Merge #13932: Additional utility RPCs for PSBT

540729ef4bf1b6c6da1ec795e441d2ce56a9a58b Implement analyzepsbt RPC and tests (Andrew Chow)
77542cf2a5f8abb97dd46f782c1b0199cc062033 Move PSBT UTXO fetching to a separate method (Andrew Chow)
cb40b3abd4514361a024a1e7a1a281da9261261b Figure out what is missing during signing (Andrew Chow)
08f749c9147a5f3fdbbd880e0974b97084429002 Implement joinpsbts RPC and tests (Andrew Chow)
7344a7b9984b99882e136efc8ad48fb31740df93 Implement utxoupdatepsbt RPC and tests (Andrew Chow)

Pull request description:

  This PR adds 3 new utility RPCs for interacting with PSBTs.

  `utxoupdatepsbt` updates a PSBT with UTXO information from the node. It only works with witness UTXOs because full transactions (as would be needed for non-witness UTXOs) are not available unless txindex is enabled.

  `joinpsbts` joins the inputs from multiple distinct PSBTs into one PSBT. e.g. if PSBT 1 has inputs 1 and 2, and PSBT 2 has inputs 3 and 4, `joinpsbts` would create a new PSBT with inputs 1, 2, 3, and 4.

  `analyzepsbt` analyzes a PSBT and determines the current state of it and all of its inputs, and the next step that needs to be done.

Tree-SHA512: 3c1fa302201abca76a8901d0c2be7b4ccbce334d989533c215f8b3e50e22f2f018ce6209544b26789f58f5980a253c0655111e1e20d47d5656e0414c64891a5c

6 files changed, 417 insertions, 7 deletions

diff --git a/src/psbt.cpp b/src/psbt.cpp
index 81633c0cc7..32fb459dec 100644
--- a/src/psbt.cpp
+++ b/src/psbt.cpp
@@ -42,6 +42,40 @@ bool PartiallySignedTransaction::IsSane() const
     return true;
 }
 
+bool PartiallySignedTransaction::AddInput(const CTxIn& txin, PSBTInput& psbtin)
+{
+    if (std::find(tx->vin.begin(), tx->vin.end(), txin) != tx->vin.end()) {
+        return false;
+    }
+    tx->vin.push_back(txin);
+    psbtin.partial_sigs.clear();
+    psbtin.final_script_sig.clear();
+    psbtin.final_script_witness.SetNull();
+    inputs.push_back(psbtin);
+    return true;
+}
+
+bool PartiallySignedTransaction::AddOutput(const CTxOut& txout, const PSBTOutput& psbtout)
+{
+    tx->vout.push_back(txout);
+    outputs.push_back(psbtout);
+    return true;
+}
+
+bool PartiallySignedTransaction::GetInputUTXO(CTxOut& utxo, int input_index) const
+{
+    PSBTInput input = inputs[input_index];
+    int prevout_index = tx->vin[input_index].prevout.n;
+    if (input.non_witness_utxo) {
+        utxo = input.non_witness_utxo->vout[prevout_index];
+    } else if (!input.witness_utxo.IsNull()) {
+        utxo = input.witness_utxo;
+    } else {
+        return false;
+    }
+    return true;
+}
+
 bool PSBTInput::IsNull() const
 {
     return !non_witness_utxo && witness_utxo.IsNull() && partial_sigs.empty() && unknown.empty() && hd_keypaths.empty() && redeem_script.empty() && witness_script.empty();
@@ -171,13 +205,12 @@ void PSBTOutput::Merge(const PSBTOutput& output)
     if (redeem_script.empty() && !output.redeem_script.empty()) redeem_script = output.redeem_script;
     if (witness_script.empty() && !output.witness_script.empty()) witness_script = output.witness_script;
 }
-
 bool PSBTInputSigned(PSBTInput& input)
 {
     return !input.final_script_sig.empty() || !input.final_script_witness.IsNull();
 }
 
-bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction& psbt, int index, int sighash)
+bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction& psbt, int index, int sighash, SignatureData* out_sigdata, bool use_dummy)
 {
     PSBTInput& input = psbt.inputs.at(index);
     const CMutableTransaction& tx = *psbt.tx;
@@ -217,9 +250,14 @@ bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction&
         return false;
     }
 
-    MutableTransactionSignatureCreator creator(&tx, index, utxo.nValue, sighash);
     sigdata.witness = false;
-    bool sig_complete = ProduceSignature(provider, creator, utxo.scriptPubKey, sigdata);
+    bool sig_complete;
+    if (use_dummy) {
+        sig_complete = ProduceSignature(provider, DUMMY_SIGNATURE_CREATOR, utxo.scriptPubKey, sigdata);
+    } else {
+        MutableTransactionSignatureCreator creator(&tx, index, utxo.nValue, sighash);
+        sig_complete = ProduceSignature(provider, creator, utxo.scriptPubKey, sigdata);
+    }
     // Verify that a witness signature was produced in case one was required.
     if (require_witness_sig && !sigdata.witness) return false;
     input.FromSignatureData(sigdata);
@@ -230,6 +268,14 @@ bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction&
         input.non_witness_utxo = nullptr;
     }
 
+    // Fill in the missing info
+    if (out_sigdata) {
+        out_sigdata->missing_pubkeys = sigdata.missing_pubkeys;
+        out_sigdata->missing_sigs = sigdata.missing_sigs;
+        out_sigdata->missing_redeem_script = sigdata.missing_redeem_script;
+        out_sigdata->missing_witness_script = sigdata.missing_witness_script;
+    }
+
     return sig_complete;
 }
 
diff --git a/src/psbt.h b/src/psbt.h
index e18790322b..27b0aedd05 100644
--- a/src/psbt.h
+++ b/src/psbt.h
@@ -389,9 +389,19 @@ struct PartiallySignedTransaction
       * same actual Bitcoin transaction.) Returns true if the merge succeeded, false otherwise. */
     NODISCARD bool Merge(const PartiallySignedTransaction& psbt);
     bool IsSane() const;
+    bool AddInput(const CTxIn& txin, PSBTInput& psbtin);
+    bool AddOutput(const CTxOut& txout, const PSBTOutput& psbtout);
     PartiallySignedTransaction() {}
     PartiallySignedTransaction(const PartiallySignedTransaction& psbt_in) : tx(psbt_in.tx), inputs(psbt_in.inputs), outputs(psbt_in.outputs), unknown(psbt_in.unknown) {}
     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 {
@@ -542,7 +552,7 @@ struct PartiallySignedTransaction
 bool PSBTInputSigned(PSBTInput& input);
 
 /** Signs a PSBTInput, verifying that all provided data matches what is being signed. */
-bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction& psbt, int index, int sighash = SIGHASH_ALL);
+bool SignPSBTInput(const SigningProvider& provider, PartiallySignedTransaction& psbt, int index, int sighash = SIGHASH_ALL, SignatureData* out_sigdata = nullptr, bool use_dummy = false);
 
 /**
  * Finalizes a PSBT if possible, combining partial signatures.
diff --git a/src/rpc/client.cpp b/src/rpc/client.cpp
index c5694e6d55..1cdc9f87a7 100644
--- a/src/rpc/client.cpp
+++ b/src/rpc/client.cpp
@@ -112,6 +112,7 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "createpsbt", 2, "locktime" },
     { "createpsbt", 3, "replaceable" },
     { "combinepsbt", 0, "txs"},
+    { "joinpsbts", 0, "txs"},
     { "finalizepsbt", 1, "extract"},
     { "converttopsbt", 1, "permitsigdata"},
     { "converttopsbt", 2, "iswitness"},
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 4d8a1b87fc..38e2dc237e 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -7,6 +7,7 @@
 #include <coins.h>
 #include <compat/byteswap.h>
 #include <consensus/validation.h>
+#include <consensus/tx_verify.h>
 #include <core_io.h>
 #include <index/txindex.h>
 #include <init.h>
@@ -31,6 +32,8 @@
 #include <validation.h>
 #include <validationinterface.h>
 
