FIDO2 support once again

15 files changed, 304 insertions, 385 deletions

diff --git a/pdf-over-gui/pom.xml b/pdf-over-gui/pom.xml
index 4cb083e3..125a3e33 100644
--- a/pdf-over-gui/pom.xml
+++ b/pdf-over-gui/pom.xml
@@ -74,6 +74,11 @@
 			<groupId>com.google.code.findbugs</groupId>
 			<artifactId>jsr305</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>at.a-sit</groupId>
+			<artifactId>webauthn-java</artifactId>
+			<version>0.0.1-SNAPSHOT</version>
+		</dependency>
 	</dependencies>
 	<dependencyManagement>
 		<dependencies>
diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/MobileBKUConnector.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/MobileBKUConnector.java
index 14971ce1..1c07376c 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/MobileBKUConnector.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/MobileBKUConnector.java
@@ -5,12 +5,16 @@ import java.net.URI;
 import java.net.URISyntaxException;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
+import java.util.Base64;
 import java.util.List;
 import java.util.Optional;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import javax.annotation.CheckForNull;
 import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import javax.swing.text.html.HTML.Tag;
 
 import org.apache.hc.client5.http.classic.methods.HttpGet;
 import org.apache.hc.client5.http.classic.methods.HttpPost;
@@ -20,6 +24,7 @@ import org.apache.hc.client5.http.entity.mime.MultipartEntityBuilder;
 import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
 import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
 import org.apache.hc.client5.http.impl.classic.HttpClients;
+import org.apache.hc.client5.http.impl.classic.RequestFailedException;
 import org.apache.hc.core5.http.ClassicHttpRequest;
 import org.apache.hc.core5.http.ContentType;
 import org.apache.hc.core5.http.Header;
@@ -46,6 +51,10 @@ import at.asit.pdfover.signer.BkuSlConnector;
 import at.asit.pdfover.signer.SignatureException;
 import at.asit.pdfover.signer.UserCancelledException;
 import at.asit.pdfover.signer.pdfas.PdfAs4SLRequest;
+import at.asit.webauthn.PublicKeyCredentialRequestOptions;
+import at.asit.webauthn.WebAuthN;
+import at.asit.webauthn.exceptions.WebAuthNOperationFailed;
+import at.asit.webauthn.exceptions.WebAuthNUserCancelled;
 
 import static at.asit.pdfover.commons.Constants.ISNOTNULL;
 
@@ -80,6 +89,9 @@ public class MobileBKUConnector implements BkuSlConnector {
         }
     }
 
+    /* some anti-infinite-loop safeguards so we don't murder the atrust servers by accident */
+    private int loopHTTPRequestCounter = 0;
+    private Long lastHTTPRequestTime = null;
     /**
      * Sends the specified request, following redirects (including meta-tag redirects) recursively
      * @return The JSOUP document retrieved
@@ -89,6 +101,16 @@ public class MobileBKUConnector implements BkuSlConnector {
      * @throws InterruptedException
      */
     private @Nonnull ATrustParser.Result sendHTTPRequest(CloseableHttpClient httpClient, ClassicHttpRequest request) throws IOException, ProtocolException, URISyntaxException {
+        long now = System.nanoTime();
+        if ((lastHTTPRequestTime != null) && ((now - lastHTTPRequestTime) < 2e+9)) { /* less than 2s since last request */
+            ++loopHTTPRequestCounter;
+            if (loopHTTPRequestCounter > 250)
+                throw new IOException("Infinite loop protection triggered");
+        } else {
+            loopHTTPRequestCounter = 0;
+        }
+        lastHTTPRequestTime = now;
+
         log.debug("Sending request to '{}'...", request.getUri().toString());
         try (final CloseableHttpResponse response = httpClient.execute(request)) {
             int httpStatus = response.getCode();
@@ -176,17 +198,30 @@ public class MobileBKUConnector implements BkuSlConnector {
         return post;
     }
 
-    private static @Nonnull ClassicHttpRequest buildFormSubmit(@Nonnull ATrustParser.HTMLResult html, @Nonnull String submitButtonId) {
+    private static @Nonnull ClassicHttpRequest buildFormSubmit(@Nonnull ATrustParser.HTMLResult html, @CheckForNull String submitButton) {
         HttpPost post = new HttpPost(html.formTarget);
         
         var builder = MultipartEntityBuilder.create();
         for (var pair : html.iterateFormOptions())
             builder.addTextBody(pair.getKey(), pair.getValue());
-        if (html.submitButtons.containsKey(submitButtonId)) {
-            var submitInfo = html.submitButtons.get(submitButtonId);
-            builder.addTextBody(submitInfo.name, submitInfo.value);
-        } else {
-            log.warn("Attempted to use submit button #{} which does not exist. Omitting.", submitButtonId);
+
+        if (submitButton != null) {
+            var submitButtonElm = html.htmlDocument.selectFirst(submitButton);
+            if (submitButtonElm != null) {
+                if ("input".equalsIgnoreCase(submitButtonElm.tagName())) {
+                    if ("submit".equalsIgnoreCase(submitButtonElm.attr("type"))) {
+                        String name = submitButtonElm.attr("name");
+                        if (!name.isEmpty())
+                            builder.addTextBody(name, submitButtonElm.attr("value"));
+                    } else {
+                        log.warn("Skipped specified submitButton {}, type is {} (not submit)", submitButton, submitButtonElm.attr("type"));
+                    }
+                } else {
+                    log.warn("Skipped specified submitButton {}, tag name is {} (not input)", submitButton, submitButtonElm.tagName());
+                }
+            } else {
+                log.warn("Skipped specified submitButton {}, element not found", submitButton);
+            }
         }
 
