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bitcoin/src/psbt.h

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// Copyright (c) 2009-2022 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_PSBT_H
#define BITCOIN_PSBT_H
#include <node/transaction.h>
#include <policy/feerate.h>
#include <primitives/transaction.h>
#include <pubkey.h>
#include <script/keyorigin.h>
#include <script/sign.h>
#include <script/signingprovider.h>
#include <span.h>
#include <streams.h>
#include <optional>
// 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;
static constexpr uint8_t PSBT_GLOBAL_XPUB = 0x01;
static constexpr uint8_t PSBT_GLOBAL_VERSION = 0xFB;
static constexpr uint8_t PSBT_GLOBAL_PROPRIETARY = 0xFC;
// 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;
static constexpr uint8_t PSBT_IN_RIPEMD160 = 0x0A;
static constexpr uint8_t PSBT_IN_SHA256 = 0x0B;
static constexpr uint8_t PSBT_IN_HASH160 = 0x0C;
static constexpr uint8_t PSBT_IN_HASH256 = 0x0D;
static constexpr uint8_t PSBT_IN_TAP_KEY_SIG = 0x13;
static constexpr uint8_t PSBT_IN_TAP_SCRIPT_SIG = 0x14;
static constexpr uint8_t PSBT_IN_TAP_LEAF_SCRIPT = 0x15;
static constexpr uint8_t PSBT_IN_TAP_BIP32_DERIVATION = 0x16;
static constexpr uint8_t PSBT_IN_TAP_INTERNAL_KEY = 0x17;
static constexpr uint8_t PSBT_IN_TAP_MERKLE_ROOT = 0x18;
static constexpr uint8_t PSBT_IN_PROPRIETARY = 0xFC;
// 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;
static constexpr uint8_t PSBT_OUT_TAP_INTERNAL_KEY = 0x05;
static constexpr uint8_t PSBT_OUT_TAP_TREE = 0x06;
static constexpr uint8_t PSBT_OUT_TAP_BIP32_DERIVATION = 0x07;
static constexpr uint8_t PSBT_OUT_PROPRIETARY = 0xFC;
// 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;
// BIP 174 does not specify a maximum file size, but we set a limit anyway
// to prevent reading a stream indefinitely and running out of memory.
const std::streamsize MAX_FILE_SIZE_PSBT = 100000000; // 100 MB
// PSBT version number
static constexpr uint32_t PSBT_HIGHEST_VERSION = 0;
/** A structure for PSBT proprietary types */
struct PSBTProprietary
{
uint64_t subtype;
std::vector<unsigned char> identifier;
std::vector<unsigned char> key;
std::vector<unsigned char> value;
bool operator<(const PSBTProprietary &b) const {
return key < b.key;
}
bool operator==(const PSBTProprietary &b) const {
return key == b.key;
}
};
// Takes a stream and multiple arguments and serializes them as if first serialized 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)
{
SizeComputer sizecomp;
SerializeMany(sizecomp, args...);
WriteCompactSize(s, sizecomp.size());
SerializeMany(s, args...);
}
// 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)
{
size_t expected_size = ReadCompactSize(s);
size_t remaining_before = s.size();
UnserializeMany(s, args...);
size_t remaining_after = s.size();
if (remaining_after + expected_size != remaining_before) {
throw std::ios_base::failure("Size of value was not the stated size");
}
}
// Deserialize bytes of given length from the stream as a KeyOriginInfo
template<typename Stream>
KeyOriginInfo DeserializeKeyOrigin(Stream& s, uint64_t length)
{
// Read in key path
if (length % 4 || length == 0) {
throw std::ios_base::failure("Invalid length for HD key path");
}
KeyOriginInfo hd_keypath;
s >> hd_keypath.fingerprint;
for (unsigned int i = 4; i < length; i += sizeof(uint32_t)) {
uint32_t index;
s >> index;
hd_keypath.path.push_back(index);
}
return hd_keypath;
}
// Deserialize a length prefixed KeyOriginInfo from a stream
template<typename Stream>
void DeserializeHDKeypath(Stream& s, KeyOriginInfo& hd_keypath)
{
hd_keypath = DeserializeKeyOrigin(s, ReadCompactSize(s));
}
// Deserialize HD keypaths into a map
template<typename Stream>
void DeserializeHDKeypaths(Stream& s, const std::vector<unsigned char>& key, std::map<CPubKey, KeyOriginInfo>& hd_keypaths)
{
// Make sure that the key is the size of pubkey + 1
if (key.size() != CPubKey::SIZE + 1 && key.size() != CPubKey::COMPRESSED_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");
}
KeyOriginInfo keypath;
DeserializeHDKeypath(s, keypath);
// Add to map