+
+#include <numeric>
 #include <stdint.h>
 
 #include <univalue.h>
@@ -1703,6 +1706,338 @@ UniValue converttopsbt(const JSONRPCRequest& request)
     return EncodeBase64((unsigned char*)ssTx.data(), ssTx.size());
 }
 
+UniValue utxoupdatepsbt(const JSONRPCRequest& request)
+{
+    if (request.fHelp || request.params.size() != 1) {
+        throw std::runtime_error(
+            RPCHelpMan{"utxoupdatepsbt",
+            "\nUpdates a PSBT with witness UTXOs retrieved from the UTXO set or the mempool.\n",
+            {
+                {"psbt", RPCArg::Type::STR, RPCArg::Optional::NO, "A base64 string of a PSBT"}
+            },
+            RPCResult {
+                "  \"psbt\"          (string) The base64-encoded partially signed transaction with inputs updated\n"
+            },
+            RPCExamples {
+                HelpExampleCli("utxoupdatepsbt", "\"psbt\"")
+            }}.ToString());
+    }
+
+    RPCTypeCheck(request.params, {UniValue::VSTR}, true);
+
+    // Unserialize the transactions
+    PartiallySignedTransaction psbtx;
+    std::string error;
+    if (!DecodeBase64PSBT(psbtx, request.params[0].get_str(), error)) {
+        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, strprintf("TX decode failed %s", error));
+    }
+
+    // Fetch previous transactions (inputs):
+    CCoinsView viewDummy;
+    CCoinsViewCache view(&viewDummy);
+    {
+        LOCK2(cs_main, mempool.cs);
+        CCoinsViewCache &viewChain = *pcoinsTip;
+        CCoinsViewMemPool viewMempool(&viewChain, mempool);
+        view.SetBackend(viewMempool); // temporarily switch cache backend to db+mempool view
+
+        for (const CTxIn& txin : psbtx.tx->vin) {
+            view.AccessCoin(txin.prevout); // Load entries from viewChain into view; can fail.
+        }
+
+        view.SetBackend(viewDummy); // switch back to avoid locking mempool for too long
+    }
+
+    // Fill the inputs
+    for (unsigned int i = 0; i < psbtx.tx->vin.size(); ++i) {
+        PSBTInput& input = psbtx.inputs.at(i);
+
+        if (input.non_witness_utxo || !input.witness_utxo.IsNull()) {
+            continue;
+        }
+
+        const Coin& coin = view.AccessCoin(psbtx.tx->vin[i].prevout);
+
+        std::vector<std::vector<unsigned char>> solutions_data;
+        txnouttype which_type = Solver(coin.out.scriptPubKey, solutions_data);
+        if (which_type == TX_WITNESS_V0_SCRIPTHASH || which_type == TX_WITNESS_V0_KEYHASH || which_type == TX_WITNESS_UNKNOWN) {
+            input.witness_utxo = coin.out;
+        }
+    }
+
+    CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
+    ssTx << psbtx;
+    return EncodeBase64((unsigned char*)ssTx.data(), ssTx.size());
+}
+
+UniValue joinpsbts(const JSONRPCRequest& request)
+{
+    if (request.fHelp || request.params.size() != 1) {
+        throw std::runtime_error(
+            RPCHelpMan{"joinpsbts",
+            "\nJoins multiple distinct PSBTs with different inputs and outputs into one PSBT with inputs and outputs from all of the PSBTs\n"
+            "No input in any of the PSBTs can be in more than one of the PSBTs.\n",
+            {
+                {"txs", RPCArg::Type::ARR, RPCArg::Optional::NO, "A json array of base64 strings of partially signed transactions",
+                    {
+                        {"psbt", RPCArg::Type::STR, RPCArg::Optional::NO, "A base64 string of a PSBT"}
+                    }}
+            },
+            RPCResult {
+                "  \"psbt\"          (string) The base64-encoded partially signed transaction\n"
+            },
+            RPCExamples {
+                HelpExampleCli("joinpsbts", "\"psbt\"")
+            }}.ToString());
+    }
+
+    RPCTypeCheck(request.params, {UniValue::VARR}, true);
+
+    // Unserialize the transactions
+    std::vector<PartiallySignedTransaction> psbtxs;
+    UniValue txs = request.params[0].get_array();
+
+    if (txs.size() <= 1) {
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "At least two PSBTs are required to join PSBTs.");
+    }
+
+    int32_t best_version = 1;
+    uint32_t best_locktime = 0xffffffff;
+    for (unsigned int i = 0; i < txs.size(); ++i) {
+        PartiallySignedTransaction psbtx;
+        std::string error;
+        if (!DecodeBase64PSBT(psbtx, txs[i].get_str(), error)) {
+            throw JSONRPCError(RPC_DESERIALIZATION_ERROR, strprintf("TX decode failed %s", error));
+        }
+        psbtxs.push_back(psbtx);
+        // Choose the highest version number
+        if (psbtx.tx->nVersion > best_version) {
+            best_version = psbtx.tx->nVersion;
+        }
+        // Choose the lowest lock time
+        if (psbtx.tx->nLockTime < best_locktime) {
+            best_locktime = psbtx.tx->nLockTime;
+        }
+    }
+
+    // Create a blank psbt where everything will be added
+    PartiallySignedTransaction merged_psbt;
+    merged_psbt.tx = CMutableTransaction();
+    merged_psbt.tx->nVersion = best_version;
+    merged_psbt.tx->nLockTime = best_locktime;
+
+    // Merge
+    for (auto& psbt : psbtxs) {
+        for (unsigned int i = 0; i < psbt.tx->vin.size(); ++i) {