         post.setEntity(builder.build());
@@ -198,26 +233,41 @@ public class MobileBKUConnector implements BkuSlConnector {
      * @return the next request to make, or null if the current response should be returned
      */
     private @Nonnull ClassicHttpRequest presentResponseToUserAndReturnNextRequest(@Nonnull ATrustParser.HTMLResult html) throws UserCancelledException {
+        if (html.errorBlock != null) {
+            try {
+                this.credentials.password = null;
+                this.state.clearRememberedPassword();
+
+                if (html.errorBlock.isRecoverable)
+                    this.state.showRecoverableError(html.errorBlock.errorText);
+                else
+                    this.state.showUnrecoverableError(html.errorBlock.errorText);
+                return buildFormSubmit(html, "#Button_Back");
+            } catch (UserCancelledException e) {
+                return buildFormSubmit(html, "#Button_Cancel");
+            }
+        }
         if (html.usernamePasswordBlock != null) {
             try {
                 while ((this.credentials.username == null) || (this.credentials.password == null)) {
                     this.state.getCredentialsFromUserTo(this.credentials, null); // TODO error message
                 }
                 html.usernamePasswordBlock.setUsernamePassword(this.credentials.username, this.credentials.password);
-                return buildFormSubmit(html, "Button_Identification");
+                return buildFormSubmit(html, "#Button_Identification");
             } catch (UserCancelledException e) {
-                return buildFormSubmit(html, "Button_Cancel");
+                return buildFormSubmit(html, "#Button_Cancel");
             }
         }
         if (html.qrCodeBlock != null) {
             try (final CloseableHttpClient httpClient = HttpClients.custom().disableRedirectHandling().build()) {
-                final HttpGet request = new HttpGet(html.qrCodeBlock.qrCodeURI);
+                final HttpGet request = new HttpGet(html.qrCodeBlock.pollingURI);
                 boolean[] done = new boolean[1];
                 done[0] = false;
                 Thread longPollThread = new Thread(() -> {
+                    long timeout = System.nanoTime() + (300l * 1000l * 1000l * 1000l); /* a-trust timeout is 5 minutes */
                     log.debug("longPollThread hello");
                     while (!done[0]) {
-                        try (final CloseableHttpResponse response = httpClient.execute(new HttpGet(html.qrCodeBlock.pollingURI))) {
+                        try (final CloseableHttpResponse response = httpClient.execute(request)) {
                             JSONObject jsonResponse = new JSONObject(EntityUtils.toString(response.getEntity()));
                             if (jsonResponse.getBoolean("Fin"))
                                 state.signalQRScanned();
@@ -233,8 +283,11 @@ public class MobileBKUConnector implements BkuSlConnector {
                                 break;
                             }
                         } catch (NoHttpResponseException e) {
-                            continue;
+                            if (timeout <= System.nanoTime())
+                                state.signalQRScanned(); /* reload to find the timeout error */
+                            continue; /* httpclient timeout */
                         } catch (IOException | ParseException | IllegalStateException e) {
+                            if (done[0]) break;
                             log.warn("QR code long polling exception", e);
                             /* sleep so we don't hammer a-trust too hard in case this goes wrong */
                             try { Thread.sleep(5000); } catch (InterruptedException e2) {}
@@ -244,19 +297,54 @@ public class MobileBKUConnector implements BkuSlConnector {
                 });
                 try {
                     longPollThread.start();
-                    MobileBKUState.QRResult result = this.state.showQRCode(html.qrCodeBlock.referenceValue, html.qrCodeBlock.qrCodeURI, null);
+                    MobileBKUState.QRResult result = this.state.showQRCode(html.qrCodeBlock.referenceValue, html.qrCodeBlock.qrCodeURI, html.signatureDataLink, html.smsTanLink != null, html.fido2Link != null, null);
                     switch (result) {
-                        case UPDATE: return new HttpGet(html.htmlDocument.baseUri());
-                        case TO_FIDO2: throw new IllegalStateException();
-                        case TO_SMS: throw new IllegalStateException();
+                        case UPDATE: break;
+                        case TO_FIDO2: if (html.fido2Link != null) return new HttpGet(html.fido2Link); break;
+                        case TO_SMS: if (html.smsTanLink != null) return new HttpGet(html.smsTanLink); break;
                     }
+                    return new HttpGet(html.htmlDocument.baseUri());
                 } finally {
                     done[0] = true;
                     request.abort();
                     try { longPollThread.join(1000); } catch (InterruptedException e) {}
                 }
             } catch (IOException e) {
-                log.warn("closing CloseableHttpClient threw exception", e);
+                log.warn("closing long-polling HttpClient threw exception", e);
+            }
+        }
+        if (html.fido2Block != null) {
+            // TODO composite for this
+            if  (WebAuthN.isAvailable()) {
+                try {
+                    var fido2Assertion = PublicKeyCredentialRequestOptions.FromJSONString(html.fido2Block.fidoOptions).get("https://service.a-trust.at");
+
+                    Base64.Encoder base64 = Base64.getEncoder();
+                    
+                    JSONObject aTrustAssertion = new JSONObject();
+                    aTrustAssertion.put("id", fido2Assertion.id);
+                    aTrustAssertion.put("rawId", base64.encodeToString(fido2Assertion.rawId));
+                    aTrustAssertion.put("type", fido2Assertion.type);
+                    aTrustAssertion.put("extensions", new JSONObject()); // TODO fix extensions in library
+
+                    JSONObject aTrustAssertionResponse = new JSONObject();
+                    aTrustAssertion.put("response", aTrustAssertionResponse);
+                    aTrustAssertionResponse.put("authenticatorData", base64.encodeToString(fido2Assertion.response.authenticatorData));
+                    aTrustAssertionResponse.put("clientDataJson", base64.encodeToString(fido2Assertion.response.clientDataJSON));
+                    aTrustAssertionResponse.put("signature", base64.encodeToString(fido2Assertion.response.signature));
+                    if (fido2Assertion.response.userHandle != null)
+                        aTrustAssertionResponse.put("userHandle", base64.encodeToString(fido2Assertion.response.userHandle));
+                    else
+                        aTrustAssertionResponse.put("userHandle", JSONObject.NULL);
+                    
+                    html.fido2Block.setFIDOResult(aTrustAssertion.toString());
+                    return buildFormSubmit(html, "#FidoContinue");
+                } catch (WebAuthNUserCancelled e) {
+                    log.debug("WebAuthN authentication cancelled by user");
+                    throw new UserCancelledException();
+                } catch (WebAuthNOperationFailed e) {
+                    log.warn("WebAuthN authentication failed", e);
+                }
             }
         }
         throw new IllegalStateException("No top-level block is set? Something has gone terribly wrong.");
diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/OLDmobile/ATrustHandler.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/OLDmobile/ATrustHandler.java
index 2e69e779..ab85645b 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/OLDmobile/ATrustHandler.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/OLDmobile/ATrustHandler.java
@@ -57,6 +57,7 @@ import at.asit.pdfover.gui.controls.Dialog.BUTTONS;
 import at.asit.pdfover.gui.controls.Dialog.ICON;
 import at.asit.pdfover.gui.exceptions.ATrustConnectionException;
 import at.asit.pdfover.gui.utils.FileUploadSource;
+import at.asit.pdfover.gui.utils.SWTUtils;
 import at.asit.pdfover.commons.Messages;
 import at.asit.pdfover.gui.workflow.states.LocalBKUState;
 import at.asit.pdfover.gui.workflow.states.MobileBKUState;
@@ -399,25 +400,13 @@ public class ATrustHandler {
 
 		status.errorMessage = null;
 
