Initial crappy commit

.gitignore

@@ -0,0 +1,8 @@
+.gradle/
+.idea/
+
+*.iml
+*/out
+*/build/
+
+out/

build.gradle

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+group 'de.vanitasvitae'
+version '1.0-SNAPSHOT'
+
+buildscript {
+
+    dependencies {
+        // Material Design
+        classpath group: 'de.dynamicfiles.projects.gradle.plugins', name: 'javafx-gradle-plugin', version: '8.8.2'
+    }
+
+    repositories {
+        mavenLocal()
+        mavenCentral()
+    }
+}
+
+allprojects {
+    apply plugin: 'java'
+    apply plugin: 'javafx-gradle-plugin'
+}
+
+sourceCompatibility = 1.8
+
+repositories {
+    mavenCentral()
+    maven {
+        url "https://igniterealtime.org/repo/"
+    }
+}
+
+ext {
+    smackVersion="4.4.0-alpha2-SNAPSHOT"
+}
+
+dependencies {
+    compileClasspath 'de.dynamicfiles.projects.gradle.plugins:javafx-gradle-plugin:8.8.2'
+    implementation 'com.jfoenix:jfoenix:8.0.7'
+    implementation 'com.google.zxing:core:3.3.3'
+
+    implementation "org.igniterealtime.smack:smack-java7:$smackVersion"
+    implementation "org.igniterealtime.smack:smack-resolver-dnsjava:$smackVersion"
+    implementation "org.igniterealtime.smack:smack-tcp:$smackVersion"
+    implementation "org.igniterealtime.smack:smack-extensions:$smackVersion"
+
+    implementation "org.igniterealtime.smack:smack-omemo-signal:$smackVersion"
+    implementation "org.igniterealtime.smack:smack-omemo:$smackVersion"
+
+    testCompile group: 'junit', name: 'junit', version: '4.12'
+}
+
+jfx {
+    mainClass = 'de.vanitasvitae.omemoqrgenerator.Main'
+
+    vendor = 'vanitasvitae'
+}

gradle/wrapper/gradle-wrapper.properties

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+#Wed Oct 24 01:10:40 CEST 2018
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.8-all.zip

gradlew

@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"

gradlew.bat

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+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

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+rootProject.name = 'omemoqrgenerator'
+

src/main/java/de/vanitasvitae/omemoqrgenerator/LoginCallback.java

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+package de.vanitasvitae.omemoqrgenerator;
+
+public interface LoginCallback {
+
+    void login(String username, String password);
+}

src/main/java/de/vanitasvitae/omemoqrgenerator/LoginController.java

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+package de.vanitasvitae.omemoqrgenerator;
+
+import com.jfoenix.controls.JFXButton;
+import com.jfoenix.controls.JFXPasswordField;
+import com.jfoenix.controls.JFXTextField;
+import javafx.fxml.FXML;
+
+public class LoginController {
+
+    @FXML
+    private JFXButton button_login;
+
+    @FXML
+    private JFXTextField text_username;
+
+    @FXML
+    private JFXPasswordField text_password;
+
+    public void setLoginCallback(LoginCallback callback) {
+        button_login.setOnAction(actionEvent -> {
+            String username = text_username.getText();
+            String password = text_password.getText();
+            callback.login(username, password);
+        });
+    }
+
+}