+            if (!merged_psbt.AddInput(psbt.tx->vin[i], psbt.inputs[i])) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Input %s:%d exists in multiple PSBTs", psbt.tx->vin[i].prevout.hash.ToString().c_str(), psbt.tx->vin[i].prevout.n));
+            }
+        }
+        for (unsigned int i = 0; i < psbt.tx->vout.size(); ++i) {
+            merged_psbt.AddOutput(psbt.tx->vout[i], psbt.outputs[i]);
+        }
+        merged_psbt.unknown.insert(psbt.unknown.begin(), psbt.unknown.end());
+    }
+
+    CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
+    ssTx << merged_psbt;
+    return EncodeBase64((unsigned char*)ssTx.data(), ssTx.size());
+}
+
+UniValue analyzepsbt(const JSONRPCRequest& request)
+{
+    if (request.fHelp || request.params.size() != 1) {
+        throw std::runtime_error(
+            RPCHelpMan{"analyzepsbt",
+            "\nAnalyzes and provides information about the current status of a PSBT and its inputs\n",
+            {
+                {"psbt", RPCArg::Type::STR, RPCArg::Optional::NO, "A base64 string of a PSBT"}
+            },
+            RPCResult {
+                "{\n"
+                "  \"inputs\" : [                      (array of json objects)\n"
+                "    {\n"
+                "      \"has_utxo\" : true|false     (boolean) Whether a UTXO is provided\n"
+                "      \"is_final\" : true|false     (boolean) Whether the input is finalized\n"
+                "      \"missing\" : {               (json object, optional) Things that are missing that are required to complete this input\n"
+                "        \"pubkeys\" : [             (array)\n"
+                "          \"keyid\"                 (string) Public key ID, hash160 of the public key, of a public key whose BIP 32 derivation path is missing\n"
+                "        ]\n"
+                "        \"signatures\" : [          (array)\n"
+                "          \"keyid\"                 (string) Public key ID, hash160 of the public key, of a public key whose signature is missing\n"
+                "        ]\n"
+                "        \"redeemscript\" : \"hash\"   (string) Hash160 of the redeemScript that is missing\n"
+                "        \"witnessscript\" : \"hash\"  (string) SHA256 of the witnessScript that is missing\n"
+                "      }\n"
+                "      \"next\" : \"role\"           (string) Role of the next person that this input needs to go to\n"
+                "    }\n"
+                "    ,...\n"
+                "  ]\n"
+                "  \"estimated_vsize\" : vsize       (numeric) Estimated vsize of the final signed transaction\n"
+                "  \"estimated_feerate\" : feerate   (numeric, optional) Estimated feerate of the final signed transaction. Shown only if all UTXO slots in the PSBT have been filled.\n"
+                "  \"fee\" : fee                     (numeric, optional) The transaction fee paid. Shown only if all UTXO slots in the PSBT have been filled.\n"
+                "  \"next\" : \"role\"                 (string) Role of the next person that this psbt needs to go to\n"
+                "}\n"
+            },
+            RPCExamples {
+                HelpExampleCli("analyzepsbt", "\"psbt\"")
+            }}.ToString());
+    }
+
+    RPCTypeCheck(request.params, {UniValue::VSTR});
+
+    // Unserialize the transaction
+    PartiallySignedTransaction psbtx;
+    std::string error;
+    if (!DecodeBase64PSBT(psbtx, request.params[0].get_str(), error)) {
+        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, strprintf("TX decode failed %s", error));
+    }
+
+    // Go through each input and build status
+    UniValue result(UniValue::VOBJ);
+    UniValue inputs_result(UniValue::VARR);
+    bool calc_fee = true;
+    bool all_final = true;
+    bool only_missing_sigs = true;
+    bool only_missing_final = false;
+    CAmount in_amt = 0;
+    for (unsigned int i = 0; i < psbtx.tx->vin.size(); ++i) {
+        PSBTInput& input = psbtx.inputs[i];
+        UniValue input_univ(UniValue::VOBJ);
+        UniValue missing(UniValue::VOBJ);
+
+        // Check for a UTXO
+        CTxOut utxo;
+        if (psbtx.GetInputUTXO(utxo, i)) {
+            in_amt += utxo.nValue;
+            input_univ.pushKV("has_utxo", true);
+        } else {
+            input_univ.pushKV("has_utxo", false);
+            input_univ.pushKV("is_final", false);
+            input_univ.pushKV("next", "updater");
+            calc_fee = false;
+        }
+
+        // Check if it is final
+        if (!utxo.IsNull() && !PSBTInputSigned(input)) {
+            input_univ.pushKV("is_final", false);
+            all_final = false;
+
+            // Figure out what is missing
+            SignatureData outdata;
+            bool complete = SignPSBTInput(DUMMY_SIGNING_PROVIDER, psbtx, i, 1, &outdata);
+
+            // Things are missing
+            if (!complete) {
+                if (!outdata.missing_pubkeys.empty()) {
+                    // Missing pubkeys
+                    UniValue missing_pubkeys_univ(UniValue::VARR);
