if (sUrandomOut == null) {
+                    sUrandomOut = new FileOutputStream(URANDOM_FILE);
+                }
+                return sUrandomOut;
+            }
+        }
+    }
+
+    /**
+     * Generates a device- and invocation-specific seed to be mixed into the
+     * Linux PRNG.
+     */
+    private static byte[] generateSeed() {
+        try {
+            ByteArrayOutputStream seedBuffer = new ByteArrayOutputStream();
+            DataOutputStream seedBufferOut =
+                    new DataOutputStream(seedBuffer);
+            seedBufferOut.writeLong(System.currentTimeMillis());
+            seedBufferOut.writeLong(System.nanoTime());
+            seedBufferOut.writeInt(Process.myPid());
+            seedBufferOut.writeInt(Process.myUid());
+            seedBufferOut.write(BUILD_FINGERPRINT_AND_DEVICE_SERIAL);
+            seedBufferOut.close();
+            return seedBuffer.toByteArray();
+        } catch (IOException e) {
+            throw new SecurityException("Failed to generate seed", e);
+        }
+    }
+
+    /**
+     * Gets the hardware serial number of this device.
+     *
+     * @return serial number or {@code null} if not available.
+     */
+    private static String getDeviceSerialNumber() {
+        // We're using the Reflection API because Build.SERIAL is only available
+        // since API Level 9 (Gingerbread, Android 2.3).
+        try {
+            return (String) Build.class.getField("SERIAL").get(null);
+        } catch (Exception ignored) {
+            return null;
+        }
+    }
+
+    private static byte[] getBuildFingerprintAndDeviceSerial() {
+        StringBuilder result = new StringBuilder();
+        String fingerprint = Build.FINGERPRINT;
+        if (fingerprint != null) {
+            result.append(fingerprint);
+        }
+        String serial = getDeviceSerialNumber();
+        if (serial != null) {
+            result.append(serial);
+        }
+        try {
+            return result.toString().getBytes("UTF-8");
+        } catch (UnsupportedEncodingException e) {
+            throw new RuntimeException("UTF-8 encoding not supported");
+        }
+    }
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/PausableThreadPoolExecutor.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/PausableThreadPoolExecutor.java
new file mode 100644
index 000000000..5ec915810
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/PausableThreadPoolExecutor.java
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2013 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * 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.util;
+
+import java.util.concurrent.BlockingQueue;
+import java.util.concurrent.RejectedExecutionHandler;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.locks.Condition;
+import java.util.concurrent.locks.ReentrantLock;
+
+/**
+ * Example from
+ * http://docs.oracle.com/javase/1.5.0/docs/api/java/util/concurrent/ThreadPoolExecutor.html
+ */
+public class PausableThreadPoolExecutor extends ThreadPoolExecutor {
+
+    public PausableThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime,
+                                      TimeUnit unit, BlockingQueue<Runnable> workQueue,
+                                      RejectedExecutionHandler handler) {
+        super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, handler);
+    }
+
+    public PausableThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime,
+                                      TimeUnit unit, BlockingQueue<Runnable> workQueue,
+                                      ThreadFactory threadFactory,
+                                      RejectedExecutionHandler handler) {
+        super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory, handler);
+    }
+
+    public PausableThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime,
+                                      TimeUnit unit, BlockingQueue<Runnable> workQueue,
+                                      ThreadFactory threadFactory) {
+        super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue, threadFactory);
+    }
+
+    public PausableThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime,
+                                      TimeUnit unit, BlockingQueue<Runnable> workQueue) {
+        super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
+    }
+
+    private boolean mIsPaused;
+    private ReentrantLock mPauseLock = new ReentrantLock();
+    private Condition mUnPaused = mPauseLock.newCondition();
+
+    protected void beforeExecute(Thread t, Runnable r) {
+        super.beforeExecute(t, r);
+        mPauseLock.lock();
+        try {
+            while (mIsPaused) {
+                mUnPaused.await();
+            }
+        } catch (InterruptedException ie) {
+            t.interrupt();
+        } finally {
+            mPauseLock.unlock();
+        }
+    }
+
+    public void pause() {
+        mPauseLock.lock();
+        try {
+            mIsPaused = true;
+        } finally {
