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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2017 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_SIGN_H
#define BITCOIN_SCRIPT_SIGN_H
#include <boost/optional.hpp>
#include <hash.h>
#include <pubkey.h>
#include <script/interpreter.h>
#include <streams.h>
class CKey;
class CKeyID;
class CScript;
class CScriptID;
class CTransaction;
struct CMutableTransaction;
/** An interface to be implemented by keystores that support signing. */
class SigningProvider
{
public:
virtual ~SigningProvider() {}
virtual bool GetCScript(const CScriptID &scriptid, CScript& script) 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; }
};
extern const SigningProvider& DUMMY_SIGNING_PROVIDER;
/** Interface for signature creators. */
class BaseSignatureCreator {
public:
virtual ~BaseSignatureCreator() {}
virtual const BaseSignatureChecker& Checker() const =0;
/** Create a singular (non-script) signature. */
virtual bool CreateSig(const SigningProvider& provider, std::vector<unsigned char>& vchSig, const CKeyID& keyid, const CScript& scriptCode, SigVersion sigversion) const =0;
};
/** A signature creator for transactions. */
class MutableTransactionSignatureCreator : public BaseSignatureCreator {
const CMutableTransaction* txTo;
unsigned int nIn;
int nHashType;
CAmount amount;
const MutableTransactionSignatureChecker checker;
public:
MutableTransactionSignatureCreator(const CMutableTransaction* txToIn, unsigned int nInIn, const CAmount& amountIn, int nHashTypeIn = SIGHASH_ALL);
const BaseSignatureChecker& Checker() const override { return checker; }
bool CreateSig(const SigningProvider& provider, std::vector<unsigned char>& vchSig, const CKeyID& keyid, const CScript& scriptCode, SigVersion sigversion) const override;
};
/** A signature creator that just produces 72-byte empty signatures. */
extern const BaseSignatureCreator& DUMMY_SIGNATURE_CREATOR;
typedef std::pair<CPubKey, std::vector<unsigned char>> SigPair;
// This struct contains information from a transaction input and also contains signatures for that input.
// The information contained here can be used to create a signature and is also filled by ProduceSignature
// in order to construct final scriptSigs and scriptWitnesses.
struct SignatureData {
bool complete = false; ///< Stores whether the scriptSig and scriptWitness are complete
CScript scriptSig; ///< The scriptSig of an input. Contains complete signatures or the traditional partial signatures format
CScript redeem_script; ///< The redeemScript (if any) for the input
CScript witness_script; ///< The witnessScript (if any) for the input. witnessScripts are used in P2WSH outputs.
CScriptWitness scriptWitness; ///< The scriptWitness of an input. Contains complete signatures or the traditional partial signatures format. scriptWitness is part of a transaction input per BIP 144.
std::map<CKeyID, SigPair> signatures; ///< BIP 174 style partial signatures for the input. May contain all signatures necessary for producing a final scriptSig or scriptWitness.
SignatureData() {}
explicit SignatureData(const CScript& script) : scriptSig(script) {}
void MergeSignatureData(SignatureData sigdata);
};
// Magic bytes
static constexpr uint8_t PSBT_MAGIC_BYTES[5] = {'p', 's', 'b', 't', 0xff};
// Global types
static constexpr uint8_t PSBT_GLOBAL_UNSIGNED_TX = 0x00;
// Input types
static constexpr uint8_t PSBT_IN_NON_WITNESS_UTXO = 0x00;
static constexpr uint8_t PSBT_IN_WITNESS_UTXO = 0x01;
static constexpr uint8_t PSBT_IN_PARTIAL_SIG = 0x02;
static constexpr uint8_t PSBT_IN_SIGHASH = 0x03;
static constexpr uint8_t PSBT_IN_REDEEMSCRIPT = 0x04;
static constexpr uint8_t PSBT_IN_WITNESSSCRIPT = 0x05;
static constexpr uint8_t PSBT_IN_BIP32_DERIVATION = 0x06;
static constexpr uint8_t PSBT_IN_SCRIPTSIG = 0x07;
static constexpr uint8_t PSBT_IN_SCRIPTWITNESS = 0x08;
// Output types
static constexpr uint8_t PSBT_OUT_REDEEMSCRIPT = 0x00;
static constexpr uint8_t PSBT_OUT_WITNESSSCRIPT = 0x01;
static constexpr uint8_t PSBT_OUT_BIP32_DERIVATION = 0x02;
// The separator is 0x00. Reading this in means that the unserializer can interpret it
// as a 0 length key which indicates that this is the separator. The separator has no value.
