Files
bitcoin/src/psbt.h

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69 KiB
C++

// 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_PSBT_H
#define BITCOIN_PSBT_H
#include <common/types.h>
#include <musig.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 <uint256.h>
#include <util/result.h>
#include <util/expected.h>
#include <optional>
#include <bitset>
namespace node {
enum class TransactionError;
} // namespace node
using common::PSBTError;
// Magic bytes
inline constexpr uint8_t PSBT_MAGIC_BYTES[5] = {'p', 's', 'b', 't', 0xff};
// Global types
inline constexpr uint8_t PSBT_GLOBAL_UNSIGNED_TX = 0x00;
inline constexpr uint8_t PSBT_GLOBAL_XPUB = 0x01;
inline constexpr uint8_t PSBT_GLOBAL_TX_VERSION = 0x02;
inline constexpr uint8_t PSBT_GLOBAL_FALLBACK_LOCKTIME = 0x03;
inline constexpr uint8_t PSBT_GLOBAL_INPUT_COUNT = 0x04;
inline constexpr uint8_t PSBT_GLOBAL_OUTPUT_COUNT = 0x05;
inline constexpr uint8_t PSBT_GLOBAL_TX_MODIFIABLE = 0x06;
inline constexpr uint8_t PSBT_GLOBAL_VERSION = 0xFB;
inline constexpr uint8_t PSBT_GLOBAL_PROPRIETARY = 0xFC;
// Input types
inline constexpr uint8_t PSBT_IN_NON_WITNESS_UTXO = 0x00;
inline constexpr uint8_t PSBT_IN_WITNESS_UTXO = 0x01;
inline constexpr uint8_t PSBT_IN_PARTIAL_SIG = 0x02;
inline constexpr uint8_t PSBT_IN_SIGHASH = 0x03;
inline constexpr uint8_t PSBT_IN_REDEEMSCRIPT = 0x04;
inline constexpr uint8_t PSBT_IN_WITNESSSCRIPT = 0x05;
inline constexpr uint8_t PSBT_IN_BIP32_DERIVATION = 0x06;
inline constexpr uint8_t PSBT_IN_SCRIPTSIG = 0x07;
inline constexpr uint8_t PSBT_IN_SCRIPTWITNESS = 0x08;
inline constexpr uint8_t PSBT_IN_RIPEMD160 = 0x0A;
inline constexpr uint8_t PSBT_IN_SHA256 = 0x0B;
inline constexpr uint8_t PSBT_IN_HASH160 = 0x0C;
inline constexpr uint8_t PSBT_IN_HASH256 = 0x0D;
inline constexpr uint8_t PSBT_IN_PREVIOUS_TXID = 0x0e;
inline constexpr uint8_t PSBT_IN_OUTPUT_INDEX = 0x0f;
inline constexpr uint8_t PSBT_IN_SEQUENCE = 0x10;
inline constexpr uint8_t PSBT_IN_REQUIRED_TIME_LOCKTIME = 0x11;
inline constexpr uint8_t PSBT_IN_REQUIRED_HEIGHT_LOCKTIME = 0x12;
inline constexpr uint8_t PSBT_IN_TAP_KEY_SIG = 0x13;
inline constexpr uint8_t PSBT_IN_TAP_SCRIPT_SIG = 0x14;
inline constexpr uint8_t PSBT_IN_TAP_LEAF_SCRIPT = 0x15;
inline constexpr uint8_t PSBT_IN_TAP_BIP32_DERIVATION = 0x16;
inline constexpr uint8_t PSBT_IN_TAP_INTERNAL_KEY = 0x17;
inline constexpr uint8_t PSBT_IN_TAP_MERKLE_ROOT = 0x18;
inline constexpr uint8_t PSBT_IN_MUSIG2_PARTICIPANT_PUBKEYS = 0x1a;
inline constexpr uint8_t PSBT_IN_MUSIG2_PUB_NONCE = 0x1b;
inline constexpr uint8_t PSBT_IN_MUSIG2_PARTIAL_SIG = 0x1c;
inline constexpr uint8_t PSBT_IN_PROPRIETARY = 0xFC;
// Output types
inline constexpr uint8_t PSBT_OUT_REDEEMSCRIPT = 0x00;
inline constexpr uint8_t PSBT_OUT_WITNESSSCRIPT = 0x01;
inline constexpr uint8_t PSBT_OUT_BIP32_DERIVATION = 0x02;
inline constexpr uint8_t PSBT_OUT_AMOUNT = 0x03;
inline constexpr uint8_t PSBT_OUT_SCRIPT = 0x04;
inline constexpr uint8_t PSBT_OUT_TAP_INTERNAL_KEY = 0x05;
inline constexpr uint8_t PSBT_OUT_TAP_TREE = 0x06;
inline constexpr uint8_t PSBT_OUT_TAP_BIP32_DERIVATION = 0x07;
inline constexpr uint8_t PSBT_OUT_MUSIG2_PARTICIPANT_PUBKEYS = 0x08;
inline 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.