-		final Document responseDocument = Jsoup.parse(responseData);
-
 		if (responseData.contains("ExpiresInfo.aspx?sid=")) {
 			// Certificate expiration interstitial - skip
 			if (!expiryNoticeDisplayed) {
 				Display.getDefault().syncExec(()->  {
 					Dialog d = new Dialog(ATrustHandler.this.shell, Messages.getString("common.info"), Messages.getString("mobileBKU.certExpiresSoon"), BUTTONS.YES_NO, ICON.WARNING);
 					if (d.open() == SWT.YES) {
-						log.debug("Trying to open " + ACTIVATION_URL);
-						if (Desktop.isDesktopSupported()) {
-							try {
-								Desktop.getDesktop().browse(new URI(ACTIVATION_URL));
-								return;
-							} catch (Exception e) {
-								log.debug("Error opening URL", e);
-							}
-						}
-						log.info("SWT Desktop is not supported on this platform");
-						Program.launch(ACTIVATION_URL);
+						SWTUtils.openURL(ACTIVATION_URL);
 					}
 				});
 				expiryNoticeDisplayed = true;
diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/mobile/ATrustParser.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/mobile/ATrustParser.java
index 890ffad1..16f571a3 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/mobile/ATrustParser.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/bku/mobile/ATrustParser.java
@@ -24,8 +24,8 @@ public class ATrustParser {
     private static class ComponentParseFailed extends Exception {}
 
     private static class TopLevelFormBlock {
-        protected @Nonnull org.jsoup.nodes.Document htmlDocument;
-        protected @Nonnull Map<String, String> formOptions;
+        protected final @Nonnull org.jsoup.nodes.Document htmlDocument;
+        protected final @Nonnull Map<String, String> formOptions;
         protected TopLevelFormBlock(@Nonnull org.jsoup.nodes.Document d, @Nonnull Map<String,String> fO) { this.htmlDocument = d; this.formOptions = fO; }
 
         protected void abortIfElementMissing(@Nonnull String selector) throws ComponentParseFailed {
@@ -56,30 +56,49 @@ public class ATrustParser {
         }
     }
 
+    public static class ErrorBlock extends TopLevelFormBlock {
+        public final boolean isRecoverable;
+        public final @Nonnull String errorText;
+
+        private ErrorBlock(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull URI formTarget, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
+            super(htmlDocument, formOptions);
+            if (!formTarget.getPath().contains("/error.aspx"))
+                throw new ComponentParseFailed();
+            
+            this.isRecoverable = (htmlDocument.selectFirst("#Button_Back") != null);
+
+            String errorText = getElementEnsureNotNull("#Label1").ownText();
+            if (errorText.startsWith("Fehler:"))
+                errorText = errorText.substring(7);
+            this.errorText = ISNOTNULL(errorText.trim());
+        }
+    }
+
     public static class UsernamePasswordBlock extends TopLevelFormBlock {
-        private @Nonnull String usernameKey;
-        private @Nonnull String passwordKey;
-        public @CheckForNull String errorMessage;
+        private final @Nonnull String usernameKey;
+        private final @Nonnull String passwordKey;
+        public final @CheckForNull String errorMessage;
 
         public void setUsernamePassword(String username, String password) {
             formOptions.put(usernameKey, username); formOptions.put(passwordKey, password);
         }
 
-        private UsernamePasswordBlock(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
+        private UsernamePasswordBlock(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull URI formTarget, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
             super(htmlDocument, formOptions);
             abortIfElementMissing("#handynummer");
             this.usernameKey = getAttributeEnsureNotNull("#handynummer", "name");
             this.passwordKey = getAttributeEnsureNotNull("#signaturpasswort", "name");
+            this.errorMessage = null;
         }
     }
 
     public static class QRCodeBlock extends TopLevelFormBlock {
-        public @Nonnull String referenceValue;
-        public @Nonnull URI qrCodeURI;
-        public @Nonnull URI pollingURI;
-        public @Nullable String errorMessage;
+        public final @Nonnull String referenceValue;
+        public final @Nonnull URI qrCodeURI;
+        public final @Nonnull URI pollingURI;
+        public final @Nullable String errorMessage;
 
-        private QRCodeBlock(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
+        private QRCodeBlock(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull URI formTarget, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
             super(htmlDocument, formOptions);
             abortIfElementMissing("#qrimage");
             
@@ -102,17 +121,18 @@ public class ATrustParser {
                 log.warn("URI '{}' could not be parsed", pollingUriString);
                 throw new ComponentParseFailed();
             }
+
+            this.errorMessage = null;
         }
     }
 
     public static class Fido2Block extends TopLevelFormBlock {
-        private @Nonnull String fidoOptions;
-        private @Nonnull String credentialResultKey;
+        public final @Nonnull String fidoOptions;
+        private final @Nonnull String credentialResultKey;
 
-        public @Nonnull String getFIDOOptions() { return fidoOptions; }
         public void setFIDOResult(String result) { formOptions.put(credentialResultKey, result); }
 
-        private Fido2Block(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
+        private Fido2Block(@Nonnull org.jsoup.nodes.Document htmlDocument, @Nonnull URI formTarget, @Nonnull Map<String, String> formOptions) throws ComponentParseFailed {
             super(htmlDocument, formOptions);
             abortIfElementMissing("#fidoBlock");
             this.fidoOptions = getAttributeEnsureNotNull("#credentialOptions", "value");
@@ -125,22 +145,15 @@ public class ATrustParser {
         public final @Nonnull URI formTarget;
         public final @Nonnull Map<String, String> formOptions = new HashMap<>();
 
-        public static class NameValuePair {
-            public final @Nonnull String name;
-            public final @Nonnull String value;
-            public NameValuePair(@Nonnull String n, @Nonnull String v) { name = n; value = v; }
-        }
-        /**
-         * map: id -> (name, value)
-         */
-        public final @Nonnull Map<String, @CheckForNull NameValuePair> submitButtons = new HashMap<>();
-
         public @Nonnull Iterable<Map.Entry<String, String>> iterateFormOptions() { return ISNOTNULL(formOptions.entrySet()); }
 
-        /* optional mode switch links (any number may or may not be null) */
+        /* optional links (any number may or may not be null) */
+        public final @CheckForNull URI signatureDataLink;
+        public final @CheckForNull URI smsTanLink;
         public final @CheckForNull URI fido2Link;
 
         /* top-level blocks (exactly one is not null) */
+        public final @CheckForNull ErrorBlock errorBlock;
         public final @CheckForNull UsernamePasswordBlock usernamePasswordBlock;
         public final @CheckForNull QRCodeBlock qrCodeBlock;
         public final @CheckForNull Fido2Block fido2Block;
@@ -148,6 +161,7 @@ public class ATrustParser {
         private void validate() {
             Set<String> populated = new HashSet<>();
 
+            if (errorBlock != null) populated.add("errorBlock");
             if (usernamePasswordBlock != null) populated.add("usernamePasswordBlock");
             if (qrCodeBlock != null) populated.add("qrCodeBlock");
             if (fido2Block != null) populated.add("fido2Block");
@@ -178,7 +192,7 @@ public class ATrustParser {
          */
         private <T extends TopLevelFormBlock> @Nullable T TryParseMainBlock(Class<T> clazz) {
             try {
-                return clazz.getDeclaredConstructor(org.jsoup.nodes.Document.class, Map.class).newInstance(this.htmlDocument, this.formOptions);
+                return clazz.getDeclaredConstructor(org.jsoup.nodes.Document.class, URI.class, Map.class).newInstance(this.htmlDocument, this.formTarget, this.formOptions);
             } catch (NoSuchMethodException | InstantiationException | IllegalAccessException | IllegalArgumentException | SecurityException e) {
                 log.error("Internal parser error; check your method signatures?", e);
                 return null;
@@ -194,6 +208,7 @@ public class ATrustParser {
         }
 
         private HTMLResult(@Nonnull org.jsoup.nodes.Document htmlDocument) {
+            log.trace("Now parsing:\n{}", htmlDocument.toString());
             this.htmlDocument = htmlDocument;
 
             var forms = htmlDocument.getElementsByTag("form");
@@ -214,20 +229,21 @@ public class ATrustParser {
             for (var input : mainForm.select("input")) {
                 String name = input.attr("name");
 
