From 5db8cd2d37eba3ca6abc66386a3b9dc2185fa3ce Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Wed, 14 Sep 2022 13:15:42 +1000
Subject: [PATCH 1/8] Move mapFlagNames and FormatScriptFlags logic to
 script/interpreter.h

Moves FormatScriptFlags logic into GetScriptFlagNames which returns a
vector of strings. For completeness, also has GetScriptFlagNames report
on any bits that do not match a known script flag.
---
 src/deploymentinfo.h           |  2 ++
 src/script/interpreter.cpp     | 46 +++++++++++++++++++++++++++++++++
 src/script/interpreter.h       |  4 +++
 src/test/script_tests.cpp      | 17 +++++++++++-
 src/test/transaction_tests.cpp | 47 +++++-----------------------------
 5 files changed, 74 insertions(+), 42 deletions(-)

diff --git a/src/deploymentinfo.h b/src/deploymentinfo.h
index 10029b0e30a..3178ea74288 100644
--- a/src/deploymentinfo.h
+++ b/src/deploymentinfo.h
@@ -8,8 +8,10 @@
 #include <consensus/params.h>
 
 #include <array>
+#include <cassert>
 #include <optional>
 #include <string>
+#include <string_view>
 
 struct VBDeploymentInfo {
     /** Deployment name */
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index 07fda48c493..85cb76873f5 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -10,6 +10,7 @@
 #include <crypto/sha256.h>
 #include <pubkey.h>
 #include <script/script.h>
+#include <tinyformat.h>
 #include <uint256.h>
 
 typedef std::vector<unsigned char> valtype;
@@ -2161,3 +2162,48 @@ size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey,
 
     return 0;
 }
+
+#define FLAG_NAME(flag) {std::string(#flag), SCRIPT_VERIFY_##flag}
+const std::map<std::string, uint32_t> g_verify_flag_names{
+    FLAG_NAME(P2SH),
+    FLAG_NAME(STRICTENC),
+    FLAG_NAME(DERSIG),
+    FLAG_NAME(LOW_S),
+    FLAG_NAME(SIGPUSHONLY),
+    FLAG_NAME(MINIMALDATA),
+    FLAG_NAME(NULLDUMMY),
+    FLAG_NAME(DISCOURAGE_UPGRADABLE_NOPS),
+    FLAG_NAME(CLEANSTACK),
+    FLAG_NAME(MINIMALIF),
+    FLAG_NAME(NULLFAIL),
+    FLAG_NAME(CHECKLOCKTIMEVERIFY),
+    FLAG_NAME(CHECKSEQUENCEVERIFY),
+    FLAG_NAME(WITNESS),
+    FLAG_NAME(DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM),
+    FLAG_NAME(WITNESS_PUBKEYTYPE),
+    FLAG_NAME(CONST_SCRIPTCODE),
+    FLAG_NAME(TAPROOT),
+    FLAG_NAME(DISCOURAGE_UPGRADABLE_PUBKEYTYPE),
+    FLAG_NAME(DISCOURAGE_OP_SUCCESS),
+    FLAG_NAME(DISCOURAGE_UPGRADABLE_TAPROOT_VERSION),
+};
+#undef FLAG_NAME
+
+std::vector<std::string> GetScriptFlagNames(uint32_t flags)
+{
+    std::vector<std::string> res;
+    if (flags == SCRIPT_VERIFY_NONE) {
+        return res;
+    }
+    uint32_t leftover = flags;
+    for (const auto& [name, flag] : g_verify_flag_names) {
+        if ((flags & flag) != 0) {
+            res.push_back(name);
+            leftover &= ~flag;
+        }
+    }
+    if (leftover != 0) {
+        res.push_back(strprintf("0x%08x", leftover));
+    }
+    return res;
+}
diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index 2108e3992fc..1ce528ac480 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -371,4 +371,8 @@ size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey,
 
 int FindAndDelete(CScript& script, const CScript& b);
 
+extern const std::map<std::string, uint32_t> g_verify_flag_names;
+
+std::vector<std::string> GetScriptFlagNames(uint32_t flags);
+
 #endif // BITCOIN_SCRIPT_INTERPRETER_H
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index 5d7593020b4..ed68dc4953b 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -9,6 +9,7 @@
 #include <core_io.h>
 #include <key.h>
 #include <rpc/util.h>
+#include <script/interpreter.h>
 #include <script/script.h>
 #include <script/script_error.h>
 #include <script/sigcache.h>
@@ -22,6 +23,7 @@
 #include <test/util/transaction_utils.h>
 #include <util/fs.h>
 #include <util/strencodings.h>
+#include <util/string.h>
 
 #include <cstdint>
 #include <fstream>
@@ -41,7 +43,6 @@ using namespace util::hex_literals;
 static const unsigned int gFlags = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC;
 
 unsigned int ParseScriptFlags(std::string strFlags);
-std::string FormatScriptFlags(unsigned int flags);
 
 struct ScriptErrorDesc
 {
@@ -95,6 +96,11 @@ static ScriptErrorDesc script_errors[]={
     {SCRIPT_ERR_SIG_FINDANDDELETE, "SIG_FINDANDDELETE"},
 };
 
+static std::string FormatScriptFlags(uint32_t flags)
+{
+    return util::Join(GetScriptFlagNames(flags), ",");
+}
+
 static std::string FormatScriptError(ScriptError_t err)
 {
     for (const auto& se : script_errors)
@@ -1706,4 +1712,13 @@ BOOST_AUTO_TEST_CASE(compute_tapleaf)
     BOOST_CHECK_EQUAL(ComputeTapleafHash(0xc2, std::span(script)), tlc2);
 }
 
+BOOST_AUTO_TEST_CASE(formatscriptflags)
+{
+    // quick check that FormatScriptFlags reports any unknown/unexpected bits
+    BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_P2SH), "P2SH");
+    BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_P2SH | (1u<<31)), "P2SH,0x80000000");
+    BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_TAPROOT | (1u<<27)), "TAPROOT,0x08000000");
+    BOOST_CHECK_EQUAL(FormatScriptFlags(1u<<26), "0x04000000");
+}
+
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
index c0443f3a0a4..e7b3ee7f3ff 100644
--- a/src/test/transaction_tests.cpp
+++ b/src/test/transaction_tests.cpp
@@ -17,6 +17,7 @@
 #include <policy/policy.h>
 #include <policy/settings.h>
 #include <primitives/transaction_identifier.h>
+#include <script/interpreter.h>
 #include <script/script.h>
 #include <script/script_error.h>
 #include <script/sigcache.h>
@@ -49,29 +50,7 @@ typedef std::vector<unsigned char> valtype;
 static CFeeRate g_dust{DUST_RELAY_TX_FEE};
 static bool g_bare_multi{DEFAULT_PERMIT_BAREMULTISIG};
 
-static std::map<std::string, unsigned int> mapFlagNames = {
-    {std::string("P2SH"), (unsigned int)SCRIPT_VERIFY_P2SH},
-    {std::string("STRICTENC"), (unsigned int)SCRIPT_VERIFY_STRICTENC},
-    {std::string("DERSIG"), (unsigned int)SCRIPT_VERIFY_DERSIG},
-    {std::string("LOW_S"), (unsigned int)SCRIPT_VERIFY_LOW_S},
-    {std::string("SIGPUSHONLY"), (unsigned int)SCRIPT_VERIFY_SIGPUSHONLY},
-    {std::string("MINIMALDATA"), (unsigned int)SCRIPT_VERIFY_MINIMALDATA},
-    {std::string("NULLDUMMY"), (unsigned int)SCRIPT_VERIFY_NULLDUMMY},
-    {std::string("DISCOURAGE_UPGRADABLE_NOPS"), (unsigned int)SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS},
-    {std::string("CLEANSTACK"), (unsigned int)SCRIPT_VERIFY_CLEANSTACK},
-    {std::string("MINIMALIF"), (unsigned int)SCRIPT_VERIFY_MINIMALIF},
-    {std::string("NULLFAIL"), (unsigned int)SCRIPT_VERIFY_NULLFAIL},
-    {std::string("CHECKLOCKTIMEVERIFY"), (unsigned int)SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY},
-    {std::string("CHECKSEQUENCEVERIFY"), (unsigned int)SCRIPT_VERIFY_CHECKSEQUENCEVERIFY},
-    {std::string("WITNESS"), (unsigned int)SCRIPT_VERIFY_WITNESS},
-    {std::string("DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM"), (unsigned int)SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM},
-    {std::string("WITNESS_PUBKEYTYPE"), (unsigned int)SCRIPT_VERIFY_WITNESS_PUBKEYTYPE},
-    {std::string("CONST_SCRIPTCODE"), (unsigned int)SCRIPT_VERIFY_CONST_SCRIPTCODE},
-    {std::string("TAPROOT"), (unsigned int)SCRIPT_VERIFY_TAPROOT},
-    {std::string("DISCOURAGE_UPGRADABLE_PUBKEYTYPE"), (unsigned int)SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_PUBKEYTYPE},
-    {std::string("DISCOURAGE_OP_SUCCESS"), (unsigned int)SCRIPT_VERIFY_DISCOURAGE_OP_SUCCESS},
-    {std::string("DISCOURAGE_UPGRADABLE_TAPROOT_VERSION"), (unsigned int)SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_TAPROOT_VERSION},
-};
+static const std::map<std::string, unsigned int>& mapFlagNames = g_verify_flag_names;
 
 unsigned int ParseScriptFlags(std::string strFlags)
 {
@@ -81,9 +60,11 @@ unsigned int ParseScriptFlags(std::string strFlags)
     std::vector<std::string> words = SplitString(strFlags, ',');
     for (const std::string& word : words)
     {
-        if (!mapFlagNames.count(word))
+        if (!mapFlagNames.count(word)) {
             BOOST_ERROR("Bad test: unknown verification flag '" << word << "'");
-        flags |= mapFlagNames[word];
+            continue;
+        }
+        flags |= mapFlagNames.at(word);
     }
     return flags;
 }
@@ -98,22 +79,6 @@ bool CheckMapFlagNames()
     return standard_flags_missing == 0;
 }
 
-std::string FormatScriptFlags(unsigned int flags)
-{
-    if (flags == SCRIPT_VERIFY_NONE) {
-        return "";
-    }
-    std::string ret;
-    std::map<std::string, unsigned int>::const_iterator it = mapFlagNames.begin();
-    while (it != mapFlagNames.end()) {
-        if (flags & it->second) {
-            ret += it->first + ",";
-        }
-        it++;
-    }
-    return ret.substr(0, ret.size() - 1);
-}
-
 /*
 * Check that the input scripts of a transaction are valid/invalid as expected.
 */

From a3986935f073be799a35dfa92ab5004e12b35467 Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Thu, 15 Sep 2022 15:32:15 +1000
Subject: [PATCH 2/8] validation: export GetBlockScriptFlags()

---
 src/validation.cpp | 5 +----
 src/validation.h   | 3 +++
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/validation.cpp b/src/validation.cpp
index 7b7c8b2d5bd..ae8e80aa6ab 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -262,9 +262,6 @@ bool CheckSequenceLocksAtTip(CBlockIndex* tip,
     return EvaluateSequenceLocks(index, {lock_points.height, lock_points.time});
 }
 
-// Returns the script flags which should be checked for a given block
-static unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const ChainstateManager& chainman);
-
 static void LimitMempoolSize(CTxMemPool& pool, CCoinsViewCache& coins_cache)
     EXCLUSIVE_LOCKS_REQUIRED(::cs_main, pool.cs)
 {
@@ -2328,7 +2325,7 @@ DisconnectResult Chainstate::DisconnectBlock(const CBlock& block, const CBlockIn
     return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN;
 }
 
-static unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const ChainstateManager& chainman)
+unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const ChainstateManager& chainman)
 {
     const Consensus::Params& consensusparams = chainman.GetConsensus();
 
diff --git a/src/validation.h b/src/validation.h
index 6be6ae287fc..86329e959cc 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -1358,4 +1358,7 @@ bool IsBIP30Repeat(const CBlockIndex& block_index);
 /** Identifies blocks which coinbase output was subsequently overwritten in the UTXO set (see BIP30) */
 bool IsBIP30Unspendable(const uint256& block_hash, int block_height);
 