+            mPauseLock.unlock();
+        }
+    }
+
+    public void resume() {
+        mPauseLock.lock();
+        try {
+            mIsPaused = false;
+            mUnPaused.signalAll();
+        } finally {
+            mPauseLock.unlock();
+        }
+    }
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/PositionAwareInputStream.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/PositionAwareInputStream.java
new file mode 100644
index 000000000..4fcd3047f
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/PositionAwareInputStream.java
@@ -0,0 +1,83 @@
+/*
+ * Copyright (C) 2010-2014 Thialfihar <thi@thialfihar.org>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.sufficientlysecure.keychain.util;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+public class PositionAwareInputStream extends InputStream {
+    private InputStream mStream;
+    private long mPosition;
+
+    public PositionAwareInputStream(InputStream in) {
+        mStream = in;
+        mPosition = 0;
+    }
+
+    @Override
+    public int read() throws IOException {
+        int ch = mStream.read();
+        ++mPosition;
+        return ch;
+    }
+
+    @Override
+    public int available() throws IOException {
+        return mStream.available();
+    }
+
+    @Override
+    public void close() throws IOException {
+        mStream.close();
+    }
+
+    @Override
+    public boolean markSupported() {
+        return false;
+    }
+
+    @Override
+    public int read(byte[] b) throws IOException {
+        int result = mStream.read(b);
+        mPosition += result;
+        return result;
+    }
+
+    @Override
+    public int read(byte[] b, int offset, int length) throws IOException {
+        int result = mStream.read(b, offset, length);
+        mPosition += result;
+        return result;
+    }
+
+    @Override
+    public synchronized void reset() throws IOException {
+        mStream.reset();
+        mPosition = 0;
+    }
+
+    @Override
+    public long skip(long n) throws IOException {
+        long result = mStream.skip(n);
+        mPosition += result;
+        return result;
+    }
+
+    public long position() {
+        return mPosition;
+    }
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/Primes.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/Primes.java
new file mode 100644
index 000000000..28a12bf37
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/Primes.java
@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2010 Thialfihar <thi@thialfihar.org>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.sufficientlysecure.keychain.util;
+
+import java.math.BigInteger;
+
+/**
+ * Primes for ElGamal
+ */
+public final class Primes {
+    // taken from http://www.ietf.org/rfc/rfc3526.txt
+    public static final String P1536 =
+            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
+                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
+                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
+                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
+                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
+                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
+                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
+                    "670C354E 4ABC9804 F1746C08 CA237327 FFFFFFFF FFFFFFFF";
+
+    public static final String P2048 =
+            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
+                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
+                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
+                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
+                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
+                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
+                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
+                    "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B" +
+                    "E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9" +
+                    "DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510" +
+                    "15728E5A 8AACAA68 FFFFFFFF FFFFFFFF";
+
+    public static final String P3072 =
+            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
+                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
+                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
+                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
+                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
+                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
+                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
+                    "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B" +
+                    "E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9" +
+                    "DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510" +
+                    "15728E5A 8AAAC42D AD33170D 04507A33 A85521AB DF1CBA64" +
