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// Copyright (c) 2024-present The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or https://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_MUSIG_H
#define BITCOIN_MUSIG_H
#include <pubkey.h>
#include <optional>
#include <vector>
struct secp256k1_musig_keyagg_cache;
class MuSig2SecNonceImpl;
struct secp256k1_musig_secnonce;
constexpr size_t MUSIG2_PUBNONCE_SIZE{66};
//! Compute the full aggregate pubkey from the given participant pubkeys in their current order.
//! Outputs the secp256k1_musig_keyagg_cache and validates that the computed aggregate pubkey matches an expected aggregate pubkey.
//! This is necessary for most MuSig2 operations.
std::optional<CPubKey> MuSig2AggregatePubkeys(const std::vector<CPubKey>& pubkeys, secp256k1_musig_keyagg_cache& keyagg_cache, const std::optional<CPubKey>& expected_aggregate);
std::optional<CPubKey> MuSig2AggregatePubkeys(const std::vector<CPubKey>& pubkeys);
//! Construct the BIP 328 synthetic xpub for a pubkey
CExtPubKey CreateMuSig2SyntheticXpub(const CPubKey& pubkey);
/**
* MuSig2SecNonce encapsulates a secret nonce in use in a MuSig2 signing session.
* Since this nonce persists outside of libsecp256k1 signing code, we must handle
* its construction and destruction ourselves.
* The secret nonce must be kept a secret, otherwise the private key may be leaked.
* As such, it needs to be treated in the same way that CKeys are treated.
* So this class handles the secure allocation of the secp256k1_musig_secnonce object
* that libsecp256k1 uses, and only gives out references to this object to avoid
* any possibility of copies being made. Furthermore, objects of this class are not
* copyable to avoid nonce reuse.
*/
class MuSig2SecNonce
{
private:
std::unique_ptr<MuSig2SecNonceImpl> m_impl;
public:
MuSig2SecNonce();
MuSig2SecNonce(MuSig2SecNonce&&) noexcept;
MuSig2SecNonce& operator=(MuSig2SecNonce&&) noexcept;
~MuSig2SecNonce();
// Delete copy constructors
MuSig2SecNonce(const MuSig2SecNonce&) = delete;
MuSig2SecNonce& operator=(const MuSig2SecNonce&) = delete;
secp256k1_musig_secnonce* Get() const;
void Invalidate();
bool IsValid();
};
uint256 MuSig2SessionID(const CPubKey& script_pubkey, const CPubKey& part_pubkey, const uint256& sighash);
std::optional<std::vector<uint8_t>> CreateMuSig2AggregateSig(const std::vector<CPubKey>& participants, const CPubKey& aggregate_pubkey, const std::vector<std::pair<uint256, bool>>& tweaks, const uint256& sighash, const std::map<CPubKey, std::vector<uint8_t>>& pubnonces, const std::map<CPubKey, uint256>& partial_sigs);
#endif // BITCOIN_MUSIG_H