src/main/java/de/vanitasvitae/omemoqrgenerator/Main.java

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+package de.vanitasvitae.omemoqrgenerator;
+
+import java.util.Arrays;
+import java.util.Map;
+
+import org.jivesoftware.smack.SmackConfiguration;
+import org.jivesoftware.smack.packet.Presence;
+import org.jivesoftware.smack.tcp.XMPPTCPConnection;
+import org.jivesoftware.smackx.disco.ServiceDiscoveryManager;
+import org.jivesoftware.smackx.omemo.internal.OmemoDevice;
+import org.jivesoftware.smackx.omemo.trust.OmemoFingerprint;
+import org.jivesoftware.smackx.pubsub.PubSubManager;
+
+import javafx.application.Application;
+import javafx.fxml.FXMLLoader;
+import javafx.scene.Parent;
+import javafx.scene.Scene;
+import javafx.stage.Stage;
+import org.jxmpp.jid.BareJid;
+
+public class Main extends Application implements LoginCallback {
+
+    private Stage stage;
+
+
+    static {
+        SmackConfiguration.DEBUG = true;
+        SmackConfiguration.addDisabledSmackClasses("org.jivesoftware.smack.ReconnectionManager",
+                "org.jivesoftware.smack.sasl.javax",
+                "org.jivesoftware.smack.legacy",
+                "org.jivesoftware.smackx.gcm",
+                "org.jivesoftware.smackx.httpfileupload",
+                "org.jivesoftware.smackx.hoxt",
+                "org.jivesoftware.smackx.iot",
+                "org.jivesoftware.smackx.json",
+                "org.jivesoftware.smackx.muc",
+                "org.jivesoftware.smackx.xdata",
+                "org.jivesoftware.smackx.xdatalayout",
+                "org.jivesoftware.smackx.xdatavalidation",
+                "org.jivesoftware.smackx.admin",
+                "org.jivesoftware.smackx.amp",
+                "org.jivesoftware.smackx.attention",
+                "org.jivesoftware.smackx.blocking",
+                "org.jivesoftware.smackx.bob",
+                "org.jivesoftware.smackx.bookmark",
+                "org.jivesoftware.smackx.bytestreams",
+                "org.jivesoftware.smackx.chatstates",
+                "org.jivesoftware.smackx.commands",
+                "org.jivesoftware.smackx.filetransfer",
+                "org.jivesoftware.smackx.forward",
+                "org.jivesoftware.smackx.sid",
+                "org.jivesoftware.smackx.eme",
+                "org.jivesoftware.smackx.vcardtemp",
+                "org.jivesoftware.smackx.xhtmlim",
+                "org.jivesoftware.smackx.time",
+                "org.jivesoftware.smackx.privacy",
+                "org.jivesoftware.smackx.ping",
+                "org.jivesoftware.smackx.iqlast",
+                "org.jivesoftware.smackx.receipts",
+                "org.jivesoftware.smackx.iqversion"
+                );
+    }
+
+    public static void main(String[] args) {
+        launch(args);
+    }
+
+    @Override
+    public void start(Stage stage) throws Exception {
+        this.stage = stage;
+        FXMLLoader loader = new FXMLLoader();
+        loader.setLocation(getClass().getResource("/fxml/login.fxml"));
+        Parent root = loader.load();
+        stage.setMinHeight(600);
+        stage.setMinWidth(400);
+        LoginController loginController = loader.getController();
+        loginController.setLoginCallback(this);
+
+        Scene scene = new Scene(root, 400, 600);
+        stage.setTitle("OMEMO QR-Code Generator - Login");
+        stage.setScene(scene);
+        stage.show();
+    }
+
+    @Override
+    public void login(String username, String password) {
+        try {
+            XMPPTCPConnection connection = new XMPPTCPConnection(username, password);
+            connection.connect().login();
+
+            BareJid jid = connection.getUser().asBareJid();
+            Map<OmemoDevice, OmemoFingerprint> fingerprints = Util.getFingerprints(connection);
+
+            connection.disconnect(new Presence(Presence.Type.unavailable));
+
+            FXMLLoader loader = new FXMLLoader();
+            loader.setLocation(getClass().getResource("/fxml/qrdisplay.fxml"));
+            Parent root = loader.load();
+            QrDisplayController controller = loader.getController();
+            controller.setFingerprints(jid, fingerprints);
+
+            Scene scene = new Scene(root, 400, 600);
+            stage.setTitle("OMEMO QR-Code Generator");
+            stage.setScene(scene);
+            stage.show();
+
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+
+
+
+}