static constexpr uint8_t PSBT_SEPARATOR = 0x00;
// Takes a stream and multiple arguments and serializes them into a vector and then into the stream
// The resulting output into the stream has the total serialized length of all of the objects followed by all objects concatenated with each other.
template<typename Stream, typename... X>
void SerializeToVector(Stream& s, const X&... args)
{
std::vector<unsigned char> ret;
CVectorWriter ss(SER_NETWORK, PROTOCOL_VERSION, ret, 0);
SerializeMany(ss, args...);
s << ret;
}
// Takes a stream and multiple arguments and unserializes them first as a vector then each object individually in the order provided in the arguments
template<typename Stream, typename... X>
void UnserializeFromVector(Stream& s, X&... args)
{
std::vector<unsigned char> data;
s >> data;
CDataStream ss(data, SER_NETWORK, PROTOCOL_VERSION);
UnserializeMany(ss, args...);
if (!ss.eof()) {
throw std::ios_base::failure("Size of value was not the stated size");
}
}
// Deserialize HD keypaths into a map
template<typename Stream>
void DeserializeHDKeypaths(Stream& s, const std::vector<unsigned char>& key, std::map<CPubKey, std::vector<uint32_t>>& hd_keypaths)
{
// Make sure that the key is the size of pubkey + 1
if (key.size() != CPubKey::PUBLIC_KEY_SIZE + 1 && key.size() != CPubKey::COMPRESSED_PUBLIC_KEY_SIZE + 1) {
throw std::ios_base::failure("Size of key was not the expected size for the type BIP32 keypath");
}
// Read in the pubkey from key
CPubKey pubkey(key.begin() + 1, key.end());
if (!pubkey.IsFullyValid()) {
throw std::ios_base::failure("Invalid pubkey");
}
if (hd_keypaths.count(pubkey) > 0) {
throw std::ios_base::failure("Duplicate Key, pubkey derivation path already provided");
}
// Read in key path
uint64_t value_len = ReadCompactSize(s);
std::vector<uint32_t> keypath;
for (unsigned int i = 0; i < value_len; i += sizeof(uint32_t)) {
uint32_t index;
s >> index;
keypath.push_back(index);
}
// Add to map
hd_keypaths.emplace(pubkey, keypath);
}
// Serialize HD keypaths to a stream from a map
template<typename Stream>
void SerializeHDKeypaths(Stream& s, const std::map<CPubKey, std::vector<uint32_t>>& hd_keypaths, uint8_t type)
{
for (auto keypath_pair : hd_keypaths) {
SerializeToVector(s, type, MakeSpan(keypath_pair.first));
WriteCompactSize(s, keypath_pair.second.size() * sizeof(uint32_t));
for (auto& path : keypath_pair.second) {
s << path;
}
}
}
/** A structure for PSBTs which contain per-input information */
struct PSBTInput
{
CTransactionRef non_witness_utxo;
CTxOut witness_utxo;
CScript redeem_script;
CScript witness_script;
CScript final_script_sig;
CScriptWitness final_script_witness;
std::map<CPubKey, std::vector<uint32_t>> hd_keypaths;
std::map<CKeyID, SigPair> partial_sigs;
std::map<std::vector<unsigned char>, std::vector<unsigned char>> unknown;
int sighash_type = 0;
bool IsNull() const;
PSBTInput() {}
template <typename Stream>
inline void Serialize(Stream& s) const {
// Write the utxo
// If there is a non-witness utxo, then don't add the witness one.