inline 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.
inline constexpr std::streamsize MAX_FILE_SIZE_PSBT{100'000'000}; // 100 MB
// PSBT version number
inline constexpr uint32_t PSBT_HIGHEST_VERSION = 2;
/** 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");
}
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, std::span{keypath_pair.first});
SerializeHDKeypath(s, keypath_pair.second);
}
}
// Deserialize a PSBT_{IN/OUT}_MUSIG2_PARTICIPANT_PUBKEYS field
template<typename Stream>
void DeserializeMuSig2ParticipantPubkeys(Stream& s, SpanReader& skey, std::map<CPubKey, std::vector<CPubKey>>& out, std::string context)
{
std::array<unsigned char, CPubKey::COMPRESSED_SIZE> agg_pubkey_bytes;
skey >> std::as_writable_bytes(std::span{agg_pubkey_bytes});
CPubKey agg_pubkey(agg_pubkey_bytes);
if (!agg_pubkey.IsFullyValid()) {
throw std::ios_base::failure(context + " musig2 aggregate pubkey is invalid");
}
std::vector<CPubKey> participants;
std::vector<unsigned char> val;
s >> val;
SpanReader s_val{val};
while (s_val.size() >= CPubKey::COMPRESSED_SIZE) {
std::array<unsigned char, CPubKey::COMPRESSED_SIZE> part_pubkey_bytes;
s_val >> std::as_writable_bytes(std::span{part_pubkey_bytes});
CPubKey participant(part_pubkey_bytes);
if (!participant.IsFullyValid()) {
throw std::ios_base::failure(context + " musig2 participant pubkey is invalid");
}
participants.push_back(participant);
}
if (!s_val.empty()) {
throw std::ios_base::failure(context + " musig2 participants pubkeys value size is not a multiple of 33");
}
out.emplace(agg_pubkey, participants);
}
// Deserialize the MuSig2 participant identifiers from PSBT_MUSIG2_{PUBNONCE/PARTIAL_SIG} fields
// Both fields contain the same data after the type byte - aggregate pubkey | participant pubkey | leaf script hash
template<typename Stream>
void DeserializeMuSig2ParticipantDataIdentifier(Stream& skey, CPubKey& agg_pub, CPubKey& part_pub, uint256& leaf_hash)
{
leaf_hash.SetNull();
std::array<unsigned char, CPubKey::COMPRESSED_SIZE> part_pubkey_bytes;
std::array<unsigned char, CPubKey::COMPRESSED_SIZE> agg_pubkey_bytes;
skey >> std::as_writable_bytes(std::span{part_pubkey_bytes}) >> std::as_writable_bytes(std::span{agg_pubkey_bytes});
agg_pub.Set(agg_pubkey_bytes.begin(), agg_pubkey_bytes.end());
if (!agg_pub.IsFullyValid()) {
throw std::ios_base::failure("musig2 aggregate pubkey is invalid");
}
part_pub.Set(part_pubkey_bytes.begin(), part_pubkey_bytes.end());
if (!part_pub.IsFullyValid()) {
throw std::ios_base::failure("musig2 participant pubkey is invalid");
}
if (!skey.empty()) {
skey >> leaf_hash;
}
}
static inline void ExpectedKeySize(const std::string& key_name, const std::vector<unsigned char>& key, uint64_t expected_size) {
if (key.size() != expected_size) {
throw std::ios_base::failure(tfm::format("Size of key was not %d for the type %s", expected_size, key_name));
}
}
/** A structure for PSBTs which contain per-input information */
class PSBTInput
{
private:
uint32_t m_psbt_version;
public:
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;
Txid prev_txid;
uint32_t prev_out;
std::optional<uint32_t> sequence;
std::optional<uint32_t> time_locktime;
std::optional<uint32_t> height_locktime;
// 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;
// MuSig2 fields
std::map<CPubKey, std::vector<CPubKey>> m_musig2_participants;
// Key is the aggregate pubkey and the script leaf hash, value is a map of participant pubkey to pubnonce
std::map<std::pair<CPubKey, uint256>, std::map<CPubKey, std::vector<uint8_t>>> m_musig2_pubnonces;
// Key is the aggregate pubkey and the script leaf hash, value is a map of participant pubkey to partial_sig
std::map<std::pair<CPubKey, uint256>, std::map<CPubKey, uint256>> m_musig2_partial_sigs;
std::map<std::vector<unsigned char>, std::vector<unsigned char>> unknown;
std::set<PSBTProprietary> m_proprietary;
std::optional<int> sighash_type;
void FillSignatureData(SignatureData& sigdata) const;
void FromSignatureData(const SignatureData& sigdata);
void Merge(const PSBTInput& input);
uint32_t GetVersion() const { return m_psbt_version; }
COutPoint GetOutPoint() const;
/**
* Retrieves the UTXO for this input
*
* @param[out] utxo The UTXO of this input
* @return Whether the UTXO could be retrieved
*/
bool GetUTXO(CTxOut& utxo) const;
bool HasSignatures() const;
explicit PSBTInput(uint32_t psbt_version, const Txid& prev_txid, uint32_t prev_out, std::optional<uint32_t> sequence = std::nullopt)