-                /* special handling for submit inputs, they only get sent if they are "clicked" */
-                if ("submit".equals(input.attr("type"))) {
-                    if (name.isEmpty())
-                        this.submitButtons.put(input.attr("id"), null);
-                    else
-                        this.submitButtons.put(input.attr("id"), new NameValuePair(name, ISNOTNULL(input.attr("value"))));
-                } else {
-                    if (!name.isEmpty())
-                        this.formOptions.put(name, input.attr("value"));
-                }
+                if (name.isEmpty())
+                    continue;
+
+                /* submit inputs omitted here, they only get sent if they are "clicked", cf. MobileBKUConnector::buildFormSubmit */
+                if ("submit".equalsIgnoreCase(input.attr("type")))
+                    continue;
+                    
+                this.formOptions.put(name, input.attr("value"));
             }
 
+            this.signatureDataLink = getHrefIfExists("#LinkList a[href*=\"ShowSigobj.aspx\"]"); /* grr, they didn't give it an ID */
+            this.smsTanLink = getHrefIfExists("#SmsButton");
             this.fido2Link = getHrefIfExists("#FidoButton");
 
+            this.errorBlock = TryParseMainBlock(ErrorBlock.class);
             this.usernamePasswordBlock = TryParseMainBlock(UsernamePasswordBlock.class);
             this.qrCodeBlock = TryParseMainBlock(QRCodeBlock.class);
             this.fido2Block = TryParseMainBlock(Fido2Block.class);
diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUEnterNumberComposite.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUEnterNumberComposite.java
index 5f228bcb..6c75b160 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUEnterNumberComposite.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUEnterNumberComposite.java
@@ -72,12 +72,11 @@ public class MobileBKUEnterNumberComposite extends StateComposite {
 				MobileBKUEnterNumberComposite.this.btn_ok.setEnabled(false);

 

 			} catch(InvalidPasswordException ex) {

-				log.error("Validating input for Mobile BKU failed!", ex);

+				log.info("Validating input for Mobile BKU failed!", ex);

 				MobileBKUEnterNumberComposite.this.setErrorMessage(ex.getMessage());

 				MobileBKUEnterNumberComposite.this.txt_password.setFocus();

-			}

-			catch (Exception ex) {

-				log.error("Validating input for Mobile BKU failed!", ex);

+			} catch (Exception ex) {

+				log.info("Validating input for Mobile BKU failed!", ex);

 				MobileBKUEnterNumberComposite.this.setErrorMessage(Messages.getString("error.InvalidPhoneNumber"));

 				MobileBKUEnterNumberComposite.this.txt_number.setFocus();

 				return;

diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUEnterTANComposite.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUEnterTANComposite.java
index 7fe40ffe..ab5f5962 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUEnterTANComposite.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUEnterTANComposite.java
@@ -41,6 +41,8 @@ import org.eclipse.swt.widgets.Text;
 import org.slf4j.Logger;

 import org.slf4j.LoggerFactory;

 

+import com.beust.jcommander.internal.Nullable;

+

 import at.asit.pdfover.commons.Constants;

 import at.asit.pdfover.commons.Messages;

 import at.asit.pdfover.gui.utils.SWTUtils;

@@ -55,11 +57,6 @@ public class MobileBKUEnterTANComposite extends StateComposite {
 	 *

 	 */

 	private final class OkSelectionListener extends SelectionAdapter {

-		/**

-		 * Empty constructor

-		 */

-		public OkSelectionListener() {

-		}

 

 		@Override

 		public void widgetSelected(SelectionEvent e) {

@@ -127,25 +124,21 @@ public class MobileBKUEnterTANComposite extends StateComposite {
 

 	String refVal;

 

-	String signatureData;

-

-	/**

-	 * @return the signatureData

-	 */

-	public String getSignatureData() {

-		return this.signatureData;

-	}

+	URI signatureDataURI;

 

 	/**

 	 * @param signatureData

 	 *            the signatureData to set

 	 */

-	public void setSignatureData(String signatureData) {

-		this.signatureData = signatureData;

+	public void setSignatureDataURI(@Nullable URI uri) {

+		this.signatureDataURI = uri;

+		this.lnk_sig_data.setEnabled(uri != null);

 	}

 

 	String tan;

 

+	private Link lnk_sig_data;

+

 	private Label lblTries;

 	private Label lblRefValLabel;

 	private Label lblTan;

@@ -268,36 +261,6 @@ public class MobileBKUEnterTANComposite extends StateComposite {
 	}

 

 	/**

-	 * Selection Listener for open button

-	 */

-	private final class ShowSignatureDataListener extends SelectionAdapter {

-		/**

-		 * Empty constructor

-		 */

-		public ShowSignatureDataListener() {

-		}

-

-		@Override

-		public void widgetSelected(SelectionEvent e) {

-			try {

-				String signatureData = MobileBKUEnterTANComposite.this

-						.getSignatureData();

-				if (signatureData != null && !signatureData.equals("")) {

-					log.debug("Trying to open " + signatureData);

-					if (Desktop.isDesktopSupported()) {

-						Desktop.getDesktop().browse(new URI(signatureData));

-					} else {

-						log.info("SWT Desktop is not supported on this platform");

-						Program.launch(signatureData);

-					}

-				}

-			} catch (Exception ex) {

-				log.error("OpenSelectionListener: ", ex);

-			}

-		}

-	}

-

-	/**

 	 * Create the composite.

