signingprovider.h

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-present 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_SCRIPT_SIGNINGPROVIDER_H
#define BITCOIN_SCRIPT_SIGNINGPROVIDER_H

#include <addresstype.h>
#include <attributes.h>
#include <key.h>
#include <musig.h>
#include <pubkey.h>
#include <script/keyorigin.h>
#include <script/script.h>
#include <sync.h>

#include <functional>
#include <optional>

struct ShortestVectorFirstComparator
{
    bool operator()(const std::vector<unsigned char>& a, const std::vector<unsigned char>& b) const
    {
        if (a.size() < b.size()) return true;
        if (a.size() > b.size()) return false;
        return a < b;
    }
};

struct TaprootSpendData
{
    XOnlyPubKey internal_key;
    uint256 merkle_root;
    std::map<std::pair<std::vector<unsigned char>, int>, std::set<std::vector<unsigned char>, ShortestVectorFirstComparator>> scripts;
    void Merge(TaprootSpendData other);
};

class TaprootBuilder
{
private:
    struct LeafInfo
    {
        std::vector<unsigned char> script;   
        int leaf_version;                    
        std::vector<uint256> merkle_branch;  
    };

    struct NodeInfo
    {
        uint256 hash;
        std::vector<LeafInfo> leaves;
    };
    bool m_valid = true;

    std::vector<std::optional<NodeInfo>> m_branch;

    XOnlyPubKey m_internal_key;  
    XOnlyPubKey m_output_key;    
    bool m_parity;               

    static NodeInfo Combine(NodeInfo&& a, NodeInfo&& b);
    void Insert(NodeInfo&& node, int depth);

public:
    TaprootBuilder& Add(int depth, std::span<const unsigned char> script, int leaf_version, bool track = true);
    TaprootBuilder& AddOmitted(int depth, const uint256& hash);
    TaprootBuilder& Finalize(const XOnlyPubKey& internal_key);

    bool IsValid() const { return m_valid; }
    bool IsComplete() const { return m_valid && (m_branch.size() == 0 || (m_branch.size() == 1 && m_branch[0].has_value())); }
    WitnessV1Taproot GetOutput();
    static bool ValidDepths(const std::vector<int>& depths);
    TaprootSpendData GetSpendData() const;
    std::vector<std::tuple<uint8_t, uint8_t, std::vector<unsigned char>>> GetTreeTuples() const;
    bool HasScripts() const { return !m_branch.empty(); }

    bool operator==(const TaprootBuilder& other) const { return GetTreeTuples() == other.GetTreeTuples(); }
};

std::optional<std::vector<std::tuple<int, std::vector<unsigned char>, int>>> InferTaprootTree(const TaprootSpendData& spenddata, const XOnlyPubKey& output);

class SigningProvider
{
public:
    virtual ~SigningProvider() = default;
    virtual bool GetCScript(const CScriptID &scriptid, CScript& script) const { return false; }
    virtual bool HaveCScript(const CScriptID &scriptid) const { return false; }
    virtual bool GetPubKey(const CKeyID &address, CPubKey& pubkey) const { return false; }
    virtual bool GetKey(const CKeyID &address, CKey& key) const { return false; }
    virtual bool HaveKey(const CKeyID &address) const { return false; }
    virtual bool GetKeyOrigin(const CKeyID& keyid, KeyOriginInfo& info) const { return false; }
    virtual bool GetTaprootSpendData(const XOnlyPubKey& output_key, TaprootSpendData& spenddata) const { return false; }
    virtual bool GetTaprootBuilder(const XOnlyPubKey& output_key, TaprootBuilder& builder) const { return false; }
    virtual std::vector<CPubKey> GetMuSig2ParticipantPubkeys(const CPubKey& pubkey) const { return {}; }
    virtual std::map<CPubKey, std::vector<CPubKey>> GetAllMuSig2ParticipantPubkeys() const {return {}; }
    virtual void SetMuSig2SecNonce(const uint256& id, MuSig2SecNonce&& nonce) const {}
    virtual std::optional<std::reference_wrapper<MuSig2SecNonce>> GetMuSig2SecNonce(const uint256& session_id) const { return std::nullopt; }
    virtual void DeleteMuSig2Session(const uint256& session_id) const {}

    bool GetKeyByXOnly(const XOnlyPubKey& pubkey, CKey& key) const
    {
        for (const auto& id : pubkey.GetKeyIDs()) {
            if (GetKey(id, key)) return true;
        }
        return false;
    }

    bool GetPubKeyByXOnly(const XOnlyPubKey& pubkey, CPubKey& out) const
    {
        for (const auto& id : pubkey.GetKeyIDs()) {
            if (GetPubKey(id, out)) return true;
        }
        return false;
    }

    bool GetKeyOriginByXOnly(const XOnlyPubKey& pubkey, KeyOriginInfo& info) const
    {
        for (const auto& id : pubkey.GetKeyIDs()) {
            if (GetKeyOrigin(id, info)) return true;
        }
        return false;
    }
};

extern const SigningProvider& DUMMY_SIGNING_PROVIDER;

class HidingSigningProvider : public SigningProvider
{
private:
    const bool m_hide_secret;
    const bool m_hide_origin;
    const SigningProvider* m_provider;