+                    "ECFB8504 58DBEF0A 8AEA7157 5D060C7D B3970F85 A6E1E4C7" +
+                    "ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 1AD2EE6B" +
+                    "F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
+                    "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31" +
+                    "43DB5BFC E0FD108E 4B82D120 A93AD2CA FFFFFFFF FFFFFFFF";
+
+    public static final String P4096 =
+            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
+                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
+                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
+                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
+                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
+                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
+                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
+                    "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B" +
+                    "E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9" +
+                    "DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510" +
+                    "15728E5A 8AAAC42D AD33170D 04507A33 A85521AB DF1CBA64" +
+                    "ECFB8504 58DBEF0A 8AEA7157 5D060C7D B3970F85 A6E1E4C7" +
+                    "ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 1AD2EE6B" +
+                    "F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
+                    "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31" +
+                    "43DB5BFC E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7" +
+                    "88719A10 BDBA5B26 99C32718 6AF4E23C 1A946834 B6150BDA" +
+                    "2583E9CA 2AD44CE8 DBBBC2DB 04DE8EF9 2E8EFC14 1FBECAA6" +
+                    "287C5947 4E6BC05D 99B2964F A090C3A2 233BA186 515BE7ED" +
+                    "1F612970 CEE2D7AF B81BDD76 2170481C D0069127 D5B05AA9" +
+                    "93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34063199" +
+                    "FFFFFFFF FFFFFFFF";
+
+    public static final String P6144 =
+            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
+                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
+                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
+                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
+                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
+                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
+                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
+                    "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B" +
+                    "E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9" +
+                    "DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510" +
+                    "15728E5A 8AAAC42D AD33170D 04507A33 A85521AB DF1CBA64" +
+                    "ECFB8504 58DBEF0A 8AEA7157 5D060C7D B3970F85 A6E1E4C7" +
+                    "ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 1AD2EE6B" +
+                    "F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
+                    "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31" +
+                    "43DB5BFC E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7" +
+                    "88719A10 BDBA5B26 99C32718 6AF4E23C 1A946834 B6150BDA" +
+                    "2583E9CA 2AD44CE8 DBBBC2DB 04DE8EF9 2E8EFC14 1FBECAA6" +
+                    "287C5947 4E6BC05D 99B2964F A090C3A2 233BA186 515BE7ED" +
+                    "1F612970 CEE2D7AF B81BDD76 2170481C D0069127 D5B05AA9" +
+                    "93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34028492" +
+                    "36C3FAB4 D27C7026 C1D4DCB2 602646DE C9751E76 3DBA37BD" +
+                    "F8FF9406 AD9E530E E5DB382F 413001AE B06A53ED 9027D831" +
+                    "179727B0 865A8918 DA3EDBEB CF9B14ED 44CE6CBA CED4BB1B" +
+                    "DB7F1447 E6CC254B 33205151 2BD7AF42 6FB8F401 378CD2BF" +
+                    "5983CA01 C64B92EC F032EA15 D1721D03 F482D7CE 6E74FEF6" +
+                    "D55E702F 46980C82 B5A84031 900B1C9E 59E7C97F BEC7E8F3" +
+                    "23A97A7E 36CC88BE 0F1D45B7 FF585AC5 4BD407B2 2B4154AA" +
+                    "CC8F6D7E BF48E1D8 14CC5ED2 0F8037E0 A79715EE F29BE328" +
+                    "06A1D58B B7C5DA76 F550AA3D 8A1FBFF0 EB19CCB1 A313D55C" +
+                    "DA56C9EC 2EF29632 387FE8D7 6E3C0468 043E8F66 3F4860EE" +
+                    "12BF2D5B 0B7474D6 E694F91E 6DCC4024 FFFFFFFF FFFFFFFF";
+
+    public static final String P8192 =
+            "FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1" +
+                    "29024E08 8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD" +
+                    "EF9519B3 CD3A431B 302B0A6D F25F1437 4FE1356D 6D51C245" +
+                    "E485B576 625E7EC6 F44C42E9 A637ED6B 0BFF5CB6 F406B7ED" +
