add option to optimize transactions for privacy and display privacy analysis

drongo

@@ -1 +1 @@
-Subproject commit 81c202198e8b057271414d15259df556a90bc6f1
+Subproject commit 7ac4bce14f04163c57b94e34945b5e4a1bf79eb6

src/main/java/com/sparrowwallet/sparrow/control/HelpLabel.java

@@ -2,13 +2,13 @@ package com.sparrowwallet.sparrow.control;
 
 import com.sparrowwallet.sparrow.glyphfont.FontAwesome5;
 import javafx.application.Platform;
+import javafx.beans.property.ObjectProperty;
+import javafx.beans.property.SimpleObjectProperty;
 import javafx.beans.property.SimpleStringProperty;
 import javafx.beans.property.StringProperty;
-import javafx.event.EventHandler;
+import javafx.scene.Node;
-import javafx.geometry.Bounds;
 import javafx.scene.control.Label;
 import javafx.scene.control.Tooltip;
-import javafx.scene.input.MouseEvent;
 import javafx.util.Duration;
 import org.controlsfx.glyphfont.Glyph;
 
@@ -19,6 +19,7 @@ public class HelpLabel extends Label {
         super("", getHelpGlyph());
         tooltip = new Tooltip();
         tooltip.textProperty().bind(helpTextProperty());
+        tooltip.graphicProperty().bind(helpGraphicProperty());
         tooltip.setShowDuration(Duration.seconds(15));
         getStyleClass().add("help-label");
 
@@ -49,4 +50,18 @@ public class HelpLabel extends Label {
     public final String getHelpText() {
         return helpText == null ? "" : helpText.getValue();
     }
+
+    public ObjectProperty<Node> helpGraphicProperty() {
+        if(helpGraphicProperty == null) {
+            helpGraphicProperty = new SimpleObjectProperty<Node>(this, "helpGraphic", null);
+        }
+
+        return helpGraphicProperty;
+    }
+
+    private ObjectProperty<Node> helpGraphicProperty;
+
+    public final void setHelpGraphic(Node graphic) {
+        helpGraphicProperty().setValue(graphic);
+    }
 }

src/main/java/com/sparrowwallet/sparrow/control/TransactionDiagram.java

@@ -162,28 +162,28 @@ public class TransactionDiagram extends GridPane {
             topYaxis.setStartX(width * 0.5);
             topYaxis.setStartY(getDiagramHeight() * 0.5 - 20.0);
             topYaxis.setEndX(width * 0.5);
-            topYaxis.setEndY(0);
+            topYaxis.setEndY(10);
             topYaxis.getStyleClass().add("inputs-type");
 
             Line topBracket = new Line();
             topBracket.setStartX(width * 0.5);
-            topBracket.setStartY(0);
+            topBracket.setStartY(10);
             topBracket.setEndX(width);
-            topBracket.setEndY(0);
+            topBracket.setEndY(10);
             topBracket.getStyleClass().add("inputs-type");
 
             Line bottomYaxis = new Line();
             bottomYaxis.setStartX(width * 0.5);
-            bottomYaxis.setStartY(getDiagramHeight());
+            bottomYaxis.setStartY(getDiagramHeight() - 10);
             bottomYaxis.setEndX(width * 0.5);
             bottomYaxis.setEndY(getDiagramHeight() * 0.5 + 20.0);
             bottomYaxis.getStyleClass().add("inputs-type");
 
             Line bottomBracket = new Line();
             bottomBracket.setStartX(width * 0.5);
-            bottomBracket.setStartY(getDiagramHeight());
+            bottomBracket.setStartY(getDiagramHeight() - 10);
             bottomBracket.setEndX(width);
-            bottomBracket.setEndY(getDiagramHeight());
+            bottomBracket.setEndY(getDiagramHeight() - 10);
             bottomBracket.getStyleClass().add("inputs-type");
 
             group.getChildren().addAll(widthLine, topYaxis, topBracket, bottomYaxis, bottomBracket);
@@ -344,7 +344,7 @@ public class TransactionDiagram extends GridPane {
         group.getChildren().add(yaxisLine);
 
         double width = 140.0;
-        int numOutputs = displayedPayments.size() + (walletTx.getChangeNode() == null ? 1 : 2);
+        int numOutputs = displayedPayments.size() + walletTx.getChangeMap().size() + 1;
         for(int i = 1; i <= numOutputs; i++) {
             CubicCurve curve = new CubicCurve();
             curve.getStyleClass().add("output-line");
@@ -391,15 +391,16 @@ public class TransactionDiagram extends GridPane {
             outputsBox.getChildren().add(createSpacer());
         }
 