+// Returns the script flags which should be checked for a given block
+unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const ChainstateManager& chainman);
+
 #endif // BITCOIN_VALIDATION_H

From 4577fb2b1e098c3f560b1ff50a37ebfef2af5f32 Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Wed, 14 Sep 2022 15:40:23 +1000
Subject: [PATCH 3/8] rpc: have getdeploymentinfo report script verify flags

---
 src/rpc/blockchain.cpp            | 9 +++++++++
 test/functional/rpc_blockchain.py | 1 +
 2 files changed, 10 insertions(+)

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index cfc0379f683..ddaa4eadbec 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -1453,6 +1453,9 @@ RPCHelpMan getdeploymentinfo()
             RPCResult::Type::OBJ, "", "", {
                 {RPCResult::Type::STR, "hash", "requested block hash (or tip)"},
                 {RPCResult::Type::NUM, "height", "requested block height (or tip)"},
+                {RPCResult::Type::ARR, "script_flags", "script verify flags for the block", {
+                    {RPCResult::Type::STR, "flag", "a script verify flag"},
+                }},
                 {RPCResult::Type::OBJ_DYN, "deployments", "", {
                     {RPCResult::Type::OBJ, "xxxx", "name of the deployment", RPCHelpForDeployment}
                 }},
@@ -1479,6 +1482,12 @@ RPCHelpMan getdeploymentinfo()
             UniValue deploymentinfo(UniValue::VOBJ);
             deploymentinfo.pushKV("hash", blockindex->GetBlockHash().ToString());
             deploymentinfo.pushKV("height", blockindex->nHeight);
+            {
+                const auto flagnames = GetScriptFlagNames(GetBlockScriptFlags(*blockindex, chainman));
+                UniValue uv_flagnames(UniValue::VARR);
+                uv_flagnames.push_backV(flagnames.begin(), flagnames.end());
+                deploymentinfo.pushKV("script_flags", uv_flagnames);
+            }
             deploymentinfo.pushKV("deployments", DeploymentInfo(blockindex, chainman));
             return deploymentinfo;
         },
diff --git a/test/functional/rpc_blockchain.py b/test/functional/rpc_blockchain.py
index 84fa8ebccf1..3c011c09ed0 100755
--- a/test/functional/rpc_blockchain.py
+++ b/test/functional/rpc_blockchain.py
@@ -213,6 +213,7 @@ class BlockchainTest(BitcoinTestFramework):
         assert_equal(gdi_result, {
           "hash": blockhash,
           "height": height,
+          "script_flags": ["CHECKLOCKTIMEVERIFY","CHECKSEQUENCEVERIFY","DERSIG","NULLDUMMY","P2SH","TAPROOT","WITNESS"],
           "deployments": {
             'bip34': {'type': 'buried', 'active': True, 'height': 2},
             'bip66': {'type': 'buried', 'active': True, 'height': 3},

From a5ead122fe060e7e582914dcb7acfaeee7a8ac48 Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Wed, 16 Jul 2025 11:24:58 +1000
Subject: [PATCH 4/8] script/interpreter: introduce script_verify_flags
 typename

Previously the SCRIPT_VERIFY_* flags were specified as either uint32_t,
unsigned int, or unsigned. This converts them to a common type alias in
preparation for changing the underlying type.
---
 src/bench/verify_script.cpp                   |  2 +-
 src/consensus/params.h                        |  3 +-
 src/consensus/tx_verify.cpp                   |  2 +-
 src/consensus/tx_verify.h                     |  3 +-
 src/policy/policy.h                           |  6 ++--
 src/script/interpreter.cpp                    | 26 +++++++--------
 src/script/interpreter.h                      | 13 ++++----
 src/script/verify_flags.h                     | 13 ++++++++
 src/signet.cpp                                |  2 +-
 src/test/fuzz/eval_script.cpp                 |  2 +-
 src/test/fuzz/script.cpp                      |  2 +-
 .../fuzz/script_assets_test_minimizer.cpp     | 30 ++++++++---------
 src/test/fuzz/script_flags.cpp                |  4 +--
 src/test/fuzz/signature_checker.cpp           |  2 +-
 src/test/multisig_tests.cpp                   |  2 +-
 src/test/script_assets_tests.cpp              | 12 +++----
 src/test/script_tests.cpp                     | 12 +++----
 src/test/sigopcount_tests.cpp                 |  4 +--
 src/test/transaction_tests.cpp                | 32 +++++++++----------
 src/test/txvalidationcache_tests.cpp          |  6 ++--
 src/test/util/script.cpp                      |  2 +-
 src/test/util/script.h                        |  3 +-
 src/validation.cpp                            | 18 +++++------
 src/validation.h                              |  9 +++---
 24 files changed, 114 insertions(+), 96 deletions(-)
 create mode 100644 src/script/verify_flags.h

diff --git a/src/bench/verify_script.cpp b/src/bench/verify_script.cpp
index 8d7e92a0556..062f9a01dc2 100644
--- a/src/bench/verify_script.cpp
+++ b/src/bench/verify_script.cpp
@@ -24,7 +24,7 @@ static void VerifyScriptBench(benchmark::Bench& bench)
 {
     ECC_Context ecc_context{};
 
-    const uint32_t flags{SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH};
+    const script_verify_flags flags{SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH};
     const int witnessversion = 0;
 
     // Key pair.
diff --git a/src/consensus/params.h b/src/consensus/params.h
index 6344349b866..f33ff15fbfe 100644
--- a/src/consensus/params.h
+++ b/src/consensus/params.h
@@ -6,6 +6,7 @@
 #ifndef BITCOIN_CONSENSUS_PARAMS_H
 #define BITCOIN_CONSENSUS_PARAMS_H
 
+#include <script/verify_flags.h>
 #include <uint256.h>
 
 #include <array>
@@ -89,7 +90,7 @@ struct Params {
      * - buried in the chain, and
      * - fail if the default script verify flags are applied.
      */
-    std::map<uint256, uint32_t> script_flag_exceptions;
+    std::map<uint256, script_verify_flags> script_flag_exceptions;
     /** Block height and hash at which BIP34 becomes active */
     int BIP34Height;
     uint256 BIP34Hash;
diff --git a/src/consensus/tx_verify.cpp b/src/consensus/tx_verify.cpp
index 95466b759cb..9d09872597a 100644
--- a/src/consensus/tx_verify.cpp
+++ b/src/consensus/tx_verify.cpp
@@ -140,7 +140,7 @@ unsigned int GetP2SHSigOpCount(const CTransaction& tx, const CCoinsViewCache& in
     return nSigOps;
 }
 
-int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& inputs, uint32_t flags)
+int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& inputs, script_verify_flags flags)
 {
     int64_t nSigOps = GetLegacySigOpCount(tx) * WITNESS_SCALE_FACTOR;
 
diff --git a/src/consensus/tx_verify.h b/src/consensus/tx_verify.h
index 8b7e6d6b385..ed44d435c1b 100644
--- a/src/consensus/tx_verify.h
+++ b/src/consensus/tx_verify.h
@@ -6,6 +6,7 @@
 #define BITCOIN_CONSENSUS_TX_VERIFY_H
 
 #include <consensus/amount.h>
+#include <script/verify_flags.h>
 
 #include <cstdint>
 #include <vector>
@@ -52,7 +53,7 @@ unsigned int GetP2SHSigOpCount(const CTransaction& tx, const CCoinsViewCache& ma
  * @param[in] flags Script verification flags
  * @return Total signature operation cost of tx
  */
-int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& inputs, uint32_t flags);
+int64_t GetTransactionSigOpCost(const CTransaction& tx, const CCoinsViewCache& inputs, script_verify_flags flags);
 
 /**
  * Check if transaction is final and can be included in a block with the
diff --git a/src/policy/policy.h b/src/policy/policy.h
index ad787630a45..f6fbb678bb0 100644
--- a/src/policy/policy.h
+++ b/src/policy/policy.h
@@ -98,7 +98,7 @@ static constexpr unsigned int MAX_DUST_OUTPUTS_PER_TX{1};
  * Note that this does not affect consensus validity; see GetBlockScriptFlags()
  * for that.
  */
-static constexpr unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS{SCRIPT_VERIFY_P2SH |
+static constexpr script_verify_flags MANDATORY_SCRIPT_VERIFY_FLAGS{SCRIPT_VERIFY_P2SH |
                                                              SCRIPT_VERIFY_DERSIG |
                                                              SCRIPT_VERIFY_NULLDUMMY |
                                                              SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY |
@@ -112,7 +112,7 @@ static constexpr unsigned int MANDATORY_SCRIPT_VERIFY_FLAGS{SCRIPT_VERIFY_P2SH |
  * the additional (non-mandatory) rules here, to improve forwards and
  * backwards compatibility.
  */
-static constexpr unsigned int STANDARD_SCRIPT_VERIFY_FLAGS{MANDATORY_SCRIPT_VERIFY_FLAGS |
+static constexpr script_verify_flags STANDARD_SCRIPT_VERIFY_FLAGS{MANDATORY_SCRIPT_VERIFY_FLAGS |
                                                              SCRIPT_VERIFY_STRICTENC |
                                                              SCRIPT_VERIFY_MINIMALDATA |
                                                              SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS |
@@ -128,7 +128,7 @@ static constexpr unsigned int STANDARD_SCRIPT_VERIFY_FLAGS{MANDATORY_SCRIPT_VERI
                                                              SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_PUBKEYTYPE};
 
 /** For convenience, standard but not mandatory verify flags. */
-static constexpr unsigned int STANDARD_NOT_MANDATORY_VERIFY_FLAGS{STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS};
+static constexpr script_verify_flags STANDARD_NOT_MANDATORY_VERIFY_FLAGS{STANDARD_SCRIPT_VERIFY_FLAGS & ~MANDATORY_SCRIPT_VERIFY_FLAGS};
 
 /** Used as the flags parameter to sequence and nLocktime checks in non-consensus code. */
 static constexpr unsigned int STANDARD_LOCKTIME_VERIFY_FLAGS{LOCKTIME_VERIFY_SEQUENCE};
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index 85cb76873f5..f6aeb5e6024 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -198,7 +198,7 @@ bool static IsDefinedHashtypeSignature(const valtype &vchSig) {
     return true;
 }
 
-bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror) {
+bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, script_verify_flags flags, ScriptError* serror) {
     // Empty signature. Not strictly DER encoded, but allowed to provide a
     // compact way to provide an invalid signature for use with CHECK(MULTI)SIG
     if (vchSig.size() == 0) {
@@ -215,7 +215,7 @@ bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned i
     return true;
 }
 
-bool static CheckPubKeyEncoding(const valtype &vchPubKey, unsigned int flags, const SigVersion &sigversion, ScriptError* serror) {
+bool static CheckPubKeyEncoding(const valtype &vchPubKey, script_verify_flags flags, const SigVersion &sigversion, ScriptError* serror) {
     if ((flags & SCRIPT_VERIFY_STRICTENC) != 0 && !IsCompressedOrUncompressedPubKey(vchPubKey)) {
         return set_error(serror, SCRIPT_ERR_PUBKEYTYPE);
     }
@@ -318,7 +318,7 @@ public:
 };
 }
 
-static bool EvalChecksigPreTapscript(const valtype& vchSig, const valtype& vchPubKey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& fSuccess)
+static bool EvalChecksigPreTapscript(const valtype& vchSig, const valtype& vchPubKey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& fSuccess)
 {
     assert(sigversion == SigVersion::BASE || sigversion == SigVersion::WITNESS_V0);
 
@@ -344,7 +344,7 @@ static bool EvalChecksigPreTapscript(const valtype& vchSig, const valtype& vchPu
     return true;
 }
 
-static bool EvalChecksigTapscript(const valtype& sig, const valtype& pubkey, ScriptExecutionData& execdata, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& success)
+static bool EvalChecksigTapscript(const valtype& sig, const valtype& pubkey, ScriptExecutionData& execdata, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& success)
 {
     assert(sigversion == SigVersion::TAPSCRIPT);
 