+                    "EE386BFB 5A899FA5 AE9F2411 7C4B1FE6 49286651 ECE45B3D" +
+                    "C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8 FD24CF5F" +
+                    "83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D" +
+                    "670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B" +
+                    "E39E772C 180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9" +
+                    "DE2BCBF6 95581718 3995497C EA956AE5 15D22618 98FA0510" +
+                    "15728E5A 8AAAC42D AD33170D 04507A33 A85521AB DF1CBA64" +
+                    "ECFB8504 58DBEF0A 8AEA7157 5D060C7D B3970F85 A6E1E4C7" +
+                    "ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226 1AD2EE6B" +
+                    "F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C" +
+                    "BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31" +
+                    "43DB5BFC E0FD108E 4B82D120 A9210801 1A723C12 A787E6D7" +
+                    "88719A10 BDBA5B26 99C32718 6AF4E23C 1A946834 B6150BDA" +
+                    "2583E9CA 2AD44CE8 DBBBC2DB 04DE8EF9 2E8EFC14 1FBECAA6" +
+                    "287C5947 4E6BC05D 99B2964F A090C3A2 233BA186 515BE7ED" +
+                    "1F612970 CEE2D7AF B81BDD76 2170481C D0069127 D5B05AA9" +
+                    "93B4EA98 8D8FDDC1 86FFB7DC 90A6C08F 4DF435C9 34028492" +
+                    "36C3FAB4 D27C7026 C1D4DCB2 602646DE C9751E76 3DBA37BD" +
+                    "F8FF9406 AD9E530E E5DB382F 413001AE B06A53ED 9027D831" +
+                    "179727B0 865A8918 DA3EDBEB CF9B14ED 44CE6CBA CED4BB1B" +
+                    "DB7F1447 E6CC254B 33205151 2BD7AF42 6FB8F401 378CD2BF" +
+                    "5983CA01 C64B92EC F032EA15 D1721D03 F482D7CE 6E74FEF6" +
+                    "D55E702F 46980C82 B5A84031 900B1C9E 59E7C97F BEC7E8F3" +
+                    "23A97A7E 36CC88BE 0F1D45B7 FF585AC5 4BD407B2 2B4154AA" +
+                    "CC8F6D7E BF48E1D8 14CC5ED2 0F8037E0 A79715EE F29BE328" +
+                    "06A1D58B B7C5DA76 F550AA3D 8A1FBFF0 EB19CCB1 A313D55C" +
+                    "DA56C9EC 2EF29632 387FE8D7 6E3C0468 043E8F66 3F4860EE" +
+                    "12BF2D5B 0B7474D6 E694F91E 6DBE1159 74A3926F 12FEE5E4" +
+                    "38777CB6 A932DF8C D8BEC4D0 73B931BA 3BC832B6 8D9DD300" +
+                    "741FA7BF 8AFC47ED 2576F693 6BA42466 3AAB639C 5AE4F568" +
+                    "3423B474 2BF1C978 238F16CB E39D652D E3FDB8BE FC848AD9" +
+                    "22222E04 A4037C07 13EB57A8 1A23F0C7 3473FC64 6CEA306B" +
+                    "4BCBC886 2F8385DD FA9D4B7F A2C087E8 79683303 ED5BDD3A" +
+                    "062B3CF5 B3A278A6 6D2A13F8 3F44F82D DF310EE0 74AB6A36" +
+                    "4597E899 A0255DC1 64F31CC5 0846851D F9AB4819 5DED7EA1" +
+                    "B1D510BD 7EE74D73 FAF36BC3 1ECFA268 359046F4 EB879F92" +
+                    "4009438B 481C6CD7 889A002E D5EE382B C9190DA6 FC026E47" +
+                    "9558E447 5677E9AA 9E3050E2 765694DF C81F56E8 80B96E71" +
+                    "60C980DD 98EDD3DF FFFFFFFF FFFFFFFF";
+
+    public static BigInteger getBestPrime(int keySize) {
+        String primeString;
+        if (keySize >= (8192 + 6144) / 2) {
+            primeString = P8192;
+        } else if (keySize >= (6144 + 4096) / 2) {
+            primeString = P6144;
+        } else if (keySize >= (4096 + 3072) / 2) {
+            primeString = P4096;
+        } else if (keySize >= (3072 + 2048) / 2) {
+            primeString = P3072;
+        } else if (keySize >= (2048 + 1536) / 2) {
+            primeString = P2048;
+        } else {
+            primeString = P1536;
+        }
+
+        return new BigInteger(primeString.replaceAll(" ", ""), 16);
+    }
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ProgressDialogUpdater.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ProgressDialogUpdater.java
new file mode 100644
index 000000000..26c05ad0a
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ProgressDialogUpdater.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2010 Thialfihar <thi@thialfihar.org>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.sufficientlysecure.keychain.util;
+
+public interface ProgressDialogUpdater {
+    void setProgress(String message, int current, int total);
+
+    void setProgress(int resourceId, int current, int total);
+
+    void setProgress(int current, int total);
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ProgressScaler.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ProgressScaler.java
new file mode 100644
index 000000000..23961c05f
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/ProgressScaler.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2012-2014 Dominik Schürmann <dominik@dominikschuermann.de>
+ *
+ * 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.util;
+
+/** This is a simple class that wraps a ProgressDialogUpdater, scaling the progress
+ * values into a specified range.