if (non_witness_utxo) {
SerializeToVector(s, PSBT_IN_NON_WITNESS_UTXO);
SerializeToVector(s, non_witness_utxo);
} else if (!witness_utxo.IsNull()) {
SerializeToVector(s, PSBT_IN_WITNESS_UTXO);
SerializeToVector(s, witness_utxo);
}
if (final_script_sig.empty() && final_script_witness.IsNull()) {
// Write any partial signatures
for (auto sig_pair : partial_sigs) {
SerializeToVector(s, PSBT_IN_PARTIAL_SIG, MakeSpan(sig_pair.second.first));
s << sig_pair.second.second;
}
// Write the sighash type
if (sighash_type > 0) {
SerializeToVector(s, PSBT_IN_SIGHASH);
SerializeToVector(s, sighash_type);
}
// Write the redeem script
if (!redeem_script.empty()) {
SerializeToVector(s, PSBT_IN_REDEEMSCRIPT);
s << redeem_script;
}
// Write the witness script
if (!witness_script.empty()) {
SerializeToVector(s, PSBT_IN_WITNESSSCRIPT);
s << witness_script;
}
// Write any hd keypaths
SerializeHDKeypaths(s, hd_keypaths, PSBT_IN_BIP32_DERIVATION);
}
// Write script sig
if (!final_script_sig.empty()) {
SerializeToVector(s, PSBT_IN_SCRIPTSIG);
s << final_script_sig;
}
// write script witness
if (!final_script_witness.IsNull()) {
SerializeToVector(s, PSBT_IN_SCRIPTWITNESS);
SerializeToVector(s, final_script_witness.stack);
}
// Write unknown things
for (auto& entry : unknown) {
s << entry.first;
s << entry.second;
}
s << PSBT_SEPARATOR;
}
template <typename Stream>
inline void Unserialize(Stream& s) {
// Read loop
while(!s.empty()) {
// Read
std::vector<unsigned char> key;
s >> key;
// the key is empty if that was actually a separator byte
// This is a special case for key lengths 0 as those are not allowed (except for separator)
if (key.empty()) return;
// First byte of key is the type
unsigned char type = key[0];
// Do stuff based on type
switch(type) {
case PSBT_IN_NON_WITNESS_UTXO:
if (non_witness_utxo) {
throw std::ios_base::failure("Duplicate Key, input non-witness utxo already provided");
}
UnserializeFromVector(s, non_witness_utxo);
break;
case PSBT_IN_WITNESS_UTXO:
if (!witness_utxo.IsNull()) {
throw std::ios_base::failure("Duplicate Key, input witness utxo already provided");
}
UnserializeFromVector(s, witness_utxo);
break;
case PSBT_IN_PARTIAL_SIG:
{
// Make sure that the key is the size of pubkey + 1
if (key.size() != CPubKey::PUBLIC_KEY_SIZE + 1 && key.size() != CPubKey::COMPRESSED_PUBLIC_KEY_SIZE + 1) {
throw std::ios_base::failure("Size of key was not the expected size for the type partial signature pubkey");
}
// Read in the pubkey from key
CPubKey pubkey(key.begin() + 1, key.end());
if (!pubkey.IsFullyValid()) {
throw std::ios_base::failure("Invalid pubkey");
}
if (partial_sigs.count(pubkey.GetID()) > 0) {
throw std::ios_base::failure("Duplicate Key, input partial signature for pubkey already provided");
}
// Read in the signature from value
std::vector<unsigned char> sig;
s >> sig;
// Add to list
partial_sigs.emplace(pubkey.GetID(), SigPair(pubkey, std::move(sig)));
break;
}
case PSBT_IN_SIGHASH:
if (sighash_type > 0) {
throw std::ios_base::failure("Duplicate Key, input sighash type already provided");
}
UnserializeFromVector(s, sighash_type);
break;
case PSBT_IN_REDEEMSCRIPT:
{
if (!redeem_script.empty()) {
throw std::ios_base::failure("Duplicate Key, input redeemScript already provided");
}
s >> redeem_script;
break;
}
case PSBT_IN_WITNESSSCRIPT:
{
if (!witness_script.empty()) {
throw std::ios_base::failure("Duplicate Key, input witnessScript already provided");
}
s >> witness_script;
break;
}
case PSBT_IN_BIP32_DERIVATION:
{
DeserializeHDKeypaths(s, key, hd_keypaths);
break;
}
case PSBT_IN_SCRIPTSIG:
{
if (!final_script_sig.empty()) {
throw std::ios_base::failure("Duplicate Key, input final scriptSig already provided");
}
s >> final_script_sig;
break;
}
case PSBT_IN_SCRIPTWITNESS:
{
if (!final_script_witness.IsNull()) {
throw std::ios_base::failure("Duplicate Key, input final scriptWitness already provided");