@@ -389,7 +389,7 @@ static bool EvalChecksigTapscript(const valtype& sig, const valtype& pubkey, Scr
  * A return value of false means the script fails entirely. When true is returned, the
  * success variable indicates whether the signature check itself succeeded.
  */
-static bool EvalChecksig(const valtype& sig, const valtype& pubkey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, ScriptExecutionData& execdata, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& success)
+static bool EvalChecksig(const valtype& sig, const valtype& pubkey, CScript::const_iterator pbegincodehash, CScript::const_iterator pend, ScriptExecutionData& execdata, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror, bool& success)
 {
     switch (sigversion) {
     case SigVersion::BASE:
@@ -404,7 +404,7 @@ static bool EvalChecksig(const valtype& sig, const valtype& pubkey, CScript::con
     assert(false);
 }
 
-bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* serror)
+bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* serror)
 {
     static const CScriptNum bnZero(0);
     static const CScriptNum bnOne(1);
@@ -1234,7 +1234,7 @@ bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript&
     return set_success(serror);
 }
 
-bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror)
+bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* serror)
 {
     ScriptExecutionData execdata;
     return EvalScript(stack, script, flags, checker, sigversion, execdata, serror);
@@ -1825,7 +1825,7 @@ bool GenericTransactionSignatureChecker<T>::CheckSequence(const CScriptNum& nSeq
 template class GenericTransactionSignatureChecker<CTransaction>;
 template class GenericTransactionSignatureChecker<CMutableTransaction>;
 
-static bool ExecuteWitnessScript(const std::span<const valtype>& stack_span, const CScript& exec_script, unsigned int flags, SigVersion sigversion, const BaseSignatureChecker& checker, ScriptExecutionData& execdata, ScriptError* serror)
+static bool ExecuteWitnessScript(const std::span<const valtype>& stack_span, const CScript& exec_script, script_verify_flags flags, SigVersion sigversion, const BaseSignatureChecker& checker, ScriptExecutionData& execdata, ScriptError* serror)
 {
     std::vector<valtype> stack{stack_span.begin(), stack_span.end()};
 
@@ -1910,7 +1910,7 @@ static bool VerifyTaprootCommitment(const std::vector<unsigned char>& control, c
     return q.CheckTapTweak(p, merkle_root, control[0] & 1);
 }
 
-static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion, const std::vector<unsigned char>& program, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror, bool is_p2sh)
+static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion, const std::vector<unsigned char>& program, script_verify_flags flags, const BaseSignatureChecker& checker, ScriptError* serror, bool is_p2sh)
 {
     CScript exec_script; //!< Actually executed script (last stack item in P2WSH; implied P2PKH script in P2WPKH; leaf script in P2TR)
     std::span stack{witness.stack};
@@ -1995,7 +1995,7 @@ static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion,
     // There is intentionally no return statement here, to be able to use "control reaches end of non-void function" warnings to detect gaps in the logic above.
 }
 
-bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror)
+bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, script_verify_flags flags, const BaseSignatureChecker& checker, ScriptError* serror)
 {
     static const CScriptWitness emptyWitness;
     if (witness == nullptr) {
@@ -2132,7 +2132,7 @@ size_t static WitnessSigOps(int witversion, const std::vector<unsigned char>& wi
     return 0;
 }
 
-size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags)
+size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, script_verify_flags flags)
 {
     static const CScriptWitness witnessEmpty;
 
@@ -2189,13 +2189,13 @@ const std::map<std::string, uint32_t> g_verify_flag_names{
 };
 #undef FLAG_NAME
 
-std::vector<std::string> GetScriptFlagNames(uint32_t flags)
+std::vector<std::string> GetScriptFlagNames(script_verify_flags flags)
 {
     std::vector<std::string> res;
     if (flags == SCRIPT_VERIFY_NONE) {
         return res;
     }
-    uint32_t leftover = flags;
+    script_verify_flags leftover = flags;
     for (const auto& [name, flag] : g_verify_flag_names) {
         if ((flags & flag) != 0) {
             res.push_back(name);
diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index 1ce528ac480..0d1a44b1f9e 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -10,6 +10,7 @@
 #include <hash.h>
 #include <primitives/transaction.h>
 #include <script/script_error.h> // IWYU pragma: export
+#include <script/verify_flags.h> // IWYU pragma: export
 #include <span.h>
 #include <uint256.h>
 
@@ -148,7 +149,7 @@ enum : uint32_t {
     SCRIPT_VERIFY_END_MARKER
 };
 
-bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, unsigned int flags, ScriptError* serror);
+bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, script_verify_flags flags, ScriptError* serror);
 
 struct PrecomputedTransactionData
 {
@@ -363,16 +364,16 @@ uint256 ComputeTapbranchHash(std::span<const unsigned char> a, std::span<const u
  *  Requires control block to have valid length (33 + k*32, with k in {0,1,..,128}). */
 uint256 ComputeTaprootMerkleRoot(std::span<const unsigned char> control, const uint256& tapleaf_hash);
 
-bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* error = nullptr);
-bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, unsigned int flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* error = nullptr);
-bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags, const BaseSignatureChecker& checker, ScriptError* serror = nullptr);
+bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptExecutionData& execdata, ScriptError* error = nullptr);
+bool EvalScript(std::vector<std::vector<unsigned char> >& stack, const CScript& script, script_verify_flags flags, const BaseSignatureChecker& checker, SigVersion sigversion, ScriptError* error = nullptr);
+bool VerifyScript(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, script_verify_flags flags, const BaseSignatureChecker& checker, ScriptError* serror = nullptr);
 
-size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, unsigned int flags);
+size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey, const CScriptWitness* witness, script_verify_flags flags);
 
 int FindAndDelete(CScript& script, const CScript& b);
 
 extern const std::map<std::string, uint32_t> g_verify_flag_names;
 
-std::vector<std::string> GetScriptFlagNames(uint32_t flags);
+std::vector<std::string> GetScriptFlagNames(script_verify_flags flags);
 
 #endif // BITCOIN_SCRIPT_INTERPRETER_H
diff --git a/src/script/verify_flags.h b/src/script/verify_flags.h
new file mode 100644
index 00000000000..360ce2b8f27
--- /dev/null
+++ b/src/script/verify_flags.h
@@ -0,0 +1,13 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-present The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_SCRIPT_VERIFY_FLAGS_H
+#define BITCOIN_SCRIPT_VERIFY_FLAGS_H
+
+#include <cstdint>
+
+using script_verify_flags = uint32_t;
+
+#endif // BITCOIN_SCRIPT_VERIFY_FLAGS_H
diff --git a/src/signet.cpp b/src/signet.cpp
index 742d03d9178..6524ebff45e 100644
--- a/src/signet.cpp
+++ b/src/signet.cpp
@@ -26,7 +26,7 @@
 
 static constexpr uint8_t SIGNET_HEADER[4] = {0xec, 0xc7, 0xda, 0xa2};
 
-static constexpr unsigned int BLOCK_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_NULLDUMMY;
+static constexpr script_verify_flags BLOCK_SCRIPT_VERIFY_FLAGS = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_DERSIG | SCRIPT_VERIFY_NULLDUMMY;
 
 static bool FetchAndClearCommitmentSection(const std::span<const uint8_t> header, CScript& witness_commitment, std::vector<uint8_t>& result)
 {
diff --git a/src/test/fuzz/eval_script.cpp b/src/test/fuzz/eval_script.cpp
index d762676c3c4..205e4f526d3 100644
--- a/src/test/fuzz/eval_script.cpp
+++ b/src/test/fuzz/eval_script.cpp
@@ -12,7 +12,7 @@
 FUZZ_TARGET(eval_script)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
-    const unsigned int flags = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
+    const script_verify_flags flags = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
     const std::vector<uint8_t> script_bytes = [&] {
         if (fuzzed_data_provider.remaining_bytes() != 0) {
             return fuzzed_data_provider.ConsumeRemainingBytes<uint8_t>();
diff --git a/src/test/fuzz/script.cpp b/src/test/fuzz/script.cpp
index 9aa50559cbd..811f0141fd3 100644
--- a/src/test/fuzz/script.cpp
+++ b/src/test/fuzz/script.cpp
@@ -119,7 +119,7 @@ FUZZ_TARGET(script, .init = initialize_script)
         }
         const std::vector<std::string> random_string_vector = ConsumeRandomLengthStringVector(fuzzed_data_provider);
         const uint32_t u32{fuzzed_data_provider.ConsumeIntegral<uint32_t>()};
-        const uint32_t flags{u32 | SCRIPT_VERIFY_P2SH};
+        const script_verify_flags flags{u32 | SCRIPT_VERIFY_P2SH};
         {
             CScriptWitness wit;
             for (const auto& s : random_string_vector) {
diff --git a/src/test/fuzz/script_assets_test_minimizer.cpp b/src/test/fuzz/script_assets_test_minimizer.cpp
index 5c5517343c5..ba6d8239245 100644
--- a/src/test/fuzz/script_assets_test_minimizer.cpp
+++ b/src/test/fuzz/script_assets_test_minimizer.cpp
@@ -90,22 +90,22 @@ CScriptWitness ScriptWitnessFromJSON(const UniValue& univalue)
     return scriptwitness;
 }
 
-const std::map<std::string, unsigned int> FLAG_NAMES = {
-    {std::string("P2SH"), (unsigned int)SCRIPT_VERIFY_P2SH},
-    {std::string("DERSIG"), (unsigned int)SCRIPT_VERIFY_DERSIG},
-    {std::string("NULLDUMMY"), (unsigned int)SCRIPT_VERIFY_NULLDUMMY},
-    {std::string("CHECKLOCKTIMEVERIFY"), (unsigned int)SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY},
-    {std::string("CHECKSEQUENCEVERIFY"), (unsigned int)SCRIPT_VERIFY_CHECKSEQUENCEVERIFY},
-    {std::string("WITNESS"), (unsigned int)SCRIPT_VERIFY_WITNESS},
-    {std::string("TAPROOT"), (unsigned int)SCRIPT_VERIFY_TAPROOT},
+const std::map<std::string, uint32_t> FLAG_NAMES = {
+    {std::string("P2SH"), SCRIPT_VERIFY_P2SH},
+    {std::string("DERSIG"), SCRIPT_VERIFY_DERSIG},
+    {std::string("NULLDUMMY"), SCRIPT_VERIFY_NULLDUMMY},
+    {std::string("CHECKLOCKTIMEVERIFY"), SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY},
+    {std::string("CHECKSEQUENCEVERIFY"), SCRIPT_VERIFY_CHECKSEQUENCEVERIFY},
+    {std::string("WITNESS"), SCRIPT_VERIFY_WITNESS},
+    {std::string("TAPROOT"), SCRIPT_VERIFY_TAPROOT},
 };
 
-std::vector<unsigned int> AllFlags()
+std::vector<script_verify_flags> AllFlags()
 {
-    std::vector<unsigned int> ret;
+    std::vector<script_verify_flags> ret;
 
     for (unsigned int i = 0; i < 128; ++i) {
-        unsigned int flag = 0;
+        script_verify_flags flag = 0;
         if (i & 1) flag |= SCRIPT_VERIFY_P2SH;
         if (i & 2) flag |= SCRIPT_VERIFY_DERSIG;
         if (i & 4) flag |= SCRIPT_VERIFY_NULLDUMMY;
@@ -125,13 +125,13 @@ std::vector<unsigned int> AllFlags()
     return ret;
 }
 
-const std::vector<unsigned int> ALL_FLAGS = AllFlags();
+const std::vector<script_verify_flags> ALL_FLAGS = AllFlags();
 
-unsigned int ParseScriptFlags(const std::string& str)
+script_verify_flags ParseScriptFlags(const std::string& str)
 {
     if (str.empty()) return 0;
 