hd_keypaths.emplace(pubkey, std::move(keypath));
}
// Serialize a KeyOriginInfo to a stream
template<typename Stream>
void SerializeKeyOrigin(Stream& s, KeyOriginInfo hd_keypath)
{
s << hd_keypath.fingerprint;
for (const auto& path : hd_keypath.path) {
s << path;
}
}
// Serialize a length prefixed KeyOriginInfo to a stream
template<typename Stream>
void SerializeHDKeypath(Stream& s, KeyOriginInfo hd_keypath)
{
WriteCompactSize(s, (hd_keypath.path.size() + 1) * sizeof(uint32_t));
SerializeKeyOrigin(s, hd_keypath);
}
// Serialize HD keypaths to a stream from a map
template<typename Stream>
void SerializeHDKeypaths(Stream& s, const std::map<CPubKey, KeyOriginInfo>& hd_keypaths, CompactSizeWriter type)
{
for (const auto& keypath_pair : hd_keypaths) {
if (!keypath_pair.first.IsValid()) {
throw std::ios_base::failure("Invalid CPubKey being serialized");
}
SerializeToVector(s, type, Span{keypath_pair.first});
SerializeHDKeypath(s, keypath_pair.second);
}
}
/** 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, KeyOriginInfo> hd_keypaths;
std::map<CKeyID, SigPair> partial_sigs;
std::map<uint160, std::vector<unsigned char>> ripemd160_preimages;
std::map<uint256, std::vector<unsigned char>> sha256_preimages;
std::map<uint160, std::vector<unsigned char>> hash160_preimages;
std::map<uint256, std::vector<unsigned char>> hash256_preimages;
// Taproot fields
std::vector<unsigned char> m_tap_key_sig;
std::map<std::pair<XOnlyPubKey, uint256>, std::vector<unsigned char>> m_tap_script_sigs;
std::map<std::pair<std::vector<unsigned char>, int>, std::set<std::vector<unsigned char>, ShortestVectorFirstComparator>> m_tap_scripts;
std::map<XOnlyPubKey, std::pair<std::set<uint256>, KeyOriginInfo>> m_tap_bip32_paths;
XOnlyPubKey m_tap_internal_key;
uint256 m_tap_merkle_root;
std::map<std::vector<unsigned char>, std::vector<unsigned char>> unknown;
std::set<PSBTProprietary> m_proprietary;
std::optional<int> sighash_type;
bool IsNull() const;
void FillSignatureData(SignatureData& sigdata) const;
void FromSignatureData(const SignatureData& sigdata);
void Merge(const PSBTInput& input);
PSBTInput() {}
template <typename Stream>
inline void Serialize(Stream& s) const {
// Write the utxo
if (non_witness_utxo) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_NON_WITNESS_UTXO));
SerializeToVector(s, TX_NO_WITNESS(non_witness_utxo));
}
if (!witness_utxo.IsNull()) {
SerializeToVector(s, CompactSizeWriter(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, CompactSizeWriter(PSBT_IN_PARTIAL_SIG), Span{sig_pair.second.first});
s << sig_pair.second.second;
}
// Write the sighash type
if (sighash_type != std::nullopt) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_SIGHASH));
SerializeToVector(s, *sighash_type);
}
// Write the redeem script
if (!redeem_script.empty()) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_REDEEMSCRIPT));
s << redeem_script;
}
// Write the witness script
if (!witness_script.empty()) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_WITNESSSCRIPT));
s << witness_script;
}
// Write any hd keypaths
SerializeHDKeypaths(s, hd_keypaths, CompactSizeWriter(PSBT_IN_BIP32_DERIVATION));
// Write any ripemd160 preimage
for (const auto& [hash, preimage] : ripemd160_preimages) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_RIPEMD160), Span{hash});
s << preimage;
}
// Write any sha256 preimage
for (const auto& [hash, preimage] : sha256_preimages) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_SHA256), Span{hash});
s << preimage;
}
// Write any hash160 preimage
for (const auto& [hash, preimage] : hash160_preimages) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_HASH160), Span{hash});
s << preimage;
}
// Write any hash256 preimage
for (const auto& [hash, preimage] : hash256_preimages) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_HASH256), Span{hash});
s << preimage;
}
// Write taproot key sig
if (!m_tap_key_sig.empty()) {
SerializeToVector(s, PSBT_IN_TAP_KEY_SIG);
s << m_tap_key_sig;
}
// Write taproot script sigs
for (const auto& [pubkey_leaf, sig] : m_tap_script_sigs) {