src/main/java/de/vanitasvitae/omemoqrgenerator/QrDisplayController.java

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+package de.vanitasvitae.omemoqrgenerator;
+
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.util.Iterator;
+import java.util.Map;
+
+import org.jivesoftware.smackx.omemo.internal.OmemoDevice;
+import org.jivesoftware.smackx.omemo.trust.OmemoFingerprint;
+
+import com.google.zxing.BarcodeFormat;
+import com.google.zxing.WriterException;
+import com.google.zxing.common.BitMatrix;
+import com.google.zxing.qrcode.QRCodeWriter;
+import com.jfoenix.controls.JFXTextArea;
+import javafx.embed.swing.SwingFXUtils;
+import javafx.fxml.FXML;
+import javafx.scene.image.ImageView;
+import org.jxmpp.jid.BareJid;
+
+public class QrDisplayController {
+
+    @FXML
+    private ImageView qr_view;
+
+    @FXML
+    private JFXTextArea content_text;
+
+    private BareJid jid;
+    private Map<OmemoDevice, OmemoFingerprint> fingerprintMap;
+
+    public void setFingerprints(BareJid jid, Map<OmemoDevice, OmemoFingerprint> fingerprints) {
+        this.jid = jid;
+        this.fingerprintMap = fingerprints;
+        drawQRCode(jid, fingerprints);
+    }
+
+    public void drawQRCode(BareJid jid, Map<OmemoDevice, OmemoFingerprint> fingerprints) {
+        int width = 300, height = 300;
+        QRCodeWriter qrCodeWriter = new QRCodeWriter();
+
+        String content = "xmpp:" + jid.toString();
+
+        Iterator<OmemoDevice> iterator = fingerprints.keySet().iterator();
+        if (iterator.hasNext()) {
+            OmemoDevice first = iterator.next();
+            content += "?omemo-sid-" + first.getDeviceId() + "=" + fingerprints.get(first);
+        }
+
+        while (iterator.hasNext()) {
+            OmemoDevice next = iterator.next();
+            content += ";omemo-sid-" + next.getDeviceId() + "=" + fingerprints.get(next);
+        }
+
+        content_text.setText(content);
+
+        BufferedImage image;
+
+        try {
+            BitMatrix byteMatrix = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, width, height);
+            image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
+            image.createGraphics();
+
+            Graphics2D graphics = (Graphics2D) image.getGraphics();
+            graphics.setColor(Color.WHITE);
+            graphics.fillRect(0, 0, width, height);
+            graphics.setColor(Color.BLACK);
+
+            for (int i = 0; i < height; i++) {
+                for (int j = 0; j < width; j++) {
+                    if (byteMatrix.get(i, j)) {
+                        graphics.fillRect(i, j, 1, 1);
+                    }
+                }
+            }
+
+            System.out.println("Success...");
+
+        } catch (WriterException ex) {
+            ex.printStackTrace();
+            return;
+        }
+
+        qr_view.setImage(SwingFXUtils.toFXImage(image, null));
+    }
+
+}