-    unsigned int flags = 0;
+    script_verify_flags flags = 0;
     std::vector<std::string> words = SplitString(str, ',');
 
     for (const std::string& word : words) {
@@ -153,7 +153,7 @@ void Test(const std::string& str)
     if (prevouts.size() != tx.vin.size()) throw std::runtime_error("Incorrect number of prevouts");
     size_t idx = test["index"].getInt<int64_t>();
     if (idx >= tx.vin.size()) throw std::runtime_error("Invalid index");
-    unsigned int test_flags = ParseScriptFlags(test["flags"].get_str());
+    script_verify_flags test_flags = ParseScriptFlags(test["flags"].get_str());
     bool final = test.exists("final") && test["final"].get_bool();
 
     if (test.exists("success")) {
diff --git a/src/test/fuzz/script_flags.cpp b/src/test/fuzz/script_flags.cpp
index accb32f1cc4..7e28b52fdc8 100644
--- a/src/test/fuzz/script_flags.cpp
+++ b/src/test/fuzz/script_flags.cpp
@@ -22,12 +22,12 @@ FUZZ_TARGET(script_flags)
     try {
         const CTransaction tx(deserialize, TX_WITH_WITNESS, ds);
 
-        unsigned int verify_flags;
+        script_verify_flags verify_flags;
         ds >> verify_flags;
 
         if (!IsValidFlagCombination(verify_flags)) return;
 
-        unsigned int fuzzed_flags;
+        script_verify_flags fuzzed_flags;
         ds >> fuzzed_flags;
 
         std::vector<CTxOut> spent_outputs;
diff --git a/src/test/fuzz/signature_checker.cpp b/src/test/fuzz/signature_checker.cpp
index 9c32b7a822b..d1591464f2a 100644
--- a/src/test/fuzz/signature_checker.cpp
+++ b/src/test/fuzz/signature_checker.cpp
@@ -51,7 +51,7 @@ public:
 FUZZ_TARGET(signature_checker)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
-    const unsigned int flags = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
+    const script_verify_flags flags = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
     const SigVersion sig_version = fuzzed_data_provider.PickValueInArray({SigVersion::BASE, SigVersion::WITNESS_V0});
     const auto script_1{ConsumeScript(fuzzed_data_provider)};
     const auto script_2{ConsumeScript(fuzzed_data_provider)};
diff --git a/src/test/multisig_tests.cpp b/src/test/multisig_tests.cpp
index b996f3cc061..7134cef61c6 100644
--- a/src/test/multisig_tests.cpp
+++ b/src/test/multisig_tests.cpp
@@ -38,7 +38,7 @@ sign_multisig(const CScript& scriptPubKey, const std::vector<CKey>& keys, const
 
 BOOST_AUTO_TEST_CASE(multisig_verify)
 {
-    unsigned int flags = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC;
+    script_verify_flags flags = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC;
 
     ScriptError err;
     CKey key[4];
diff --git a/src/test/script_assets_tests.cpp b/src/test/script_assets_tests.cpp
index 0e2fec87c03..e25cd4fbe6c 100644
--- a/src/test/script_assets_tests.cpp
+++ b/src/test/script_assets_tests.cpp
@@ -25,7 +25,7 @@
 
 #include <univalue.h>
 
-unsigned int ParseScriptFlags(std::string strFlags);
+script_verify_flags ParseScriptFlags(std::string strFlags);
 
 BOOST_AUTO_TEST_SUITE(script_assets_tests)
 
@@ -71,12 +71,12 @@ static CScriptWitness ScriptWitnessFromJSON(const UniValue& univalue)
     return scriptwitness;
 }
 
-static std::vector<unsigned int> AllConsensusFlags()
+static std::vector<script_verify_flags> AllConsensusFlags()
 {
-    std::vector<unsigned int> ret;
+    std::vector<script_verify_flags> ret;
 
     for (unsigned int i = 0; i < 128; ++i) {
-        unsigned int flag = 0;
+        script_verify_flags flag = 0;
         if (i & 1) flag |= SCRIPT_VERIFY_P2SH;
         if (i & 2) flag |= SCRIPT_VERIFY_DERSIG;
         if (i & 4) flag |= SCRIPT_VERIFY_NULLDUMMY;
@@ -97,7 +97,7 @@ static std::vector<unsigned int> AllConsensusFlags()
 }
 
 /** Precomputed list of all valid combinations of consensus-relevant script validation flags. */
-static const std::vector<unsigned int> ALL_CONSENSUS_FLAGS = AllConsensusFlags();
+static const std::vector<script_verify_flags> ALL_CONSENSUS_FLAGS = AllConsensusFlags();
 
 static void AssetTest(const UniValue& test, SignatureCache& signature_cache)
 {
@@ -107,7 +107,7 @@ static void AssetTest(const UniValue& test, SignatureCache& signature_cache)
     const std::vector<CTxOut> prevouts = TxOutsFromJSON(test["prevouts"]);
     BOOST_CHECK(prevouts.size() == mtx.vin.size());
     size_t idx = test["index"].getInt<int64_t>();
-    uint32_t test_flags{ParseScriptFlags(test["flags"].get_str())};
+    script_verify_flags test_flags{ParseScriptFlags(test["flags"].get_str())};
     bool fin = test.exists("final") && test["final"].get_bool();
 
     if (test.exists("success")) {
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index ed68dc4953b..561660464a9 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -40,9 +40,9 @@
 
 using namespace util::hex_literals;
 
-static const unsigned int gFlags = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC;
+static const script_verify_flags gFlags = SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_STRICTENC;
 
-unsigned int ParseScriptFlags(std::string strFlags);
+script_verify_flags ParseScriptFlags(std::string strFlags);
 
 struct ScriptErrorDesc
 {
@@ -120,7 +120,7 @@ static ScriptError_t ParseScriptError(const std::string& name)
 }
 
 struct ScriptTest : BasicTestingSetup {
-void DoTest(const CScript& scriptPubKey, const CScript& scriptSig, const CScriptWitness& scriptWitness, uint32_t flags, const std::string& message, int scriptError, CAmount nValue = 0)
+void DoTest(const CScript& scriptPubKey, const CScript& scriptSig, const CScriptWitness& scriptWitness, script_verify_flags flags, const std::string& message, int scriptError, CAmount nValue = 0)
 {
     bool expect = (scriptError == SCRIPT_ERR_OK);
     if (flags & SCRIPT_VERIFY_CLEANSTACK) {
@@ -232,7 +232,7 @@ private:
     bool havePush{false};
     std::vector<unsigned char> push;
     std::string comment;
-    uint32_t flags;
+    script_verify_flags flags;
     int scriptError{SCRIPT_ERR_OK};
     CAmount nValue;
 
@@ -252,7 +252,7 @@ private:
     }
 
 public:
-    TestBuilder(const CScript& script_, const std::string& comment_, uint32_t flags_, bool P2SH = false, WitnessMode wm = WitnessMode::NONE, int witnessversion = 0, CAmount nValue_ = 0) : script(script_), comment(comment_), flags(flags_), nValue(nValue_)
+    TestBuilder(const CScript& script_, const std::string& comment_, script_verify_flags flags_, bool P2SH = false, WitnessMode wm = WitnessMode::NONE, int witnessversion = 0, CAmount nValue_ = 0) : script(script_), comment(comment_), flags(flags_), nValue(nValue_)
     {
         CScript scriptPubKey = script;
         if (wm == WitnessMode::PKH) {
@@ -969,7 +969,7 @@ BOOST_AUTO_TEST_CASE(script_json_test)
         } else {
             scriptPubKey = ParseScript(scriptPubKeyString);
         }
-        unsigned int scriptflags = ParseScriptFlags(test[pos++].get_str());
+        script_verify_flags scriptflags = ParseScriptFlags(test[pos++].get_str());
         int scriptError = ParseScriptError(test[pos++].get_str());
 
         DoTest(scriptPubKey, scriptSig, witness, scriptflags, strTest, scriptError, nValue);
diff --git a/src/test/sigopcount_tests.cpp b/src/test/sigopcount_tests.cpp
index aed67d5f3cf..e33603129c2 100644
--- a/src/test/sigopcount_tests.cpp
+++ b/src/test/sigopcount_tests.cpp
@@ -69,7 +69,7 @@ BOOST_AUTO_TEST_CASE(GetSigOpCount)
  * Verifies script execution of the zeroth scriptPubKey of tx output and
  * zeroth scriptSig and witness of tx input.
  */
-static ScriptError VerifyWithFlag(const CTransaction& output, const CMutableTransaction& input, uint32_t flags)
+static ScriptError VerifyWithFlag(const CTransaction& output, const CMutableTransaction& input, script_verify_flags flags)
 {
     ScriptError error;
     CTransaction inputi(input);
@@ -122,7 +122,7 @@ BOOST_AUTO_TEST_CASE(GetTxSigOpCost)
     CKey key = GenerateRandomKey();
     CPubKey pubkey = key.GetPubKey();
     // Default flags
-    const uint32_t flags{SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH};
+    const script_verify_flags flags{SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_P2SH};
 
     // Multisig script (legacy counting)
     {
diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
index e7b3ee7f3ff..c2f64cc8217 100644
--- a/src/test/transaction_tests.cpp
+++ b/src/test/transaction_tests.cpp
@@ -52,9 +52,9 @@ static bool g_bare_multi{DEFAULT_PERMIT_BAREMULTISIG};
 
 static const std::map<std::string, unsigned int>& mapFlagNames = g_verify_flag_names;
 
-unsigned int ParseScriptFlags(std::string strFlags)
+script_verify_flags ParseScriptFlags(std::string strFlags)
 {
-    unsigned int flags = SCRIPT_VERIFY_NONE;
+    script_verify_flags flags = SCRIPT_VERIFY_NONE;
     if (strFlags.empty() || strFlags == "NONE") return flags;
 
     std::vector<std::string> words = SplitString(strFlags, ',');
@@ -72,7 +72,7 @@ unsigned int ParseScriptFlags(std::string strFlags)
 // Check that all flags in STANDARD_SCRIPT_VERIFY_FLAGS are present in mapFlagNames.
 bool CheckMapFlagNames()
 {
-    unsigned int standard_flags_missing{STANDARD_SCRIPT_VERIFY_FLAGS};
+    script_verify_flags standard_flags_missing{STANDARD_SCRIPT_VERIFY_FLAGS};
     for (const auto& pair : mapFlagNames) {
         standard_flags_missing &= ~(pair.second);
     }
@@ -83,7 +83,7 @@ bool CheckMapFlagNames()
 * Check that the input scripts of a transaction are valid/invalid as expected.
 */
 bool CheckTxScripts(const CTransaction& tx, const std::map<COutPoint, CScript>& map_prevout_scriptPubKeys,
-    const std::map<COutPoint, int64_t>& map_prevout_values, unsigned int flags,
+    const std::map<COutPoint, int64_t>& map_prevout_values, script_verify_flags flags,
     const PrecomputedTransactionData& txdata, const std::string& strTest, bool expect_valid)
 {
     bool tx_valid = true;
@@ -117,18 +117,18 @@ bool CheckTxScripts(const CTransaction& tx, const std::map<COutPoint, CScript>&
  * CLEANSTACK must be used WITNESS and P2SH
  */
 
-unsigned int TrimFlags(unsigned int flags)
+script_verify_flags TrimFlags(script_verify_flags flags)
 {
     // WITNESS requires P2SH
-    if (!(flags & SCRIPT_VERIFY_P2SH)) flags &= ~(unsigned int)SCRIPT_VERIFY_WITNESS;
+    if (!(flags & SCRIPT_VERIFY_P2SH)) flags &= ~SCRIPT_VERIFY_WITNESS;
 
     // CLEANSTACK requires WITNESS (and transitively CLEANSTACK requires P2SH)
-    if (!(flags & SCRIPT_VERIFY_WITNESS)) flags &= ~(unsigned int)SCRIPT_VERIFY_CLEANSTACK;
+    if (!(flags & SCRIPT_VERIFY_WITNESS)) flags &= ~SCRIPT_VERIFY_CLEANSTACK;
     Assert(IsValidFlagCombination(flags));
     return flags;
 }
 