-        if(walletTx.getChangeNode() != null) {
+        for(Map.Entry<WalletNode, Long> changeEntry : walletTx.getChangeMap().entrySet()) {
+            WalletNode changeNode = changeEntry.getKey();
             WalletNode defaultChangeNode = walletTx.getWallet().getFreshNode(KeyPurpose.CHANGE);
-            boolean overGapLimit = (walletTx.getChangeNode().getIndex() - defaultChangeNode.getIndex()) > walletTx.getWallet().getGapLimit();
+            boolean overGapLimit = (changeNode.getIndex() - defaultChangeNode.getIndex()) > walletTx.getWallet().getGapLimit();
 
             HBox actionBox = new HBox();
-            String changeDesc = walletTx.getChangeAddress().toString().substring(0, 8) + "...";
+            String changeDesc = walletTx.getChangeAddress(changeNode).toString().substring(0, 8) + "...";
             Label changeLabel = new Label(changeDesc, overGapLimit ? getChangeWarningGlyph() : getChangeGlyph());
             changeLabel.getStyleClass().addAll("output-label", "change-label");
-            Tooltip changeTooltip = new Tooltip("Change of " + getSatsValue(walletTx.getChangeAmount()) + " sats to " + walletTx.getChangeNode().getDerivationPath().replace("m", "..") + "\n" + walletTx.getChangeAddress().toString() + (overGapLimit ? "\nAddress is beyond the gap limit!" : ""));
+            Tooltip changeTooltip = new Tooltip("Change of " + getSatsValue(changeEntry.getValue()) + " sats to " + changeNode.getDerivationPath().replace("m", "..") + "\n" + walletTx.getChangeAddress(changeNode).toString() + (overGapLimit ? "\nAddress is beyond the gap limit!" : ""));
             changeTooltip.getStyleClass().add("change-label");
             changeTooltip.setShowDelay(new Duration(TOOLTIP_SHOW_DELAY));
             changeLabel.setTooltip(changeTooltip);
@@ -469,7 +470,9 @@ public class TransactionDiagram extends GridPane {
     }
 
     public Glyph getOutputGlyph(Payment payment) {
-        if(walletTx.isConsolidationSend(payment)) {
+        if(payment.getType().equals(Payment.Type.FAKE_MIX)) {
+            return getFakeMixGlyph();
+        } else if(walletTx.isConsolidationSend(payment)) {
             return getConsolidationGlyph();
         } else if(walletTx.isPremixSend(payment)) {
             return getPremixGlyph();
@@ -526,6 +529,13 @@ public class TransactionDiagram extends GridPane {
         return whirlpoolFeeGlyph;
     }
 
+    public static Glyph getFakeMixGlyph() {
+        Glyph fakeMixGlyph = new Glyph(FontAwesome5.FONT_NAME, FontAwesome5.Glyph.THEATER_MASKS);
+        fakeMixGlyph.getStyleClass().add("fakemix-icon");
+        fakeMixGlyph.setFontSize(12);
+        return fakeMixGlyph;
+    }
+
     public static Glyph getTxoGlyph() {
         return getChangeGlyph();
     }

