utxo privacy analysis:

 - show number of parents in tab
 - full list of parents in details dialog

electrum/address_synchronizer.py

@@ -88,6 +88,7 @@ def __init__(self, db: 'WalletDB', config: 'SimpleConfig', *, name: str = None):
         self.threadlocal_cache = threading.local()
 
         self._get_balance_cache = {}
+        self._tx_parents_cache = {}
 
         self.load_and_cleanup()
 
@@ -348,6 +349,7 @@ def add_value_from_prev_output():
             # save
             self.db.add_transaction(tx_hash, tx)
             self.db.add_num_inputs_to_tx(tx_hash, len(tx.inputs()))
+            self._tx_parents_cache.clear()
             if is_new:
                 util.trigger_callback('adb_added_tx', self, tx_hash)
             return True
@@ -951,3 +953,33 @@ def address_is_old(self, address: str, *, req_conf: int = 3) -> bool:
                     tx_age = self.get_local_height() - tx_height + 1
             max_conf = max(max_conf, tx_age)
         return max_conf >= req_conf
+
+    def get_tx_parents(self, txid) -> Dict:
+        """
+        recursively calls itself and returns a flat dict:
+        txid -> input_index ->  prevout
+        note: this does not take into account address reuse
+        """
+        from .util import ShortID
+        if not self.is_up_to_date():
+            return {}
+
+        with self.lock, self.transaction_lock:
+            result = self._tx_parents_cache.get(txid, None)
+            if result is not None:
+                return result
+            result = {}
+            parents = []
+            tx = self.get_transaction(txid)
+            for i, txin in enumerate(tx.inputs()):
+                _txid = txin.prevout.txid.hex()
+                if _txid in self.db.transactions:
+                    #parents.append(txin.prevout)
+                    parents.append(str(txin.short_id))
+                    result.update(self.get_tx_parents(_txid))
+                else:
+                    # maybe add it too?
+                    parents.append(None)
+            result[txid] = parents
+            self._tx_parents_cache[txid] = result
+            return result

electrum/gui/qt/main_window.py

@@ -1065,6 +1065,11 @@ def show_address(self, addr: str, *, parent: QWidget = None):
         d = address_dialog.AddressDialog(self, addr, parent=parent)
         d.exec_()
 
+    def show_utxo(self, utxo):
+        from . import utxo_dialog
+        d = utxo_dialog.UTXODialog(self, utxo)
+        d.exec_()
+
     def show_channel_details(self, chan):
         from .channel_details import ChannelDetailsDialog
         ChannelDetailsDialog(self, chan).show()

electrum/gui/qt/utxo_dialog.py

@@ -0,0 +1,105 @@
+#!/usr/bin/env python
+#
+# Electrum - lightweight Bitcoin client
+# Copyright (C) 2023 The Electrum Developers
+#
+# Permission is hereby granted, free of charge, to any person
+# obtaining a copy of this software and associated documentation files
+# (the "Software"), to deal in the Software without restriction,
+# including without limitation the rights to use, copy, modify, merge,
+# publish, distribute, sublicense, and/or sell copies of the Software,
+# and to permit persons to whom the Software is furnished to do so,
+# subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+from typing import TYPE_CHECKING
+
+from PyQt5.QtCore import Qt, QUrl
+from PyQt5.QtGui import QTextCharFormat, QFont
+from PyQt5.QtWidgets import QVBoxLayout, QLabel, QTextBrowser
+
+from electrum.i18n import _
+
+from .util import WindowModalDialog, ButtonsLineEdit, ShowQRLineEdit, ColorScheme, Buttons, CloseButton, MONOSPACE_FONT
+from .history_list import HistoryList, HistoryModel
+from .qrtextedit import ShowQRTextEdit
+
+if TYPE_CHECKING:
+    from .main_window import ElectrumWindow
+
+# todo:
+#  - edit label in tx detail window
+
+
+class UTXODialog(WindowModalDialog):
+
+    def __init__(self, window: 'ElectrumWindow', utxo):
+        WindowModalDialog.__init__(self, window, _("Coin Privacy Analysis"))
+        self.main_window = window
+        self.config = window.config
+        self.wallet = window.wallet
+        self.utxo = utxo
+
+        txid = self.utxo.prevout.txid.hex()
+        parents = self.wallet.adb.get_tx_parents(txid)
+        out = []
+        for _txid, _list in sorted(parents.items()):
+            tx_height, tx_pos = self.wallet.adb.get_txpos(_txid)
+            label = self.wallet.get_label_for_txid(_txid) or "<no label>"
+            out.append((tx_height, tx_pos, _txid, label, _list))
+
+        self.parents_list = QTextBrowser()
+        self.parents_list.setOpenLinks(False)  # disable automatic link opening
+        self.parents_list.anchorClicked.connect(self.open_tx)  # send links to our handler
+        self.parents_list.setFont(QFont(MONOSPACE_FONT))
+        self.parents_list.setReadOnly(True)
+        self.parents_list.setTextInteractionFlags(self.parents_list.textInteractionFlags() | Qt.LinksAccessibleByMouse | Qt.LinksAccessibleByKeyboard)
+        self.parents_list.setMinimumWidth(900)
+        self.parents_list.setMinimumHeight(400)
+        self.parents_list.setLineWrapMode(QTextBrowser.NoWrap)
+
+        cursor = self.parents_list.textCursor()
+        ext = QTextCharFormat()
+
+        for tx_height, tx_pos, _txid, label, _list in reversed(sorted(out)):
+            key = "%dx%d"%(tx_height, tx_pos) if tx_pos >= 0 else _txid[0:8]
+            list_str = ','.join(filter(None, _list))
+            lnk = QTextCharFormat()
+            lnk.setToolTip(_('Click to open, right-click for menu'))
+            lnk.setAnchorHref(_txid)
+            #lnk.setAnchorNames([a_name])
+            lnk.setAnchor(True)
+            lnk.setUnderlineStyle(QTextCharFormat.SingleUnderline)
+            cursor.insertText(key, lnk)
+            cursor.insertText("\t", ext)
+            cursor.insertText("%-32s\t-> "%label[0:32], ext)
+            cursor.insertText(list_str, ext)
+            cursor.insertBlock()
+
+        vbox = QVBoxLayout()
+        vbox.addWidget(QLabel(_("Output point") + ":" + str(self.utxo.short_id)))
+        vbox.addWidget(QLabel(_("Amount") + ":" + self.main_window.format_amount_and_units(self.utxo.value_sats())))
+        vbox.addWidget(QLabel(_("This UTXO has {} parent transactions in your wallet").format(len(parents))))
+        vbox.addWidget(self.parents_list)
+        vbox.addLayout(Buttons(CloseButton(self)))
+        self.setLayout(vbox)
+
+    def open_tx(self, txid):
+        if isinstance(txid, QUrl):
+            txid = txid.toString(QUrl.None_)
+        tx = self.wallet.adb.get_transaction(txid)
+        if not tx:
+            return
+        label = self.wallet.get_label_for_txid(txid)
+        self.main_window.show_transaction(tx, tx_desc=label)