-unsigned int FillFlags(unsigned int flags)
+script_verify_flags FillFlags(script_verify_flags flags)
 {
     // CLEANSTACK implies WITNESS
     if (flags & SCRIPT_VERIFY_CLEANSTACK) flags |= SCRIPT_VERIFY_WITNESS;
@@ -143,11 +143,11 @@ unsigned int FillFlags(unsigned int flags)
 // that are valid and without duplicates. For example: if flags=1111 and the 4 possible flags are
 // 0001, 0010, 0100, and 1000, this should return the set {0111, 1011, 1101, 1110}.
 // Assumes that mapFlagNames contains all script verify flags.
-std::set<unsigned int> ExcludeIndividualFlags(unsigned int flags)
+std::set<script_verify_flags> ExcludeIndividualFlags(script_verify_flags flags)
 {
-    std::set<unsigned int> flags_combos;
+    std::set<script_verify_flags> flags_combos;
     for (const auto& pair : mapFlagNames) {
-        const unsigned int flags_excluding_one = TrimFlags(flags & ~(pair.second));
+        script_verify_flags flags_excluding_one = TrimFlags(flags & ~(pair.second));
         if (flags != flags_excluding_one) {
             flags_combos.insert(flags_excluding_one);
         }
@@ -212,7 +212,7 @@ BOOST_AUTO_TEST_CASE(tx_valid)
             BOOST_CHECK(state.IsValid());
 
             PrecomputedTransactionData txdata(tx);
-            unsigned int verify_flags = ParseScriptFlags(test[2].get_str());
+            script_verify_flags verify_flags = ParseScriptFlags(test[2].get_str());
 
             // Check that the test gives a valid combination of flags (otherwise VerifyScript will throw). Don't edit the flags.
             if (~verify_flags != FillFlags(~verify_flags)) {
@@ -225,7 +225,7 @@ BOOST_AUTO_TEST_CASE(tx_valid)
             // Backwards compatibility of script verification flags: Removing any flag(s) should not invalidate a valid transaction
             for (const auto& [name, flag] : mapFlagNames) {
                 // Removing individual flags
-                unsigned int flags = TrimFlags(~(verify_flags | flag));
+                script_verify_flags flags = TrimFlags(~(verify_flags | flag));
                 if (!CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, flags, txdata, strTest, /*expect_valid=*/true)) {
                     BOOST_ERROR("Tx unexpectedly failed with flag " << name << " unset: " << strTest);
                 }
@@ -302,7 +302,7 @@ BOOST_AUTO_TEST_CASE(tx_invalid)
             }
 
             PrecomputedTransactionData txdata(tx);
-            unsigned int verify_flags = ParseScriptFlags(test[2].get_str());
+            script_verify_flags verify_flags = ParseScriptFlags(test[2].get_str());
 
             // Check that the test gives a valid combination of flags (otherwise VerifyScript will throw). Don't edit the flags.
             if (verify_flags != FillFlags(verify_flags)) {
@@ -315,7 +315,7 @@ BOOST_AUTO_TEST_CASE(tx_invalid)
 
             // Backwards compatibility of script verification flags: Adding any flag(s) should not validate an invalid transaction
             for (const auto& [name, flag] : mapFlagNames) {
-                unsigned int flags = FillFlags(verify_flags | flag);
+                script_verify_flags flags = FillFlags(verify_flags | flag);
                 // Adding individual flags
                 if (!CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, flags, txdata, strTest, /*expect_valid=*/false)) {
                     BOOST_ERROR("Tx unexpectedly passed with flag " << name << " set: " << strTest);
@@ -453,7 +453,7 @@ static void CreateCreditAndSpend(const FillableSigningProvider& keystore, const
     assert(input.vin[0].scriptWitness.stack == inputm.vin[0].scriptWitness.stack);
 }
 
-static void CheckWithFlag(const CTransactionRef& output, const CMutableTransaction& input, uint32_t flags, bool success)
+static void CheckWithFlag(const CTransactionRef& output, const CMutableTransaction& input, script_verify_flags flags, bool success)
 {
     ScriptError error;
     CTransaction inputi(input);
diff --git a/src/test/txvalidationcache_tests.cpp b/src/test/txvalidationcache_tests.cpp
index af36a956931..8c14dd65a14 100644
--- a/src/test/txvalidationcache_tests.cpp
+++ b/src/test/txvalidationcache_tests.cpp
@@ -21,7 +21,7 @@ struct Dersig100Setup : public TestChain100Setup {
 };
 
 bool CheckInputScripts(const CTransaction& tx, TxValidationState& state,
-                       const CCoinsViewCache& inputs, unsigned int flags, bool cacheSigStore,
+                       const CCoinsViewCache& inputs, script_verify_flags flags, bool cacheSigStore,
                        bool cacheFullScriptStore, PrecomputedTransactionData& txdata,
                        ValidationCache& validation_cache,
                        std::vector<CScriptCheck>* pvChecks) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
@@ -120,7 +120,7 @@ BOOST_FIXTURE_TEST_CASE(tx_mempool_block_doublespend, Dersig100Setup)
 // should fail.
 // Capture this interaction with the upgraded_nop argument: set it when evaluating
 // any script flag that is implemented as an upgraded NOP code.
-static void ValidateCheckInputsForAllFlags(const CTransaction &tx, uint32_t failing_flags, bool add_to_cache, CCoinsViewCache& active_coins_tip, ValidationCache& validation_cache) EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
+static void ValidateCheckInputsForAllFlags(const CTransaction &tx, script_verify_flags failing_flags, bool add_to_cache, CCoinsViewCache& active_coins_tip, ValidationCache& validation_cache) EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
 {
     PrecomputedTransactionData txdata;
 
@@ -130,7 +130,7 @@ static void ValidateCheckInputsForAllFlags(const CTransaction &tx, uint32_t fail
         TxValidationState state;
 
         // Randomly selects flag combinations
-        uint32_t test_flags = (uint32_t) insecure_rand.randrange((SCRIPT_VERIFY_END_MARKER - 1) << 1);
+        script_verify_flags test_flags = (uint32_t) insecure_rand.randrange((SCRIPT_VERIFY_END_MARKER - 1) << 1);
 
         // Filter out incompatible flag choices
         if ((test_flags & SCRIPT_VERIFY_CLEANSTACK)) {
diff --git a/src/test/util/script.cpp b/src/test/util/script.cpp
index a5852daa602..34c30233d71 100644
--- a/src/test/util/script.cpp
+++ b/src/test/util/script.cpp
@@ -5,7 +5,7 @@
 #include <script/interpreter.h>
 #include <test/util/script.h>
 
-bool IsValidFlagCombination(unsigned flags)
+bool IsValidFlagCombination(script_verify_flags flags)
 {
     if (flags & SCRIPT_VERIFY_CLEANSTACK && ~flags & (SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS)) return false;
     if (flags & SCRIPT_VERIFY_WITNESS && ~flags & SCRIPT_VERIFY_P2SH) return false;
diff --git a/src/test/util/script.h b/src/test/util/script.h
index 96c4d55e5a5..2f11fa797f2 100644
--- a/src/test/util/script.h
+++ b/src/test/util/script.h
@@ -7,6 +7,7 @@
 
 #include <crypto/sha256.h>
 #include <script/script.h>
+#include <script/verify_flags.h>
 
 static const std::vector<uint8_t> WITNESS_STACK_ELEM_OP_TRUE{uint8_t{OP_TRUE}};
 static const CScript P2WSH_OP_TRUE{
@@ -31,6 +32,6 @@ static const std::vector<std::vector<uint8_t>> P2WSH_EMPTY_TRUE_STACK{{static_ca
 static const std::vector<std::vector<uint8_t>> P2WSH_EMPTY_TWO_STACK{{static_cast<uint8_t>(OP_2)}, {}};
 
 /** Flags that are not forbidden by an assert in script validation */
-bool IsValidFlagCombination(unsigned flags);
+bool IsValidFlagCombination(script_verify_flags flags);
 
 #endif // BITCOIN_TEST_UTIL_SCRIPT_H
diff --git a/src/validation.cpp b/src/validation.cpp
index ae8e80aa6ab..429454678c9 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -139,7 +139,7 @@ const CBlockIndex* Chainstate::FindForkInGlobalIndex(const CBlockLocator& locato
 }
 
 bool CheckInputScripts(const CTransaction& tx, TxValidationState& state,
-                       const CCoinsViewCache& inputs, unsigned int flags, bool cacheSigStore,
+                       const CCoinsViewCache& inputs, script_verify_flags flags, bool cacheSigStore,
                        bool cacheFullScriptStore, PrecomputedTransactionData& txdata,
                        ValidationCache& validation_cache,
                        std::vector<CScriptCheck>* pvChecks = nullptr)
@@ -395,7 +395,7 @@ void Chainstate::MaybeUpdateMempoolForReorg(
 * */
 static bool CheckInputsFromMempoolAndCache(const CTransaction& tx, TxValidationState& state,
                 const CCoinsViewCache& view, const CTxMemPool& pool,
-                unsigned int flags, PrecomputedTransactionData& txdata, CCoinsViewCache& coins_tip,
+                script_verify_flags flags, PrecomputedTransactionData& txdata, CCoinsViewCache& coins_tip,
                 ValidationCache& validation_cache)
                 EXCLUSIVE_LOCKS_REQUIRED(cs_main, pool.cs)
 {
@@ -1246,7 +1246,7 @@ bool MemPoolAccept::PolicyScriptChecks(const ATMPArgs& args, Workspace& ws)
     const CTransaction& tx = *ws.m_ptx;
     TxValidationState& state = ws.m_state;
 
-    constexpr unsigned int scriptVerifyFlags = STANDARD_SCRIPT_VERIFY_FLAGS;
+    constexpr script_verify_flags scriptVerifyFlags = STANDARD_SCRIPT_VERIFY_FLAGS;
 
     // Check input scripts and signatures.
     // This is done last to help prevent CPU exhaustion denial-of-service attacks.
@@ -1285,7 +1285,7 @@ bool MemPoolAccept::ConsensusScriptChecks(const ATMPArgs& args, Workspace& ws)
     // There is a similar check in CreateNewBlock() to prevent creating
     // invalid blocks (using TestBlockValidity), however allowing such
     // transactions into the mempool can be exploited as a DoS attack.
-    unsigned int currentBlockScriptVerifyFlags{GetBlockScriptFlags(*m_active_chainstate.m_chain.Tip(), m_active_chainstate.m_chainman)};
+    script_verify_flags currentBlockScriptVerifyFlags{GetBlockScriptFlags(*m_active_chainstate.m_chain.Tip(), m_active_chainstate.m_chainman)};
     if (!CheckInputsFromMempoolAndCache(tx, state, m_view, m_pool, currentBlockScriptVerifyFlags,
                                         ws.m_precomputed_txdata, m_active_chainstate.CoinsTip(), GetValidationCache())) {
         LogPrintf("BUG! PLEASE REPORT THIS! CheckInputScripts failed against latest-block but not STANDARD flags %s, %s\n", hash.ToString(), state.ToString());
@@ -2093,7 +2093,7 @@ std::optional<std::pair<ScriptError, std::string>> CScriptCheck::operator()() {
     const CScript &scriptSig = ptxTo->vin[nIn].scriptSig;
     const CScriptWitness *witness = &ptxTo->vin[nIn].scriptWitness;
     ScriptError error{SCRIPT_ERR_UNKNOWN_ERROR};
-    if (VerifyScript(scriptSig, m_tx_out.scriptPubKey, witness, nFlags, CachingTransactionSignatureChecker(ptxTo, nIn, m_tx_out.nValue, cacheStore, *m_signature_cache, *txdata), &error)) {
+    if (VerifyScript(scriptSig, m_tx_out.scriptPubKey, witness, m_flags, CachingTransactionSignatureChecker(ptxTo, nIn, m_tx_out.nValue, cacheStore, *m_signature_cache, *txdata), &error)) {
         return std::nullopt;
     } else {
         auto debug_str = strprintf("input %i of %s (wtxid %s), spending %s:%i", nIn, ptxTo->GetHash().ToString(), ptxTo->GetWitnessHash().ToString(), ptxTo->vin[nIn].prevout.hash.ToString(), ptxTo->vin[nIn].prevout.n);
@@ -2137,7 +2137,7 @@ ValidationCache::ValidationCache(const size_t script_execution_cache_bytes, cons
  * Non-static (and redeclared) in src/test/txvalidationcache_tests.cpp
  */
 bool CheckInputScripts(const CTransaction& tx, TxValidationState& state,
-                       const CCoinsViewCache& inputs, unsigned int flags, bool cacheSigStore,
+                       const CCoinsViewCache& inputs, script_verify_flags flags, bool cacheSigStore,
                        bool cacheFullScriptStore, PrecomputedTransactionData& txdata,
                        ValidationCache& validation_cache,
                        std::vector<CScriptCheck>* pvChecks)
@@ -2325,7 +2325,7 @@ DisconnectResult Chainstate::DisconnectBlock(const CBlock& block, const CBlockIn
     return fClean ? DISCONNECT_OK : DISCONNECT_UNCLEAN;
 }
 
-unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const ChainstateManager& chainman)
+script_verify_flags GetBlockScriptFlags(const CBlockIndex& block_index, const ChainstateManager& chainman)
 {
     const Consensus::Params& consensusparams = chainman.GetConsensus();
 
@@ -2337,7 +2337,7 @@ unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const Chainstat
     // mainnet.
     // For simplicity, always leave P2SH+WITNESS+TAPROOT on except for the two
     // violating blocks.
-    uint32_t flags{SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_TAPROOT};
+    script_verify_flags flags{SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS | SCRIPT_VERIFY_TAPROOT};
     const auto it{consensusparams.script_flag_exceptions.find(*Assert(block_index.phashBlock))};
     if (it != consensusparams.script_flag_exceptions.end()) {
         flags = it->second;
@@ -2551,7 +2551,7 @@ bool Chainstate::ConnectBlock(const CBlock& block, BlockValidationState& state,
     }
 
     // Get the script flags for this block
-    unsigned int flags{GetBlockScriptFlags(*pindex, m_chainman)};
+    script_verify_flags flags{GetBlockScriptFlags(*pindex, m_chainman)};
 
     const auto time_2{SteadyClock::now()};
     m_chainman.time_forks += time_2 - time_1;
diff --git a/src/validation.h b/src/validation.h
index 86329e959cc..d8516b28a11 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -23,6 +23,7 @@
 #include <policy/policy.h>
 #include <script/script_error.h>
 #include <script/sigcache.h>
+#include <script/verify_flags.h>
 #include <sync.h>
 #include <txdb.h>
 #include <txmempool.h>
@@ -336,14 +337,14 @@ private:
     CTxOut m_tx_out;
     const CTransaction *ptxTo;
     unsigned int nIn;
-    unsigned int nFlags;
+    script_verify_flags m_flags;
     bool cacheStore;
     PrecomputedTransactionData *txdata;
     SignatureCache* m_signature_cache;
 
 public:
-    CScriptCheck(const CTxOut& outIn, const CTransaction& txToIn, SignatureCache& signature_cache, unsigned int nInIn, unsigned int nFlagsIn, bool cacheIn, PrecomputedTransactionData* txdataIn) :
-        m_tx_out(outIn), ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn), cacheStore(cacheIn), txdata(txdataIn), m_signature_cache(&signature_cache) { }
+    CScriptCheck(const CTxOut& outIn, const CTransaction& txToIn, SignatureCache& signature_cache, unsigned int nInIn, script_verify_flags flags, bool cacheIn, PrecomputedTransactionData* txdataIn) :
+        m_tx_out(outIn), ptxTo(&txToIn), nIn(nInIn), m_flags(flags), cacheStore(cacheIn), txdata(txdataIn), m_signature_cache(&signature_cache) { }
 
     CScriptCheck(const CScriptCheck&) = delete;
     CScriptCheck& operator=(const CScriptCheck&) = delete;
@@ -1359,6 +1360,6 @@ bool IsBIP30Repeat(const CBlockIndex& block_index);
 bool IsBIP30Unspendable(const uint256& block_hash, int block_height);
 
 // Returns the script flags which should be checked for a given block
-unsigned int GetBlockScriptFlags(const CBlockIndex& block_index, const ChainstateManager& chainman);
+script_verify_flags GetBlockScriptFlags(const CBlockIndex& block_index, const ChainstateManager& chainman);
 
 #endif // BITCOIN_VALIDATION_H

From bddcadee82daf3ed1441820a0ffc4c5ef78f64f1 Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Sat, 26 Jul 2025 18:51:24 +1000
Subject: [PATCH 5/8] script/verify_flags: make script_verify_flags type safe

`using script_verify_flags = uint32_t` allows implicit conversion to
and from int, so replace it with a class to have the compiler ensure we
use the correct type. Provide from_int and as_int to allow for explicit
conversions when desired.

Introduces the type `script_verify_flag_name` for the individual flag
name enumeration.
---
 src/script/interpreter.cpp                    |  4 +-
 src/script/interpreter.h                      | 15 ++++-
 src/script/verify_flags.h                     | 60 ++++++++++++++++++-
 src/test/fuzz/coins_view.cpp                  |  2 +-
 src/test/fuzz/eval_script.cpp                 |  2 +-
 src/test/fuzz/script.cpp                      |  4 +-
 .../fuzz/script_assets_test_minimizer.cpp     |  2 +-
 src/test/fuzz/script_flags.cpp                |  8 +++
 src/test/fuzz/signature_checker.cpp           |  2 +-
 src/test/script_tests.cpp                     | 16 ++---
 src/test/transaction_tests.cpp                |  8 +--
 src/test/txvalidationcache_tests.cpp          |  2 +-
 12 files changed, 100 insertions(+), 25 deletions(-)

diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index f6aeb5e6024..11d313928d9 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -2164,7 +2164,7 @@ size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey,
 }
 
 #define FLAG_NAME(flag) {std::string(#flag), SCRIPT_VERIFY_##flag}
-const std::map<std::string, uint32_t> g_verify_flag_names{
+const std::map<std::string, script_verify_flag_name> g_verify_flag_names{
     FLAG_NAME(P2SH),
     FLAG_NAME(STRICTENC),
     FLAG_NAME(DERSIG),
@@ -2203,7 +2203,7 @@ std::vector<std::string> GetScriptFlagNames(script_verify_flags flags)
         }
     }
     if (leftover != 0) {
-        res.push_back(strprintf("0x%08x", leftover));
+        res.push_back(strprintf("0x%08x", leftover.as_int()));
     }
     return res;
 }
diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index 0d1a44b1f9e..9ae29e0f1f4 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -14,6 +14,7 @@
 #include <span.h>
 #include <uint256.h>
 
+#include <bit>
 #include <cstddef>
 #include <cstdint>
 #include <optional>
@@ -43,9 +44,10 @@ enum
  *  All flags are intended to be soft forks: the set of acceptable scripts under
  *  flags (A | B) is a subset of the acceptable scripts under flag (A).
  */
-enum : uint32_t {
-    SCRIPT_VERIFY_NONE      = 0,
 
+static constexpr script_verify_flags SCRIPT_VERIFY_NONE{0};
+
+enum class script_verify_flag_name : uint32_t {
     // Evaluate P2SH subscripts (BIP16).
     SCRIPT_VERIFY_P2SH      = (1U << 0),
 
@@ -148,6 +150,13 @@ enum : uint32_t {
     //
     SCRIPT_VERIFY_END_MARKER
 };
+using enum script_verify_flag_name;
+
+// assert there is still a spare bit
+static_assert(static_cast<script_verify_flags::value_type>(SCRIPT_VERIFY_END_MARKER) < (1u << 31));
+
+static constexpr script_verify_flags::value_type MAX_SCRIPT_VERIFY_FLAGS = ((static_cast<script_verify_flags::value_type>(SCRIPT_VERIFY_END_MARKER) - 1) << 1) - 1;
+static constexpr int MAX_SCRIPT_VERIFY_FLAGS_BITS = std::bit_width(MAX_SCRIPT_VERIFY_FLAGS);
 
 bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, script_verify_flags flags, ScriptError* serror);
 
@@ -372,7 +381,7 @@ size_t CountWitnessSigOps(const CScript& scriptSig, const CScript& scriptPubKey,
 
 int FindAndDelete(CScript& script, const CScript& b);
 
-extern const std::map<std::string, uint32_t> g_verify_flag_names;
+extern const std::map<std::string, script_verify_flag_name> g_verify_flag_names;
 
 std::vector<std::string> GetScriptFlagNames(script_verify_flags flags);
 
diff --git a/src/script/verify_flags.h b/src/script/verify_flags.h
index 360ce2b8f27..ba75f0894be 100644
--- a/src/script/verify_flags.h
+++ b/src/script/verify_flags.h
@@ -6,8 +6,66 @@
 #ifndef BITCOIN_SCRIPT_VERIFY_FLAGS_H
 #define BITCOIN_SCRIPT_VERIFY_FLAGS_H
 
+#include <compare>
 #include <cstdint>
 
-using script_verify_flags = uint32_t;
+enum class script_verify_flag_name : uint32_t;
+
+class script_verify_flags
+{
+public:
+    using value_type = uint32_t;
+
+    consteval script_verify_flags() = default;
+
+    // also allow construction with hard-coded 0 (but not other integers)
+    consteval explicit(false) script_verify_flags(value_type f) : m_value{f} { if (f != 0) throw 0; }
+
+    // implicit construction from a hard-coded SCRIPT_VERIFY_* constant is also okay
+    constexpr explicit(false) script_verify_flags(script_verify_flag_name f) : m_value{static_cast<value_type>(f)} { }
+
+    // rule of 5
+    constexpr script_verify_flags(const script_verify_flags&) = default;
+    constexpr script_verify_flags(script_verify_flags&&) = default;
+    constexpr script_verify_flags& operator=(const script_verify_flags&) = default;
+    constexpr script_verify_flags& operator=(script_verify_flags&&) = default;
+    constexpr ~script_verify_flags() = default;
+
+    // integer conversion needs to be very explicit
+    static constexpr script_verify_flags from_int(value_type f) { script_verify_flags r; r.m_value = f; return r; }
+    constexpr value_type as_int() const { return m_value; }
+
+    // bitwise operations
+    constexpr script_verify_flags operator~() const { return from_int(~m_value); }
+    friend constexpr script_verify_flags operator|(script_verify_flags a, script_verify_flags b) { return from_int(a.m_value | b.m_value); }
+    friend constexpr script_verify_flags operator&(script_verify_flags a, script_verify_flags b) { return from_int(a.m_value & b.m_value); }
+
+    // in-place bitwise operations
+    constexpr script_verify_flags& operator|=(script_verify_flags vf) { m_value |= vf.m_value; return *this; }
+    constexpr script_verify_flags& operator&=(script_verify_flags vf) { m_value &= vf.m_value; return *this; }
+
+    // tests
+    constexpr explicit operator bool() const { return m_value != 0; }
+    constexpr bool operator==(script_verify_flags other) const { return m_value == other.m_value; }
+
+    /** Compare two script_verify_flags. <, >, <=, and >= are auto-generated from this. */
+    friend constexpr std::strong_ordering operator<=>(const script_verify_flags& a, const script_verify_flags& b) noexcept
+    {
+        return a.m_value <=> b.m_value;
+    }
+
+private:
+    value_type m_value{0}; // default value is SCRIPT_VERIFY_NONE
+};
+
+inline constexpr script_verify_flags operator~(script_verify_flag_name f)
+{
+    return ~script_verify_flags{f};
+}
+
+inline constexpr script_verify_flags operator|(script_verify_flag_name f1, script_verify_flag_name f2)
+{
+    return script_verify_flags{f1} | f2;
+}
 
