From f283edf8f0d6266a40c5c98e1e2ddc2f7e7d1cd4 Mon Sep 17 00:00:00 2001
From: Capri <caprimc@yahoo.com>
Date: Mon, 31 Aug 2026 19:23:30 +0000
Subject: [PATCH] Add post-quantum wallet integration

---
 src/chainparams.cpp            |   4 +-
 src/interfaces/chain.h         |   4 +
 src/node/interfaces.cpp        |   9 +
 src/outputtype.cpp             |  14 +-
 src/outputtype.h               |   4 +
 src/script/interpreter.cpp     |   6 +-
 src/script/sign.cpp            |   6 +-
 src/validation.cpp             |  28 +-
 src/wallet/rpcwallet.cpp       |  17 +
 src/wallet/salvage.cpp         |   2 +-
 src/wallet/scriptpubkeyman.cpp | 693 ++++++++++++++++++++++++++++++++-
 src/wallet/scriptpubkeyman.h   |  54 +++
 src/wallet/wallet.cpp          |  37 +-
 src/wallet/walletdb.cpp        | 116 +++++-
 src/wallet/walletdb.h          |  35 ++
 15 files changed, 1013 insertions(+), 16 deletions(-)

diff --git a/src/chainparams.cpp b/src/chainparams.cpp
index 15fbf01..8e2fd4e 100644
--- a/src/chainparams.cpp
+++ b/src/chainparams.cpp
@@ -475,9 +475,9 @@ public:
         consensus.vDeployments[Consensus::DEPLOYMENT_TAPROOT].min_activation_height = 0; // No activation delay
 
         // VEXTA quantum-resistant witness v2/v3.
-        // Integrated but intentionally not active yet.
+        // Always active on regtest for development and testing.
         consensus.vDeployments[Consensus::DEPLOYMENT_PQR].bit = 3;
-        consensus.vDeployments[Consensus::DEPLOYMENT_PQR].nStartTime = Consensus::BIP9Deployment::NEVER_ACTIVE;
+        consensus.vDeployments[Consensus::DEPLOYMENT_PQR].nStartTime = Consensus::BIP9Deployment::ALWAYS_ACTIVE;
         consensus.vDeployments[Consensus::DEPLOYMENT_PQR].nTimeout = Consensus::BIP9Deployment::NO_TIMEOUT;
         consensus.vDeployments[Consensus::DEPLOYMENT_PQR].min_activation_height = 0;
 
diff --git a/src/interfaces/chain.h b/src/interfaces/chain.h
index 1a63f25..1f15ca6 100644
--- a/src/interfaces/chain.h
+++ b/src/interfaces/chain.h
@@ -5,6 +5,7 @@
 #ifndef DIGIBYTE_INTERFACES_CHAIN_H
 #define DIGIBYTE_INTERFACES_CHAIN_H
 
+#include <consensus/params.h>
 #include <primitives/transaction.h> // For CTransactionRef
 #include <util/settings.h>          // For util::SettingsValue
 
@@ -96,6 +97,9 @@ public:
     //! any blocks)
     virtual std::optional<int> getHeight() = 0;
 
+    //! Return whether a versionbits deployment is active at the current chain tip.
+    virtual bool isDeploymentActive(Consensus::DeploymentPos deployment) = 0;
+
     //! Get block hash. Height must be valid or this function will abort.
     virtual uint256 getBlockHash(int height) = 0;
 
diff --git a/src/node/interfaces.cpp b/src/node/interfaces.cpp
index f5621d1..375f298 100644
--- a/src/node/interfaces.cpp
+++ b/src/node/interfaces.cpp
@@ -441,6 +441,15 @@ public:
         }
         return std::nullopt;
     }
+    bool isDeploymentActive(Consensus::DeploymentPos deployment) override
+    {
+        LOCK(::cs_main);
+        const CBlockIndex* tip = Assert(m_node.chainman)->ActiveChain().Tip();
+        if (!tip) {
+            return false;
+        }
+        return DeploymentActiveAt(*tip, Params().GetConsensus(), deployment);
+    }
     uint256 getBlockHash(int height) override
     {
         LOCK(::cs_main);
diff --git a/src/outputtype.cpp b/src/outputtype.cpp
index d84ccb9..a706970 100644
--- a/src/outputtype.cpp
+++ b/src/outputtype.cpp
@@ -20,6 +20,8 @@ static const std::string OUTPUT_TYPE_STRING_LEGACY = "legacy";
 static const std::string OUTPUT_TYPE_STRING_P2SH_SEGWIT = "p2sh-segwit";
 static const std::string OUTPUT_TYPE_STRING_BECH32 = "bech32";
 static const std::string OUTPUT_TYPE_STRING_BECH32M = "bech32m";
+static const std::string OUTPUT_TYPE_STRING_MLDSA = "mldsa";
+static const std::string OUTPUT_TYPE_STRING_SLHDSA = "slhdsa";
 
 bool ParseOutputType(const std::string& type, OutputType& output_type)
 {
@@ -35,6 +37,12 @@ bool ParseOutputType(const std::string& type, OutputType& output_type)
     } else if (type == OUTPUT_TYPE_STRING_BECH32M) {
         output_type = OutputType::BECH32M;
         return true;
+    } else if (type == OUTPUT_TYPE_STRING_MLDSA) {
+        output_type = OutputType::MLDSA;
+        return true;
+    } else if (type == OUTPUT_TYPE_STRING_SLHDSA) {
+        output_type = OutputType::SLHDSA;
+        return true;
     }
     return false;
 }
@@ -46,6 +54,8 @@ const std::string& FormatOutputType(OutputType type)
     case OutputType::P2SH_SEGWIT: return OUTPUT_TYPE_STRING_P2SH_SEGWIT;
     case OutputType::BECH32: return OUTPUT_TYPE_STRING_BECH32;
     case OutputType::BECH32M: return OUTPUT_TYPE_STRING_BECH32M;
+    case OutputType::MLDSA: return OUTPUT_TYPE_STRING_MLDSA;
+    case OutputType::SLHDSA: return OUTPUT_TYPE_STRING_SLHDSA;
     } // no default case, so the compiler can warn about missing cases
     assert(false);
 }
@@ -65,7 +75,9 @@ CTxDestination GetDestinationForKey(const CPubKey& key, OutputType type)
             return witdest;
         }
     }
-    case OutputType::BECH32M: {} // This function should never be used with BECH32M, so let it assert
+    case OutputType::BECH32M:
+    case OutputType::MLDSA:
+    case OutputType::SLHDSA: {} // These functions should never be used with non-EC output types, so let it assert
     } // no default case, so the compiler can warn about missing cases
     assert(false);
 }
diff --git a/src/outputtype.h b/src/outputtype.h
index 976737f..24c708e 100644
--- a/src/outputtype.h
+++ b/src/outputtype.h
@@ -20,6 +20,8 @@ enum class OutputType {
     P2SH_SEGWIT,
     BECH32,
     BECH32M,
+    MLDSA,
+    SLHDSA,
 };
 
 static constexpr auto OUTPUT_TYPES = std::array{
@@ -27,6 +29,8 @@ static constexpr auto OUTPUT_TYPES = std::array{
     OutputType::P2SH_SEGWIT,
     OutputType::BECH32,
     OutputType::BECH32M,
+    OutputType::MLDSA,
+    OutputType::SLHDSA,
 };
 