+                    for (const CKeyID& pubkey : outdata.missing_pubkeys) {
+                        missing_pubkeys_univ.push_back(HexStr(pubkey));
+                    }
+                    missing.pushKV("pubkeys", missing_pubkeys_univ);
+                }
+                if (!outdata.missing_redeem_script.IsNull()) {
+                    // Missing redeemScript
+                    missing.pushKV("redeemscript", HexStr(outdata.missing_redeem_script));
+                }
+                if (!outdata.missing_witness_script.IsNull()) {
+                    // Missing witnessScript
+                    missing.pushKV("witnessscript", HexStr(outdata.missing_witness_script));
+                }
+                if (!outdata.missing_sigs.empty()) {
+                    // Missing sigs
+                    UniValue missing_sigs_univ(UniValue::VARR);
+                    for (const CKeyID& pubkey : outdata.missing_sigs) {
+                        missing_sigs_univ.push_back(HexStr(pubkey));
+                    }
+                    missing.pushKV("signatures", missing_sigs_univ);
+                }
+                input_univ.pushKV("missing", missing);
+
+                // If we are only missing signatures and nothing else, then next is signer
+                if (outdata.missing_pubkeys.empty() && outdata.missing_redeem_script.IsNull() && outdata.missing_witness_script.IsNull() && !outdata.missing_sigs.empty()) {
+                    input_univ.pushKV("next", "signer");
+                } else {
+                    only_missing_sigs = false;
+                    input_univ.pushKV("next", "updater");
+                }
+            } else {
+                only_missing_final = true;
+                input_univ.pushKV("next", "finalizer");
+            }
+        } else if (!utxo.IsNull()){
+            input_univ.pushKV("is_final", true);
+        }
+        inputs_result.push_back(input_univ);
+    }
+    result.pushKV("inputs", inputs_result);
+
+    if (all_final) {
+        only_missing_sigs = false;
+        result.pushKV("next", "extractor");
+    }
+    if (calc_fee) {
+        // Get the output amount
+        CAmount out_amt = std::accumulate(psbtx.tx->vout.begin(), psbtx.tx->vout.end(), 0,
+            [](int a, const CTxOut& b) {
+                return a += b.nValue;
+            }
+        );
+
+        // Get the fee
+        CAmount fee = in_amt - out_amt;
+
+        // Estimate the size
+        CMutableTransaction mtx(*psbtx.tx);
+        CCoinsView view_dummy;
+        CCoinsViewCache view(&view_dummy);
+        bool success = true;
+
+        for (unsigned int i = 0; i < psbtx.tx->vin.size(); ++i) {
+            PSBTInput& input = psbtx.inputs[i];
+            if (SignPSBTInput(DUMMY_SIGNING_PROVIDER, psbtx, i, 1, nullptr, true)) {
+                mtx.vin[i].scriptSig = input.final_script_sig;
+                mtx.vin[i].scriptWitness = input.final_script_witness;
+
+                Coin newcoin;
+                if (!psbtx.GetInputUTXO(newcoin.out, i)) {
+                    success = false;
+                    break;
+                }
+                newcoin.nHeight = 1;
+                view.AddCoin(psbtx.tx->vin[i].prevout, std::move(newcoin), true);
+            } else {
+                success = false;
+                break;
+            }
+        }
+
+        if (success) {
+            CTransaction ctx = CTransaction(mtx);
+            size_t size = GetVirtualTransactionSize(ctx, GetTransactionSigOpCost(ctx, view, STANDARD_SCRIPT_VERIFY_FLAGS));
+            result.pushKV("estimated_vsize", (int)size);
+            // Estimate fee rate
+            CFeeRate feerate(fee, size);
+            result.pushKV("estimated_feerate", feerate.ToString());
+        }
+        result.pushKV("fee", ValueFromAmount(fee));
+
+        if (only_missing_sigs) {
+            result.pushKV("next", "signer");
+        } else if (only_missing_final) {
+            result.pushKV("next", "finalizer");
+        } else if (all_final) {
+            result.pushKV("next", "extractor");
+        } else {
+            result.pushKV("next", "updater");
+        }
+    } else {
+        result.pushKV("next", "updater");
+    }
+    return result;
+}
+
 // clang-format off
 static const CRPCCommand commands[] =
 { //  category              name                            actor (function)            argNames
@@ -1721,6 +2056,9 @@ static const CRPCCommand commands[] =
     { "rawtransactions",    "finalizepsbt",                 &finalizepsbt,              {"psbt", "extract"} },
     { "rawtransactions",    "createpsbt",                   &createpsbt,                {"inputs","outputs","locktime","replaceable"} },
     { "rawtransactions",    "converttopsbt",                &converttopsbt,             {"hexstring","permitsigdata","iswitness"} },
+    { "rawtransactions",    "utxoupdatepsbt",               &utxoupdatepsbt,            {"psbt"} },
+    { "rawtransactions",    "joinpsbts",                    &joinpsbts,                 {"txs"} },
+    { "rawtransactions",    "analyzepsbt",                  &analyzepsbt,               {"psbt"} },
 