: m_psbt_version(psbt_version),
prev_txid(prev_txid),
prev_out(prev_out),
sequence(sequence)
{
assert(m_psbt_version == 0 || m_psbt_version == 2);
}
// Construct a PSBTInput when the previous txid and output index are expected to be serialized
template <typename Stream>
explicit PSBTInput(deserialize_type, Stream& s, uint32_t psbt_version)
: m_psbt_version(psbt_version)
{
assert(m_psbt_version == 2);
Unserialize(s);
}
bool operator==(const PSBTInput&) const = default;
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 (const auto& sig_pair : partial_sigs) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_PARTIAL_SIG), std::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), std::span{hash});
s << preimage;
}
// Write any sha256 preimage
for (const auto& [hash, preimage] : sha256_preimages) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_SHA256), std::span{hash});
s << preimage;
}
// Write any hash160 preimage
for (const auto& [hash, preimage] : hash160_preimages) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_HASH160), std::span{hash});
s << preimage;
}
// Write any hash256 preimage
for (const auto& [hash, preimage] : hash256_preimages) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_HASH256), std::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, std::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 MuSig2 Participants
for (const auto& [agg_pubkey, part_pubs] : m_musig2_participants) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_MUSIG2_PARTICIPANT_PUBKEYS), std::span{agg_pubkey});
std::vector<unsigned char> value;
VectorWriter s_value{value, 0};
for (auto& pk : part_pubs) {
s_value << std::span{pk};
}
s << value;
}
// Write MuSig2 pubnonces
for (const auto& [agg_pubkey_leaf_hash, pubnonces] : m_musig2_pubnonces) {
const auto& [agg_pubkey, leaf_hash] = agg_pubkey_leaf_hash;
for (const auto& [part_pubkey, pubnonce] : pubnonces) {
if (leaf_hash.IsNull()) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_MUSIG2_PUB_NONCE), std::span{part_pubkey}, std::span{agg_pubkey});
} else {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_MUSIG2_PUB_NONCE), std::span{part_pubkey}, std::span{agg_pubkey}, leaf_hash);
}
s << pubnonce;
}
}
// Write MuSig2 partial signatures
for (const auto& [agg_pubkey_leaf_hash, psigs] : m_musig2_partial_sigs) {
const auto& [agg_pubkey, leaf_hash] = agg_pubkey_leaf_hash;
for (const auto& [pubkey, psig] : psigs) {
if (leaf_hash.IsNull()) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_MUSIG2_PARTIAL_SIG), std::span{pubkey}, std::span{agg_pubkey});
} else {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_MUSIG2_PARTIAL_SIG), std::span{pubkey}, std::span{agg_pubkey}, leaf_hash);
}
SerializeToVector(s, psig);
}
}
}
// 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 PSBTv2 fields
if (m_psbt_version >= 2) {
// Write prev txid, vout, sequence, and lock times
SerializeToVector(s, CompactSizeWriter(PSBT_IN_PREVIOUS_TXID));
SerializeToVector(s, prev_txid);
SerializeToVector(s, CompactSizeWriter(PSBT_IN_OUTPUT_INDEX));
SerializeToVector(s, prev_out);
if (sequence != std::nullopt) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_SEQUENCE));
SerializeToVector(s, *sequence);
}
if (time_locktime != std::nullopt) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_REQUIRED_TIME_LOCKTIME));
SerializeToVector(s, *time_locktime);
}
if (height_locktime != std::nullopt) {
SerializeToVector(s, CompactSizeWriter(PSBT_IN_REQUIRED_HEIGHT_LOCKTIME));
SerializeToVector(s, *height_locktime);
}
}
// 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;
// Cache whether PSBTv2 required fields were seen
bool found_prev_txid = false;
bool found_prev_out = false;
// Read loop
bool found_sep = false;
while(!s.empty()) {
// Read the key of format "<keylen><keytype><keydata>" after which
// "key" will contain "<keytype><keydata>"
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;
}
// Duplicate keys are not permitted
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure(tfm::format("Duplicate Key, input key \"%s\" already provided", HexStr(key)));
}
// "skey" is used so that "key" is unchanged after reading keytype below
SpanReader skey{key};
// keytype is of the format compact size uint at the beginning of "key"
uint64_t type = ReadCompactSize(skey);
// Do stuff based on keytype "type", i.e., key checks, reading values of the