 [[nodiscard]] bool ParseOutputType(const std::string& str, OutputType& output_type);
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index c44962b..d8bb113 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -2045,8 +2045,12 @@ static bool VerifyWitnessProgram(const CScriptWitness& witness, int witversion,
         // VEXTA quantum-resistant witness:
         // v2 = ML-DSA-65, v3 = SLH-DSA/SPHINCS+-128s.
         //
-        // Before softfork activation, retain unknown-witness semantics.
+        // Before softfork activation, retain unknown-witness consensus semantics,
+        // but reject these spends under standard relay policy.
         if (!(flags & SCRIPT_VERIFY_PQR)) {
+            if (flags & SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM) {
+                return set_error(serror, SCRIPT_ERR_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM);
+            }
             return set_success(serror);
         }
 
diff --git a/src/script/sign.cpp b/src/script/sign.cpp
index 7c194f3..d67ce33 100644
--- a/src/script/sign.cpp
+++ b/src/script/sign.cpp
@@ -257,6 +257,8 @@ static bool SignStep(const SigningProvider& provider, const BaseSignatureCreator
     case TxoutType::NONSTANDARD:
     case TxoutType::NULL_DATA:
     case TxoutType::WITNESS_UNKNOWN:
+    case TxoutType::WITNESS_V2_MLDSA:
+    case TxoutType::WITNESS_V3_SLHDSA:
         return false;
     case TxoutType::PUBKEY:
         if (!CreateSig(creator, sigdata, provider, sig, CPubKey(vSolutions[0]), scriptPubKey, sigversion)) return false;
@@ -389,7 +391,9 @@ bool ProduceSignature(const SigningProvider& provider, const BaseSignatureCreato
             sigdata.scriptWitness.stack = std::move(result);
         }
         result.clear();
-    } else if (solved && whichType == TxoutType::WITNESS_UNKNOWN) {
+    } else if (whichType == TxoutType::WITNESS_UNKNOWN ||
+               whichType == TxoutType::WITNESS_V2_MLDSA ||
+               whichType == TxoutType::WITNESS_V3_SLHDSA) {
         sigdata.witness = true;
     }
 
diff --git a/src/validation.cpp b/src/validation.cpp
index 0153fbc..80af40d 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -583,6 +583,26 @@ bool MemPoolAccept::PreChecks(ATMPArgs& args, Workspace& ws)
     if (fRequireStandard && !IsStandardTx(tx, reason))
         return state.Invalid(TxValidationResult::TX_NOT_STANDARD, reason);
 
+    // Do not relay transactions creating post-quantum outputs before PQR activation.
+    if (fRequireStandard) {
+        const CBlockIndex* tip = m_active_chainstate.m_chain.Tip();
+        const bool pqr_active =
+            tip && DeploymentActiveAt(*tip, Params().GetConsensus(), Consensus::DEPLOYMENT_PQR);
+
+        if (!pqr_active) {
+            for (const CTxOut& txout : tx.vout) {
+                std::vector<std::vector<unsigned char>> solutions;
+                const TxoutType type = Solver(txout.scriptPubKey, solutions);
+                if (type == TxoutType::WITNESS_V2_MLDSA ||
+                    type == TxoutType::WITNESS_V3_SLHDSA) {
+                    return state.Invalid(
+                        TxValidationResult::TX_NOT_STANDARD,
+                        "pqr-premature");
+                }
+            }
+        }
+    }
+
     // Do not work on transactions that are too small.
     // A transaction with 1 segwit input and 1 P2WPHK output has non-witness size of 82 bytes.
     // Transactions smaller than this are not relayed to mitigate CVE-2017-12842 by not relaying
@@ -932,7 +952,13 @@ bool MemPoolAccept::PolicyScriptChecks(const ATMPArgs& args, Workspace& ws, Prec
     const CTransaction& tx = *ws.m_ptx;
     TxValidationState& state = ws.m_state;
 
-    constexpr unsigned int scriptVerifyFlags = STANDARD_SCRIPT_VERIFY_FLAGS;
+    unsigned int scriptVerifyFlags = STANDARD_SCRIPT_VERIFY_FLAGS;
+
+    const CBlockIndex* tip = m_active_chainstate.m_chain.Tip();
+    if (tip &&
+        DeploymentActiveAt(*tip, Params().GetConsensus(), Consensus::DEPLOYMENT_PQR)) {
+        scriptVerifyFlags |= SCRIPT_VERIFY_PQR;
+    }
 
     // Check input scripts and signatures.
     // This is done last to help prevent CPU exhaustion denial-of-service attacks.
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 1b0999f..a29b50c 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -275,6 +275,13 @@ static RPCHelpMan getnewaddress()
         }
     }
 
+    if ((output_type == OutputType::MLDSA || output_type == OutputType::SLHDSA) &&
+        !pwallet->chain().isDeploymentActive(Consensus::DEPLOYMENT_PQR)) {
+        throw JSONRPCError(
+            RPC_INVALID_PARAMETER,
+            "Post-quantum addresses are not available before PQR activation");
+    }
+
     CTxDestination dest;
     std::string error;
     if (!pwallet->GetNewDestination(output_type, label, dest, error)) {
@@ -320,6 +327,11 @@ static RPCHelpMan getrawchangeaddress()
         if (output_type == OutputType::BECH32M && pwallet->GetLegacyScriptPubKeyMan()) {
             throw JSONRPCError(RPC_INVALID_PARAMETER, "Legacy wallets cannot provide bech32m addresses");
         }
+        if (output_type == OutputType::MLDSA || output_type == OutputType::SLHDSA) {
+            throw JSONRPCError(
+                RPC_INVALID_PARAMETER,
+                "Post-quantum address types cannot be used for change addresses");
+        }
     }
 
     CTxDestination dest;
@@ -3137,6 +3149,11 @@ void FundTransaction(CWallet& wallet, CMutableTransaction& tx, CAmount& fee_out,
             if (!ParseOutputType(options["change_type"].get_str(), out_type)) {
                 throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("Unknown change type '%s'", options["change_type"].get_str()));
             }
+            if (out_type == OutputType::MLDSA || out_type == OutputType::SLHDSA) {
+                throw JSONRPCError(
+                    RPC_INVALID_PARAMETER,
+                    "Post-quantum address types cannot be used for change addresses");
+            }
             coinControl.m_change_type.emplace(out_type);
         }
 
diff --git a/src/wallet/salvage.cpp b/src/wallet/salvage.cpp
index 29e896b..03298ab 100644
--- a/src/wallet/salvage.cpp
+++ b/src/wallet/salvage.cpp
@@ -19,7 +19,7 @@ typedef std::pair<std::vector<unsigned char>, std::vector<unsigned char> > KeyVa
 
 static bool KeyFilter(const std::string& type)
 {
-    return WalletBatch::IsKeyType(type) || type == DBKeys::HDCHAIN;
+    return WalletBatch::IsKeyType(type) || type == DBKeys::HDCHAIN || type == DBKeys::PQHDCHAIN;
 }
 
 bool RecoverDatabaseFile(const fs::path& file_path, bilingual_str& error, std::vector<bilingual_str>& warnings)
diff --git a/src/wallet/scriptpubkeyman.cpp b/src/wallet/scriptpubkeyman.cpp
index 9ced1d0..e56f920 100644
--- a/src/wallet/scriptpubkeyman.cpp
+++ b/src/wallet/scriptpubkeyman.cpp
@@ -2,10 +2,15 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <crypto/pq/pq.h>
+#include <crypto/hmac_sha512.h>
+#include <crypto/sha256.h>
 #include <key_io.h>
 #include <logging.h>
 #include <outputtype.h>
+#include <policy/policy.h>
 #include <script/descriptor.h>
+#include <script/interpreter.h>
 #include <script/sign.h>
 #include <util/bip32.h>
 #include <util/strencodings.h>
@@ -20,10 +25,168 @@
 //! Value for the first BIP 32 hardened derivation. Can be used as a bit mask and as a value. See BIP 32 for more details.
 const uint32_t BIP32_HARDENED_KEY_LIMIT = 0x80000000;
 