 #endif // BITCOIN_SCRIPT_VERIFY_FLAGS_H
diff --git a/src/test/fuzz/coins_view.cpp b/src/test/fuzz/coins_view.cpp
index 2b9b81e0306..dacef9a70ad 100644
--- a/src/test/fuzz/coins_view.cpp
+++ b/src/test/fuzz/coins_view.cpp
@@ -288,7 +288,7 @@ void TestCoinsView(FuzzedDataProvider& fuzzed_data_provider, CCoinsView& backend
                     // consensus/tx_verify.cpp:130: unsigned int GetP2SHSigOpCount(const CTransaction &, const CCoinsViewCache &): Assertion `!coin.IsSpent()' failed.
                     return;
                 }
-                const auto flags{fuzzed_data_provider.ConsumeIntegral<uint32_t>()};
+                const auto flags = script_verify_flags::from_int(fuzzed_data_provider.ConsumeIntegral<script_verify_flags::value_type>());
                 if (!transaction.vin.empty() && (flags & SCRIPT_VERIFY_WITNESS) != 0 && (flags & SCRIPT_VERIFY_P2SH) == 0) {
                     // Avoid:
                     // script/interpreter.cpp:1705: size_t CountWitnessSigOps(const CScript &, const CScript &, const CScriptWitness *, unsigned int): Assertion `(flags & SCRIPT_VERIFY_P2SH) != 0' failed.
diff --git a/src/test/fuzz/eval_script.cpp b/src/test/fuzz/eval_script.cpp
index 205e4f526d3..43e3546627f 100644
--- a/src/test/fuzz/eval_script.cpp
+++ b/src/test/fuzz/eval_script.cpp
@@ -12,7 +12,7 @@
 FUZZ_TARGET(eval_script)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
-    const script_verify_flags flags = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
+    const auto flags = script_verify_flags::from_int(fuzzed_data_provider.ConsumeIntegral<script_verify_flags::value_type>());
     const std::vector<uint8_t> script_bytes = [&] {
         if (fuzzed_data_provider.remaining_bytes() != 0) {
             return fuzzed_data_provider.ConsumeRemainingBytes<uint8_t>();
diff --git a/src/test/fuzz/script.cpp b/src/test/fuzz/script.cpp
index 811f0141fd3..dfad0b71848 100644
--- a/src/test/fuzz/script.cpp
+++ b/src/test/fuzz/script.cpp
@@ -118,8 +118,8 @@ FUZZ_TARGET(script, .init = initialize_script)
             (void)FindAndDelete(script_mut, *other_script);
         }
         const std::vector<std::string> random_string_vector = ConsumeRandomLengthStringVector(fuzzed_data_provider);
-        const uint32_t u32{fuzzed_data_provider.ConsumeIntegral<uint32_t>()};
-        const script_verify_flags flags{u32 | SCRIPT_VERIFY_P2SH};
+        const auto flags_rand{fuzzed_data_provider.ConsumeIntegral<script_verify_flags::value_type>()};
+        const auto flags = script_verify_flags::from_int(flags_rand) | SCRIPT_VERIFY_P2SH;
         {
             CScriptWitness wit;
             for (const auto& s : random_string_vector) {
diff --git a/src/test/fuzz/script_assets_test_minimizer.cpp b/src/test/fuzz/script_assets_test_minimizer.cpp
index ba6d8239245..b26aa84e6eb 100644
--- a/src/test/fuzz/script_assets_test_minimizer.cpp
+++ b/src/test/fuzz/script_assets_test_minimizer.cpp
@@ -90,7 +90,7 @@ CScriptWitness ScriptWitnessFromJSON(const UniValue& univalue)
     return scriptwitness;
 }
 
-const std::map<std::string, uint32_t> FLAG_NAMES = {
+const std::map<std::string, script_verify_flag_name> FLAG_NAMES = {
     {std::string("P2SH"), SCRIPT_VERIFY_P2SH},
     {std::string("DERSIG"), SCRIPT_VERIFY_DERSIG},
     {std::string("NULLDUMMY"), SCRIPT_VERIFY_NULLDUMMY},
diff --git a/src/test/fuzz/script_flags.cpp b/src/test/fuzz/script_flags.cpp
index 7e28b52fdc8..0920f7a408e 100644
--- a/src/test/fuzz/script_flags.cpp
+++ b/src/test/fuzz/script_flags.cpp
@@ -15,6 +15,14 @@
 #include <utility>
 #include <vector>
 
+static DataStream& operator>>(DataStream& ds, script_verify_flags& f)
+{
+    script_verify_flags::value_type n{0};
+    ds >> n;
+    f = script_verify_flags::from_int(n);
+    return ds;
+}
+
 FUZZ_TARGET(script_flags)
 {
     if (buffer.size() > 100'000) return;
diff --git a/src/test/fuzz/signature_checker.cpp b/src/test/fuzz/signature_checker.cpp
index d1591464f2a..d38dbf2ae08 100644
--- a/src/test/fuzz/signature_checker.cpp
+++ b/src/test/fuzz/signature_checker.cpp
@@ -51,7 +51,7 @@ public:
 FUZZ_TARGET(signature_checker)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
-    const script_verify_flags flags = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
+    const auto flags = script_verify_flags::from_int(fuzzed_data_provider.ConsumeIntegral<script_verify_flags::value_type>());
     const SigVersion sig_version = fuzzed_data_provider.PickValueInArray({SigVersion::BASE, SigVersion::WITNESS_V0});
     const auto script_1{ConsumeScript(fuzzed_data_provider)};
     const auto script_2{ConsumeScript(fuzzed_data_provider)};
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index 561660464a9..c1a9947395a 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -96,7 +96,7 @@ static ScriptErrorDesc script_errors[]={
     {SCRIPT_ERR_SIG_FINDANDDELETE, "SIG_FINDANDDELETE"},
 };
 
-static std::string FormatScriptFlags(uint32_t flags)
+static std::string FormatScriptFlags(script_verify_flags flags)
 {
     return util::Join(GetScriptFlagNames(flags), ",");
 }
@@ -134,13 +134,13 @@ void DoTest(const CScript& scriptPubKey, const CScript& scriptSig, const CScript
     BOOST_CHECK_MESSAGE(err == scriptError, FormatScriptError(err) + " where " + FormatScriptError((ScriptError_t)scriptError) + " expected: " + message);
 
     // Verify that removing flags from a passing test or adding flags to a failing test does not change the result.
-    for (int i = 0; i < 16; ++i) {
-        uint32_t extra_flags(m_rng.randbits(16));
-        uint32_t combined_flags{expect ? (flags & ~extra_flags) : (flags | extra_flags)};
+    for (int i = 0; i < 256; ++i) {
+        script_verify_flags extra_flags = script_verify_flags::from_int(m_rng.randbits(MAX_SCRIPT_VERIFY_FLAGS_BITS));
+        script_verify_flags combined_flags{expect ? (flags & ~extra_flags) : (flags | extra_flags)};
         // Weed out some invalid flag combinations.
         if (combined_flags & SCRIPT_VERIFY_CLEANSTACK && ~combined_flags & (SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_WITNESS)) continue;
         if (combined_flags & SCRIPT_VERIFY_WITNESS && ~combined_flags & SCRIPT_VERIFY_P2SH) continue;
-        BOOST_CHECK_MESSAGE(VerifyScript(scriptSig, scriptPubKey, &scriptWitness, combined_flags, MutableTransactionSignatureChecker(&tx, 0, txCredit.vout[0].nValue, MissingDataBehavior::ASSERT_FAIL), &err) == expect, message + strprintf(" (with flags %x)", combined_flags));
+        BOOST_CHECK_MESSAGE(VerifyScript(scriptSig, scriptPubKey, &scriptWitness, combined_flags, MutableTransactionSignatureChecker(&tx, 0, txCredit.vout[0].nValue, MissingDataBehavior::ASSERT_FAIL), &err) == expect, message + strprintf(" (with flags %x)", combined_flags.as_int()));
     }
 }
 }; // struct ScriptTest
@@ -1716,9 +1716,9 @@ BOOST_AUTO_TEST_CASE(formatscriptflags)
 {
     // quick check that FormatScriptFlags reports any unknown/unexpected bits
     BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_P2SH), "P2SH");
-    BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_P2SH | (1u<<31)), "P2SH,0x80000000");
-    BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_TAPROOT | (1u<<27)), "TAPROOT,0x08000000");
-    BOOST_CHECK_EQUAL(FormatScriptFlags(1u<<26), "0x04000000");
+    BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_P2SH | script_verify_flags::from_int(1u<<31)), "P2SH,0x80000000");
+    BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_TAPROOT | script_verify_flags::from_int(1u<<27)), "TAPROOT,0x08000000");
+    BOOST_CHECK_EQUAL(FormatScriptFlags(script_verify_flags::from_int(1u<<26)), "0x04000000");
 }
 
 BOOST_AUTO_TEST_SUITE_END()
diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp
index c2f64cc8217..b2a70057d5b 100644
--- a/src/test/transaction_tests.cpp
+++ b/src/test/transaction_tests.cpp
@@ -50,7 +50,7 @@ typedef std::vector<unsigned char> valtype;
 static CFeeRate g_dust{DUST_RELAY_TX_FEE};
 static bool g_bare_multi{DEFAULT_PERMIT_BAREMULTISIG};
 
-static const std::map<std::string, unsigned int>& mapFlagNames = g_verify_flag_names;
+static const std::map<std::string, script_verify_flag_name>& mapFlagNames = g_verify_flag_names;
 
 script_verify_flags ParseScriptFlags(std::string strFlags)
 {
@@ -230,9 +230,9 @@ BOOST_AUTO_TEST_CASE(tx_valid)
                     BOOST_ERROR("Tx unexpectedly failed with flag " << name << " unset: " << strTest);
                 }
                 // Removing random combinations of flags
-                flags = TrimFlags(~(verify_flags | (unsigned int)m_rng.randbits(mapFlagNames.size())));
+                flags = TrimFlags(~(verify_flags | script_verify_flags::from_int(m_rng.randbits(MAX_SCRIPT_VERIFY_FLAGS_BITS))));
                 if (!CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, flags, txdata, strTest, /*expect_valid=*/true)) {
-                    BOOST_ERROR("Tx unexpectedly failed with random flags " << ToString(flags) << ": " << strTest);
+                    BOOST_ERROR("Tx unexpectedly failed with random flags " << ToString(flags.as_int()) << ": " << strTest);
                 }
             }
 
@@ -321,7 +321,7 @@ BOOST_AUTO_TEST_CASE(tx_invalid)
                     BOOST_ERROR("Tx unexpectedly passed with flag " << name << " set: " << strTest);
                 }
                 // Adding random combinations of flags
-                flags = FillFlags(verify_flags | (unsigned int)m_rng.randbits(mapFlagNames.size()));
+                flags = FillFlags(verify_flags | script_verify_flags::from_int(m_rng.randbits(MAX_SCRIPT_VERIFY_FLAGS_BITS)));
                 if (!CheckTxScripts(tx, mapprevOutScriptPubKeys, mapprevOutValues, flags, txdata, strTest, /*expect_valid=*/false)) {
                     BOOST_ERROR("Tx unexpectedly passed with random flags " << name << ": " << strTest);
                 }
diff --git a/src/test/txvalidationcache_tests.cpp b/src/test/txvalidationcache_tests.cpp
index 8c14dd65a14..46cb84824d7 100644
--- a/src/test/txvalidationcache_tests.cpp
+++ b/src/test/txvalidationcache_tests.cpp
@@ -130,7 +130,7 @@ static void ValidateCheckInputsForAllFlags(const CTransaction &tx, script_verify
         TxValidationState state;
 
         // Randomly selects flag combinations
-        script_verify_flags test_flags = (uint32_t) insecure_rand.randrange((SCRIPT_VERIFY_END_MARKER - 1) << 1);
+        script_verify_flags test_flags = script_verify_flags::from_int(insecure_rand.randrange(MAX_SCRIPT_VERIFY_FLAGS));
 
         // Filter out incompatible flag choices
         if ((test_flags & SCRIPT_VERIFY_CLEANSTACK)) {

From 3cbbcb66efc39c6566ab31836e4eb582b77581d2 Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Wed, 16 Jul 2025 15:48:30 +1000
Subject: [PATCH 6/8] script/interpreter: make script_verify_flag_name an
 ordinary enum

Instead of having `SCRIPT_VERIFY_FOO = (1U << n)` just have it
be `n` directly, and do the bit shifting when converting it to
`script_verify_flags`.
---
 src/script/interpreter.h  | 54 +++++++++++++++++++--------------------
 src/script/verify_flags.h |  4 +--
 2 files changed, 29 insertions(+), 29 deletions(-)

diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index 9ae29e0f1f4..15f37fba3bb 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -14,7 +14,6 @@
 #include <span.h>
 #include <uint256.h>
 
-#include <bit>
 #include <cstddef>
 #include <cstdint>
 #include <optional>
@@ -47,33 +46,33 @@ enum
 
 static constexpr script_verify_flags SCRIPT_VERIFY_NONE{0};
 
-enum class script_verify_flag_name : uint32_t {
+enum class script_verify_flag_name : uint8_t {
     // Evaluate P2SH subscripts (BIP16).
-    SCRIPT_VERIFY_P2SH      = (1U << 0),
+    SCRIPT_VERIFY_P2SH,
 