 	 *

 	 * @param parent

@@ -368,27 +331,22 @@ public class MobileBKUEnterTANComposite extends StateComposite {
 				if (text.length() > 3

 						&& MobileBKUEnterTANComposite.this.getRefVal()

 								.startsWith(text.trim())) {

-					MobileBKUEnterTANComposite.this.setMessage(Messages

-							.getString("error.EnteredReferenceValue"));

+					MobileBKUEnterTANComposite.this.setMessage(Messages.getString("error.EnteredReferenceValue"));

 				}

 			}

 		});

 

-		Link lnk_sig_data = new Link(containerComposite, SWT.NATIVE | SWT.RESIZE);

+		this.lnk_sig_data = new Link(containerComposite, SWT.NATIVE | SWT.RESIZE);

 		SWTUtils.anchor(lnk_sig_data).right(100,-20).top(0,20);

 		lnk_sig_data.setEnabled(true);

-		lnk_sig_data.addSelectionListener(new ShowSignatureDataListener());

-		SWTUtils.setLocalizedText(lnk_sig_data, "mobileBKU.show");

-		SWTUtils.setLocalizedToolTipText(lnk_sig_data, "mobileBKU.show_tooltip");

+		SWTUtils.addSelectionListener(lnk_sig_data, (e) -> { SWTUtils.openURL(this.signatureDataURI); });

 

 		this.btn_ok = new Button(containerComposite, SWT.NATIVE);

 		SWTUtils.anchor(btn_ok).right(100,-20).bottom(100,-20);

-		SWTUtils.setLocalizedText(btn_ok, "common.Ok");

 		this.btn_ok.addSelectionListener(new OkSelectionListener());

 		

 		this.btn_cancel = new Button(containerComposite, SWT.NATIVE);

 		SWTUtils.anchor(btn_cancel).right(btn_ok, -20).bottom(100, -20);

-		SWTUtils.setLocalizedText(btn_cancel, "common.Cancel");

 		this.btn_cancel.addSelectionListener(new CancelSelectionListener());

 

 		this.lblTries = new Label(containerComposite, SWT.WRAP | SWT.NATIVE);

@@ -417,7 +375,11 @@ public class MobileBKUEnterTANComposite extends StateComposite {
 	 */

 	@Override

 	public void reloadResources() {

+		SWTUtils.setLocalizedText(lnk_sig_data, "mobileBKU.show");

+		SWTUtils.setLocalizedToolTipText(lnk_sig_data, "mobileBKU.show_tooltip");

 		SWTUtils.setLocalizedText(lblRefValLabel, "tanEnter.ReferenceValue");

 		SWTUtils.setLocalizedText(lblTan, "tanEnter.TAN");

+		SWTUtils.setLocalizedText(btn_cancel, "common.Cancel");

+		SWTUtils.setLocalizedText(btn_ok, "common.Ok");

 	}

 }

diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUFingerprintComposite.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUFingerprintComposite.java
index af630b8d..afa71f9f 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUFingerprintComposite.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUFingerprintComposite.java
@@ -201,37 +201,6 @@ public class MobileBKUFingerprintComposite extends StateComposite {
 

 	}

 

-

-	/**

-	 * Selection Listener for open button

-	 */

-	private final class ShowSignatureDataListener extends SelectionAdapter {

-		/**

-		 * Empty constructor

-		 */

-		public ShowSignatureDataListener() {

-		}

-

-		@Override

-		public void widgetSelected(SelectionEvent e) {

-			try {

-				String signatureData = MobileBKUFingerprintComposite.this

-						.getSignatureData();

-				if (signatureData != null && !signatureData.equals("")) {

-					log.debug("Trying to open " + signatureData);

-					if (Desktop.isDesktopSupported()) {

-						Desktop.getDesktop().browse(new URI(signatureData));

-					} else {

-						log.info("SWT Desktop is not supported on this platform");

-						Program.launch(signatureData);

-					}

-				}

-			} catch (Exception ex) {

-				log.error("OpenSelectionListener: ", ex);

-			}

-		}

-	}

-

 	/**

 	 * Create the composite.

 	 *

@@ -279,7 +248,7 @@ public class MobileBKUFingerprintComposite extends StateComposite {
 		this.lnk_sig_data = new Link(containerComposite, SWT.NATIVE | SWT.RESIZE);

 		SWTUtils.anchor(lnk_sig_data).right(100, -20).top(0, 20);

 		this.lnk_sig_data.setEnabled(true);

-		this.lnk_sig_data.addSelectionListener(new ShowSignatureDataListener());

+		SWTUtils.addSelectionListener(lnk_sig_data, (e) -> { SWTUtils.openURL(getSignatureData()); });

 

 		this.btn_cancel = new Button(containerComposite, SWT.NATIVE);

 		SWTUtils.anchor(btn_cancel).right(100, -20).bottom(100, -20);

diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUQRComposite.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUQRComposite.java
index 3f1aa04d..652baed4 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUQRComposite.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/MobileBKUQRComposite.java
@@ -20,6 +20,9 @@ import java.awt.Desktop;
 import java.io.ByteArrayInputStream;

 import java.io.InputStream;

 import java.net.URI;

+import java.util.Objects;

+

+import javax.annotation.Nullable;

 

 import org.eclipse.swt.SWT;

 import org.eclipse.swt.SWTException;

@@ -51,52 +54,16 @@ import at.asit.pdfover.gui.workflow.states.State;
 public class MobileBKUQRComposite extends StateComposite {

 

 	/**

-	 *

-	 */

-	private final class SMSSelectionListener extends SelectionAdapter {

-		/**

-		 * Empty constructor

-		 */

-		public SMSSelectionListener() {

-		}

-

-		@Override

-		public void widgetSelected(SelectionEvent e) {

-			if(!MobileBKUQRComposite.this.btn_sms.getEnabled()) {

-				return;

-			}

-

-			MobileBKUQRComposite.this.setUserSMS(true);

-			MobileBKUQRComposite.this.btn_sms.setEnabled(false);

-		}

-	}

-

-	/**

-	 *

-	 */

-	private final class CancelSelectionListener extends SelectionAdapter {

-		/**

-		 * Empty constructor

-		 */

-		public CancelSelectionListener() {

-		}

-

-		@Override

-		public void widgetSelected(SelectionEvent e) {

-			MobileBKUQRComposite.this.setUserCancel(true);

-		}

-	}

-

-	/**

 	 * SLF4J Logger instance

 	 **/

 	static final Logger log = LoggerFactory.getLogger(MobileBKUQRComposite.class);

 

 	private Label lblQR;

 

-	private boolean userCancel = false;

-	private boolean userSMS = false;

-	private boolean done = false;

+	private boolean userCancelClicked = false;

+	private boolean userSMSClicked = false;

+	private boolean userFIDO2Clicked = false;

+	private boolean pollingDone = false;

 

 	private Label lblRefVal;

 

@@ -104,52 +71,24 @@ public class MobileBKUQRComposite extends StateComposite {
 

 	private ImageData currentQRImage;

 

-	private String signatureData;

-

-	/**

-	 * @return the signatureData

-	 */

-	public String getSignatureData() {

-		return this.signatureData;

-	}

-

-	/**

-	 * @param signatureData

-	 *            the signatureData to set

-	 */

-	public void setSignatureData(String signatureData) {

-		this.signatureData = signatureData;

-	}

+	private URI signatureDataURI;

 

 	private Label lblError;

 	private Label lblRefValLabel;

 	private Label lblQRLabel;

 

+	private Button btn_fido2;

 	private Button btn_sms;

 	private Button btn_cancel;

 

 	private Link lnk_sig_data;

 

-	/**

-	 * @return the userCancel

-	 */

-	public boolean isUserCancel() {

-		return this.userCancel;

-	}

-

-	/**

-	 * @return the userSMS

-	 */

-	public boolean isUserSMS() {

-		return this.userSMS;

-	}

-

-	/**

-	 * @return the done

-	 */

-	public boolean isDone() {

-		return this.done;