+static std::array<unsigned char, 64> DerivePQSeedMaterial(
+    const CKey& wallet_seed,
+    OutputType type,
+    uint32_t counter)
+{
+    static constexpr unsigned char DOMAIN[] = "Vexta-PQ-HD-v1";
+
+    std::array<unsigned char, 64> out{};
+    const uint8_t algo =
+        type == OutputType::MLDSA ? 2 :
+        type == OutputType::SLHDSA ? 3 : 0;
+
+    unsigned char data[sizeof(DOMAIN) - 1 + 1 + 4];
+    size_t pos = 0;
+
+    std::memcpy(data + pos, DOMAIN, sizeof(DOMAIN) - 1);
+    pos += sizeof(DOMAIN) - 1;
+
+    data[pos++] = algo;
+    data[pos++] = static_cast<unsigned char>((counter >> 24) & 0xff);
+    data[pos++] = static_cast<unsigned char>((counter >> 16) & 0xff);
+    data[pos++] = static_cast<unsigned char>((counter >> 8) & 0xff);
+    data[pos++] = static_cast<unsigned char>(counter & 0xff);
+
+    CHMAC_SHA512(wallet_seed.begin(), wallet_seed.size())
+        .Write(data, pos)
+        .Finalize(out.data());
+
+    return out;
+}
+
 bool LegacyScriptPubKeyMan::GetNewDestination(const OutputType type, CTxDestination& dest, std::string& error)
 {
+    if (type == OutputType::MLDSA || type == OutputType::SLHDSA) {
+        if (m_storage.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
+            error = _("Error: Private keys are disabled for this wallet").translated;
+            return false;
+        }
+
+        if (m_storage.IsLocked()) {
+            error = _("Error: Please enter the wallet passphrase with walletpassphrase first.").translated;
+            return false;
+        }
+
+        // Serialize PQ derivation so two concurrent address requests cannot
+        // derive from the same counter.
+        LOCK(cs_KeyStore);
+
+        CKey wallet_seed;
+        uint32_t counter = 0;
+
+        {
+            LOCK(cs_KeyStore);
+
+            if (m_hd_chain.seed_id.IsNull() || !GetKey(m_hd_chain.seed_id, wallet_seed)) {
+                error = _("Error: Wallet HD seed is not available for post-quantum key derivation").translated;
+                return false;
+            }
+
+            if (m_pq_hd_chain.seed_id.IsNull() ||
+                m_pq_hd_chain.seed_id != m_hd_chain.seed_id) {
+                error = _("Error: Post-quantum HD chain does not match the active wallet seed").translated;
+                return false;
+            }
+
+            counter = type == OutputType::MLDSA
+                ? m_pq_hd_chain.nMLDSAExternalCounter
+                : m_pq_hd_chain.nSLHDSAExternalCounter;
+
+            if (counter == std::numeric_limits<uint32_t>::max()) {
+                error = _("Error: Post-quantum address derivation counter exhausted").translated;
+                return false;
+            }
+        }
+
+        const auto seed_material = DerivePQSeedMaterial(wallet_seed, type, counter);
+
+        std::vector<unsigned char> pubkey;
+        CKeyingMaterial secret;
+
+        if (type == OutputType::MLDSA) {
+            pubkey.resize(pq::MLDSA65::PUBKEY_BYTES);
+            secret.resize(pq::MLDSA65::SECKEY_BYTES);
+            if (!pq::MLDSA65::keygen_from_seed(pubkey.data(), secret.data(), seed_material.data())) {
+                error = _("Error: Failed to derive ML-DSA key").translated;
+                return false;
+            }
+        } else {
+            pubkey.resize(pq::SPHINCS128s::PUBKEY_BYTES);
+            secret.resize(pq::SPHINCS128s::SECKEY_BYTES);
+            if (!pq::SPHINCS128s::keygen_from_seed(pubkey.data(), secret.data(), seed_material.data())) {
+                error = _("Error: Failed to derive SLH-DSA key").translated;
+                return false;
+            }
+        }
+
+        WalletBatch batch(m_storage.GetDatabase());
+        if (!batch.TxnBegin()) {
+            error = _("Error: Failed to begin post-quantum wallet database transaction").translated;
+            return false;
+        }
+
+        uint256 key_id;
+        if (!AddPQKey(batch, type, pubkey, secret, key_id)) {
+            batch.TxnAbort();
+            {
+                LOCK(cs_KeyStore);
+                mapPQKeys.erase(key_id);
+                mapCryptedPQKeys.erase(key_id);
+            }
+            error = _("Error: Failed to store post-quantum key").translated;
+            return false;
+        }
+
+        CKeyMetadata metadata(GetTime());
+        metadata.hd_seed_id = wallet_seed.GetPubKey().GetID();
+        metadata.hdKeypath = strprintf(
+            "pq/%s/%u",
+            type == OutputType::MLDSA ? "mldsa" : "slhdsa",
+            counter);
+
+        PQHDChain next_pq_hd_chain;
+        {
+            LOCK(cs_KeyStore);
+            next_pq_hd_chain = m_pq_hd_chain;
+        }
+
+        if (type == OutputType::MLDSA) {
+            ++next_pq_hd_chain.nMLDSAExternalCounter;
+        } else {
+            ++next_pq_hd_chain.nSLHDSAExternalCounter;
+        }
+
+        if (!batch.WritePQKeyMetadata(metadata, key_id, false) ||
+            !batch.WritePQHDChain(next_pq_hd_chain) ||
+            !batch.TxnCommit()) {
+            batch.TxnAbort();
+            {
+                LOCK(cs_KeyStore);
+                mapPQKeys.erase(key_id);
+                mapCryptedPQKeys.erase(key_id);
+            }
+            error = _("Error: Failed to commit post-quantum key data").translated;
+            return false;
+        }
+
+        {
+            LOCK(cs_KeyStore);
+            m_pq_hd_chain = next_pq_hd_chain;
+            mapPQKeyMetadata[key_id] = metadata;
+            UpdateTimeFirstKey(metadata.nCreateTime);
+        }
+
+        dest = type == OutputType::MLDSA
+            ? CTxDestination{WitnessV2MLDSA(key_id)}
+            : CTxDestination{WitnessV3SLHDSA(key_id)};
+        error.clear();
+        return true;
+    }
+
     if (LEGACY_OUTPUT_TYPES.count(type) == 0) {
-        error = _("Error: Legacy wallets only support the \"legacy\", \"p2sh-segwit\", and \"bech32\" address types").translated;
+        error = _("Error: Legacy wallets only support the \"legacy\", \"p2sh-segwit\", \"bech32\", \"mldsa\", and \"slhdsa\" address types").translated;
         return false;
     }
     assert(type != OutputType::BECH32M);
@@ -176,6 +339,21 @@ IsMineResult IsMineInner(const LegacyScriptPubKeyMan& keystore, const CScript& s
         break;
     }
 