const auto& [xonly, leaf_hash] = pubkey_leaf;
SerializeToVector(s, PSBT_IN_TAP_SCRIPT_SIG, xonly, leaf_hash);
s << sig;
}
// Write taproot leaf scripts
for (const auto& [leaf, control_blocks] : m_tap_scripts) {
const auto& [script, leaf_ver] = leaf;
for (const auto& control_block : control_blocks) {
SerializeToVector(s, PSBT_IN_TAP_LEAF_SCRIPT, Span{control_block});
std::vector<unsigned char> value_v(script.begin(), script.end());
value_v.push_back((uint8_t)leaf_ver);
s << value_v;
}
}
// Write taproot bip32 keypaths
for (const auto& [xonly, leaf_origin] : m_tap_bip32_paths) {
const auto& [leaf_hashes, origin] = leaf_origin;
SerializeToVector(s, PSBT_IN_TAP_BIP32_DERIVATION, xonly);
std::vector<unsigned char> value;
VectorWriter s_value{value, 0};
s_value << leaf_hashes;
SerializeKeyOrigin(s_value, origin);
s << value;
}
// Write taproot internal key
if (!m_tap_internal_key.IsNull()) {
SerializeToVector(s, PSBT_IN_TAP_INTERNAL_KEY);
s << ToByteVector(m_tap_internal_key);
}
// Write taproot merkle root
if (!m_tap_merkle_root.IsNull()) {
SerializeToVector(s, PSBT_IN_TAP_MERKLE_ROOT);
SerializeToVector(s, m_tap_merkle_root);
}
}
// Write script sig
if (!final_script_sig.empty()) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_SCRIPTSIG));
s << final_script_sig;
}
// write script witness
if (!final_script_witness.IsNull()) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_SCRIPTWITNESS));
SerializeToVector(s, final_script_witness.stack);
}
// Write proprietary things
for (const auto& entry : m_proprietary) {
s << entry.key;
s << entry.value;
}
// Write unknown things
for (auto& entry : unknown) {
s << entry.first;
s << entry.second;
}
s << PSBT_SEPARATOR;
}
template <typename Stream>
inline void Unserialize(Stream& s) {
// Used for duplicate key detection
std::set<std::vector<unsigned char>> key_lookup;
// Read loop
bool found_sep = false;
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()) {
found_sep = true;
break;
}
// Type is compact size uint at beginning of key
SpanReader skey{key};
uint64_t type = ReadCompactSize(skey);
// Do stuff based on type
switch(type) {
case PSBT_IN_NON_WITNESS_UTXO:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input non-witness utxo already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Non-witness utxo key is more than one byte type");
}
// Set the stream to unserialize with witness since this is always a valid network transaction
UnserializeFromVector(s, TX_WITH_WITNESS(non_witness_utxo));
break;
}
case PSBT_IN_WITNESS_UTXO:
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input witness utxo already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Witness utxo key is more than one byte type");
}
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::SIZE + 1 && key.size() != CPubKey::COMPRESSED_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 (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input sighash type already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Sighash type key is more than one byte type");
}
int sighash;
UnserializeFromVector(s, sighash);
sighash_type = sighash;
break;
case PSBT_IN_REDEEMSCRIPT:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input redeemScript already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Input redeemScript key is more than one byte type");
}
s >> redeem_script;
break;
}
case PSBT_IN_WITNESSSCRIPT:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input witnessScript already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Input witnessScript key is more than one byte type");
}
s >> witness_script;
break;
}
case PSBT_IN_BIP32_DERIVATION:
{
DeserializeHDKeypaths(s, key, hd_keypaths);
break;
}
case PSBT_IN_SCRIPTSIG:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input final scriptSig already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Final scriptSig key is more than one byte type");
}
s >> final_script_sig;
break;
}
case PSBT_IN_SCRIPTWITNESS:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input final scriptWitness already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Final scriptWitness key is more than one byte type");
