diff --git a/libcockatrice_deck_list/libcockatrice/deck_list/deck_list_node_tree.cpp b/libcockatrice_deck_list/libcockatrice/deck_list/deck_list_node_tree.cpp
index 35c7943b4..575d99340 100644
--- a/libcockatrice_deck_list/libcockatrice/deck_list/deck_list_node_tree.cpp
+++ b/libcockatrice_deck_list/libcockatrice/deck_list/deck_list_node_tree.cpp
@@ -7,6 +7,47 @@
 
 static constexpr int MAX_DECK_SIZE = 1e5;
 
+namespace
+{
+
+/**
+ * @brief Expands card nodes into one lowercase name entry per copy.
+ *
+ * @param nodes The card nodes to expand.
+ * @param prefix Optional prefix prepended to every entry (e.g. "SB:" for the sideboard).
+ * @return One entry per copy, in node order.
+ */
+QStringList cardNodesToCopies(const QList<const DecklistCardNode *> &nodes, const QString &prefix = {})
+{
+    QStringList result;
+    for (auto node : nodes) {
+        for (int i = 0; i < node->getNumber(); ++i) {
+            result.append(prefix + node->getName().toLower());
+        }
+    }
+    return result;
+}
+
+/**
+ * @brief Packs the first five bytes of a SHA-1 digest into a compact base-32 number.
+ *
+ * The bytes are placed in most-significant-byte-first order (byte 0 shifted by 32,
+ * byte 4 unshifted) so decks that only differ in their low-order hash bytes still
+ * produce distinct identifiers.
+ *
+ * @return The 8-character base-32 representation of the packed number.
+ */
+QString encodeDeckHash(const QByteArray &digest)
+{
+    quint64 number = 0;
+    for (int i = 0; i < 5; ++i) {
+        number |= static_cast<quint64>(static_cast<unsigned char>(digest[i])) << (32 - 8 * i);
+    }
+    return QString::number(number, 32).rightJustified(8, '0');
+}
+
+} // namespace
+
 DecklistNodeTree::DecklistNodeTree() : root(new InnerDecklistNode())
 {
 }
@@ -83,25 +124,11 @@ QString DecklistNodeTree::computeDeckHash() const
     auto mainDeckNodes = getCardNodes({DECK_ZONE_MAIN});
     auto sideDeckNodes = getCardNodes({DECK_ZONE_SIDE});
 
-    static auto nodesToCardList = [](const QList<const DecklistCardNode *> &nodes, const QString &prefix = {}) {
-        QStringList result;
-        for (auto node : nodes) {
-            for (int i = 0; i < node->getNumber(); ++i) {
-                result.append(prefix + node->getName().toLower());
-            }
-        }
-        return result;
-    };
-
-    QStringList cardList = nodesToCardList(mainDeckNodes) + nodesToCardList(sideDeckNodes, "SB:");
+    QStringList cardList = cardNodesToCopies(mainDeckNodes) + cardNodesToCopies(sideDeckNodes, "SB:");
 
     cardList.sort();
     QByteArray deckHashArray = QCryptographicHash::hash(cardList.join(";").toUtf8(), QCryptographicHash::Sha1);
-    quint64 number = (((quint64)(unsigned char)deckHashArray[0]) << 32) +
-                     (((quint64)(unsigned char)deckHashArray[1]) << 24) +
-                     (((quint64)(unsigned char)deckHashArray[2] << 16)) +
-                     (((quint64)(unsigned char)deckHashArray[3]) << 8) + (quint64)(unsigned char)deckHashArray[4];
-    return QString::number(number, 32).rightJustified(8, '0');
+    return encodeDeckHash(deckHashArray);
 }
 
 void DecklistNodeTree::write(QXmlStreamWriter *xml) const