+ */
+public class ProgressScaler implements ProgressDialogUpdater {
+
+    final ProgressDialogUpdater mWrapped;
+    final int mFrom, mTo, mMax;
+
+    public ProgressScaler(ProgressDialogUpdater wrapped, int from, int to, int max) {
+        this.mWrapped = wrapped;
+        this.mFrom = from;
+        this.mTo = to;
+        this.mMax = max;
+    }
+
+    /**
+     * Set progressDialogUpdater of ProgressDialog by sending message to handler on UI thread
+     */
+    public void setProgress(String message, int progress, int max) {
+        mWrapped.setProgress(message, mFrom + progress * (mTo - mFrom) / max, mMax);
+    }
+
+    public void setProgress(int resourceId, int progress, int max) {
+        mWrapped.setProgress(resourceId, progress, mMax);
+    }
+
+    public void setProgress(int progress, int max) {
+        mWrapped.setProgress(progress, max);
+    }
+
+}
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/QrCodeUtils.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/QrCodeUtils.java
new file mode 100644
index 000000000..af9034aa7
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/QrCodeUtils.java
@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2013 Dominik Schürmann <dominik@dominikschuermann.de>
+ * Copyright (C) 2011 Andreas Schildbach
+ *
+ * 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.util;
+
+import com.google.zxing.BarcodeFormat;
+import com.google.zxing.EncodeHintType;
+import com.google.zxing.WriterException;
+import com.google.zxing.common.BitMatrix;
+import com.google.zxing.qrcode.QRCodeWriter;
+import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
+
+import android.graphics.Bitmap;
+import android.graphics.Color;
+
+import org.sufficientlysecure.keychain.Constants;
+
+import java.util.Hashtable;
+
+public class QrCodeUtils {
+    public static final QRCodeWriter QR_CODE_WRITER = new QRCodeWriter();
+
+    /**
+     * Generate Bitmap with QR Code based on input.
+     *
+     * @param input
+     * @param size
+     * @return QR Code as Bitmap
+     */
+    public static Bitmap getQRCodeBitmap(final String input, final int size) {
+        try {
+            final Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
+            hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);
+            final BitMatrix result = QR_CODE_WRITER.encode(input, BarcodeFormat.QR_CODE, size,
+                    size, hints);
+
+            final int width = result.getWidth();
+            final int height = result.getHeight();
+            final int[] pixels = new int[width * height];
+
+            for (int y = 0; y < height; y++) {
+                final int offset = y * width;
+                for (int x = 0; x < width; x++) {
+                    pixels[offset + x] = result.get(x, y) ? Color.BLACK : Color.TRANSPARENT;
+                }
+            }
+
+            final Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
+            bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
+            return bitmap;
+        } catch (final WriterException e) {
+            Log.e(Constants.TAG, "QrCodeUtils", e);
+            return null;
+        }
+    }
+
+}