-	}

+	public void signalPollingDone() { this.pollingDone = true; getDisplay().wake(); }

+	public boolean isDone() { return (this.userCancelClicked || this.userSMSClicked || this.userFIDO2Clicked || this.pollingDone); }

+	public boolean wasCancelClicked() { return this.userCancelClicked; }

+	public boolean wasSMSClicked() { return this.userSMSClicked; }

+	public boolean wasFIDO2Clicked() { return this.userFIDO2Clicked; }

+	public void reset() { this.userCancelClicked = this.userSMSClicked = this.userFIDO2Clicked = this.pollingDone = false; }

 

 	/**

 	 * Set an error message

@@ -163,48 +102,10 @@ public class MobileBKUQRComposite extends StateComposite {
 					Messages.getString("error.Title") + ": " + errorMessage);

 	}

 

-	/**

-	 * @param userCancel

-	 *            the userCancel to set

-	 */

-	public void setUserCancel(boolean userCancel) {

-		this.userCancel = userCancel;

-	}

-

-	/**

-	 * @param userSMS

-	 *            the userSMS to set

-	 */

-	public void setUserSMS(boolean userSMS) {

-		this.userSMS = userSMS;

-	}

-

-	/**

-	 * @param done

-	 *            the done to set

-	 */

-	public void setDone(boolean done) {

-		this.done = done;

-	}

-

-	/**

-	 * @return the reference value

-	 */

-	public String getRefVal() {

-		return this.refVal;

-	}

-

-	/**

-	 * @param refVal

-	 *            the reference value to set

-	 */

+	public String getRefVal() { return this.refVal; }

 	public void setRefVal(String refVal) {

-		if (this.refVal != null) {

-			this.refVal = refVal.trim();

-			this.lblRefVal.setText(this.refVal);

-		} else {

-			this.lblRefVal.setText("");

-		}

+		this.refVal = (refVal != null) ? refVal.trim() : null;

+		this.lblRefVal.setText(Objects.requireNonNullElse(this.refVal, ""));

 	}

 

 	private void updateQRImage() {

@@ -238,34 +139,17 @@ public class MobileBKUQRComposite extends StateComposite {
 		updateQRImage();

 	}

 

-	/**

-	 * Selection Listener for open button

-	 */

-	private final class ShowSignatureDataListener extends SelectionAdapter {

-		/**

-		 * Empty constructor

-		 */

-		public ShowSignatureDataListener() {

-		}

+	public void setSMSEnabled(boolean state) {

+		this.btn_sms.setEnabled(state);

+	}

 

-		@Override

-		public void widgetSelected(SelectionEvent e) {

-			try {

-				String signatureData = MobileBKUQRComposite.this

-						.getSignatureData();

-				if (signatureData != null && !signatureData.equals("")) {

-					log.debug("Trying to open " + signatureData);

-					if (Desktop.isDesktopSupported()) {

-						Desktop.getDesktop().browse(new URI(signatureData));

-					} else {

-						log.info("SWT Desktop is not supported on this platform");

-						Program.launch(signatureData);

-					}

-				}

-			} catch (Exception ex) {

-				log.error("OpenSelectionListener: ", ex);

-			}

-		}

+	public void setFIDO2Enabled(boolean state) {

+		this.btn_fido2.setEnabled(state);

+	}

+

+	public void setSignatureDataURI(@Nullable URI uri) {

+		this.signatureDataURI = uri;

+		this.lnk_sig_data.setEnabled(uri != null);

 	}

 

 	/**

@@ -317,16 +201,20 @@ public class MobileBKUQRComposite extends StateComposite {
 

 		this.lnk_sig_data = new Link(containerComposite, SWT.NATIVE | SWT.RESIZE);

 		SWTUtils.anchor(lnk_sig_data).right(100, -20).top(0, 20);

-		this.lnk_sig_data.setEnabled(true);

-		this.lnk_sig_data.addSelectionListener(new ShowSignatureDataListener());

+		SWTUtils.addSelectionListener(lnk_sig_data, (e) -> { SWTUtils.openURL(this.signatureDataURI); });

 

 		this.btn_cancel = new Button(containerComposite, SWT.NATIVE);

 		SWTUtils.anchor(btn_cancel).right(100, -20).bottom(100, -5);

-		this.btn_cancel.addSelectionListener(new CancelSelectionListener());

+		SWTUtils.addSelectionListener(btn_cancel, (e) -> { this.userCancelClicked = true; });

 

 		this.btn_sms = new Button(containerComposite, SWT.NATIVE);

 		SWTUtils.anchor(btn_sms).right(btn_cancel, -20).bottom(100, -5);

-		this.btn_sms.addSelectionListener(new SMSSelectionListener());

+		SWTUtils.addSelectionListener(btn_sms, (e) -> { this.userSMSClicked = true; });

+

+		this.btn_fido2 = new Button(containerComposite, SWT.NATIVE);

+		SWTUtils.anchor(btn_fido2).right(btn_sms, -20).bottom(100, -5);

+		SWTUtils.addSelectionListener(btn_fido2, (e) -> {this.userFIDO2Clicked = true; });

+

 

 		SWTUtils.anchor(lblQR).left(50, 10).right(100, -20).top(lblRefVal, 10).bottom(btn_sms, -10);

 

@@ -364,5 +252,6 @@ public class MobileBKUQRComposite extends StateComposite {
 		SWTUtils.setLocalizedToolTipText(lnk_sig_data, "mobileBKU.show_tooltip");

 		SWTUtils.setLocalizedText(btn_cancel, "common.Cancel");

 		SWTUtils.setLocalizedText(btn_sms, "tanEnter.SMS");

+		SWTUtils.setLocalizedText(btn_fido2, "tanEnter.FIDO2");

 	}

 }

diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/configuration/AboutComposite.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/configuration/AboutComposite.java
index 35b73e7b..b4675e2a 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/configuration/AboutComposite.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/composites/configuration/AboutComposite.java
@@ -47,6 +47,7 @@ public class AboutComposite extends ConfigurationCompositeBase {
 		this.lnkAbout = new Link(this, SWT.WRAP);
 		SWTUtils.anchor(lnkAbout).top(0,5).right(100,-5).left(0,5);
 		SWTUtils.setFontHeight(lnkAbout, Constants.TEXT_SIZE_NORMAL);
+		SWTUtils.addSelectionListener(lnkAbout, (e) -> { SWTUtils.openURL(Messages.getString("config.LicenseURL")); });
 
 		this.lblDataProtection = new Label(this, SWT.WRAP);
 		SWTUtils.anchor(lblDataProtection).top(lnkAbout, 15).left(0,5).right(100,-5);
@@ -56,6 +57,7 @@ public class AboutComposite extends ConfigurationCompositeBase {
 		this.lnkDataProtection = new Link(this, SWT.WRAP);
 		SWTUtils.anchor(lnkDataProtection).top(lblDataProtection,10).left(0,5).right(100,-5);
 		SWTUtils.setFontHeight(lnkDataProtection, Constants.TEXT_SIZE_NORMAL);
+		SWTUtils.addSelectionListener(lnkDataProtection, (e) -> { SWTUtils.openURL(Messages.getString("config.DataProtectionURL")); });
 
 		this.lnkUpdateCheckStatus = new Link(this, SWT.NONE);
 		SWTUtils.anchor(lnkUpdateCheckStatus).bottom(100, -5).left(0,5);
@@ -84,56 +86,13 @@ public class AboutComposite extends ConfigurationCompositeBase {
 