+    case TxoutType::WITNESS_V2_MLDSA:
+    case TxoutType::WITNESS_V3_SLHDSA:
+    {
+        if (sigversion != IsMineSigVersion::TOP || vSolutions.size() != 1 || vSolutions[0].size() != 32) {
+            return IsMineResult::INVALID;
+        }
+
+        uint256 key_id;
+        std::copy(vSolutions[0].begin(), vSolutions[0].end(), key_id.begin());
+        if (keystore.HavePQKey(key_id)) {
+            ret = std::max(ret, IsMineResult::SPENDABLE);
+        }
+        break;
+    }
+
     case TxoutType::MULTISIG:
     {
         // Never treat bare multisig outputs as ours (they can still be made watchonly-though)
@@ -230,8 +408,9 @@ bool LegacyScriptPubKeyMan::CheckDecryptionKey(const CKeyingMaterial& master_key
     {
         LOCK(cs_KeyStore);
         assert(mapKeys.empty());
+        assert(mapPQKeys.empty());
 
-        bool keyPass = mapCryptedKeys.empty(); // Always pass when there are no encrypted keys
+        bool keyPass = mapCryptedKeys.empty() && mapCryptedPQKeys.empty();
         bool keyFail = false;
         CryptedKeyMap::const_iterator mi = mapCryptedKeys.begin();
         WalletBatch batch(m_storage.GetDatabase());
@@ -253,6 +432,48 @@ bool LegacyScriptPubKeyMan::CheckDecryptionKey(const CKeyingMaterial& master_key
                 batch.WriteCryptedKey(vchPubKey, vchCryptedSecret, mapKeyMetadata[vchPubKey.GetID()]);
             }
         }
+
+        if (!keyFail && !mapCryptedPQKeys.empty()) {
+            for (const auto& item : mapCryptedPQKeys) {
+                const uint256& key_id = item.first;
+                const CryptedPQKeyData& pq_key = item.second;
+
+                uint256 calculated_id;
+                CSHA256().Write(pq_key.pubkey.data(), pq_key.pubkey.size()).Finalize(calculated_id.begin());
+                if (calculated_id != key_id) {
+                    keyFail = true;
+                    break;
+                }
+
+                const size_t expected_secret_size =
+                    pq_key.type == OutputType::MLDSA ? pq::MLDSA65::SECKEY_BYTES :
+                    pq_key.type == OutputType::SLHDSA ? pq::SPHINCS128s::SECKEY_BYTES : 0;
+
+                const size_t expected_pubkey_size =
+                    pq_key.type == OutputType::MLDSA ? pq::MLDSA65::PUBKEY_BYTES :
+                    pq_key.type == OutputType::SLHDSA ? pq::SPHINCS128s::PUBKEY_BYTES : 0;
+
+                if (expected_secret_size == 0 || pq_key.pubkey.size() != expected_pubkey_size) {
+                    keyFail = true;
+                    break;
+                }
+
+                CKeyingMaterial plain_secret;
+                if (!DecryptSecret(master_key, pq_key.crypted_secret, key_id, plain_secret) ||
+                    plain_secret.size() != expected_secret_size) {
+                    keyFail = true;
+                    break;
+                }
+
+                keyPass = true;
+
+                // After a full successful check, later unlocks only need to
+                // verify one PQ key. Before that, verify every PQ key.
+                if (fDecryptionThoroughlyChecked) {
+                    break;
+                }
+            }
+        }
         if (keyPass && keyFail)
         {
             LogPrintf("The wallet is probably corrupted: Some keys decrypt but not all.\n");
@@ -269,7 +490,7 @@ bool LegacyScriptPubKeyMan::Encrypt(const CKeyingMaterial& master_key, WalletBat
 {
     LOCK(cs_KeyStore);
     encrypted_batch = batch;
-    if (!mapCryptedKeys.empty()) {
+    if (!mapCryptedKeys.empty() || !mapCryptedPQKeys.empty()) {
         encrypted_batch = nullptr;
         return false;
     }
@@ -291,12 +512,47 @@ bool LegacyScriptPubKeyMan::Encrypt(const CKeyingMaterial& master_key, WalletBat
             return false;
         }
     }
+
+    PQKeyMap pq_keys_to_encrypt;
+    pq_keys_to_encrypt.swap(mapPQKeys);
+    for (const auto& item : pq_keys_to_encrypt) {
+        const uint256& key_id = item.first;
+        const PQKeyData& pq_key = item.second;
+
+        CKeyingMaterial plain_secret(pq_key.secret.begin(), pq_key.secret.end());
+        std::vector<unsigned char> crypted_secret;
+        if (!EncryptSecret(master_key, plain_secret, key_id, crypted_secret)) {
+            encrypted_batch = nullptr;
+            return false;
+        }
+
+        if (!AddCryptedPQKeyInner(key_id, pq_key.type, pq_key.pubkey, crypted_secret)) {
+            encrypted_batch = nullptr;
+            return false;
+        }
+
+        bool write_ok = batch
+            ? batch->WriteCryptedPQKey(key_id, pq_key.type, pq_key.pubkey, crypted_secret)
+            : WalletBatch(m_storage.GetDatabase()).WriteCryptedPQKey(
+                  key_id, pq_key.type, pq_key.pubkey, crypted_secret);
+
+        if (!write_ok) {
+            encrypted_batch = nullptr;
+            return false;
+        }
+    }
+
     encrypted_batch = nullptr;
     return true;
 }
 
 bool LegacyScriptPubKeyMan::GetReservedDestination(const OutputType type, bool internal, CTxDestination& address, int64_t& index, CKeyPool& keypool, std::string& error)
 {
+    if (type == OutputType::MLDSA || type == OutputType::SLHDSA) {
+        error = _("Error: Post-quantum addresses are not available from the legacy keypool").translated;
+        return false;
+    }
+
     if (LEGACY_OUTPUT_TYPES.count(type) == 0) {
         error = _("Error: Legacy wallets only support the \"legacy\", \"p2sh-segwit\", and \"bech32\" address types").translated;
         return false;
@@ -507,7 +763,10 @@ bool LegacyScriptPubKeyMan::Upgrade(int prev_version, int new_version, bilingual
 bool LegacyScriptPubKeyMan::HavePrivateKeys() const
 {
     LOCK(cs_KeyStore);
-    return !mapKeys.empty() || !mapCryptedKeys.empty();
+    return !mapKeys.empty() ||
+           !mapCryptedKeys.empty() ||
+           !mapPQKeys.empty() ||
+           !mapCryptedPQKeys.empty();
 }
 
 void LegacyScriptPubKeyMan::RewriteDB()
@@ -601,7 +860,141 @@ bool LegacyScriptPubKeyMan::CanProvide(const CScript& script, SignatureData& sig
 