// format "<valuelen><valuedata>" from the stream "s", and value checks
switch(type) {
case PSBT_IN_NON_WITNESS_UTXO:
{
ExpectedKeySize("Input Non-witness UTXO", key, 1);
// 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:
ExpectedKeySize("Input Witness UTXO", key, 1);
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");
}
// Read in the signature from value
std::vector<unsigned char> sig;
s >> sig;
// Check that the signature is validly encoded
if (sig.empty() || !CheckSignatureEncoding(sig, SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_STRICTENC, nullptr)) {
throw std::ios_base::failure("Signature is not a valid encoding");
}
// Add to list
partial_sigs.emplace(pubkey.GetID(), SigPair(pubkey, std::move(sig)));
break;
}
case PSBT_IN_SIGHASH:
ExpectedKeySize("Input Sighash Type", key, 1);
int sighash;
UnserializeFromVector(s, sighash);
sighash_type = sighash;
break;
case PSBT_IN_REDEEMSCRIPT:
{
ExpectedKeySize("Input redeemScript", key, 1);
s >> redeem_script;
break;
}
case PSBT_IN_WITNESSSCRIPT:
{
ExpectedKeySize("Input witnessScript", key, 1);
s >> witness_script;
break;
}
case PSBT_IN_BIP32_DERIVATION:
{
DeserializeHDKeypaths(s, key, hd_keypaths);
break;
}
case PSBT_IN_SCRIPTSIG:
{
ExpectedKeySize("Input Final scriptSig", key, 1);
s >> final_script_sig;
break;
}
case PSBT_IN_SCRIPTWITNESS:
{
ExpectedKeySize("Input Final scriptWitness", key, 1);
UnserializeFromVector(s, final_script_witness.stack);
break;
}
case PSBT_IN_RIPEMD160:
{
ExpectedKeySize("Input RIPEMD160 Preimage", key, CRIPEMD160::OUTPUT_SIZE + 1);
// Read in the hash from key
std::vector<unsigned char> hash_vec(key.begin() + 1, key.end());
uint160 hash(hash_vec);
// 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:
{
ExpectedKeySize("Input SHA256 Preimage", key, CSHA256::OUTPUT_SIZE + 1);
// Read in the hash from key
std::vector<unsigned char> hash_vec(key.begin() + 1, key.end());
uint256 hash(hash_vec);
// 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:
{
ExpectedKeySize("Input Hash160 Preimage", key, CHash160::OUTPUT_SIZE + 1);
// Read in the hash from key
std::vector<unsigned char> hash_vec(key.begin() + 1, key.end());
uint160 hash(hash_vec);
// 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:
{
ExpectedKeySize("Input Hash256 Preimage", key, CHash256::OUTPUT_SIZE + 1);
// Read in the hash from key
std::vector<unsigned char> hash_vec(key.begin() + 1, key.end());
uint256 hash(hash_vec);
// 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_PREVIOUS_TXID:
{
ExpectedKeySize("Input Previous TXID", key, 1);
if (m_psbt_version < 2) {
throw std::ios_base::failure("Previous txid is not allowed in PSBTv0");
}
UnserializeFromVector(s, prev_txid);
found_prev_txid = true;
break;
}
case PSBT_IN_OUTPUT_INDEX:
{
ExpectedKeySize("Input Previous Output's Index", key, 1);
if (m_psbt_version < 2) {
throw std::ios_base::failure("Previous output's index is not allowed in PSBTv0");
}
UnserializeFromVector(s, prev_out);
found_prev_out = true;
break;
}
case PSBT_IN_SEQUENCE:
{
ExpectedKeySize("Input Sequence", key, 1);
if (m_psbt_version < 2) {
throw std::ios_base::failure("Sequence is not allowed in PSBTv0");
}
sequence.emplace();
UnserializeFromVector(s, *sequence);
break;
}
case PSBT_IN_REQUIRED_TIME_LOCKTIME:
{
ExpectedKeySize("Input Required Time Based Locktime", key, 1);
if (m_psbt_version < 2) {
throw std::ios_base::failure("Required time based locktime is not allowed in PSBTv0");
}
time_locktime.emplace();
UnserializeFromVector(s, *time_locktime);
if (*time_locktime < LOCKTIME_THRESHOLD) {
throw std::ios_base::failure("Required time based locktime is invalid (less than 500000000)");
}
break;
}
case PSBT_IN_REQUIRED_HEIGHT_LOCKTIME:
{
ExpectedKeySize("Input Required Height Based Locktime", key, 1);
if (m_psbt_version < 2) {
throw std::ios_base::failure("Required height based locktime is not allowed in PSBTv0");
}
height_locktime.emplace();
UnserializeFromVector(s, *height_locktime);
if (*height_locktime >= LOCKTIME_THRESHOLD) {
throw std::ios_base::failure("Required height based locktime is invalid (greater than or equal to 500000000)");
} else if (*height_locktime == 0) {
throw std::ios_base::failure("Required height based locktime is invalid (0)");
}
break;
}
case PSBT_IN_TAP_KEY_SIG:
{
ExpectedKeySize("Input Taproot Key Path Signature", key, 1);
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:
{