}
UnserializeFromVector(s, final_script_witness.stack);
break;
}
// Unknown stuff
default:
if (unknown.count(key) > 0) {
throw std::ios_base::failure("Duplicate Key, key for unknown value already provided");
}
// Read in the value
std::vector<unsigned char> val_bytes;
s >> val_bytes;
unknown.emplace(std::move(key), std::move(val_bytes));
break;
}
}
}
template <typename Stream>
PSBTInput(deserialize_type, Stream& s) {
Unserialize(s);
}
};
/** A structure for PSBTs which contains per output information */
struct PSBTOutput
{
CScript redeem_script;
CScript witness_script;
std::map<CPubKey, std::vector<uint32_t>> hd_keypaths;
std::map<std::vector<unsigned char>, std::vector<unsigned char>> unknown;
bool IsNull() const;
PSBTOutput() {}
template <typename Stream>
inline void Serialize(Stream& s) const {
// Write the redeem script
if (!redeem_script.empty()) {
SerializeToVector(s, PSBT_OUT_REDEEMSCRIPT);
s << redeem_script;
}
// Write the witness script
if (!witness_script.empty()) {
SerializeToVector(s, PSBT_OUT_WITNESSSCRIPT);
s << witness_script;
}
// Write any hd keypaths
SerializeHDKeypaths(s, hd_keypaths, PSBT_OUT_BIP32_DERIVATION);
// Write unknown things
for (auto& entry : unknown) {
s << entry.first;
s << entry.second;
}
s << PSBT_SEPARATOR;
}
template <typename Stream>
inline void Unserialize(Stream& s) {
// Read loop
while(!s.empty()) {
// Read
std::vector<unsigned char> key;
s >> key;
// the key is empty if that was actually a separator byte
// This is a special case for key lengths 0 as those are not allowed (except for separator)
if (key.empty()) return;
// First byte of key is the type
unsigned char type = key[0];
// Do stuff based on type
switch(type) {
case PSBT_OUT_REDEEMSCRIPT:
{
if (!redeem_script.empty()) {
throw std::ios_base::failure("Duplicate Key, output redeemScript already provided");
}
s >> redeem_script;
break;
}
case PSBT_OUT_WITNESSSCRIPT:
{
if (!witness_script.empty()) {
throw std::ios_base::failure("Duplicate Key, output witnessScript already provided");
}
s >> witness_script;
break;
}
case PSBT_OUT_BIP32_DERIVATION:
{
DeserializeHDKeypaths(s, key, hd_keypaths);
break;
}
// Unknown stuff
default: {
if (unknown.count(key) > 0) {
throw std::ios_base::failure("Duplicate Key, key for unknown value already provided");
}
// Read in the value
std::vector<unsigned char> val_bytes;
s >> val_bytes;
unknown.emplace(std::move(key), std::move(val_bytes));
break;
}
}
}
}
template <typename Stream>
PSBTOutput(deserialize_type, Stream& s) {
Unserialize(s);
}
};
/** A version of CTransaction with the PSBT format*/
struct PartiallySignedTransaction
{
boost::optional<CMutableTransaction> tx;
std::vector<PSBTInput> inputs;
std::vector<PSBTOutput> outputs;
std::map<std::vector<unsigned char>, std::vector<unsigned char>> unknown;
bool IsNull() const;
PartiallySignedTransaction() {}
PartiallySignedTransaction(const PartiallySignedTransaction& psbt_in) : tx(psbt_in.tx), inputs(psbt_in.inputs), outputs(psbt_in.outputs), unknown(psbt_in.unknown) {}
// Only checks if they refer to the same transaction
friend bool operator==(const PartiallySignedTransaction& a, const PartiallySignedTransaction &b)
{
return a.tx->GetHash() == b.tx->GetHash();
}
friend bool operator!=(const PartiallySignedTransaction& a, const PartiallySignedTransaction &b)
{
return !(a == b);
}
template <typename Stream>
inline void Serialize(Stream& s) const {
// magic bytes
s << PSBT_MAGIC_BYTES;
// unsigned tx flag
SerializeToVector(s, PSBT_GLOBAL_UNSIGNED_TX);
// Write serialized tx to a stream
SerializeToVector(s, *tx);
// Write the unknown things
for (auto& entry : unknown) {
s << entry.first;
s << entry.second;
}
// Separator
s << PSBT_SEPARATOR;
// Write inputs
for (const PSBTInput& input : inputs) {
s << input;
}
// Write outputs
for (const PSBTOutput& output : outputs) {