public:
    HidingSigningProvider(const SigningProvider* provider, bool hide_secret, bool hide_origin) : m_hide_secret(hide_secret), m_hide_origin(hide_origin), m_provider(provider) {}
    bool GetCScript(const CScriptID& scriptid, CScript& script) const override;
    bool GetPubKey(const CKeyID& keyid, CPubKey& pubkey) const override;
    bool GetKey(const CKeyID& keyid, CKey& key) const override;
    bool GetKeyOrigin(const CKeyID& keyid, KeyOriginInfo& info) const override;
    bool GetTaprootSpendData(const XOnlyPubKey& output_key, TaprootSpendData& spenddata) const override;
    bool GetTaprootBuilder(const XOnlyPubKey& output_key, TaprootBuilder& builder) const override;
    std::vector<CPubKey> GetMuSig2ParticipantPubkeys(const CPubKey& pubkey) const override;
    std::map<CPubKey, std::vector<CPubKey>> GetAllMuSig2ParticipantPubkeys() const override;
    void SetMuSig2SecNonce(const uint256& id, MuSig2SecNonce&& nonce) const override;
    std::optional<std::reference_wrapper<MuSig2SecNonce>> GetMuSig2SecNonce(const uint256& session_id) const override;
    void DeleteMuSig2Session(const uint256& session_id) const override;
};

struct FlatSigningProvider final : public SigningProvider
{
    std::map<CScriptID, CScript> scripts;
    std::map<CKeyID, CPubKey> pubkeys;
    std::map<CKeyID, std::pair<CPubKey, KeyOriginInfo>> origins;
    std::map<CKeyID, CKey> keys;
    std::map<XOnlyPubKey, TaprootBuilder> tr_trees; 
    std::map<CPubKey, std::vector<CPubKey>> aggregate_pubkeys; 
    std::map<uint256, MuSig2SecNonce>* musig2_secnonces{nullptr};

    bool GetCScript(const CScriptID& scriptid, CScript& script) const override;
    bool GetPubKey(const CKeyID& keyid, CPubKey& pubkey) const override;
    bool GetKeyOrigin(const CKeyID& keyid, KeyOriginInfo& info) const override;
    bool HaveKey(const CKeyID &keyid) const override;
    bool GetKey(const CKeyID& keyid, CKey& key) const override;
    bool GetTaprootSpendData(const XOnlyPubKey& output_key, TaprootSpendData& spenddata) const override;
    bool GetTaprootBuilder(const XOnlyPubKey& output_key, TaprootBuilder& builder) const override;
    std::vector<CPubKey> GetMuSig2ParticipantPubkeys(const CPubKey& pubkey) const override;
    std::map<CPubKey, std::vector<CPubKey>> GetAllMuSig2ParticipantPubkeys() const override;
    void SetMuSig2SecNonce(const uint256& id, MuSig2SecNonce&& nonce) const override;
    std::optional<std::reference_wrapper<MuSig2SecNonce>> GetMuSig2SecNonce(const uint256& session_id) const override;
    void DeleteMuSig2Session(const uint256& session_id) const override;

    FlatSigningProvider& Merge(FlatSigningProvider&& b) LIFETIMEBOUND;
};

class FillableSigningProvider : public SigningProvider
{
protected:
    using KeyMap = std::map<CKeyID, CKey>;
    using ScriptMap = std::map<CScriptID, CScript>;

    KeyMap mapKeys GUARDED_BY(cs_KeyStore);

    ScriptMap mapScripts GUARDED_BY(cs_KeyStore);

    void ImplicitlyLearnRelatedKeyScripts(const CPubKey& pubkey) EXCLUSIVE_LOCKS_REQUIRED(cs_KeyStore);

public:
    mutable RecursiveMutex cs_KeyStore;

    virtual bool AddKeyPubKey(const CKey& key, const CPubKey &pubkey);
    virtual bool AddKey(const CKey &key) { return AddKeyPubKey(key, key.GetPubKey()); }
    virtual bool GetPubKey(const CKeyID &address, CPubKey& vchPubKeyOut) const override;
    virtual bool HaveKey(const CKeyID &address) const override;
    virtual std::set<CKeyID> GetKeys() const;
    virtual bool GetKey(const CKeyID &address, CKey &keyOut) const override;
    virtual bool AddCScript(const CScript& redeemScript);
    virtual bool HaveCScript(const CScriptID &hash) const override;
    virtual std::set<CScriptID> GetCScripts() const;
    virtual bool GetCScript(const CScriptID &hash, CScript& redeemScriptOut) const override;
};

CKeyID GetKeyForDestination(const SigningProvider& store, const CTxDestination& dest);

class MultiSigningProvider: public SigningProvider {
    std::vector<std::unique_ptr<SigningProvider>> m_providers;

public:
    void AddProvider(std::unique_ptr<SigningProvider> provider);

    bool GetCScript(const CScriptID& scriptid, CScript& script) const override;
    bool GetPubKey(const CKeyID& keyid, CPubKey& pubkey) const override;
    bool GetKeyOrigin(const CKeyID& keyid, KeyOriginInfo& info) const override;
    bool GetKey(const CKeyID& keyid, CKey& key) const override;
    bool GetTaprootSpendData(const XOnlyPubKey& output_key, TaprootSpendData& spenddata) const override;
    bool GetTaprootBuilder(const XOnlyPubKey& output_key, TaprootBuilder& builder) const override;
};

#endif // BITCOIN_SCRIPT_SIGNINGPROVIDER_H