ExpectedKeySize("Input Taproot Script Path Signature", key, 65);
SpanReader s_key{std::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.size() < 34) {
throw std::ios_base::failure("Input 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:
{
ExpectedKeySize("Input Taproot BIP32 Keypath", key, 33);
SpanReader s_key{std::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:
{
ExpectedKeySize("Input Taproot Internal Key", key, 1);
UnserializeFromVector(s, m_tap_internal_key);
break;
}
case PSBT_IN_TAP_MERKLE_ROOT:
{
ExpectedKeySize("Input Taproot Merkle Root", key, 1);
UnserializeFromVector(s, m_tap_merkle_root);
break;
}
case PSBT_IN_MUSIG2_PARTICIPANT_PUBKEYS:
{
ExpectedKeySize("Input MuSig2 Participants Pubkeys", key, CPubKey::COMPRESSED_SIZE + 1);
DeserializeMuSig2ParticipantPubkeys(s, skey, m_musig2_participants, std::string{"Input"});
break;
}
case PSBT_IN_MUSIG2_PUB_NONCE:
{
if (key.size() != 2 * CPubKey::COMPRESSED_SIZE + 1 && key.size() != 2 * CPubKey::COMPRESSED_SIZE + CSHA256::OUTPUT_SIZE + 1) {
throw std::ios_base::failure("Input musig2 pubnonce key is not expected size of 67 or 99 bytes");
}
CPubKey agg_pub, part_pub;
uint256 leaf_hash;
DeserializeMuSig2ParticipantDataIdentifier(skey, agg_pub, part_pub, leaf_hash);
std::vector<uint8_t> pubnonce;
s >> pubnonce;
if (pubnonce.size() != MUSIG2_PUBNONCE_SIZE) {
throw std::ios_base::failure("Input musig2 pubnonce value is not 66 bytes");
}
m_musig2_pubnonces[std::make_pair(agg_pub, leaf_hash)].emplace(part_pub, pubnonce);
break;
}
case PSBT_IN_MUSIG2_PARTIAL_SIG:
{
if (key.size() != 2 * CPubKey::COMPRESSED_SIZE + 1 && key.size() != 2 * CPubKey::COMPRESSED_SIZE + CSHA256::OUTPUT_SIZE + 1) {
throw std::ios_base::failure("Input musig2 partial sig key is not expected size of 67 or 99 bytes");
}
CPubKey agg_pub, part_pub;
uint256 leaf_hash;
DeserializeMuSig2ParticipantDataIdentifier(skey, agg_pub, part_pub, leaf_hash);
uint256 partial_sig;
UnserializeFromVector(s, partial_sig);
m_musig2_partial_sigs[std::make_pair(agg_pub, leaf_hash)].emplace(part_pub, partial_sig);
break;
}
case PSBT_IN_PROPRIETARY:
{
PSBTProprietary this_prop;
skey >> this_prop.identifier;
this_prop.subtype = ReadCompactSize(skey);
this_prop.key = key;
s >> this_prop.value;
m_proprietary.insert(this_prop);
break;
}
// Unknown stuff
default:
// 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");
}
// Make sure required PSBTv2 fields are present
if (m_psbt_version >= 2) {
if (!found_prev_txid) {
throw std::ios_base::failure("Previous TXID is required in PSBTv2");
}
if (!found_prev_out) {
throw std::ios_base::failure("Previous output's index is required in PSBTv2");
}
}
}
};
/** A structure for PSBTs which contains per output information */
class PSBTOutput
{
private:
uint32_t m_psbt_version;
public:
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<CPubKey, std::vector<CPubKey>> m_musig2_participants;
std::map<std::vector<unsigned char>, std::vector<unsigned char>> unknown;
std::set<PSBTProprietary> m_proprietary;
CAmount amount;
CScript script;
void FillSignatureData(SignatureData& sigdata) const;
void FromSignatureData(const SignatureData& sigdata);
void Merge(const PSBTOutput& output);
uint32_t GetVersion() const { return m_psbt_version; }
explicit PSBTOutput(uint32_t psbt_version, CAmount amount, const CScript& script)
: m_psbt_version(psbt_version),
amount(amount),
script(script)
{
assert(m_psbt_version == 0 || m_psbt_version == 2);
}
// Construct a PSBTOutput when the amount and script are expected to be serialized
template <typename Stream>
explicit PSBTOutput(deserialize_type, Stream& s, uint32_t psbt_version)
: m_psbt_version(psbt_version)
{
assert(m_psbt_version == 2);
Unserialize(s);
}
bool operator==(const PSBTOutput&) const = default;
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));
if (m_psbt_version >= 2) {
// Write amount and spk
SerializeToVector(s, CompactSizeWriter(PSBT_OUT_AMOUNT));
SerializeToVector(s, amount);
SerializeToVector(s, CompactSizeWriter(PSBT_OUT_SCRIPT));
s << script;
}
// 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 MuSig2 Participants
for (const auto& [agg_pubkey, part_pubs] : m_musig2_participants) {
SerializeToVector(s, CompactSizeWriter(PSBT_OUT_MUSIG2_PARTICIPANT_PUBKEYS), std::span{agg_pubkey});
std::vector<unsigned char> value;
VectorWriter s_value{value, 0};
for (auto& pk : part_pubs) {
s_value << std::span{pk};
}