 		SWTUtils.reanchor(lnkDataProtection).bottom(btnUpdateCheck,-5);
 
-		this.lnkAbout.addSelectionListener(new SelectionAdapter() {
-			@Override
-			public void widgetSelected(SelectionEvent e) {
-				try {
-					URI url = new URI(Messages.getString("config.LicenseURL"));
-					log.debug("Trying to open " + url.toString());
-					if (Desktop.isDesktopSupported()) {
-						Desktop.getDesktop().browse(url);
-					} else {
-						log.info("AWT Desktop is not supported on this platform");
-						Program.launch(url.toString());
-					}
-				} catch (IOException ex) {
-					log.error("AboutComposite: ", ex);
-				} catch (URISyntaxException ex) {
-					log.error("AboutComposite: ", ex);
-				}
-			}
-		});
-
-		this.lnkDataProtection.addSelectionListener(new SelectionAdapter() {
-			@Override
-			public void widgetSelected(SelectionEvent e) {
-				try {
-					URI url = new URI(Messages.getString("config.DataProtectionURL"));
-					log.debug("Trying to open " + url.toString());
-					if (Desktop.isDesktopSupported()) {
-						Desktop.getDesktop().browse(url);
-					} else {
-						log.info("AWT Desktop is not supported on this platform");
-						Program.launch(url.toString());
-					}
-				} catch (IOException ex) {
-					log.error("AboutComposite: ", ex);
-				} catch (URISyntaxException ex) {
-					log.error("AboutComposite: ", ex);
-				}
-			}
-		});
-
-		this.btnOpenLogDirectory.addSelectionListener(new SelectionAdapter() {
-			@Override
-			public void widgetSelected(SelectionEvent e) {
-				try
-				{
-					if (Desktop.isDesktopSupported())
-						Desktop.getDesktop().open(new File(Constants.CONFIG_DIRECTORY + File.separator + "logs"));
-				} catch (Exception ex) {
-					log.warn("Failed to open log directory: ", ex);
-				}
+		SWTUtils.addSelectionListener(btnOpenLogDirectory, (e) -> {
+			try
+			{
+				if (Desktop.isDesktopSupported())
+					Desktop.getDesktop().open(new File(Constants.CONFIG_DIRECTORY + File.separator + "logs"));
+			} catch (Exception ex) {
+				log.warn("Failed to open log directory: ", ex);
 			}
 		});
 
diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/utils/SWTUtils.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/utils/SWTUtils.java
index ef93e3e9..d276ecd6 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/utils/SWTUtils.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/utils/SWTUtils.java
@@ -1,9 +1,14 @@
 package at.asit.pdfover.gui.utils;
 
+import java.awt.Desktop;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.net.URI;
+import java.net.URISyntaxException;
 import java.util.function.Consumer;
 
+import javax.annotation.Nullable;
+
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.ScrolledComposite;
 import org.eclipse.swt.events.SelectionAdapter;
@@ -14,6 +19,7 @@ import org.eclipse.swt.graphics.FontData;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.layout.FormAttachment;
 import org.eclipse.swt.layout.FormData;
+import org.eclipse.swt.program.Program;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Event;
@@ -171,4 +177,26 @@ public final class SWTUtils {
 			log.error("Failed to add selection listener on object of type {}", swtObj.getClass().getSimpleName(), e);
 		}
 	}
+
+	public static void openURL(@Nullable URI uri) {
+		try {
+			if (uri == null) return;
+			if (Desktop.isDesktopSupported()) {
+				Desktop.getDesktop().browse(uri);
+			} else {
+				Program.launch(uri.toURL().toExternalForm());
+			}
+		} catch (Exception e) {
+			log.warn("Failed to open URI: {}", uri, e);
+		}
+	}
+
+	public static void openURL(@Nullable String uri) {
+		if (uri == null) return;
+		try {
+			openURL(new URI(uri));
+		} catch (URISyntaxException e) {
+			log.warn("Failed to open URI: {}", uri, e);
+		}
+	}
 }
diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/utils/UpdateCheckManager.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/utils/UpdateCheckManager.java
index 92104176..133ecdcb 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/utils/UpdateCheckManager.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/utils/UpdateCheckManager.java
@@ -70,18 +70,7 @@ public final class UpdateCheckManager {
                             BUTTONS.OK_CANCEL, ICON.INFORMATION);
 
                     if (info.open() == SWT.OK)
-                    {
-                        if (Desktop.isDesktopSupported()) {
-                            try {
-                                Desktop.getDesktop().browse(new URI(Constants.UPDATE_URL));
-                            } catch (Exception e) {
-                                log.error("Error opening update location ", e);
-                            }
-                        } else {
-                            log.info("SWT Desktop is not supported on this platform");
-                            Program.launch(Constants.UPDATE_URL);
-                        }
-                    }
+                        SWTUtils.openURL(Constants.UPDATE_URL);
                 });
             }
 
diff --git a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/workflow/states/MobileBKUState.java b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/workflow/states/MobileBKUState.java
index 9c3fc807..563b3b88 100644
--- a/pdf-over-gui/src/main/java/at/asit/pdfover/gui/workflow/states/MobileBKUState.java
+++ b/pdf-over-gui/src/main/java/at/asit/pdfover/gui/workflow/states/MobileBKUState.java
@@ -190,6 +190,32 @@ public class MobileBKUState extends State {
 		});

 	}

 

+	/**

+	 * Show an error message to the user with "retry" or "cancel" as options

+	 * returns normally on "retry", throws UserCancelledException on "cancel"

+	 */

+	public void showRecoverableError(final @Nonnull String errorMessage) throws UserCancelledException {

+		Display.getDefault().syncCall(() -> {

+			ErrorDialog error = new ErrorDialog(getStateMachine().getMainShell(), errorMessage, BUTTONS.RETRY_CANCEL);

+			int result = error.open();

+			if (result == SWT.CANCEL)

+				throw new UserCancelledException();

+			return true; /* dummy return */

+		});

+	}

+

+	/**

+	 * Show an error message to the user with only an "ok" option

+	 * throws UserCancelledException afterwards

+	 */

+	public void showUnrecoverableError(final @Nonnull String errorMessage) throws UserCancelledException {

+		Display.getDefault().syncCall(() -> {

+			ErrorDialog error = new ErrorDialog(getStateMachine().getMainShell(), errorMessage, BUTTONS.OK);

+			error.open();

+			throw new UserCancelledException();

+		});