src/main/java/de/vanitasvitae/omemoqrgenerator/Util.java

@@ -0,0 +1,97 @@
+package de.vanitasvitae.omemoqrgenerator;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.jivesoftware.smack.SmackException;
+import org.jivesoftware.smack.XMPPConnection;
+import org.jivesoftware.smack.XMPPException;
+import org.jivesoftware.smack.tcp.XMPPTCPConnection;
+import org.jivesoftware.smackx.omemo.element.OmemoBundleElement;
+import org.jivesoftware.smackx.omemo.element.OmemoDeviceListElement;
+import org.jivesoftware.smackx.omemo.exceptions.CorruptedOmemoKeyException;
+import org.jivesoftware.smackx.omemo.internal.OmemoDevice;
+import org.jivesoftware.smackx.omemo.signal.SignalOmemoKeyUtil;
+import org.jivesoftware.smackx.omemo.trust.OmemoFingerprint;
+import org.jivesoftware.smackx.omemo.util.OmemoConstants;
+import org.jivesoftware.smackx.pubsub.LeafNode;
+import org.jivesoftware.smackx.pubsub.PayloadItem;
+import org.jivesoftware.smackx.pubsub.PubSubException;
+import org.jivesoftware.smackx.pubsub.PubSubManager;
+
+import org.jxmpp.jid.BareJid;
+
+public class Util {
+
+    private static final SignalOmemoKeyUtil KEYUTIL = new SignalOmemoKeyUtil();
+
+    public static Map<OmemoDevice, OmemoFingerprint> getFingerprints(XMPPTCPConnection connection)
+            throws InterruptedException, PubSubException.NotALeafNodeException,
+            SmackException.NoResponseException, SmackException.NotConnectedException,
+            XMPPException.XMPPErrorException, PubSubException.NotAPubSubNodeException,
+            CorruptedOmemoKeyException {
+        BareJid jid = connection.getUser().asBareJid();
+        Map<OmemoDevice, OmemoFingerprint> fingerprintMap = new HashMap<>();
+
+        OmemoDeviceListElement deviceList = fetchDeviceList(connection, jid);
+        if (deviceList == null) {
+            return fingerprintMap;
+        }
+
+        for (int id : deviceList.getDeviceIds()) {
+            OmemoDevice device = new OmemoDevice(jid, id);
+            OmemoBundleElement bundle = fetchBundle(connection, device);
+            if (bundle == null) {
+                continue;
+            }
+
+            OmemoFingerprint fingerprint = KEYUTIL.getFingerprintOfIdentityKey(KEYUTIL.BUNDLE.identityKey(bundle));
+            fingerprintMap.put(device, fingerprint);
+        }
+
+        return fingerprintMap;
+    }
+
+    public static OmemoBundleElement fetchBundle(XMPPConnection connection,
+                                                 OmemoDevice contactsDevice)
+            throws SmackException.NotConnectedException, InterruptedException, SmackException.NoResponseException,
+            XMPPException.XMPPErrorException, PubSubException.NotALeafNodeException,
+            PubSubException.NotAPubSubNodeException {
+
+        PubSubManager pm = PubSubManager.getInstance(connection, contactsDevice.getJid());
+        LeafNode node = pm.getLeafNode(contactsDevice.getBundleNodeName());
+
+        if (node == null) {
+            return null;
+        }
+
+        List<PayloadItem<OmemoBundleElement>> bundleItems = node.getItems();
+        if (bundleItems.isEmpty()) {
+            return null;
+        }
+
+        return bundleItems.get(bundleItems.size() - 1).getPayload();
+    }
+
+    public static OmemoDeviceListElement fetchDeviceList(XMPPConnection connection, BareJid contact)
+            throws InterruptedException, PubSubException.NotALeafNodeException, SmackException.NoResponseException,
+            SmackException.NotConnectedException, XMPPException.XMPPErrorException,
+            PubSubException.NotAPubSubNodeException {
+
+        PubSubManager pm = PubSubManager.getInstance(connection, contact);
+        String nodeName = OmemoConstants.PEP_NODE_DEVICE_LIST;
+        LeafNode node = pm.getLeafNode(nodeName);
+
+        if (node == null) {
+            return null;
+        }
+
+        List<PayloadItem<OmemoDeviceListElement>> items = node.getItems();
+        if (items.isEmpty()) {
+            return null;
+        }
+
+        return items.get(items.size() - 1).getPayload();
+    }
+}

src/main/resources/fxml/login.fxml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import com.jfoenix.controls.JFXButton?>
+<?import com.jfoenix.controls.JFXPasswordField?>
+<?import com.jfoenix.controls.JFXTextField?>
+<?import javafx.geometry.Insets?>
+<?import javafx.scene.layout.HBox?>
+<?import javafx.scene.layout.VBox?>
+
+<VBox alignment="CENTER" minHeight="400.0" minWidth="600.0" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8.0.162-ea" xmlns:fx="http://javafx.com/fxml/1" fx:controller="de.vanitasvitae.omemoqrgenerator.LoginController">
+   <children>
+      <HBox alignment="CENTER" prefHeight="100.0" prefWidth="200.0">
+          <VBox alignment="CENTER" maxHeight="150.0" maxWidth="300.0" minHeight="150.0" minWidth="300.0" prefHeight="150.0" prefWidth="300.0" spacing="8.0">
+              <children>
+                  <JFXTextField fx:id="text_username" promptText="Username" />
+                  <JFXPasswordField fx:id="text_password" promptText="Password" />
+                  <JFXButton fx:id="button_login" mnemonicParsing="false" text="Login" />
+              </children>
+              <padding>
+                  <Insets bottom="16.0" left="16.0" right="16.0" top="16.0" />
+              </padding>
+          </VBox>
+      </HBox>
+   </children>
+</VBox>

src/main/resources/fxml/qrdisplay.fxml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.image.ImageView?>
+<?import javafx.scene.layout.VBox?>
+<?import com.jfoenix.controls.JFXTextArea?>
+<?import javafx.scene.layout.HBox?>
+<VBox alignment="TOP_CENTER" minHeight="400.0" minWidth="600.0" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8.0.162-ea" xmlns:fx="http://javafx.com/fxml/1" fx:controller="de.vanitasvitae.omemoqrgenerator.QrDisplayController">
+    <children>
+        <ImageView fx:id="qr_view"/>
+        <HBox>
+            <JFXTextArea fx:id="content_text" />
+        </HBox>
+
+    </children>
+</VBox>