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;
// Cache whether PSBTv2 required fields are found
bool found_amount = false;
bool found_script = false;
// Read loop
bool found_sep = false;
while(!s.empty()) {
// Read the key of format "<keylen><keytype><keydata>" after which
// "key" will contain "<keytype><keydata>"
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;
}
// Duplicate keys are not permitted
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure(tfm::format("Duplicate Key, output key \"%s\" already provided", HexStr(key)));
}
// "skey" is used so that "key" is unchanged after reading keytype below
SpanReader skey{key};
// keytype is of the format compact size uint at the beginning of "key"
uint64_t type = ReadCompactSize(skey);
// Do stuff based on keytype "type", i.e., key checks, reading values of the
// format "<valuelen><valuedata>" from the stream "s", and value checks
switch(type) {
case PSBT_OUT_REDEEMSCRIPT:
{
ExpectedKeySize("Output redeemScript", key, 1);
s >> redeem_script;
break;
}
case PSBT_OUT_WITNESSSCRIPT:
{
ExpectedKeySize("Output witnessScript", key, 1);
s >> witness_script;
break;
}
case PSBT_OUT_BIP32_DERIVATION:
{
DeserializeHDKeypaths(s, key, hd_keypaths);
break;
}
case PSBT_OUT_AMOUNT:
{
ExpectedKeySize("Output Amount", key, 1);
if (m_psbt_version < 2) {
throw std::ios_base::failure("Output amount is not allowed in PSBTv0");
}
UnserializeFromVector(s, amount);
found_amount = true;
break;
}
case PSBT_OUT_SCRIPT:
{
ExpectedKeySize("Output Script", key, 1);
if (m_psbt_version < 2) {
throw std::ios_base::failure("Output script is not allowed in PSBTv0");
}
s >> script;
found_script = true;
break;
}
case PSBT_OUT_TAP_INTERNAL_KEY:
{
ExpectedKeySize("Output Taproot Internal Key", key, 1);
UnserializeFromVector(s, m_tap_internal_key);
break;
}
case PSBT_OUT_TAP_TREE:
{
ExpectedKeySize("Output Taproot Tree Key", key, 1);
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:
{
ExpectedKeySize("Output Taproot BIP32 Keypath", key, 33);
XOnlyPubKey xonly(uint256(std::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_MUSIG2_PARTICIPANT_PUBKEYS:
{
ExpectedKeySize("Output MuSig2 Participants Pubkeys", key, CPubKey::COMPRESSED_SIZE + 1);
DeserializeMuSig2ParticipantPubkeys(s, skey, m_musig2_participants, std::string{"Output"});
break;
}
case PSBT_OUT_PROPRIETARY:
{
PSBTProprietary this_prop;
skey >> this_prop.identifier;
this_prop.subtype = ReadCompactSize(skey);
this_prop.key = key;
s >> this_prop.value;
m_proprietary.insert(this_prop);
break;
}
// Unknown stuff
default: {
// 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");
}
// Make sure required PSBTv2 fields are present
if (m_psbt_version >= 2) {
if (!found_amount) {
throw std::ios_base::failure("Output amount is required in PSBTv2");
}
if (!found_script) {
throw std::ios_base::failure("Output script is required in PSBTv2");
}
}
}
};
/** A version of CTransaction with the PSBT format*/
class PartiallySignedTransaction
{
private:
std::optional<uint32_t> m_version;
public:
// 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::optional<std::bitset<8>> m_tx_modifiable;
std::vector<PSBTInput> inputs;
std::vector<PSBTOutput> outputs;
std::map<std::vector<unsigned char>, std::vector<unsigned char>> unknown;
std::set<PSBTProprietary> m_proprietary;
uint32_t tx_version;
std::optional<uint32_t> fallback_locktime;
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);
/** Merge the global xpubs of psbt into this, keeping the existing origin for an xpub
* seen again with a different one, as the serialized records are keyed by xpub. */
void MergeGlobalXPubs(const PartiallySignedTransaction& psbt);
bool AddInput(const PSBTInput& psbtin);
bool AddOutput(const PSBTOutput& psbtout);
std::optional<uint32_t> ComputeTimeLock() const;
std::optional<CMutableTransaction> GetUnsignedTx() const;
std::optional<Txid> GetUniqueID() const;
explicit PartiallySignedTransaction(const CMutableTransaction& tx, uint32_t version = 2);
template <typename Stream>
inline void Serialize(Stream& s) const {
// magic bytes
s << PSBT_MAGIC_BYTES;
if (GetVersion() < 2) {
// unsigned tx flag
SerializeToVector(s, CompactSizeWriter(PSBT_GLOBAL_UNSIGNED_TX));
// Write serialized tx to a stream
SerializeToVector(s, TX_NO_WITNESS(*GetUnsignedTx()));
}
// 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);
}
}
if (GetVersion() >= 2) {
// Write PSBTv2 tx version, locktime, counts, etc.