src/main/java/com/sparrowwallet/sparrow/glyphfont/FontAwesome5.java

@@ -33,6 +33,7 @@ public class FontAwesome5 extends GlyphFont {
         EXTERNAL_LINK_ALT('\uf35d'),
         ELLIPSIS_H('\uf141'),
         EYE('\uf06e'),
+        FEATHER_ALT('\uf56b'),
         FILE_CSV('\uf6dd'),
         HAND_HOLDING('\uf4bd'),
         HAND_HOLDING_MEDICAL('\ue05c'),
@@ -42,6 +43,7 @@ public class FontAwesome5 extends GlyphFont {
         LAPTOP('\uf109'),
         LOCK('\uf023'),
         LOCK_OPEN('\uf3c1'),
+        MINUS_CIRCLE('\uf056'),
         PEN_FANCY('\uf5ac'),
         PLUS('\uf067'),
         PLAY_CIRCLE('\uf144'),
@@ -58,13 +60,15 @@ public class FontAwesome5 extends GlyphFont {
         SQUARE('\uf0c8'),
         SNOWFLAKE('\uf2dc'),
         SUN('\uf185'),
+        THEATER_MASKS('\uf630'),
         TIMES_CIRCLE('\uf057'),
         TOGGLE_OFF('\uf204'),
         TOGGLE_ON('\uf205'),
         TOOLS('\uf7d9'),
         UNDO('\uf0e2'),
         USER_FRIENDS('\uf500'),
-        WALLET('\uf555');
+        WALLET('\uf555'),
+        WEIGHT('\uf496');
 
         private final char ch;
 

src/main/java/com/sparrowwallet/sparrow/io/Config.java

@@ -6,6 +6,7 @@ import com.sparrowwallet.sparrow.Mode;
 import com.sparrowwallet.sparrow.Theme;
 import com.sparrowwallet.sparrow.net.*;
 import com.sparrowwallet.sparrow.wallet.FeeRatesSelection;
+import com.sparrowwallet.sparrow.wallet.OptimizationStrategy;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -26,6 +27,7 @@ public class Config {
     private BitcoinUnit bitcoinUnit;
     private FeeRatesSource feeRatesSource;
     private FeeRatesSelection feeRatesSelection;
+    private OptimizationStrategy sendOptimizationStrategy;
     private Currency fiatCurrency;
     private ExchangeSource exchangeSource;
     private boolean loadRecentWallets = true;
@@ -139,6 +141,15 @@ public class Config {
         flush();
     }
 
+    public OptimizationStrategy getSendOptimizationStrategy() {
+        return sendOptimizationStrategy;
+    }
+
+    public void setSendOptimizationStrategy(OptimizationStrategy sendOptimizationStrategy) {
+        this.sendOptimizationStrategy = sendOptimizationStrategy;
+        flush();
+    }
+
     public Currency getFiatCurrency() {
         return fiatCurrency;
     }

src/main/java/com/sparrowwallet/sparrow/wallet/OptimizationStrategy.java

@@ -0,0 +1,20 @@
+package com.sparrowwallet.sparrow.wallet;
+
+public enum OptimizationStrategy {
+    EFFICIENCY("Efficiency"), PRIVACY("Privacy");
+
+    private final String name;
+
+    private OptimizationStrategy(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public String toString() {
+        return name;
+    }
+}

src/main/java/com/sparrowwallet/sparrow/wallet/SendController.java

@@ -3,6 +3,7 @@ package com.sparrowwallet.sparrow.wallet;
 import com.google.common.eventbus.Subscribe;
 import com.samourai.whirlpool.client.whirlpool.beans.Pool;
 import com.sparrowwallet.drongo.BitcoinUnit;
+import com.sparrowwallet.drongo.KeyPurpose;
 import com.sparrowwallet.drongo.SecureString;
 import com.sparrowwallet.drongo.address.InvalidAddressException;
 import com.sparrowwallet.drongo.protocol.Sha256Hash;
@@ -36,6 +37,7 @@ import javafx.fxml.Initializable;
 import javafx.scene.Node;
 import javafx.scene.control.*;
 import javafx.scene.layout.StackPane;
+import javafx.scene.layout.VBox;
 import javafx.util.Duration;
 import javafx.util.StringConverter;
 import org.controlsfx.glyphfont.Glyph;
@@ -116,6 +118,18 @@ public class SendController extends WalletFormController implements Initializabl
     @FXML
     private TransactionDiagram transactionDiagram;
 
