privacy analysis: detect address reuse

add tx position to get_addr_io

electrum/address_synchronizer.py

@@ -778,13 +778,13 @@ class AddressSynchronizer(Logger, EventListener):
             sent = {}
             for tx_hash, height in h:
                 hh, pos = self.get_txpos(tx_hash)
+                assert hh == height
                 d = self.db.get_txo_addr(tx_hash, address)
                 for n, (v, is_cb) in d.items():
                     received[tx_hash + ':%d'%n] = (height, pos, v, is_cb)
-            for tx_hash, height in h:
                 l = self.db.get_txi_addr(tx_hash, address)
                 for txi, v in l:
-                    sent[txi] = tx_hash, height
+                    sent[txi] = tx_hash, height, pos
         return received, sent
 
     def get_addr_outputs(self, address: str) -> Dict[TxOutpoint, PartialTxInput]:
@@ -799,7 +799,7 @@ class AddressSynchronizer(Logger, EventListener):
             utxo.block_height = tx_height
             utxo.block_txpos = tx_pos
             if prevout_str in sent:
-                txid, height = sent[prevout_str]
+                txid, height, pos = sent[prevout_str]
                 utxo.spent_txid = txid
                 utxo.spent_height = height
             else:

electrum/gui/qt/utxo_dialog.py

@@ -28,13 +28,14 @@ import copy
 
 from PyQt5.QtCore import Qt, QUrl
 from PyQt5.QtGui import QTextCharFormat, QFont
-from PyQt5.QtWidgets import QVBoxLayout, QLabel, QTextBrowser
+from PyQt5.QtWidgets import QVBoxLayout, QHBoxLayout, QLabel, QTextBrowser
 
 from electrum.i18n import _
 
 from .util import WindowModalDialog, ButtonsLineEdit, ShowQRLineEdit, ColorScheme, Buttons, CloseButton, MONOSPACE_FONT, WWLabel
 from .history_list import HistoryList, HistoryModel
 from .qrtextedit import ShowQRTextEdit
+from .transaction_dialog import TxOutputColoring
 
 if TYPE_CHECKING:
     from .main_window import ElectrumWindow
@@ -66,6 +67,10 @@ class UTXODialog(WindowModalDialog):
         self.parents_list.setMinimumWidth(900)
         self.parents_list.setMinimumHeight(400)
         self.parents_list.setLineWrapMode(QTextBrowser.NoWrap)
+        self.txo_color_parent = TxOutputColoring(
+            legend=_("Direct parent"), color=ColorScheme.BLUE, tooltip=_("Direct parent"))
+        self.txo_color_uncle = TxOutputColoring(
+            legend=_("Address reuse"), color=ColorScheme.RED, tooltip=_("Address reuse"))
 
         cursor = self.parents_list.textCursor()
         ext = QTextCharFormat()
@@ -81,7 +86,7 @@ class UTXODialog(WindowModalDialog):
             ASCII_PIPE   = '│'
             ASCII_SPACE  = ' '
 
-        def print_ascii_tree(_txid, prefix, is_last):
+        def print_ascii_tree(_txid, prefix, is_last, is_uncle):
             if _txid not in parents:
                 return
             tx_height, tx_pos = self.wallet.adb.get_txpos(_txid)
@@ -91,7 +96,10 @@ class UTXODialog(WindowModalDialog):
                 label = '[duplicate]'
             c = '' if _txid == txid else (ASCII_EDGE if is_last else ASCII_BRANCH)
             cursor.insertText(prefix + c, ext)
-            lnk = QTextCharFormat()
+            if is_uncle:
+                lnk = QTextCharFormat(self.txo_color_uncle.text_char_format)
+            else:
+                lnk = QTextCharFormat(self.txo_color_parent.text_char_format)
             lnk.setToolTip(_('Click to open, right-click for menu'))
             lnk.setAnchorHref(_txid)
             #lnk.setAnchorNames([a_name])
@@ -102,22 +110,27 @@ class UTXODialog(WindowModalDialog):
             cursor.insertText(label, ext)
             cursor.insertBlock()
             next_prefix = '' if txid == _txid else prefix + (ASCII_SPACE if is_last else ASCII_PIPE)
-            parents_list = parents_copy.pop(_txid, [])
-            for i, p in enumerate(parents_list):
-                is_last = i == len(parents_list) - 1
-                print_ascii_tree(p, next_prefix, is_last)
+            parents_list, uncle_list = parents_copy.pop(_txid, ([],[]))
+            for i, p in enumerate(parents_list + uncle_list):
+                is_last = (i == len(parents_list) + len(uncle_list)- 1)
+                is_uncle = (i > len(parents_list) - 1)
+                print_ascii_tree(p, next_prefix, is_last, is_uncle)
+
         # recursively build the tree
-        print_ascii_tree(txid, '', False)
+        print_ascii_tree(txid, '', False, False)
         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(num_parents)))
         vbox.addWidget(self.parents_list)
-        msg = ' '.join([
-            _("Note: This analysis only shows parent transactions, and does not take address reuse into consideration."),
-            _("If you reuse addresses, more links can be established between your transactions, that are not displayed here.")
-        ])
-        vbox.addWidget(WWLabel(msg))
+        legend_hbox = QHBoxLayout()
+        legend_hbox.setContentsMargins(0, 0, 0, 0)
+        legend_hbox.addStretch(2)
+        legend_hbox.addWidget(self.txo_color_parent.legend_label)
+        legend_hbox.addWidget(self.txo_color_uncle.legend_label)
+        vbox.addLayout(legend_hbox)
+        self.txo_color_parent.legend_label.setVisible(True)
+        self.txo_color_uncle.legend_label.setVisible(True)
         vbox.addLayout(Buttons(CloseButton(self)))
         self.setLayout(vbox)
         # set cursor to top

electrum/wallet.py

@@ -871,23 +871,37 @@ class Abstract_Wallet(ABC, Logger, EventListener):
         """
         if not self.is_up_to_date():
             return {}
-        if self._last_full_history is None:
-            self._last_full_history = self.get_full_history(None)
-
         with self.lock, self.transaction_lock:
+            if self._last_full_history is None:
+                self._last_full_history = self.get_full_history(None)
             result = self._tx_parents_cache.get(txid, None)
             if result is not None:
                 return result
             result = {}
             parents = []
+            uncles = []
             tx = self.adb.get_transaction(txid)
             assert tx, f"cannot find {txid} in db"
             for i, txin in enumerate(tx.inputs()):
                 _txid = txin.prevout.txid.hex()
                 parents.append(_txid)
+                # detect address reuse
+                addr = self.adb.get_txin_address(txin)
+                received, sent = self.adb.get_addr_io(addr)
+                if len(sent) > 1:
+                    my_txid, my_height, my_pos = sent[txin.prevout.to_str()]
+                    assert my_txid == txid
+                    for k, v in sent.items():
+                        if k != txin.prevout.to_str():
+                            reuse_txid, reuse_height, reuse_pos = v
+                            if (reuse_height, reuse_pos) < (my_height, my_pos):
+                                uncle_txid, uncle_index = k.split(':')
+                                uncles.append(uncle_txid)
+
+            for _txid in parents + uncles:
                 if _txid in self._last_full_history.keys():
                     result.update(self.get_tx_parents(_txid))
-            result[txid] = parents
+            result[txid] = parents, uncles
             self._tx_parents_cache[txid] = result
             return result