}
UnserializeFromVector(s, final_script_witness.stack);
break;
}
case PSBT_IN_RIPEMD160:
{
// Make sure that the key is the size of a ripemd160 hash + 1
if (key.size() != CRIPEMD160::OUTPUT_SIZE + 1) {
throw std::ios_base::failure("Size of key was not the expected size for the type ripemd160 preimage");
}
// Read in the hash from key
std::vector<unsigned char> hash_vec(key.begin() + 1, key.end());
uint160 hash(hash_vec);
if (ripemd160_preimages.count(hash) > 0) {
throw std::ios_base::failure("Duplicate Key, input ripemd160 preimage already provided");
}
// Read in the preimage from value
std::vector<unsigned char> preimage;
s >> preimage;
// Add to preimages list
ripemd160_preimages.emplace(hash, std::move(preimage));
break;
}
case PSBT_IN_SHA256:
{
// Make sure that the key is the size of a sha256 hash + 1
if (key.size() != CSHA256::OUTPUT_SIZE + 1) {
throw std::ios_base::failure("Size of key was not the expected size for the type sha256 preimage");
}
// Read in the hash from key
std::vector<unsigned char> hash_vec(key.begin() + 1, key.end());
uint256 hash(hash_vec);
if (sha256_preimages.count(hash) > 0) {
throw std::ios_base::failure("Duplicate Key, input sha256 preimage already provided");
}
// Read in the preimage from value
std::vector<unsigned char> preimage;
s >> preimage;
// Add to preimages list
sha256_preimages.emplace(hash, std::move(preimage));
break;
}
case PSBT_IN_HASH160:
{
// Make sure that the key is the size of a hash160 hash + 1
if (key.size() != CHash160::OUTPUT_SIZE + 1) {
throw std::ios_base::failure("Size of key was not the expected size for the type hash160 preimage");
}
// Read in the hash from key
std::vector<unsigned char> hash_vec(key.begin() + 1, key.end());
uint160 hash(hash_vec);
if (hash160_preimages.count(hash) > 0) {
throw std::ios_base::failure("Duplicate Key, input hash160 preimage already provided");
}
// Read in the preimage from value
std::vector<unsigned char> preimage;
s >> preimage;
// Add to preimages list
hash160_preimages.emplace(hash, std::move(preimage));
break;
}
case PSBT_IN_HASH256:
{
// Make sure that the key is the size of a hash256 hash + 1
if (key.size() != CHash256::OUTPUT_SIZE + 1) {
throw std::ios_base::failure("Size of key was not the expected size for the type hash256 preimage");
}
// Read in the hash from key
std::vector<unsigned char> hash_vec(key.begin() + 1, key.end());
uint256 hash(hash_vec);
if (hash256_preimages.count(hash) > 0) {
throw std::ios_base::failure("Duplicate Key, input hash256 preimage already provided");
}
// Read in the preimage from value
std::vector<unsigned char> preimage;
s >> preimage;
// Add to preimages list
hash256_preimages.emplace(hash, std::move(preimage));
break;
}
case PSBT_IN_TAP_KEY_SIG:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input Taproot key signature already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Input Taproot key signature key is more than one byte type");
}
s >> m_tap_key_sig;
if (m_tap_key_sig.size() < 64) {
throw std::ios_base::failure("Input Taproot key path signature is shorter than 64 bytes");
} else if (m_tap_key_sig.size() > 65) {
throw std::ios_base::failure("Input Taproot key path signature is longer than 65 bytes");
}
break;
}
case PSBT_IN_TAP_SCRIPT_SIG:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input Taproot script signature already provided");
} else if (key.size() != 65) {
throw std::ios_base::failure("Input Taproot script signature key is not 65 bytes");
}
SpanReader s_key{Span{key}.subspan(1)};
XOnlyPubKey xonly;
uint256 hash;
s_key >> xonly;
s_key >> hash;
std::vector<unsigned char> sig;
s >> sig;
if (sig.size() < 64) {
throw std::ios_base::failure("Input Taproot script path signature is shorter than 64 bytes");
} else if (sig.size() > 65) {
throw std::ios_base::failure("Input Taproot script path signature is longer than 65 bytes");
}
m_tap_script_sigs.emplace(std::make_pair(xonly, hash), sig);
break;
}
case PSBT_IN_TAP_LEAF_SCRIPT:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input Taproot leaf script already provided");