electrum/gui/qt/utxo_list.py

@@ -49,10 +49,12 @@ class Columns(IntEnum):
         ADDRESS = 1
         LABEL = 2
         AMOUNT = 3
+        PARENTS = 4
 
     headers = {
         Columns.OUTPOINT: _('Output point'),
         Columns.ADDRESS: _('Address'),
+        Columns.PARENTS: _('Parents'),
         Columns.LABEL: _('Label'),
         Columns.AMOUNT: _('Amount'),
     }
@@ -87,14 +89,15 @@ def update(self):
             name = utxo.prevout.to_str()
             self._utxo_dict[name] = utxo
             address = utxo.address
-            amount = self.parent.format_amount(utxo.value_sats(), whitespaces=True)
-            labels = [str(utxo.short_id), address, '', amount]
+            amount_str = self.parent.format_amount(utxo.value_sats(), whitespaces=True)
+            labels = [str(utxo.short_id), address, '', amount_str, '']
             utxo_item = [QStandardItem(x) for x in labels]
             self.set_editability(utxo_item)
             utxo_item[self.Columns.OUTPOINT].setData(name, self.ROLE_CLIPBOARD_DATA)
             utxo_item[self.Columns.OUTPOINT].setData(name, self.ROLE_PREVOUT_STR)
             utxo_item[self.Columns.ADDRESS].setFont(QFont(MONOSPACE_FONT))
             utxo_item[self.Columns.AMOUNT].setFont(QFont(MONOSPACE_FONT))
+            utxo_item[self.Columns.PARENTS].setFont(QFont(MONOSPACE_FONT))
             utxo_item[self.Columns.OUTPOINT].setFont(QFont(MONOSPACE_FONT))
             self.model().insertRow(idx, utxo_item)
             self.refresh_row(name, idx)
@@ -117,8 +120,10 @@ def refresh_row(self, key, row):
         assert row is not None
         utxo = self._utxo_dict[key]
         utxo_item = [self.std_model.item(row, col) for col in self.Columns]
-        address = utxo.address
-        label = self.wallet.get_label_for_txid(utxo.prevout.txid.hex()) or self.wallet.get_label_for_address(address)
+        txid = utxo.prevout.txid.hex()
+        parents = self.wallet.adb.get_tx_parents(txid)
+        utxo_item[self.Columns.PARENTS].setText('%6s'%len(parents))
+        label = self.wallet.get_label_for_txid(txid) or ''
         utxo_item[self.Columns.LABEL].setText(label)
         SELECTED_TO_SPEND_TOOLTIP = _('Coin selected to be spent')
         if key in self._spend_set:
@@ -130,7 +135,7 @@ def refresh_row(self, key, row):
         for col in utxo_item:
             col.setBackground(color)
             col.setToolTip(tooltip)
-        if self.wallet.is_frozen_address(address):
+        if self.wallet.is_frozen_address(utxo.address):
             utxo_item[self.Columns.ADDRESS].setBackground(ColorScheme.BLUE.as_color(True))
             utxo_item[self.Columns.ADDRESS].setToolTip(_('Address is frozen'))
         if self.wallet.is_frozen_coin(utxo):
@@ -261,12 +266,7 @@ def create_menu(self, position):
         if len(coins) == 1:
             utxo = coins[0]
             addr = utxo.address
-            txid = utxo.prevout.txid.hex()
-            # "Details"
-            tx = self.wallet.adb.get_transaction(txid)
-            if tx:
-                label = self.wallet.get_label_for_txid(txid)
-                menu.addAction(_("Details"), lambda: self.parent.show_transaction(tx, tx_desc=label))
+            menu.addAction(_("View Parents"), lambda: self.parent.show_utxo(utxo))
             # "Copy ..."
             idx = self.indexAt(position)
             if not idx.isValid():