+    @FXML
+    private ToggleGroup optimizationToggleGroup;
+
+    @FXML
+    private ToggleButton efficiencyToggle;
+
+    @FXML
+    private ToggleButton privacyToggle;
+
+    @FXML
+    private HelpLabel privacyAnalysis;
+
     @FXML
     private Button clearButton;
 
@@ -145,7 +159,7 @@ public class SendController extends WalletFormController implements Initializabl
 
     private final BooleanProperty includeSpentMempoolOutputsProperty = new SimpleBooleanProperty(false);
 
-    private final List<WalletNode> excludedChangeNodes = new ArrayList<>();
+    private final Set<WalletNode> excludedChangeNodes = new HashSet<>();
 
     private final ChangeListener<String> feeListener = new ChangeListener<>() {
         @Override
@@ -208,6 +222,8 @@ public class SendController extends WalletFormController implements Initializabl
 
     private WalletTransactionService walletTransactionService;
 
+    private boolean overrideOptimizationStrategy;
+
     @Override
     public void initialize(URL location, ResourceBundle resources) {
         EventManager.get().register(this);
@@ -357,7 +373,7 @@ public class SendController extends WalletFormController implements Initializabl
 
         walletTransactionProperty.addListener((observable, oldValue, walletTransaction) -> {
             if(walletTransaction != null) {
-                setPayments(walletTransaction.getPayments());
+                setPayments(walletTransaction.getPayments().stream().filter(payment -> payment.getType() != Payment.Type.FAKE_MIX).collect(Collectors.toList()));
 
                 double feeRate = walletTransaction.getFeeRate();
                 if(userFeeSet.get()) {
@@ -372,6 +388,7 @@ public class SendController extends WalletFormController implements Initializabl
             }
 
             transactionDiagram.update(walletTransaction);
+            updatePrivacyAnalysis(walletTransaction);
             createButton.setDisable(walletTransaction == null || isInsufficientFeeRate());
         });
 
@@ -386,6 +403,21 @@ public class SendController extends WalletFormController implements Initializabl
 
         addFeeRangeTrackHighlight(0);
 
+        efficiencyToggle.setOnAction(event -> {
+            if(getWalletForm().getWallet().isWhirlpoolMixWallet() && !overrideOptimizationStrategy) {
+                AppServices.showWarningDialog("Privacy may be lost!", "It is recommended to optimize for privacy when sending coinjoined outputs.");
+                overrideOptimizationStrategy = true;
+            }
+            Config.get().setSendOptimizationStrategy(OptimizationStrategy.EFFICIENCY);
+            updateTransaction();
+        });
+        privacyToggle.setOnAction(event -> {
+            Config.get().setSendOptimizationStrategy(OptimizationStrategy.PRIVACY);
+            updateTransaction();
+        });
+        setPreferredOptimizationStrategy();
+        updatePrivacyAnalysis(null);
+
         createButton.managedProperty().bind(createButton.visibleProperty());
         premixButton.managedProperty().bind(premixButton.visibleProperty());
         createButton.visibleProperty().bind(premixButton.visibleProperty().not());
@@ -508,6 +540,7 @@ public class SendController extends WalletFormController implements Initializabl
 
         try {
             List<Payment> payments = transactionPayments != null ? transactionPayments : getPayments();
+            updateOptimizationButtons(payments);
             if(!userFeeSet.get() || (getFeeValueSats() != null && getFeeValueSats() > 0)) {
                 Wallet wallet = getWalletForm().getWallet();
                 Long userFee = userFeeSet.get() ? getFeeValueSats() : null;
@@ -517,7 +550,7 @@ public class SendController extends WalletFormController implements Initializabl
                 boolean includeMempoolOutputs = Config.get().isIncludeMempoolOutputs();
                 boolean includeSpentMempoolOutputs = includeSpentMempoolOutputsProperty.get();
 