SerializeToVector(s, CompactSizeWriter(PSBT_GLOBAL_TX_VERSION));
SerializeToVector(s, tx_version);
if (fallback_locktime != std::nullopt) {
SerializeToVector(s, CompactSizeWriter(PSBT_GLOBAL_FALLBACK_LOCKTIME));
SerializeToVector(s, *fallback_locktime);
}
SerializeToVector(s, CompactSizeWriter(PSBT_GLOBAL_INPUT_COUNT));
SerializeToVector(s, CompactSizeWriter(inputs.size()));
SerializeToVector(s, CompactSizeWriter(PSBT_GLOBAL_OUTPUT_COUNT));
SerializeToVector(s, CompactSizeWriter(outputs.size()));
if (m_tx_modifiable != std::nullopt) {
SerializeToVector(s, CompactSizeWriter(PSBT_GLOBAL_TX_MODIFIABLE));
SerializeToVector(s, static_cast<uint8_t>(m_tx_modifiable->to_ulong()));
}
}
// 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;
// Read global data
bool found_sep = false;
std::optional<CMutableTransaction> tx;
uint64_t input_count = 0;
uint64_t output_count = 0;
bool found_input_count = false;
bool found_output_count = false;
bool found_tx_version = false;
bool found_fallback_locktime = false;
while(!s.empty()) {
// Read the key of format "<keylen><keytype><keydata>" after which
// "key" will contain "<keytype><keydata>"
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;
}
// Duplicate keys are not permitted
if (!key_lookup.emplace(key).second) {
throw std::ios_base::failure(tfm::format("Duplicate Key, global key \"%s\" already provided", HexStr(key)));
}
// "skey" is used so that "key" is unchanged after reading keytype below
SpanReader skey{key};
// keytype is of the format compact size uint at the beginning of "key"
uint64_t type = ReadCompactSize(skey);
// Do stuff based on keytype "type", i.e., key checks, reading values of the
// format "<valuelen><valuedata>" from the stream "s", and value checks
switch(type) {
case PSBT_GLOBAL_UNSIGNED_TX:
{
ExpectedKeySize("Global Unsigned TX", key, 1);
// Set the stream to serialize with non-witness since this should always be non-witness
tx.emplace();
UnserializeFromVector(s, TX_NO_WITNESS(*tx));
// 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.");
}
}
tx_version = tx->version;
fallback_locktime = tx->nLockTime;
// Set the input and output counts
input_count = tx->vin.size();
output_count = tx->vout.size();
break;
}
case PSBT_GLOBAL_TX_VERSION:
{
ExpectedKeySize("Global Transaction Version", key, 1);
UnserializeFromVector(s, tx_version);
found_tx_version = true;
break;
}
case PSBT_GLOBAL_FALLBACK_LOCKTIME:
{
ExpectedKeySize("Global Fallback Locktime", key, 1);
fallback_locktime.emplace();
UnserializeFromVector(s, *fallback_locktime);
found_fallback_locktime = true;
break;
}
case PSBT_GLOBAL_INPUT_COUNT:
{
ExpectedKeySize("Global Input Count", key, 1);
CompactSizeReader reader(input_count);
UnserializeFromVector(s, reader);
found_input_count = true;
break;
}
case PSBT_GLOBAL_OUTPUT_COUNT:
{
ExpectedKeySize("Global Output Count", key, 1);
CompactSizeReader reader(output_count);
UnserializeFromVector(s, reader);
found_output_count = true;
break;
}
case PSBT_GLOBAL_TX_MODIFIABLE:
{
ExpectedKeySize("Global TX Modifiable Flags", key, 1);
uint8_t tx_mod;
UnserializeFromVector(s, tx_mod);
m_tx_modifiable.emplace(tx_mod);
break;
}
case PSBT_GLOBAL_XPUB:
{
ExpectedKeySize("Global XPUB", key, BIP32_EXTKEY_WITH_VERSION_SIZE + 1);
// Read in the xpub from key
CExtPubKey xpub;
xpub.DecodeWithVersion(&key.data()[1]);
if (!xpub.pubkey.IsFullyValid()) {
throw std::ios_base::failure("Invalid pubkey");
}
// 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.contains(keypath)) {
// 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:
{
ExpectedKeySize("Global PSBT Version", key, 1);
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;
s >> this_prop.value;
m_proprietary.insert(this_prop);
break;
}
// Unknown stuff
default: {
// 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");
}
const uint32_t psbt_ver = GetVersion();
// Check PSBT version constraints
if (psbt_ver == 0) {
// Make sure that we got an unsigned tx for PSBTv0
if (!tx) {