     { "blockchain",         "gettxoutproof",                &gettxoutproof,             {"txids", "blockhash"} },
     { "blockchain",         "verifytxoutproof",             &verifytxoutproof,          {"proof"} },
diff --git a/src/script/sign.cpp b/src/script/sign.cpp
index 9d6a390ea2..320956d0c4 100644
--- a/src/script/sign.cpp
+++ b/src/script/sign.cpp
@@ -83,6 +83,8 @@ static bool CreateSig(const BaseSignatureCreator& creator, SignatureData& sigdat
         assert(i.second);
         return true;
     }
+    // Could not make signature or signature not found, add keyid to missing
+    sigdata.missing_sigs.push_back(keyid);
     return false;
 }
 
@@ -116,17 +118,24 @@ static bool SignStep(const SigningProvider& provider, const BaseSignatureCreator
     case TX_PUBKEYHASH: {
         CKeyID keyID = CKeyID(uint160(vSolutions[0]));
         CPubKey pubkey;
-        if (!GetPubKey(provider, sigdata, keyID, pubkey)) return false;
+        if (!GetPubKey(provider, sigdata, keyID, pubkey)) {
+            // Pubkey could not be found, add to missing
+            sigdata.missing_pubkeys.push_back(keyID);
+            return false;
+        }
         if (!CreateSig(creator, sigdata, provider, sig, pubkey, scriptPubKey, sigversion)) return false;
         ret.push_back(std::move(sig));
         ret.push_back(ToByteVector(pubkey));
         return true;
     }
     case TX_SCRIPTHASH:
-        if (GetCScript(provider, sigdata, uint160(vSolutions[0]), scriptRet)) {
+        h160 = uint160(vSolutions[0]);
+        if (GetCScript(provider, sigdata, h160, scriptRet)) {
             ret.push_back(std::vector<unsigned char>(scriptRet.begin(), scriptRet.end()));
             return true;
         }
+        // Could not find redeemScript, add to missing
+        sigdata.missing_redeem_script = h160;
         return false;
 