-                walletTransactionService = new WalletTransactionService(wallet, getUtxoSelectors(), getUtxoFilters(), payments, excludedChangeNodes, feeRate, getMinimumFeeRate(), userFee, currentBlockHeight, groupByAddress, includeMempoolOutputs, includeSpentMempoolOutputs);
+                walletTransactionService = new WalletTransactionService(wallet, getUtxoSelectors(payments), getUtxoFilters(), payments, excludedChangeNodes, feeRate, getMinimumFeeRate(), userFee, currentBlockHeight, groupByAddress, includeMempoolOutputs, includeSpentMempoolOutputs);
                 walletTransactionService.setOnSucceeded(event -> {
                     if(!walletTransactionService.isIgnoreResult()) {
                         walletTransactionProperty.setValue(walletTransactionService.getValue());
@@ -551,7 +584,7 @@ public class SendController extends WalletFormController implements Initializabl
         }
     }
 
-    private List<UtxoSelector> getUtxoSelectors() throws InvalidAddressException {
+    private List<UtxoSelector> getUtxoSelectors(List<Payment> payments) throws InvalidAddressException {
         if(utxoSelectorProperty.get() != null) {
             return List.of(utxoSelectorProperty.get());
         }
@@ -560,7 +593,16 @@ public class SendController extends WalletFormController implements Initializabl
         long noInputsFee = wallet.getNoInputsFee(getPayments(), getUserFeeRate());
         long costOfChange = wallet.getCostOfChange(getUserFeeRate(), getMinimumFeeRate());
 
-        return List.of(new BnBUtxoSelector(noInputsFee, costOfChange), new KnapsackUtxoSelector(noInputsFee));
+        List<UtxoSelector> selectors = new ArrayList<>();
+        OptimizationStrategy optimizationStrategy = (OptimizationStrategy)optimizationToggleGroup.getSelectedToggle().getUserData();
+        if(optimizationStrategy == OptimizationStrategy.PRIVACY
+                && payments.size() == 1
+                && (payments.get(0).getAddress().getScriptType() == getWalletForm().getWallet().getAddress(getWalletForm().wallet.getFreshNode(KeyPurpose.RECEIVE)).getScriptType())) {
+            selectors.add(new StonewallUtxoSelector(noInputsFee));
+        }
+
+        selectors.addAll(List.of(new BnBUtxoSelector(noInputsFee, costOfChange), new KnapsackUtxoSelector(noInputsFee)));
+        return selectors;
     }
 
     private static class WalletTransactionService extends Service<WalletTransaction> {
@@ -568,7 +610,7 @@ public class SendController extends WalletFormController implements Initializabl
         private final List<UtxoSelector> utxoSelectors;
         private final List<UtxoFilter> utxoFilters;
         private final List<Payment> payments;
-        private final List<WalletNode> excludedChangeNodes;
+        private final Set<WalletNode> excludedChangeNodes;
         private final double feeRate;
         private final double longTermFeeRate;
         private final Long fee;
@@ -578,7 +620,7 @@ public class SendController extends WalletFormController implements Initializabl
         private final boolean includeSpentMempoolOutputs;
         private boolean ignoreResult;
 
-        public WalletTransactionService(Wallet wallet, List<UtxoSelector> utxoSelectors, List<UtxoFilter> utxoFilters, List<Payment> payments, List<WalletNode> excludedChangeNodes, double feeRate, double longTermFeeRate, Long fee, Integer currentBlockHeight, boolean groupByAddress, boolean includeMempoolOutputs, boolean includeSpentMempoolOutputs) {
+        public WalletTransactionService(Wallet wallet, List<UtxoSelector> utxoSelectors, List<UtxoFilter> utxoFilters, List<Payment> payments, Set<WalletNode> excludedChangeNodes, double feeRate, double longTermFeeRate, Long fee, Integer currentBlockHeight, boolean groupByAddress, boolean includeMempoolOutputs, boolean includeSpentMempoolOutputs) {
             this.wallet = wallet;
             this.utxoSelectors = utxoSelectors;
             this.utxoFilters = utxoFilters;
@@ -898,6 +940,45 @@ public class SendController extends WalletFormController implements Initializabl
         }
     }
 