} else if (key.size() < 34) {
throw std::ios_base::failure("Taproot leaf script key is not at least 34 bytes");
} else if ((key.size() - 2) % 32 != 0) {
throw std::ios_base::failure("Input Taproot leaf script key's control block size is not valid");
}
std::vector<unsigned char> script_v;
s >> script_v;
if (script_v.empty()) {
throw std::ios_base::failure("Input Taproot leaf script must be at least 1 byte");
}
uint8_t leaf_ver = script_v.back();
script_v.pop_back();
const auto leaf_script = std::make_pair(script_v, (int)leaf_ver);
m_tap_scripts[leaf_script].insert(std::vector<unsigned char>(key.begin() + 1, key.end()));
break;
}
case PSBT_IN_TAP_BIP32_DERIVATION:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input Taproot BIP32 keypath already provided");
} else if (key.size() != 33) {
throw std::ios_base::failure("Input Taproot BIP32 keypath key is not at 33 bytes");
}
SpanReader s_key{Span{key}.subspan(1)};
XOnlyPubKey xonly;
s_key >> xonly;
std::set<uint256> leaf_hashes;
uint64_t value_len = ReadCompactSize(s);
size_t before_hashes = s.size();
s >> leaf_hashes;
size_t after_hashes = s.size();
size_t hashes_len = before_hashes - after_hashes;
if (hashes_len > value_len) {
throw std::ios_base::failure("Input Taproot BIP32 keypath has an invalid length");
}
size_t origin_len = value_len - hashes_len;
m_tap_bip32_paths.emplace(xonly, std::make_pair(leaf_hashes, DeserializeKeyOrigin(s, origin_len)));
break;
}
case PSBT_IN_TAP_INTERNAL_KEY:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input Taproot internal key already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Input Taproot internal key key is more than one byte type");
}
UnserializeFromVector(s, m_tap_internal_key);
break;
}
case PSBT_IN_TAP_MERKLE_ROOT:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, input Taproot merkle root already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Input Taproot merkle root key is more than one byte type");
}
UnserializeFromVector(s, m_tap_merkle_root);
break;
}
case PSBT_IN_PROPRIETARY:
{
PSBTProprietary this_prop;
skey >> this_prop.identifier;
this_prop.subtype = ReadCompactSize(skey);
this_prop.key = key;
if (m_proprietary.count(this_prop) > 0) {
throw std::ios_base::failure("Duplicate Key, proprietary key already found");
}
s >> this_prop.value;
m_proprietary.insert(this_prop);
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;
}
}
if (!found_sep) {
throw std::ios_base::failure("Separator is missing at the end of an input map");
}
}
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, KeyOriginInfo> hd_keypaths;
XOnlyPubKey m_tap_internal_key;
std::vector<std::tuple<uint8_t, uint8_t, std::vector<unsigned char>>> m_tap_tree;
std::map<XOnlyPubKey, std::pair<std::set<uint256>, KeyOriginInfo>> m_tap_bip32_paths;
std::map<std::vector<unsigned char>, std::vector<unsigned char>> unknown;
std::set<PSBTProprietary> m_proprietary;
bool IsNull() const;
void FillSignatureData(SignatureData& sigdata) const;
void FromSignatureData(const SignatureData& sigdata);
void Merge(const PSBTOutput& output);
PSBTOutput() {}
template <typename Stream>
inline void Serialize(Stream& s) const {
// Write the redeem script
if (!redeem_script.empty()) {
SerializeToVector(s, CompactSizeWriter(PSBT_OUT_REDEEMSCRIPT));
s << redeem_script;
}
// Write the witness script
if (!witness_script.empty()) {
SerializeToVector(s, CompactSizeWriter(PSBT_OUT_WITNESSSCRIPT));
s << witness_script;
}
// Write any hd keypaths
SerializeHDKeypaths(s, hd_keypaths, CompactSizeWriter(PSBT_OUT_BIP32_DERIVATION));
// Write proprietary things
for (const auto& entry : m_proprietary) {
s << entry.key;
s << entry.value;
}
// Write taproot internal key
if (!m_tap_internal_key.IsNull()) {
SerializeToVector(s, PSBT_OUT_TAP_INTERNAL_KEY);
s << ToByteVector(m_tap_internal_key);
}
// Write taproot tree
if (!m_tap_tree.empty()) {
SerializeToVector(s, PSBT_OUT_TAP_TREE);
std::vector<unsigned char> value;
VectorWriter s_value{value, 0};
for (const auto& [depth, leaf_ver, script] : m_tap_tree) {
s_value << depth;