     // Passing a non-strict-DER signature or one with undefined hashtype to a checksig operation causes script failure.
     // Evaluating a pubkey that is not (0x04 + 64 bytes) or (0x02 or 0x03 + 32 bytes) by checksig causes script failure.
     // (not used or intended as a consensus rule).
-    SCRIPT_VERIFY_STRICTENC = (1U << 1),
+    SCRIPT_VERIFY_STRICTENC,
 
     // Passing a non-strict-DER signature to a checksig operation causes script failure (BIP62 rule 1)
-    SCRIPT_VERIFY_DERSIG    = (1U << 2),
+    SCRIPT_VERIFY_DERSIG,
 
     // Passing a non-strict-DER signature or one with S > order/2 to a checksig operation causes script failure
     // (BIP62 rule 5).
-    SCRIPT_VERIFY_LOW_S     = (1U << 3),
+    SCRIPT_VERIFY_LOW_S,
 
     // verify dummy stack item consumed by CHECKMULTISIG is of zero-length (BIP62 rule 7).
-    SCRIPT_VERIFY_NULLDUMMY = (1U << 4),
+    SCRIPT_VERIFY_NULLDUMMY,
 
     // Using a non-push operator in the scriptSig causes script failure (BIP62 rule 2).
-    SCRIPT_VERIFY_SIGPUSHONLY = (1U << 5),
+    SCRIPT_VERIFY_SIGPUSHONLY,
 
     // Require minimal encodings for all push operations (OP_0... OP_16, OP_1NEGATE where possible, direct
     // pushes up to 75 bytes, OP_PUSHDATA up to 255 bytes, OP_PUSHDATA2 for anything larger). Evaluating
     // any other push causes the script to fail (BIP62 rule 3).
     // In addition, whenever a stack element is interpreted as a number, it must be of minimal length (BIP62 rule 4).
-    SCRIPT_VERIFY_MINIMALDATA = (1U << 6),
+    SCRIPT_VERIFY_MINIMALDATA,
 
     // Discourage use of NOPs reserved for upgrades (NOP1-10)
     //
@@ -85,7 +84,7 @@ enum class script_verify_flag_name : uint32_t {
     // executed, e.g.  within an unexecuted IF ENDIF block, are *not* rejected.
     // NOPs that have associated forks to give them new meaning (CLTV, CSV)
     // are not subject to this rule.
-    SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS  = (1U << 7),
+    SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_NOPS,
 
     // Require that only a single stack element remains after evaluation. This changes the success criterion from
     // "At least one stack element must remain, and when interpreted as a boolean, it must be true" to
@@ -94,57 +93,57 @@ enum class script_verify_flag_name : uint32_t {
     // Note: CLEANSTACK should never be used without P2SH or WITNESS.
     // Note: WITNESS_V0 and TAPSCRIPT script execution have behavior similar to CLEANSTACK as part of their
     //       consensus rules. It is automatic there and does not need this flag.
-    SCRIPT_VERIFY_CLEANSTACK = (1U << 8),
+    SCRIPT_VERIFY_CLEANSTACK,
 
     // Verify CHECKLOCKTIMEVERIFY
     //
     // See BIP65 for details.
-    SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY = (1U << 9),
+    SCRIPT_VERIFY_CHECKLOCKTIMEVERIFY,
 
     // support CHECKSEQUENCEVERIFY opcode
     //
     // See BIP112 for details
-    SCRIPT_VERIFY_CHECKSEQUENCEVERIFY = (1U << 10),
+    SCRIPT_VERIFY_CHECKSEQUENCEVERIFY,
 
     // Support segregated witness
     //
-    SCRIPT_VERIFY_WITNESS = (1U << 11),
+    SCRIPT_VERIFY_WITNESS,
 
     // Making v1-v16 witness program non-standard
     //
-    SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM = (1U << 12),
+    SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM,
 
     // Segwit script only: Require the argument of OP_IF/NOTIF to be exactly 0x01 or empty vector
     //
     // Note: TAPSCRIPT script execution has behavior similar to MINIMALIF as part of its consensus
     //       rules. It is automatic there and does not depend on this flag.
-    SCRIPT_VERIFY_MINIMALIF = (1U << 13),
+    SCRIPT_VERIFY_MINIMALIF,
 
     // Signature(s) must be empty vector if a CHECK(MULTI)SIG operation failed
     //
-    SCRIPT_VERIFY_NULLFAIL = (1U << 14),
+    SCRIPT_VERIFY_NULLFAIL,
 
     // Public keys in segregated witness scripts must be compressed
     //
-    SCRIPT_VERIFY_WITNESS_PUBKEYTYPE = (1U << 15),
+    SCRIPT_VERIFY_WITNESS_PUBKEYTYPE,
 
     // Making OP_CODESEPARATOR and FindAndDelete fail any non-segwit scripts
     //
-    SCRIPT_VERIFY_CONST_SCRIPTCODE = (1U << 16),
+    SCRIPT_VERIFY_CONST_SCRIPTCODE,
 
     // Taproot/Tapscript validation (BIPs 341 & 342)
     //
-    SCRIPT_VERIFY_TAPROOT = (1U << 17),
+    SCRIPT_VERIFY_TAPROOT,
 
     // Making unknown Taproot leaf versions non-standard
     //
-    SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_TAPROOT_VERSION = (1U << 18),
+    SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_TAPROOT_VERSION,
 
     // Making unknown OP_SUCCESS non-standard
-    SCRIPT_VERIFY_DISCOURAGE_OP_SUCCESS = (1U << 19),
+    SCRIPT_VERIFY_DISCOURAGE_OP_SUCCESS,
 
     // Making unknown public key versions (in BIP 342 scripts) non-standard
-    SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_PUBKEYTYPE = (1U << 20),
+    SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_PUBKEYTYPE,
 
     // Constants to point to the highest flag in use. Add new flags above this line.
     //
@@ -152,11 +151,12 @@ enum class script_verify_flag_name : uint32_t {
 };
 using enum script_verify_flag_name;
 
-// assert there is still a spare bit
-static_assert(static_cast<script_verify_flags::value_type>(SCRIPT_VERIFY_END_MARKER) < (1u << 31));
+static constexpr int MAX_SCRIPT_VERIFY_FLAGS_BITS = static_cast<int>(SCRIPT_VERIFY_END_MARKER);
 
-static constexpr script_verify_flags::value_type MAX_SCRIPT_VERIFY_FLAGS = ((static_cast<script_verify_flags::value_type>(SCRIPT_VERIFY_END_MARKER) - 1) << 1) - 1;
-static constexpr int MAX_SCRIPT_VERIFY_FLAGS_BITS = std::bit_width(MAX_SCRIPT_VERIFY_FLAGS);
+// assert there is still a spare bit
+static_assert(0 < MAX_SCRIPT_VERIFY_FLAGS_BITS && MAX_SCRIPT_VERIFY_FLAGS_BITS <= 31);
+
+static constexpr script_verify_flags::value_type MAX_SCRIPT_VERIFY_FLAGS = ((script_verify_flags::value_type{1} << MAX_SCRIPT_VERIFY_FLAGS_BITS) - 1);
 
 bool CheckSignatureEncoding(const std::vector<unsigned char> &vchSig, script_verify_flags flags, ScriptError* serror);
 
diff --git a/src/script/verify_flags.h b/src/script/verify_flags.h
index ba75f0894be..0d34174eb22 100644
--- a/src/script/verify_flags.h
+++ b/src/script/verify_flags.h
@@ -9,7 +9,7 @@
 #include <compare>
 #include <cstdint>
 
-enum class script_verify_flag_name : uint32_t;
+enum class script_verify_flag_name : uint8_t;
 
 class script_verify_flags
 {
@@ -22,7 +22,7 @@ public:
     consteval explicit(false) script_verify_flags(value_type f) : m_value{f} { if (f != 0) throw 0; }
 
     // implicit construction from a hard-coded SCRIPT_VERIFY_* constant is also okay
-    constexpr explicit(false) script_verify_flags(script_verify_flag_name f) : m_value{static_cast<value_type>(f)} { }
+    constexpr explicit(false) script_verify_flags(script_verify_flag_name f) : m_value{value_type{1} << static_cast<uint8_t>(f)} { }
 
     // rule of 5
     constexpr script_verify_flags(const script_verify_flags&) = default;

From 417437eb01ac014c57aca47f44d7f8d3da351987 Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Wed, 16 Jul 2025 16:02:52 +1000
Subject: [PATCH 7/8] script/verify_flags: extend script_verify_flags to 64
 bits

---
 src/script/interpreter.h  | 2 +-
 src/script/verify_flags.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index 15f37fba3bb..986b6b0d78a 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -154,7 +154,7 @@ using enum script_verify_flag_name;
 static constexpr int MAX_SCRIPT_VERIFY_FLAGS_BITS = static_cast<int>(SCRIPT_VERIFY_END_MARKER);
 
 // assert there is still a spare bit
-static_assert(0 < MAX_SCRIPT_VERIFY_FLAGS_BITS && MAX_SCRIPT_VERIFY_FLAGS_BITS <= 31);
+static_assert(0 < MAX_SCRIPT_VERIFY_FLAGS_BITS && MAX_SCRIPT_VERIFY_FLAGS_BITS <= 63);
 
 static constexpr script_verify_flags::value_type MAX_SCRIPT_VERIFY_FLAGS = ((script_verify_flags::value_type{1} << MAX_SCRIPT_VERIFY_FLAGS_BITS) - 1);
 
diff --git a/src/script/verify_flags.h b/src/script/verify_flags.h
index 0d34174eb22..95a55d2c79e 100644
--- a/src/script/verify_flags.h
+++ b/src/script/verify_flags.h
@@ -14,7 +14,7 @@ enum class script_verify_flag_name : uint8_t;
 class script_verify_flags
 {
 public:
-    using value_type = uint32_t;
+    using value_type = uint64_t;
 
     consteval script_verify_flags() = default;
 

From 652424ad162b63d73ecb6bd65bd26946e90c617f Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Thu, 11 Sep 2025 11:21:22 +1000
Subject: [PATCH 8/8] test: additional test coverage for script_verify_flags

---
 src/test/fuzz/script_flags.cpp | 3 +++
 src/test/script_tests.cpp      | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/src/test/fuzz/script_flags.cpp b/src/test/fuzz/script_flags.cpp
index 0920f7a408e..ca38c6a6d4a 100644
--- a/src/test/fuzz/script_flags.cpp
+++ b/src/test/fuzz/script_flags.cpp
@@ -20,6 +20,7 @@ static DataStream& operator>>(DataStream& ds, script_verify_flags& f)
     script_verify_flags::value_type n{0};
     ds >> n;
     f = script_verify_flags::from_int(n);
+    assert(n == f.as_int());
     return ds;
 }
 
@@ -33,6 +34,8 @@ FUZZ_TARGET(script_flags)
         script_verify_flags verify_flags;
         ds >> verify_flags;
 
+        assert(verify_flags == script_verify_flags::from_int(verify_flags.as_int()));
+
         if (!IsValidFlagCombination(verify_flags)) return;
 
         script_verify_flags fuzzed_flags;
diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp
index c1a9947395a..fc4550bb7b7 100644
--- a/src/test/script_tests.cpp
+++ b/src/test/script_tests.cpp
@@ -1716,8 +1716,10 @@ BOOST_AUTO_TEST_CASE(formatscriptflags)
 {
     // quick check that FormatScriptFlags reports any unknown/unexpected bits
     BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_P2SH), "P2SH");
+    BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_P2SH | SCRIPT_VERIFY_TAPROOT), "P2SH,TAPROOT");
     BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_P2SH | script_verify_flags::from_int(1u<<31)), "P2SH,0x80000000");
     BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_TAPROOT | script_verify_flags::from_int(1u<<27)), "TAPROOT,0x08000000");
+    BOOST_CHECK_EQUAL(FormatScriptFlags(SCRIPT_VERIFY_TAPROOT | script_verify_flags::from_int((1u<<28) | (1ull<<58))), "TAPROOT,0x400000010000000");
     BOOST_CHECK_EQUAL(FormatScriptFlags(script_verify_flags::from_int(1u<<26)), "0x04000000");
 }