s << output;
}
}
template <typename Stream>
inline void Unserialize(Stream& s) {
// Read the magic bytes
uint8_t magic[5];
s >> magic;
if (!std::equal(magic, magic + 5, PSBT_MAGIC_BYTES)) {
throw std::ios_base::failure("Invalid PSBT magic bytes");
}
// Read global data
while(!s.empty()) {
// Read
std::vector<unsigned char> key;
s >> key;
// the key is empty if that was actually a separator byte
// This is a special case for key lengths 0 as those are not allowed (except for separator)
if (key.empty()) break;
// First byte of key is the type
unsigned char type = key[0];
// Do stuff based on type
switch(type) {
case PSBT_GLOBAL_UNSIGNED_TX:
{
if (tx) {
throw std::ios_base::failure("Duplicate Key, unsigned tx already provided");
}
CMutableTransaction mtx;
UnserializeFromVector(s, mtx);
tx = std::move(mtx);
// Make sure that all scriptSigs and scriptWitnesses are empty
for (const CTxIn& txin : tx->vin) {
if (!txin.scriptSig.empty() || !txin.scriptWitness.IsNull()) {
throw std::ios_base::failure("Unsigned tx does not have empty scriptSigs and scriptWitnesses.");
}
}
break;
}
// Unknown stuff
default: {
if (unknown.count(key) > 0) {
throw std::ios_base::failure("Duplicate Key, key for unknown value already provided");
}
// Read in the value
std::vector<unsigned char> val_bytes;
s >> val_bytes;
unknown.emplace(std::move(key), std::move(val_bytes));
}
}
}
// Make sure that we got an unsigned tx
if (!tx) {
throw std::ios_base::failure("No unsigned transcation was provided");
}
// Read input data
unsigned int i = 0;
while (!s.empty() && i < tx->vin.size()) {
PSBTInput input;
s >> input;
inputs.push_back(input);
// Make sure the non-witness utxo matches the outpoint
if (input.non_witness_utxo && input.non_witness_utxo->GetHash() != tx->vin[i].prevout.hash) {
throw std::ios_base::failure("Non-witness UTXO does not match outpoint hash");
}
++i;
}
// Make sure that the number of inputs matches the number of inputs in the transaction
if (inputs.size() != tx->vin.size()) {
throw std::ios_base::failure("Inputs provided does not match the number of inputs in transaction.");
}
// Read output data
i = 0;
while (!s.empty() && i < tx->vout.size()) {
PSBTOutput output;
s >> output;
outputs.push_back(output);
++i;
}
// Make sure that the number of outputs matches the number of outputs in the transaction
if (outputs.size() != tx->vout.size()) {
throw std::ios_base::failure("Outputs provided does not match the number of outputs in transaction.");
}
}
template <typename Stream>
PartiallySignedTransaction(deserialize_type, Stream& s) {
Unserialize(s);
}
};
/** Produce a script signature using a generic signature creator. */
bool ProduceSignature(const SigningProvider& provider, const BaseSignatureCreator& creator, const CScript& scriptPubKey, SignatureData& sigdata);
/** Produce a script signature for a transaction. */
bool SignSignature(const SigningProvider &provider, const CScript& fromPubKey, CMutableTransaction& txTo, unsigned int nIn, const CAmount& amount, int nHashType);
bool SignSignature(const SigningProvider &provider, const CTransaction& txFrom, CMutableTransaction& txTo, unsigned int nIn, int nHashType);
/** Extract signature data from a transaction input, and insert it. */
SignatureData DataFromTransaction(const CMutableTransaction& tx, unsigned int nIn, const CTxOut& txout);
void UpdateInput(CTxIn& input, const SignatureData& data);
/* Check whether we know how to sign for an output like this, assuming we
* have all private keys. While this function does not need private keys, the passed
* provider is used to look up public keys and redeemscripts by hash.
* Solvability is unrelated to whether we consider this output to be ours. */
bool IsSolvable(const SigningProvider& provider, const CScript& script);
#endif // BITCOIN_SCRIPT_SIGN_H
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