 bool LegacyScriptPubKeyMan::SignTransaction(CMutableTransaction& tx, const std::map<COutPoint, Coin>& coins, int sighash, std::map<int, std::string>& input_errors) const
 {
-    return ::SignTransaction(tx, this, coins, sighash, input_errors);
+    const int effective_sighash = sighash == SIGHASH_DEFAULT ? SIGHASH_ALL : sighash;
+
+    if (effective_sighash != SIGHASH_ALL) {
+        return ::SignTransaction(tx, this, coins, effective_sighash, input_errors);
+    }
+
+    // Sign all conventional inputs first. Post-quantum inputs are handled
+    // separately below so their witness data and verification errors cannot
+    // be overwritten by the generic signing path.
+    (void)::SignTransaction(tx, this, coins, effective_sighash, input_errors);
+
+    const CTransaction tx_const(tx);
+
+    std::vector<CTxOut> spent_outputs(tx.vin.size());
+    bool have_all_spent_outputs = true;
+
+    for (unsigned int i = 0; i < tx.vin.size(); ++i) {
+        auto coin = coins.find(tx.vin[i].prevout);
+        if (coin == coins.end() || coin->second.IsSpent()) {
+            have_all_spent_outputs = false;
+            continue;
+        }
+        spent_outputs[i] = coin->second.out;
+    }
+
+    PrecomputedTransactionData txdata;
+    if (have_all_spent_outputs) {
+        txdata.Init(tx_const, std::move(spent_outputs), true);
+    } else {
+        txdata.Init(tx_const, {}, true);
+    }
+
+    for (unsigned int i = 0; i < tx.vin.size(); ++i) {
+        auto coin = coins.find(tx.vin[i].prevout);
+        if (coin == coins.end() || coin->second.IsSpent()) {
+            continue;
+        }
+
+        std::vector<valtype> solutions;
+        const TxoutType type = Solver(coin->second.out.scriptPubKey, solutions);
+
+        int witness_version = 0;
+        OutputType output_type;
+
+        if (type == TxoutType::WITNESS_V2_MLDSA) {
+            witness_version = 2;
+            output_type = OutputType::MLDSA;
+        } else if (type == TxoutType::WITNESS_V3_SLHDSA) {
+            witness_version = 3;
+            output_type = OutputType::SLHDSA;
+        } else {
+            continue;
+        }
+
+        if (solutions.size() != 1 || solutions[0].size() != 32) {
+            input_errors[i] = "Invalid post-quantum witness program";
+            continue;
+        }
+
+        uint256 key_id;
+        std::copy(solutions[0].begin(), solutions[0].end(), key_id.begin());
+
+        OutputType stored_type;
+        std::vector<unsigned char> pubkey;
+        CKeyingMaterial secret;
+
+        if (!GetPQKey(key_id, stored_type, pubkey, secret) || stored_type != output_type) {
+            input_errors[i] = "Post-quantum private key not available";
+            continue;
+        }
+
+        const uint256 hash = SignatureHashPQR(
+            tx_const,
+            i,
+            witness_version,
+            solutions[0],
+            coin->second.out.nValue,
+            txdata);
+
+        std::vector<unsigned char> signature(
+            output_type == OutputType::MLDSA
+                ? pq::MLDSA65::SIG_BYTES
+                : pq::SPHINCS128s::SIG_BYTES);
+
+        size_t siglen = 0;
+        const bool signed_ok =
+            output_type == OutputType::MLDSA
+                ? pq::MLDSA65::sign(
+                      signature.data(),
+                      &siglen,
+                      hash.begin(),
+                      hash.size(),
+                      secret.data())
+                : pq::SPHINCS128s::sign(
+                      signature.data(),
+                      &siglen,
+                      hash.begin(),
+                      hash.size(),
+                      secret.data());
+
+        if (!signed_ok || siglen != signature.size()) {
+            input_errors[i] = "Post-quantum signing failed";
+            continue;
+        }
+
+        tx.vin[i].scriptSig.clear();
+        tx.vin[i].scriptWitness.stack.clear();
+        tx.vin[i].scriptWitness.stack.push_back(std::move(signature));
+        tx.vin[i].scriptWitness.stack.push_back(std::move(pubkey));
+
+        ScriptError serror = SCRIPT_ERR_OK;
+        const unsigned int pqr_flags =
+            (STANDARD_SCRIPT_VERIFY_FLAGS & ~SCRIPT_VERIFY_DISCOURAGE_UPGRADABLE_WITNESS_PROGRAM) |
+            SCRIPT_VERIFY_PQR;
+
+        if (!VerifyScript(
+                tx.vin[i].scriptSig,
+                coin->second.out.scriptPubKey,
+                &tx.vin[i].scriptWitness,
+                pqr_flags,
+                TransactionSignatureChecker(
+                    &tx_const,
+                    i,
+                    coin->second.out.nValue,
+                    txdata,
+                    MissingDataBehavior::FAIL),
+                &serror)) {
+            input_errors[i] = ScriptErrorString(serror);
+            continue;
+        }
+
+        input_errors.erase(i);
+    }
+
+    return input_errors.empty();
 }
 
 SigningResult LegacyScriptPubKeyMan::SignMessage(const std::string& message, const PKHash& pkhash, std::string& str_sig) const
@@ -669,6 +1062,24 @@ std::unique_ptr<CKeyMetadata> LegacyScriptPubKeyMan::GetMetadata(const CTxDestin
 {
     LOCK(cs_KeyStore);
 
+    uint256 pq_key_id;
+    bool have_pq_key_id = false;
+
+    if (const auto* mldsa = std::get_if<WitnessV2MLDSA>(&dest)) {
+        pq_key_id = uint256(*mldsa);
+        have_pq_key_id = true;
+    } else if (const auto* slhdsa = std::get_if<WitnessV3SLHDSA>(&dest)) {
+        pq_key_id = uint256(*slhdsa);
+        have_pq_key_id = true;
+    }
+
+    if (have_pq_key_id) {
+        auto it = mapPQKeyMetadata.find(pq_key_id);
+        if (it != mapPQKeyMetadata.end()) {
+            return std::make_unique<CKeyMetadata>(it->second);
+        }
+    }
+
     CKeyID key_id = GetKeyForDestination(*this, dest);
     if (!key_id.IsNull()) {
         auto it = mapKeyMetadata.find(key_id);
@@ -781,6 +1192,13 @@ void LegacyScriptPubKeyMan::LoadKeyMetadata(const CKeyID& keyID, const CKeyMetad
     mapKeyMetadata[keyID] = meta;
 }
 
+void LegacyScriptPubKeyMan::LoadPQKeyMetadata(const uint256& key_id, const CKeyMetadata& meta)
+{
+    LOCK(cs_KeyStore);
+    UpdateTimeFirstKey(meta.nCreateTime);
+    mapPQKeyMetadata[key_id] = meta;
+}
+
 void LegacyScriptPubKeyMan::LoadScriptMetadata(const CScriptID& script_id, const CKeyMetadata& meta)
 {
     LOCK(cs_KeyStore);
@@ -821,6 +1239,174 @@ bool LegacyScriptPubKeyMan::LoadCryptedKey(const CPubKey &vchPubKey, const std::
     return AddCryptedKeyInner(vchPubKey, vchCryptedSecret);
 }
 