+    private boolean isFakeMixPossible(List<Payment> payments) {
+        return (utxoSelectorProperty.get() == null
+                && payments.size() == 1
+                && (payments.get(0).getAddress().getScriptType() == getWalletForm().getWallet().getAddress(getWalletForm().wallet.getFreshNode(KeyPurpose.RECEIVE)).getScriptType()));
+    }
+
+    private void updateOptimizationButtons(List<Payment> payments) {
+        if(isFakeMixPossible(payments)) {
+            setPreferredOptimizationStrategy();
+            privacyToggle.setDisable(false);
+        } else {
+            optimizationToggleGroup.selectToggle(efficiencyToggle);
+            privacyToggle.setDisable(true);
+        }
+    }
+
+    private OptimizationStrategy getPreferredOptimizationStrategy() {
+        OptimizationStrategy optimizationStrategy = Config.get().getSendOptimizationStrategy();
+        if(getWalletForm().getWallet().isWhirlpoolMixWallet() && !overrideOptimizationStrategy) {
+            optimizationStrategy = OptimizationStrategy.PRIVACY;
+        }
+
+        return optimizationStrategy;
+    }
+
+    private void setPreferredOptimizationStrategy() {
+        optimizationToggleGroup.selectToggle(getPreferredOptimizationStrategy() == OptimizationStrategy.PRIVACY ? privacyToggle : efficiencyToggle);
+    }
+
+    private void updatePrivacyAnalysis(WalletTransaction walletTransaction) {
+        if(walletTransaction == null) {
+            privacyAnalysis.setHelpText("Determines whether to optimize the transaction for low fees or greater privacy");
+            privacyAnalysis.setHelpGraphic(null);
+        } else {
+            privacyAnalysis.setHelpText("");
+            privacyAnalysis.setHelpGraphic(new PrivacyAnalysisTooltip(walletTransaction));
+        }
+    }
+
     public void clear(ActionEvent event) {
         boolean firstTab = true;
         for(Iterator<Tab> iterator = paymentTabs.getTabs().iterator(); iterator.hasNext(); ) {
@@ -990,9 +1071,9 @@ public class SendController extends WalletFormController implements Initializabl
                 List<String> nodeHashes = inputHashes.computeIfAbsent(node, k -> new ArrayList<>());
                 nodeHashes.add(ElectrumServer.getScriptHash(walletForm.getWallet(), node));
             }
-            Map<WalletNode, List<String>> changeHash = Collections.emptyMap();
+            Map<WalletNode, List<String>> changeHash = new LinkedHashMap<>();
-            if(walletTransactionProperty.get().getChangeNode() != null) {
+            for(WalletNode changeNode : walletTransactionProperty.get().getChangeMap().keySet()) {
-                changeHash = Map.of(walletTransactionProperty.get().getChangeNode(), List.of(ElectrumServer.getScriptHash(walletForm.getWallet(), walletTransactionProperty.get().getChangeNode())));
+                changeHash.put(changeNode, List.of(ElectrumServer.getScriptHash(walletForm.getWallet(), changeNode)));
             }
             log.debug("Creating tx " + walletTransactionProperty.get().getTransaction().getTxId() + ", expecting notifications for \ninputs \n" + inputHashes + " and \nchange \n" + changeHash);
         }
@@ -1006,9 +1087,7 @@ public class SendController extends WalletFormController implements Initializabl
     private void addWalletTransactionNodes() {
         WalletTransaction walletTransaction = walletTransactionProperty.get();
         Set<WalletNode> nodes = new LinkedHashSet<>(walletTransaction.getSelectedUtxos().values());
-        if(walletTransaction.getChangeNode() != null) {
+        nodes.addAll(walletTransaction.getChangeMap().keySet());
-            nodes.add(walletTransaction.getChangeNode());
-        }
         List<WalletNode> consolidationNodes = walletTransaction.getConsolidationSendNodes();
         nodes.addAll(consolidationNodes);
 