s_value << leaf_ver;
s_value << script;
}
s << value;
}
// Write taproot bip32 keypaths
for (const auto& [xonly, leaf] : m_tap_bip32_paths) {
const auto& [leaf_hashes, origin] = leaf;
SerializeToVector(s, PSBT_OUT_TAP_BIP32_DERIVATION, xonly);
std::vector<unsigned char> value;
VectorWriter s_value{value, 0};
s_value << leaf_hashes;
SerializeKeyOrigin(s_value, origin);
s << value;
}
// Write unknown things
for (auto& entry : unknown) {
s << entry.first;
s << entry.second;
}
s << PSBT_SEPARATOR;
}
template <typename Stream>
inline void Unserialize(Stream& s) {
// Used for duplicate key detection
std::set<std::vector<unsigned char>> key_lookup;
// Read loop
bool found_sep = false;
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()) {
found_sep = true;
break;
}
// Type is compact size uint at beginning of key
SpanReader skey{key};
uint64_t type = ReadCompactSize(skey);
// Do stuff based on type
switch(type) {
case PSBT_OUT_REDEEMSCRIPT:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, output redeemScript already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Output redeemScript key is more than one byte type");
}
s >> redeem_script;
break;
}
case PSBT_OUT_WITNESSSCRIPT:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, output witnessScript already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Output witnessScript key is more than one byte type");
}
s >> witness_script;
break;
}
case PSBT_OUT_BIP32_DERIVATION:
{
DeserializeHDKeypaths(s, key, hd_keypaths);
break;
}
case PSBT_OUT_TAP_INTERNAL_KEY:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, output Taproot internal key already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Output Taproot internal key key is more than one byte type");
}
UnserializeFromVector(s, m_tap_internal_key);
break;
}
case PSBT_OUT_TAP_TREE:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, output Taproot tree already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Output Taproot tree key is more than one byte type");
}
std::vector<unsigned char> tree_v;
s >> tree_v;
SpanReader s_tree{tree_v};
if (s_tree.empty()) {
throw std::ios_base::failure("Output Taproot tree must not be empty");
}
TaprootBuilder builder;
while (!s_tree.empty()) {
uint8_t depth;
uint8_t leaf_ver;
std::vector<unsigned char> script;
s_tree >> depth;
s_tree >> leaf_ver;
s_tree >> script;
if (depth > TAPROOT_CONTROL_MAX_NODE_COUNT) {
throw std::ios_base::failure("Output Taproot tree has as leaf greater than Taproot maximum depth");
}
if ((leaf_ver & ~TAPROOT_LEAF_MASK) != 0) {
throw std::ios_base::failure("Output Taproot tree has a leaf with an invalid leaf version");
}
m_tap_tree.emplace_back(depth, leaf_ver, script);
builder.Add((int)depth, script, (int)leaf_ver, /*track=*/true);
}
if (!builder.IsComplete()) {
throw std::ios_base::failure("Output Taproot tree is malformed");
}
break;
}
case PSBT_OUT_TAP_BIP32_DERIVATION:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, output Taproot BIP32 keypath already provided");
} else if (key.size() != 33) {
throw std::ios_base::failure("Output Taproot BIP32 keypath key is not at 33 bytes");
}
XOnlyPubKey xonly(uint256(Span<uint8_t>(key).last(32)));
std::set<uint256> leaf_hashes;
uint64_t value_len = ReadCompactSize(s);
size_t before_hashes = s.size();
s >> leaf_hashes;
size_t after_hashes = s.size();
size_t hashes_len = before_hashes - after_hashes;
if (hashes_len > value_len) {
throw std::ios_base::failure("Output Taproot BIP32 keypath has an invalid length");
}
size_t origin_len = value_len - hashes_len;
m_tap_bip32_paths.emplace(xonly, std::make_pair(leaf_hashes, DeserializeKeyOrigin(s, origin_len)));
break;
}
case PSBT_OUT_PROPRIETARY:
{
PSBTProprietary this_prop;
skey >> this_prop.identifier;
this_prop.subtype = ReadCompactSize(skey);
this_prop.key = key;
if (m_proprietary.count(this_prop) > 0) {
throw std::ios_base::failure("Duplicate Key, proprietary key already found");
}
s >> this_prop.value;
m_proprietary.insert(this_prop);
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;
}
}
}
if (!found_sep) {