+bool LegacyScriptPubKeyMan::AddPQKeyInner(const uint256& key_id, OutputType type,
+                                           const std::vector<unsigned char>& pubkey,
+                                           const CKeyingMaterial& secret)
+{
+    LOCK(cs_KeyStore);
+    mapPQKeys[key_id] = PQKeyData{type, pubkey, secret};
+    return true;
+}
+
+bool LegacyScriptPubKeyMan::AddCryptedPQKeyInner(const uint256& key_id, OutputType type,
+                                                  const std::vector<unsigned char>& pubkey,
+                                                  const std::vector<unsigned char>& crypted_secret)
+{
+    LOCK(cs_KeyStore);
+    mapCryptedPQKeys[key_id] = CryptedPQKeyData{type, pubkey, crypted_secret};
+    return true;
+}
+
+bool LegacyScriptPubKeyMan::AddPQKey(WalletBatch& batch,
+                                     OutputType type,
+                                     const std::vector<unsigned char>& pubkey,
+                                     const CKeyingMaterial& secret,
+                                     uint256& key_id)
+{
+    const size_t expected_pubkey_size =
+        type == OutputType::MLDSA ? pq::MLDSA65::PUBKEY_BYTES :
+        type == OutputType::SLHDSA ? pq::SPHINCS128s::PUBKEY_BYTES : 0;
+
+    const size_t expected_secret_size =
+        type == OutputType::MLDSA ? pq::MLDSA65::SECKEY_BYTES :
+        type == OutputType::SLHDSA ? pq::SPHINCS128s::SECKEY_BYTES : 0;
+
+    if (expected_pubkey_size == 0 ||
+        pubkey.size() != expected_pubkey_size ||
+        secret.size() != expected_secret_size) {
+        return false;
+    }
+
+    CSHA256().Write(pubkey.data(), pubkey.size()).Finalize(key_id.begin());
+
+    LOCK(cs_KeyStore);
+
+    if (!m_storage.HasEncryptionKeys()) {
+        CKeyingMaterial secure_secret(secret.begin(), secret.end());
+        if (!AddPQKeyInner(key_id, type, pubkey, secure_secret)) {
+            return false;
+        }
+        const std::vector<unsigned char> db_secret(secret.begin(), secret.end());
+        return batch.WritePQKey(key_id, type, pubkey, db_secret);
+    }
+
+    if (m_storage.IsLocked()) {
+        return false;
+    }
+
+    CKeyingMaterial plain_secret(secret.begin(), secret.end());
+    std::vector<unsigned char> crypted_secret;
+    if (!EncryptSecret(m_storage.GetEncryptionKey(), plain_secret, key_id, crypted_secret)) {
+        return false;
+    }
+
+    if (!AddCryptedPQKeyInner(key_id, type, pubkey, crypted_secret)) {
+        return false;
+    }
+
+    return batch.WriteCryptedPQKey(
+        key_id, type, pubkey, crypted_secret);
+}
+
+bool LegacyScriptPubKeyMan::HavePQKey(const uint256& key_id) const
+{
+    LOCK(cs_KeyStore);
+    return mapPQKeys.count(key_id) != 0 || mapCryptedPQKeys.count(key_id) != 0;
+}
+
+bool LegacyScriptPubKeyMan::GetPQKey(const uint256& key_id, OutputType& type,
+                                     std::vector<unsigned char>& pubkey,
+                                     CKeyingMaterial& secret) const
+{
+    LOCK(cs_KeyStore);
+
+    auto plain_it = mapPQKeys.find(key_id);
+    if (plain_it != mapPQKeys.end()) {
+        type = plain_it->second.type;
+        pubkey = plain_it->second.pubkey;
+        secret.assign(plain_it->second.secret.begin(), plain_it->second.secret.end());
+        return true;
+    }
+
+    auto crypted_it = mapCryptedPQKeys.find(key_id);
+    if (crypted_it == mapCryptedPQKeys.end() || m_storage.IsLocked()) {
+        return false;
+    }
+
+    type = crypted_it->second.type;
+    pubkey = crypted_it->second.pubkey;
+
+    if (!DecryptSecret(
+            m_storage.GetEncryptionKey(),
+            crypted_it->second.crypted_secret,
+            key_id,
+            secret)) {
+        return false;
+    }
+
+    const size_t expected_secret_size =
+        type == OutputType::MLDSA ? pq::MLDSA65::SECKEY_BYTES :
+        type == OutputType::SLHDSA ? pq::SPHINCS128s::SECKEY_BYTES : 0;
+
+    return expected_secret_size != 0 && secret.size() == expected_secret_size;
+}
+
+bool LegacyScriptPubKeyMan::LoadPQKey(const uint256& key_id, OutputType type,
+                                      const std::vector<unsigned char>& pubkey,
+                                      const std::vector<unsigned char>& secret)
+{
+    const size_t expected_pubkey_size =
+        type == OutputType::MLDSA ? pq::MLDSA65::PUBKEY_BYTES :
+        type == OutputType::SLHDSA ? pq::SPHINCS128s::PUBKEY_BYTES : 0;
+
+    const size_t expected_secret_size =
+        type == OutputType::MLDSA ? pq::MLDSA65::SECKEY_BYTES :
+        type == OutputType::SLHDSA ? pq::SPHINCS128s::SECKEY_BYTES : 0;
+
+    if (expected_pubkey_size == 0 ||
+        pubkey.size() != expected_pubkey_size ||
+        secret.size() != expected_secret_size) {
+        return false;
+    }
+
+    uint256 calculated_id;
+    CSHA256().Write(pubkey.data(), pubkey.size()).Finalize(calculated_id.begin());
+    if (calculated_id != key_id) {
+        return false;
+    }
+
+    LOCK(cs_KeyStore);
+    CKeyingMaterial secure_secret(secret.begin(), secret.end());
+    mapPQKeys[key_id] = PQKeyData{type, pubkey, std::move(secure_secret)};
+    return true;
+}
+
+bool LegacyScriptPubKeyMan::LoadCryptedPQKey(const uint256& key_id, OutputType type,
+                                             const std::vector<unsigned char>& pubkey,
+                                             const std::vector<unsigned char>& crypted_secret)
+{
+    const size_t expected_pubkey_size =
+        type == OutputType::MLDSA ? pq::MLDSA65::PUBKEY_BYTES :
+        type == OutputType::SLHDSA ? pq::SPHINCS128s::PUBKEY_BYTES : 0;
+
+    if (expected_pubkey_size == 0 ||
+        pubkey.size() != expected_pubkey_size ||
+        crypted_secret.empty()) {
+        return false;
+    }
+
+    uint256 calculated_id;
+    CSHA256().Write(pubkey.data(), pubkey.size()).Finalize(calculated_id.begin());
+    if (calculated_id != key_id) {
+        return false;
+    }
+
+    LOCK(cs_KeyStore);
+    mapCryptedPQKeys[key_id] = CryptedPQKeyData{type, pubkey, crypted_secret};
+    return true;
+}
+
+
 bool LegacyScriptPubKeyMan::AddCryptedKeyInner(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret)
 {
     LOCK(cs_KeyStore);
@@ -944,6 +1530,95 @@ void LegacyScriptPubKeyMan::LoadHDChain(const CHDChain& chain)
     m_hd_chain = chain;
 }
 
