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diff --git a/src/node/txreconciliation.h b/src/node/txreconciliation.h
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+// Copyright (c) 2022 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_NODE_TXRECONCILIATION_H
+#define BITCOIN_NODE_TXRECONCILIATION_H
+
+#include <net.h>
+#include <sync.h>
+
+#include <memory>
+#include <tuple>
+
+/** Whether transaction reconciliation protocol should be enabled by default. */
+static constexpr bool DEFAULT_TXRECONCILIATION_ENABLE{false};
+/** Supported transaction reconciliation protocol version */
+static constexpr uint32_t TXRECONCILIATION_VERSION{1};
+
+enum ReconciliationRegisterResult {
+    NOT_FOUND = 0,
+    SUCCESS = 1,
+    PROTOCOL_VIOLATION = 2,
+};
+
+/**
+ * Transaction reconciliation is a way for nodes to efficiently announce transactions.
+ * This object keeps track of all txreconciliation-related communications with the peers.
+ * The high-level protocol is:
+ * 0.  Txreconciliation protocol handshake.
+ * 1.  Once we receive a new transaction, add it to the set instead of announcing immediately.
+ * 2.  At regular intervals, a txreconciliation initiator requests a sketch from a peer, where a
+ *     sketch is a compressed representation of short form IDs of the transactions in their set.
+ * 3.  Once the initiator received a sketch from the peer, the initiator computes a local sketch,
+ *     and combines the two sketches to attempt finding the difference in *sets*.
+ * 4a. If the difference was not larger than estimated, see SUCCESS below.
+ * 4b. If the difference was larger than estimated, initial txreconciliation fails. The initiator
+ *     requests a larger sketch via an extension round (allowed only once).
+ *     - If extension succeeds (a larger sketch is sufficient), see SUCCESS below.
+ *     - If extension fails (a larger sketch is insufficient), see FAILURE below.
+ *
+ * SUCCESS. The initiator knows full symmetrical difference and can request what the initiator is
+ *          missing and announce to the peer what the peer is missing.
+ *
+ * FAILURE. The initiator notifies the peer about the failure and announces all transactions from
+ *          the corresponding set. Once the peer received the failure notification, the peer
+ *          announces all transactions from their set.
+
+ * This is a modification of the Erlay protocol (https://arxiv.org/abs/1905.10518) with two
+ * changes (sketch extensions instead of bisections, and an extra INV exchange round), both
+ * are motivated in BIP-330.
+ */
+class TxReconciliationTracker
+{
+private:
+    class Impl;
+    const std::unique_ptr<Impl> m_impl;
+
+public:
+    explicit TxReconciliationTracker(uint32_t recon_version);
+    ~TxReconciliationTracker();
+
+    /**
+     * Step 0. Generates initial part of the state (salt) required to reconcile txs with the peer.
+     * The salt is used for short ID computation required for txreconciliation.
+     * The function returns the salt.
+     * A peer can't participate in future txreconciliations without this call.
+     * This function must be called only once per peer.
+     */
+    uint64_t PreRegisterPeer(NodeId peer_id);
+
+    /**
+     * Step 0. Once the peer agreed to reconcile txs with us, generate the state required to track
+     * ongoing reconciliations. Must be called only after pre-registering the peer and only once.
+     */
+    ReconciliationRegisterResult RegisterPeer(NodeId peer_id, bool is_peer_inbound, bool is_peer_recon_initiator,
+                                     bool is_peer_recon_responder, uint32_t peer_recon_version, uint64_t remote_salt);
+
+    /**
+     * Attempts to forget txreconciliation-related state of the peer (if we previously stored any).
+     * After this, we won't be able to reconcile transactions with the peer.
+     */
+    void ForgetPeer(NodeId peer_id);
+
+    /**
+     * Check if a peer is registered to reconcile transactions with us.
+     */
+    bool IsPeerRegistered(NodeId peer_id) const;
+};
+
+#endif // BITCOIN_NODE_TXRECONCILIATION_H