@@ -1262,7 +1341,7 @@ public class SendController extends WalletFormController implements Initializabl
     @Subscribe
     public void replaceChangeAddress(ReplaceChangeAddressEvent event) {
         if(event.getWalletTransaction() == walletTransactionProperty.get()) {
-            excludedChangeNodes.add(event.getWalletTransaction().getChangeNode());
+            excludedChangeNodes.addAll(event.getWalletTransaction().getChangeMap().keySet());
             updateTransaction();
         }
     }
@@ -1295,4 +1374,85 @@ public class SendController extends WalletFormController implements Initializabl
             updateTransaction();
         }
     }
+
+    private class PrivacyAnalysisTooltip extends VBox {
+        private List<Label> analysisLabels = new ArrayList<>();
+
+        public PrivacyAnalysisTooltip(WalletTransaction walletTransaction) {
+            List<Payment> payments = walletTransaction.getPayments();
+            List<Payment> userPayments = payments.stream().filter(payment -> payment.getType() != Payment.Type.FAKE_MIX).collect(Collectors.toList());
+            OptimizationStrategy optimizationStrategy = getPreferredOptimizationStrategy();
+            boolean fakeMixPresent = payments.stream().anyMatch(payment -> payment.getType() == Payment.Type.FAKE_MIX);
+            boolean roundPaymentAmounts = userPayments.stream().anyMatch(payment -> payment.getAmount() % 100 == 0);
+            boolean mixedAddressTypes = userPayments.stream().anyMatch(payment -> payment.getAddress().getScriptType() != getWalletForm().getWallet().getAddress(getWalletForm().wallet.getFreshNode(KeyPurpose.RECEIVE)).getScriptType());
+            boolean addressReuse = userPayments.stream().anyMatch(payment -> getWalletForm().getWallet().getWalletAddresses().get(payment.getAddress()) != null && !getWalletForm().getWallet().getWalletAddresses().get(payment.getAddress()).getTransactionOutputs().isEmpty());
+
+            if(optimizationStrategy == OptimizationStrategy.PRIVACY) {
+                if(fakeMixPresent) {
+                    addLabel("Appears as a two person coinjoin", getPlusGlyph());
+                } else {
+                    if(mixedAddressTypes) {
+                        addLabel("Cannot fake coinjoin due to mixed address types", getWarningGlyph());
+                    } else if(utxoSelectorProperty().get() != null) {
+                        addLabel("Cannot fake coinjoin due to coin control", getWarningGlyph());
+                    } else if(userPayments.size() > 1) {
+                        addLabel("Cannot fake coinjoin due to multiple payments", getWarningGlyph());
+                    } else {
+                        addLabel("Cannot fake coinjoin due to insufficient funds", getWarningGlyph());
+                    }
+                }
+            }
+
+            if(mixedAddressTypes) {
+                addLabel("Address types different to the wallet indicate external payments", getMinusGlyph());
+            }
+
+            if(roundPaymentAmounts && !fakeMixPresent) {
+                addLabel("Rounded payment amounts indicate external payments", getMinusGlyph());
+            }
+
+            if(addressReuse) {
+                addLabel("Address reuse detected", getMinusGlyph());
+            }
+
+            if(analysisLabels.isEmpty() || (analysisLabels.size() == 1 && analysisLabels.get(0).getText().startsWith("Cannot fake coinjoin"))) {
+                addLabel("Appears as a possible self transfer", getPlusGlyph());
+            }
+
+            analysisLabels.sort(Comparator.comparingInt(o -> (Integer)o.getGraphic().getUserData()));
+            getChildren().addAll(analysisLabels);
+            setSpacing(5);
+        }
+
+        private void addLabel(String text, Node graphic) {
+            Label label = new Label(text);
+            label.setStyle("-fx-font-size: 11px");
+            label.setGraphic(graphic);
+            analysisLabels.add(label);
+        }
+
+        private static Glyph getPlusGlyph() {
+            Glyph plusGlyph = new Glyph(FontAwesome5.FONT_NAME, FontAwesome5.Glyph.PLUS_CIRCLE);
+            plusGlyph.setUserData(0);
+            plusGlyph.setStyle("-fx-text-fill: rgb(80, 161, 79)");
+            plusGlyph.setFontSize(12);
+            return plusGlyph;
+        }
+
+        private static Glyph getWarningGlyph() {
+            Glyph warningGlyph = new Glyph(FontAwesome5.FONT_NAME, FontAwesome5.Glyph.EXCLAMATION_TRIANGLE);
+            warningGlyph.setUserData(1);
+            warningGlyph.setStyle("-fx-text-fill: rgb(238, 210, 2)");
+            warningGlyph.setFontSize(12);
+            return warningGlyph;
+        }
+
+        private static Glyph getMinusGlyph() {
+            Glyph minusGlyph = new Glyph(FontAwesome5.FONT_NAME, FontAwesome5.Glyph.MINUS_CIRCLE);
+            minusGlyph.setUserData(2);
+            minusGlyph.setStyle("-fx-text-fill: #e06c75");
+            minusGlyph.setFontSize(12);
+            return minusGlyph;
+        }
+    }
 }