+	}

+

 	public static class UsernameAndPassword {

 		public @CheckForNull String username;

 		public @CheckForNull String password;

@@ -313,7 +339,7 @@ public class MobileBKUState extends State {
 			if (!tan.isUserAck()) {

 				// we need the TAN

 				tan.setRefVal(mobileStatus.refVal);

-				tan.setSignatureData(mobileStatus.signatureDataURL);

+				try { tan.setSignatureDataURI(new URI(mobileStatus.signatureDataURL)); } catch (URISyntaxException e) {}

 				tan.setErrorMessage(mobileStatus.errorMessage);

 				if (mobileStatus.tanTries < ATrustStatus.MOBILE_MAX_TAN_TRIES

 						&& mobileStatus.tanTries > 0) {

@@ -367,7 +393,7 @@ public class MobileBKUState extends State {
 	 * it is the responsibility of the caller to perform AJAX long polling

 	 * @return

 	 */

-	public QRResult showQRCode(@Nonnull String referenceValue, @Nonnull URI qrCodeURI, @Nullable String errorMessage) throws UserCancelledException {

+	public QRResult showQRCode(final @Nonnull String referenceValue, @Nonnull URI qrCodeURI, @Nullable URI signatureDataURI, final boolean showSmsTan, final boolean showFido2, final @Nullable String errorMessage) throws UserCancelledException {

 		byte[] qrCode;

 		try (final CloseableHttpClient httpClient = HttpClients.createDefault()) {

 			try (final CloseableHttpResponse response = httpClient.execute(new HttpGet(qrCodeURI))) {

@@ -381,18 +407,18 @@ public class MobileBKUState extends State {
 		final byte[] qrCodeCopy = qrCode; /* because java is silly */

 		return Display.getDefault().syncCall(() -> {

 			MobileBKUQRComposite qr = getMobileBKUQRComposite();

-			qr.setUserCancel(false);

-			qr.setUserSMS(false);

-			qr.setDone(false);

+			qr.reset();

 

-			qr.setRefVal(status.refVal);

-			qr.setSignatureData(status.signatureDataURL);

-			qr.setErrorMessage(status.errorMessage);

+			qr.setRefVal(referenceValue);

+			qr.setSignatureDataURI(signatureDataURI);

+			qr.setErrorMessage(errorMessage);

 			qr.setQR(qrCodeCopy);

+			qr.setSMSEnabled(showSmsTan);

+			qr.setFIDO2Enabled(showFido2);

 			getStateMachine().display(qr);

 

 			Display display = getStateMachine().getMainShell().getDisplay();

-			while (!qr.isUserCancel() && !qr.isUserSMS() && !qr.isDone()) {

+			while (!qr.isDone()) {

 				if (!display.readAndDispatch()) {

 					display.sleep();

 				}

@@ -400,18 +426,18 @@ public class MobileBKUState extends State {
 

 			getStateMachine().display(this.getWaitingComposite());

 

-			if (qr.isUserCancel()) {

+			if (qr.wasCancelClicked()) {

 				clearRememberedPassword();

 				throw new UserCancelledException();

 			}

 

-			if (qr.isUserSMS())

+			if (qr.wasSMSClicked())

 				return QRResult.TO_SMS;

-

-			if (qr.isDone())

-				return QRResult.UPDATE;

 			

-			throw new RuntimeException("unexpected display wake");

+			if (qr.wasFIDO2Clicked())

+				return QRResult.TO_FIDO2;

+

+			return QRResult.UPDATE;

 		});

 	}

 

@@ -420,10 +446,7 @@ public class MobileBKUState extends State {
 	 * (any ongoing showQRCode call will then return)

 	 */

 	public void signalQRScanned() {

-		getMobileBKUQRComposite().setDone(true);

-		Display display = getStateMachine().

-				getMainShell().getDisplay();

-		display.wake();

+		getMobileBKUQRComposite().signalPollingDone();

 	}

 

 	/**

@@ -455,7 +478,7 @@ public class MobileBKUState extends State {
 			}

 		}, 0, 5000);

 

-		QRResult result = showQRCode(status.refVal, new URI(status.baseURL).resolve(status.qrCodeURL), status.errorMessage);

+		QRResult result = showQRCode(status.refVal, new URI(status.baseURL).resolve(status.qrCodeURL), new URI(status.baseURL).resolve(status.signatureDataURL), true, false, status.errorMessage);

 		checkDone.cancel();

 		if (result == QRResult.TO_SMS)

 			status.qrCodeURL = null;

diff --git a/pdf-over-gui/src/main/resources/at/asit/pdfover/gui/messages.properties b/pdf-over-gui/src/main/resources/at/asit/pdfover/gui/messages.properties
index 65e353a1..2d5d74f1 100644
--- a/pdf-over-gui/src/main/resources/at/asit/pdfover/gui/messages.properties
+++ b/pdf-over-gui/src/main/resources/at/asit/pdfover/gui/messages.properties
@@ -253,6 +253,7 @@ tanEnter.FP=Please open the Handy-Signature app\nand confirm the signature.
 tanEnter.QR=QR code\:
 tanEnter.ReferenceValue=Reference value\:
 tanEnter.SMS=Request &SMS
+tanEnter.FIDO2=&FIDO2
 tanEnter.TAN=TAN\:
 tanEnter.tries=%d tries left\!
 tanEnter.try=Only 1 try left\!
diff --git a/pdf-over-gui/src/main/resources/at/asit/pdfover/gui/messages_de.properties b/pdf-over-gui/src/main/resources/at/asit/pdfover/gui/messages_de.properties
index a2afff03..a75dfbb4 100644
--- a/pdf-over-gui/src/main/resources/at/asit/pdfover/gui/messages_de.properties
+++ b/pdf-over-gui/src/main/resources/at/asit/pdfover/gui/messages_de.properties
@@ -244,6 +244,7 @@ tanEnter.QR=QR Code\:
 tanEnter.FP=Bitte öffnen Sie die Handy-Signatur App\nund bestätigen Sie die Signatur.
 tanEnter.ReferenceValue=Vergleichswert\:
 tanEnter.SMS=&SMS anfordern
+tanEnter.FIDO2=&FIDO2
 tanEnter.TAN=TAN\:
 tanEnter.APPTAN=Bitte öffnen Sie die Handy-Signatur App\nTAN\:
 tanEnter.tries=%d Versuche übrig\!
diff --git a/pdf-over-gui/src/main/resources/logback.xml b/pdf-over-gui/src/main/resources/logback.xml
index 866a82f7..4e33264a 100644
--- a/pdf-over-gui/src/main/resources/logback.xml
+++ b/pdf-over-gui/src/main/resources/logback.xml
@@ -22,6 +22,7 @@
     </triggeringPolicy>
   </appender>
   <logger name="at.asit.pdfover" level="INFO"/>
+  <logger name="at.asit.pdfover.gui.bku" level="TRACE"/>
   <root level="WARN">
     <appender-ref ref="STDOUT"/>
     <appender-ref ref="LOGFILE"/>