throw std::ios_base::failure("No unsigned transaction was provided");
}
// Make sure no PSBTv2 fields are present
if (found_tx_version) {
throw std::ios_base::failure("PSBT_GLOBAL_TX_VERSION is not allowed in PSBTv0");
}
if (found_fallback_locktime) {
throw std::ios_base::failure("PSBT_GLOBAL_FALLBACK_LOCKTIME is not allowed in PSBTv0");
}
if (found_input_count) {
throw std::ios_base::failure("PSBT_GLOBAL_INPUT_COUNT is not allowed in PSBTv0");
}
if (found_output_count) {
throw std::ios_base::failure("PSBT_GLOBAL_OUTPUT_COUNT is not allowed in PSBTv0");
}
if (m_tx_modifiable != std::nullopt) {
throw std::ios_base::failure("PSBT_GLOBAL_TX_MODIFIABLE is not allowed in PSBTv0");
}
}
// Disallow v1
if (psbt_ver == 1) {
throw std::ios_base::failure("There is no PSBT version 1");
}
if (psbt_ver == 2) {
// Tx version, input, and output counts are required
if (!found_tx_version) {
throw std::ios_base::failure("PSBT_GLOBAL_TX_VERSION is required in PSBTv2");
}
if (!found_input_count) {
throw std::ios_base::failure("PSBT_GLOBAL_INPUT_COUNT is required in PSBTv2");
}
if (!found_output_count) {
throw std::ios_base::failure("PSBT_GLOBAL_OUTPUT_COUNT is required in PSBTv2");
}
// Unsigned tx is disallowed
if (tx) {
throw std::ios_base::failure("PSBT_GLOBAL_UNSIGNED_TX is not allowed in PSBTv2");
}
}
if (psbt_ver > 2) {
throw std::ios_base::failure("Unknown PSBT version");
}
// Read input data
unsigned int i = 0;
while (!s.empty() && i < input_count) {
if (psbt_ver < 2) {
inputs.emplace_back(psbt_ver, tx->vin[i].prevout.hash, tx->vin[i].prevout.n, tx->vin[i].nSequence);
s >> inputs.back();
} else {
inputs.emplace_back(deserialize, s, psbt_ver);
}
// Make sure the non-witness utxo matches the outpoint
const PSBTInput& input = inputs.back();
if (input.non_witness_utxo) {
if (psbt_ver < 2) {
if (input.non_witness_utxo->GetHash() != tx->vin[i].prevout.hash) {
throw std::ios_base::failure("Non-witness UTXO does not match outpoint hash");
}
if (tx->vin[i].prevout.n >= input.non_witness_utxo->vout.size()) {
throw std::ios_base::failure("Input specifies output index that does not exist");
}
} else {
if (input.non_witness_utxo->GetHash() != input.prev_txid) {
throw std::ios_base::failure("Non-witness UTXO does not match outpoint hash");
}
if (input.prev_out >= input.non_witness_utxo->vout.size()) {
throw std::ios_base::failure("Input specifies output index that does not exist");
}
}
}
++i;
}
// Make sure that the number of inputs matches the number of inputs in the transaction
if (inputs.size() != input_count) {
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 < output_count) {
if (psbt_ver < 2) {
outputs.emplace_back(psbt_ver, tx->vout[i].nValue, tx->vout[i].scriptPubKey);
s >> outputs.back();
} else {
outputs.emplace_back(deserialize, s, psbt_ver);
}
++i;
}
// Make sure that the number of outputs matches the number of outputs in the transaction
if (outputs.size() != output_count) {
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. */
std::optional<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.
**/
[[nodiscard]] util::Expected<void, PSBTError> SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction& psbt, int index, const PrecomputedTransactionData* txdata, const common::PSBTFillOptions& options, SignatureData* out_sigdata = nullptr);
/** 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);
/** 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[in] psbtxs the PSBTs to combine
* @return The combined PSBT or std::nullopt if the PSBTs cannot be combined
*/
[[nodiscard]] std::optional<PartiallySignedTransaction> CombinePSBTs(const std::vector<PartiallySignedTransaction>& psbtxs);
//! Decode a base64ed PSBT into a PartiallySignedTransaction
[[nodiscard]] util::Result<PartiallySignedTransaction> DecodeBase64PSBT(const std::string& base64_tx);
//! Decode a raw (binary blob) PSBT into a PartiallySignedTransaction
[[nodiscard]] util::Result<PartiallySignedTransaction> DecodeRawPSBT(std::span<const std::byte> tx_data);
#endif // BITCOIN_PSBT_H