src/main/resources/com/sparrowwallet/sparrow/wallet/send.css

@@ -6,7 +6,7 @@
     -fx-pref-height: 40px;
 }
 
-.send-form .form .fieldset:horizontal .label-container {
+.send-form .form .fieldset:horizontal .label-container, .buttonRowLabel {
     -fx-pref-width: 90px;
 }
 

src/main/resources/com/sparrowwallet/sparrow/wallet/send.fxml

@@ -23,6 +23,8 @@
 <?import com.sparrowwallet.sparrow.control.MempoolSizeFeeRatesChart?>
 <?import org.controlsfx.control.SegmentedButton?>
 <?import com.sparrowwallet.sparrow.wallet.FeeRatesSelection?>
+<?import com.sparrowwallet.sparrow.wallet.OptimizationStrategy?>
+<?import com.sparrowwallet.sparrow.control.HelpLabel?>
 
 <BorderPane stylesheets="@send.css, @wallet.css, @../script.css, @../general.css" styleClass="wallet-pane" xmlns="http://javafx.com/javafx/10.0.2-internal" xmlns:fx="http://javafx.com/fxml/1" fx:controller="com.sparrowwallet.sparrow.wallet.SendController">
     <center>
@@ -149,6 +151,33 @@
             <padding>
                 <Insets left="25.0" right="25.0" bottom="25.0" />
             </padding>
+            <HBox AnchorPane.leftAnchor="5" alignment="CENTER_LEFT">
+                <Label text="Optimize:" styleClass="buttonRowLabel" />
+                <SegmentedButton>
+                    <toggleGroup>
+                        <ToggleGroup fx:id="optimizationToggleGroup" />
+                    </toggleGroup>
+                    <buttons>
+                        <ToggleButton fx:id="efficiencyToggle" text="Efficiency" toggleGroup="$optimizationToggleGroup">
+                            <tooltip>
+                                <Tooltip text="Smallest transaction size for lowest fees"/>
+                            </tooltip>
+                            <userData>
+                                <OptimizationStrategy fx:constant="EFFICIENCY"/>
+                            </userData>
+                        </ToggleButton>
+                        <ToggleButton fx:id="privacyToggle" text="Privacy" toggleGroup="$optimizationToggleGroup">
+                            <tooltip>
+                                <Tooltip text="Higher entropy transactions that reduce probabilities in blockchain analysis"/>
+                            </tooltip>
+                            <userData>
+                                <OptimizationStrategy fx:constant="PRIVACY"/>
+                            </userData>
+                        </ToggleButton>
+                    </buttons>
+                </SegmentedButton>
+                <HelpLabel fx:id="privacyAnalysis" />
+            </HBox>
             <HBox AnchorPane.rightAnchor="10">
                 <Button fx:id="clearButton" text="Clear" cancelButton="true" onAction="#clear" />
                 <Region HBox.hgrow="ALWAYS" style="-fx-min-width: 20px" />