throw std::ios_base::failure("Separator is missing at the end of an output map");
}
}
template <typename Stream>
PSBTOutput(deserialize_type, Stream& s) {
Unserialize(s);
}
};
/** A version of CTransaction with the PSBT format*/
struct PartiallySignedTransaction
{
std::optional<CMutableTransaction> tx;
// We use a vector of CExtPubKey in the event that there happens to be the same KeyOriginInfos for different CExtPubKeys
// Note that this map swaps the key and values from the serialization
std::map<KeyOriginInfo, std::set<CExtPubKey>> m_xpubs;
std::vector<PSBTInput> inputs;
std::vector<PSBTOutput> outputs;
std::map<std::vector<unsigned char>, std::vector<unsigned char>> unknown;
std::optional<uint32_t> m_version;
std::set<PSBTProprietary> m_proprietary;
bool IsNull() const;
uint32_t GetVersion() const;
/** Merge psbt into this. The two psbts must have the same underlying CTransaction (i.e. the
* same actual Bitcoin transaction.) Returns true if the merge succeeded, false otherwise. */
[[nodiscard]] bool Merge(const PartiallySignedTransaction& psbt);
bool AddInput(const CTxIn& txin, PSBTInput& psbtin);
bool AddOutput(const CTxOut& txout, const PSBTOutput& psbtout);
PartiallySignedTransaction() {}
explicit PartiallySignedTransaction(const CMutableTransaction& tx);
/**
* Finds the UTXO for a given input index
*
* @param[out] utxo The UTXO of the input if found
* @param[in] input_index Index of the input to retrieve the UTXO of
* @return Whether the UTXO for the specified input was found
*/
bool GetInputUTXO(CTxOut& utxo, int input_index) const;
template <typename Stream>
inline void Serialize(Stream& s) const {
// magic bytes
s << PSBT_MAGIC_BYTES;
// unsigned tx flag
SerializeToVector(s, CompactSizeWriter(PSBT_GLOBAL_UNSIGNED_TX));
// Write serialized tx to a stream
SerializeToVector(s, TX_NO_WITNESS(*tx));
// Write xpubs
for (const auto& xpub_pair : m_xpubs) {
for (const auto& xpub : xpub_pair.second) {
unsigned char ser_xpub[BIP32_EXTKEY_WITH_VERSION_SIZE];
xpub.EncodeWithVersion(ser_xpub);
// Note that the serialization swaps the key and value
// The xpub is the key (for uniqueness) while the path is the value
SerializeToVector(s, PSBT_GLOBAL_XPUB, ser_xpub);
SerializeHDKeypath(s, xpub_pair.first);
}
}
// PSBT version
if (GetVersion() > 0) {
SerializeToVector(s, CompactSizeWriter(PSBT_GLOBAL_VERSION));
SerializeToVector(s, *m_version);
}
// Write proprietary things
for (const auto& entry : m_proprietary) {
s << entry.key;
s << entry.value;
}
// 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");
}
// Used for duplicate key detection
std::set<std::vector<unsigned char>> key_lookup;
// Track the global xpubs we have already seen. Just for sanity checking
std::set<CExtPubKey> global_xpubs;
// Read global data
bool found_sep = false;
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()) {
found_sep = true;
break;
}
// Type is compact size uint at beginning of key
SpanReader skey{key};
uint64_t type = ReadCompactSize(skey);
// Do stuff based on type
switch(type) {
case PSBT_GLOBAL_UNSIGNED_TX:
{
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure("Duplicate Key, unsigned tx already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Global unsigned tx key is more than one byte type");
}
CMutableTransaction mtx;
// Set the stream to serialize with non-witness since this should always be non-witness
UnserializeFromVector(s, TX_NO_WITNESS(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;
}
case PSBT_GLOBAL_XPUB:
{
if (key.size() != BIP32_EXTKEY_WITH_VERSION_SIZE + 1) {
throw std::ios_base::failure("Size of key was not the expected size for the type global xpub");
}
// Read in the xpub from key
CExtPubKey xpub;
xpub.DecodeWithVersion(&key.data()[1]);
if (!xpub.pubkey.IsFullyValid()) {
throw std::ios_base::failure("Invalid pubkey");
}
if (global_xpubs.count(xpub) > 0) {
throw std::ios_base::failure("Duplicate key, global xpub already provided");
}
global_xpubs.insert(xpub);
// Read in the keypath from stream
KeyOriginInfo keypath;
DeserializeHDKeypath(s, keypath);
// Note that we store these swapped to make searches faster.