+void LegacyScriptPubKeyMan::LoadPQHDChain(const PQHDChain& chain)
+{
+    LOCK(cs_KeyStore);
+    m_pq_hd_chain = chain;
+}
+
+bool LegacyScriptPubKeyMan::ReconcilePQHDChain(WalletBatch& batch, std::string& error)
+{
+    LOCK(cs_KeyStore);
+
+    if (m_hd_chain.seed_id.IsNull()) {
+        return true;
+    }
+
+    uint32_t next_mldsa = 0;
+    uint32_t next_slhdsa = 0;
+    bool have_pq_metadata = false;
+
+    for (const auto& item : mapPQKeyMetadata) {
+        const CKeyMetadata& meta = item.second;
+
+        if (meta.hd_seed_id != m_hd_chain.seed_id) {
+            continue;
+        }
+
+        const std::string mldsa_prefix = "pq/mldsa/";
+        const std::string slhdsa_prefix = "pq/slhdsa/";
+
+        uint32_t index = 0;
+
+        if (meta.hdKeypath.rfind(mldsa_prefix, 0) == 0) {
+            if (!ParseUInt32(meta.hdKeypath.substr(mldsa_prefix.size()), &index)) {
+                error = "Invalid ML-DSA post-quantum derivation metadata";
+                return false;
+            }
+            if (index == std::numeric_limits<uint32_t>::max()) {
+                error = "ML-DSA post-quantum derivation counter exhausted";
+                return false;
+            }
+            next_mldsa = std::max(next_mldsa, index + 1);
+            have_pq_metadata = true;
+        } else if (meta.hdKeypath.rfind(slhdsa_prefix, 0) == 0) {
+            if (!ParseUInt32(meta.hdKeypath.substr(slhdsa_prefix.size()), &index)) {
+                error = "Invalid SLH-DSA post-quantum derivation metadata";
+                return false;
+            }
+            if (index == std::numeric_limits<uint32_t>::max()) {
+                error = "SLH-DSA post-quantum derivation counter exhausted";
+                return false;
+            }
+            next_slhdsa = std::max(next_slhdsa, index + 1);
+            have_pq_metadata = true;
+        }
+    }
+
+    PQHDChain reconciled = m_pq_hd_chain;
+
+    if (reconciled.seed_id.IsNull()) {
+        reconciled.seed_id = m_hd_chain.seed_id;
+        reconciled.nMLDSAExternalCounter = next_mldsa;
+        reconciled.nSLHDSAExternalCounter = next_slhdsa;
+    } else if (reconciled.seed_id != m_hd_chain.seed_id) {
+        if (!have_pq_metadata) {
+            error = "Post-quantum HD chain seed does not match the active wallet seed";
+            return false;
+        }
+        reconciled.seed_id = m_hd_chain.seed_id;
+        reconciled.nMLDSAExternalCounter = next_mldsa;
+        reconciled.nSLHDSAExternalCounter = next_slhdsa;
+    } else {
+        reconciled.nMLDSAExternalCounter =
+            std::max(reconciled.nMLDSAExternalCounter, next_mldsa);
+        reconciled.nSLHDSAExternalCounter =
+            std::max(reconciled.nSLHDSAExternalCounter, next_slhdsa);
+    }
+
+    if (reconciled.seed_id != m_pq_hd_chain.seed_id ||
+        reconciled.nMLDSAExternalCounter != m_pq_hd_chain.nMLDSAExternalCounter ||
+        reconciled.nSLHDSAExternalCounter != m_pq_hd_chain.nSLHDSAExternalCounter) {
+        if (!batch.WritePQHDChain(reconciled)) {
+            error = "Failed to write reconciled post-quantum HD chain";
+            return false;
+        }
+        m_pq_hd_chain = reconciled;
+    }
+
+    return true;
+}
+
 void LegacyScriptPubKeyMan::AddHDChain(const CHDChain& chain)
 {
     LOCK(cs_KeyStore);
@@ -1208,6 +1883,14 @@ void LegacyScriptPubKeyMan::SetHDSeed(const CPubKey& seed)
     newHdChain.nVersion = m_storage.CanSupportFeature(FEATURE_HD_SPLIT) ? CHDChain::VERSION_HD_CHAIN_SPLIT : CHDChain::VERSION_HD_BASE;
     newHdChain.seed_id = seed.GetID();
     AddHDChain(newHdChain);
+
+    PQHDChain newPQHDChain;
+    newPQHDChain.seed_id = seed.GetID();
+    if (!WalletBatch(m_storage.GetDatabase()).WritePQHDChain(newPQHDChain)) {
+        throw std::runtime_error(std::string(__func__) + ": writing post-quantum HD chain failed");
+    }
+    m_pq_hd_chain = newPQHDChain;
+
     NotifyCanGetAddressesChanged();
     WalletBatch batch(m_storage.GetDatabase());
     m_storage.UnsetBlankWalletFlag(batch);
diff --git a/src/wallet/scriptpubkeyman.h b/src/wallet/scriptpubkeyman.h
index c0b5c1c..2fbceba 100644
--- a/src/wallet/scriptpubkeyman.h
+++ b/src/wallet/scriptpubkeyman.h
@@ -256,6 +256,8 @@ static const std::unordered_set<OutputType> LEGACY_OUTPUT_TYPES {
     OutputType::LEGACY,
     OutputType::P2SH_SEGWIT,
     OutputType::BECH32,
+    OutputType::MLDSA,
+    OutputType::SLHDSA,
 };
 
 class LegacyScriptPubKeyMan : public ScriptPubKeyMan, public FillableSigningProvider
@@ -271,7 +273,24 @@ private:
 
     using CryptedKeyMap = std::map<CKeyID, std::pair<CPubKey, std::vector<unsigned char>>>;
 
+    struct PQKeyData {
+        OutputType type;
+        std::vector<unsigned char> pubkey;
+        CKeyingMaterial secret;
+    };
+
+    struct CryptedPQKeyData {
+        OutputType type;
+        std::vector<unsigned char> pubkey;
+        std::vector<unsigned char> crypted_secret;
+    };
+
+    using PQKeyMap = std::map<uint256, PQKeyData>;
+    using CryptedPQKeyMap = std::map<uint256, CryptedPQKeyData>;
+
     CryptedKeyMap mapCryptedKeys GUARDED_BY(cs_KeyStore);
+    PQKeyMap mapPQKeys GUARDED_BY(cs_KeyStore);
+    CryptedPQKeyMap mapCryptedPQKeys GUARDED_BY(cs_KeyStore);
     WatchOnlySet setWatchOnly GUARDED_BY(cs_KeyStore);
     WatchKeyMap mapWatchKeys GUARDED_BY(cs_KeyStore);
 
@@ -280,6 +299,13 @@ private:
     bool AddKeyPubKeyInner(const CKey& key, const CPubKey &pubkey);
     bool AddCryptedKeyInner(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret);
 
+    bool AddPQKeyInner(const uint256& key_id, OutputType type,
+                       const std::vector<unsigned char>& pubkey,
+                       const CKeyingMaterial& secret);
+    bool AddCryptedPQKeyInner(const uint256& key_id, OutputType type,
+                              const std::vector<unsigned char>& pubkey,
+                              const std::vector<unsigned char>& crypted_secret);
+
     /**
      * Private version of AddWatchOnly method which does not accept a
      * timestamp, and which will reset the wallet's nTimeFirstKey value to 1 if
@@ -308,6 +334,7 @@ private:
 
     /* the HD chain data model (external chain counters) */
     CHDChain m_hd_chain;
+    PQHDChain m_pq_hd_chain GUARDED_BY(cs_KeyStore);
     std::unordered_map<CKeyID, CHDChain, SaltedSipHasher> m_inactive_hd_chains;
 