     case TX_MULTISIG: {
@@ -154,6 +163,8 @@ static bool SignStep(const SigningProvider& provider, const BaseSignatureCreator
             ret.push_back(std::vector<unsigned char>(scriptRet.begin(), scriptRet.end()));
             return true;
         }
+        // Could not find witnessScript, add to missing
+        sigdata.missing_witness_script = uint256(vSolutions[0]);
         return false;
 
     default:
diff --git a/src/script/sign.h b/src/script/sign.h
index 3e9a3b38c6..491fb54c45 100644
--- a/src/script/sign.h
+++ b/src/script/sign.h
@@ -131,6 +131,10 @@ struct SignatureData {
     CScriptWitness scriptWitness; ///< The scriptWitness of an input. Contains complete signatures or the traditional partial signatures format. scriptWitness is part of a transaction input per BIP 144.
     std::map<CKeyID, SigPair> signatures; ///< BIP 174 style partial signatures for the input. May contain all signatures necessary for producing a final scriptSig or scriptWitness.
     std::map<CKeyID, std::pair<CPubKey, KeyOriginInfo>> misc_pubkeys;
+    std::vector<CKeyID> missing_pubkeys; ///< KeyIDs of pubkeys which could not be found
+    std::vector<CKeyID> missing_sigs; ///< KeyIDs of pubkeys for signatures which could not be found
+    uint160 missing_redeem_script; ///< ScriptID of the missing redeemScript (if any)
+    uint256 missing_witness_script; ///< SHA256 of the missing witnessScript (if any)
 
     SignatureData() {}
     explicit SignatureData(const CScript& script) : scriptSig(script) {}