// Serialization uses xpub -> keypath to enqure key uniqueness
if (m_xpubs.count(keypath) == 0) {
// Make a new set to put the xpub in
m_xpubs[keypath] = {xpub};
} else {
// Insert xpub into existing set
m_xpubs[keypath].insert(xpub);
}
break;
}
case PSBT_GLOBAL_VERSION:
{
if (m_version) {
throw std::ios_base::failure("Duplicate Key, version already provided");
} else if (key.size() != 1) {
throw std::ios_base::failure("Global version key is more than one byte type");
}
uint32_t v;
UnserializeFromVector(s, v);
m_version = v;
if (*m_version > PSBT_HIGHEST_VERSION) {
throw std::ios_base::failure("Unsupported version number");
}
break;
}
case PSBT_GLOBAL_PROPRIETARY:
{
PSBTProprietary this_prop;
skey >> this_prop.identifier;
this_prop.subtype = ReadCompactSize(skey);
this_prop.key = key;
if (m_proprietary.count(this_prop) > 0) {
throw std::ios_base::failure("Duplicate Key, proprietary key already found");
}
s >> this_prop.value;
m_proprietary.insert(this_prop);
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));
}
}
}
if (!found_sep) {
throw std::ios_base::failure("Separator is missing at the end of the global map");
}
// Make sure that we got an unsigned tx
if (!tx) {
throw std::ios_base::failure("No unsigned transaction 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);
}
};
enum class PSBTRole {
CREATOR,
UPDATER,
SIGNER,
FINALIZER,
EXTRACTOR
};
std::string PSBTRoleName(PSBTRole role);
/** Compute a PrecomputedTransactionData object from a psbt. */
PrecomputedTransactionData PrecomputePSBTData(const PartiallySignedTransaction& psbt);
/** Checks whether a PSBTInput is already signed by checking for non-null finalized fields. */
bool PSBTInputSigned(const PSBTInput& input);
/** Checks whether a PSBTInput is already signed by doing script verification using final fields. */
bool PSBTInputSignedAndVerified(const PartiallySignedTransaction psbt, unsigned int input_index, const PrecomputedTransactionData* txdata);
/** Signs a PSBTInput, verifying that all provided data matches what is being signed.
*
* txdata should be the output of PrecomputePSBTData (which can be shared across
* multiple SignPSBTInput calls). If it is nullptr, a dummy signature will be created.
**/
bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction& psbt, int index, const PrecomputedTransactionData* txdata, int sighash = SIGHASH_ALL, SignatureData* out_sigdata = nullptr, bool finalize = true);
/** Reduces the size of the PSBT by dropping unnecessary `non_witness_utxos` (i.e. complete previous transactions) from a psbt when all inputs are segwit v1. */
void RemoveUnnecessaryTransactions(PartiallySignedTransaction& psbtx, const int& sighash_type);
/** Counts the unsigned inputs of a PSBT. */
size_t CountPSBTUnsignedInputs(const PartiallySignedTransaction& psbt);
/** Updates a PSBTOutput with information from provider.
*
* This fills in the redeem_script, witness_script, and hd_keypaths where possible.
*/
void UpdatePSBTOutput(const SigningProvider& provider, PartiallySignedTransaction& psbt, int index);
/**
* Finalizes a PSBT if possible, combining partial signatures.
*
* @param[in,out] psbtx PartiallySignedTransaction to finalize
* return True if the PSBT is now complete, false otherwise
*/
bool FinalizePSBT(PartiallySignedTransaction& psbtx);
/**
* Finalizes a PSBT if possible, and extracts it to a CMutableTransaction if it could be finalized.
*
* @param[in] psbtx PartiallySignedTransaction
* @param[out] result CMutableTransaction representing the complete transaction, if successful
* @return True if we successfully extracted the transaction, false otherwise
*/
bool FinalizeAndExtractPSBT(PartiallySignedTransaction& psbtx, CMutableTransaction& result);
/**
* Combines PSBTs with the same underlying transaction, resulting in a single PSBT with all partial signatures from each input.
*
* @param[out] out the combined PSBT, if successful
* @param[in] psbtxs the PSBTs to combine
* @return error (OK if we successfully combined the transactions, other error if they were not compatible)
*/
[[nodiscard]] TransactionError CombinePSBTs(PartiallySignedTransaction& out, const std::vector<PartiallySignedTransaction>& psbtxs);
//! Decode a base64ed PSBT into a PartiallySignedTransaction
[[nodiscard]] bool DecodeBase64PSBT(PartiallySignedTransaction& decoded_psbt, const std::string& base64_psbt, std::string& error);
//! Decode a raw (binary blob) PSBT into a PartiallySignedTransaction
[[nodiscard]] bool DecodeRawPSBT(PartiallySignedTransaction& decoded_psbt, Span<const std::byte> raw_psbt, std::string& error);
#endif // BITCOIN_PSBT_H
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