     /* HD derive new child key (on internal or external chain) */
@@ -405,6 +432,9 @@ public:
     // Map from Key ID to key metadata.
     std::map<CKeyID, CKeyMetadata> mapKeyMetadata GUARDED_BY(cs_KeyStore);
 
+    // Map from post-quantum key ID to key metadata.
+    std::map<uint256, CKeyMetadata> mapPQKeyMetadata GUARDED_BY(cs_KeyStore);
+
     // Map from Script ID to key metadata (for watch-only keys).
     std::map<CScriptID, CKeyMetadata> m_script_metadata GUARDED_BY(cs_KeyStore);
 
@@ -416,11 +446,32 @@ public:
     bool AddCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret);
     //! Adds an encrypted key to the store, without saving it to disk (used by LoadWallet)
     bool LoadCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret, bool checksum_valid);
+
+    //! Load post-quantum keys from the wallet database.
+    bool LoadPQKey(const uint256& key_id, OutputType type,
+                   const std::vector<unsigned char>& pubkey,
+                   const std::vector<unsigned char>& secret);
+    bool LoadCryptedPQKey(const uint256& key_id, OutputType type,
+                          const std::vector<unsigned char>& pubkey,
+                          const std::vector<unsigned char>& crypted_secret);
+
+    bool AddPQKey(WalletBatch& batch,
+                  OutputType type,
+                  const std::vector<unsigned char>& pubkey,
+                  const CKeyingMaterial& secret,
+                  uint256& key_id);
+
+    bool HavePQKey(const uint256& key_id) const;
+    bool GetPQKey(const uint256& key_id, OutputType& type,
+                  std::vector<unsigned char>& pubkey,
+                  CKeyingMaterial& secret) const;
+
     void UpdateTimeFirstKey(int64_t nCreateTime) EXCLUSIVE_LOCKS_REQUIRED(cs_KeyStore);
     //! Adds a CScript to the store
     bool LoadCScript(const CScript& redeemScript);
     //! Load metadata (used by LoadWallet)
     void LoadKeyMetadata(const CKeyID& keyID, const CKeyMetadata &metadata);
+    void LoadPQKeyMetadata(const uint256& key_id, const CKeyMetadata &metadata);
     void LoadScriptMetadata(const CScriptID& script_id, const CKeyMetadata &metadata);
     //! Generate a new key
     CPubKey GenerateNewKey(WalletBatch& batch, CHDChain& hd_chain, bool internal = false) EXCLUSIVE_LOCKS_REQUIRED(cs_KeyStore);
@@ -429,7 +480,10 @@ public:
     void AddHDChain(const CHDChain& chain);
     //! Load a HD chain model (used by LoadWallet)
     void LoadHDChain(const CHDChain& chain);
+    void LoadPQHDChain(const PQHDChain& chain);
+    bool ReconcilePQHDChain(WalletBatch& batch, std::string& error);
     const CHDChain& GetHDChain() const { return m_hd_chain; }
+    const PQHDChain& GetPQHDChain() const { return m_pq_hd_chain; }
     void AddInactiveHDChain(const CHDChain& chain);
 
     //! Adds a watch-only address to the store, without saving it to disk (used by LoadWallet)
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 66cb671..fcc7e05 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -9,6 +9,7 @@
 #include <chain.h>
 #include <consensus/consensus.h>
 #include <consensus/validation.h>
+#include <crypto/pq/pq.h>
 #include <external_signer.h>
 #include <fs.h>
 #include <interfaces/chain.h>
@@ -1452,6 +1453,26 @@ bool CWallet::DummySignInput(CTxIn &tx_in, const CTxOut &txout, bool use_max_sig
     const CScript& scriptPubKey = txout.scriptPubKey;
     SignatureData sigdata;
 
+    TxoutType type;
+    std::vector<std::vector<unsigned char>> solutions;
+    type = Solver(scriptPubKey, solutions);
+
+    if (type == TxoutType::WITNESS_V2_MLDSA) {
+        tx_in.scriptWitness.stack = {
+            std::vector<unsigned char>(pq::MLDSA65::SIG_BYTES),
+            std::vector<unsigned char>(pq::MLDSA65::PUBKEY_BYTES),
+        };
+        return true;
+    }
+
+    if (type == TxoutType::WITNESS_V3_SLHDSA) {
+        tx_in.scriptWitness.stack = {
+            std::vector<unsigned char>(pq::SPHINCS128s::SIG_BYTES),
+            std::vector<unsigned char>(pq::SPHINCS128s::PUBKEY_BYTES),
+        };
+        return true;
+    }
+
     std::unique_ptr<SigningProvider> provider = GetSolvingProvider(scriptPubKey);
     if (!provider) {
         // We don't know about this scriptpbuKey;
@@ -2598,6 +2619,11 @@ std::shared_ptr<CWallet> CWallet::Create(interfaces::Chain* chain, const std::st
             error = strprintf(_("Unknown address type '%s'"), gArgs.GetArg("-addresstype", ""));
             return nullptr;
         }
+        if (walletInstance->m_default_address_type == OutputType::MLDSA ||
+            walletInstance->m_default_address_type == OutputType::SLHDSA) {
+            error = _("Post-quantum address types cannot be used as the default wallet address type");
+            return nullptr;
+        }
     }
 
     if (!gArgs.GetArg("-changetype", "").empty()) {
@@ -2606,6 +2632,10 @@ std::shared_ptr<CWallet> CWallet::Create(interfaces::Chain* chain, const std::st
             error = strprintf(_("Unknown change type '%s'"), gArgs.GetArg("-changetype", ""));
             return nullptr;
         }
+        if (out_type == OutputType::MLDSA || out_type == OutputType::SLHDSA) {
+            error = _("Post-quantum address types cannot be used for change addresses");
+            return nullptr;
+        }
         walletInstance->m_default_change_type = out_type;
     }
 
@@ -3123,9 +3153,10 @@ void CWallet::SetupDescriptorScriptPubKeyMans()
 
         for (bool internal : {false, true}) {
             for (OutputType t : OUTPUT_TYPES) {
-                if (t == OutputType::BECH32M) {
-                    // Skip taproot (bech32m) for now
-                    // TODO: Setup taproot (bech32m) descriptors by default
+                if (t == OutputType::BECH32M ||
+                    t == OutputType::MLDSA ||
+                    t == OutputType::SLHDSA) {
+                    // Skip output types that do not use the standard EC descriptor path.
                     continue;
                 }
                 auto spk_manager = std::unique_ptr<DescriptorScriptPubKeyMan>(new DescriptorScriptPubKeyMan(*this));
diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index b3544be..c9851ef 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -34,6 +34,7 @@ const std::string ACTIVEINTERNALSPK{"activeinternalspk"};
 const std::string BESTBLOCK_NOMERKLE{"bestblock_nomerkle"};
 const std::string BESTBLOCK{"bestblock"};
 const std::string CRYPTED_KEY{"ckey"};
+const std::string CRYPTED_PQKEY{"cpqkey"};
 const std::string CSCRIPT{"cscript"};
 const std::string DEFAULTKEY{"defaultkey"};
 const std::string DESTDATA{"destdata"};
@@ -47,6 +48,9 @@ const std::string NAME{"name"};
 const std::string OLD_KEY{"wkey"};
 const std::string ORDERPOSNEXT{"orderposnext"};
 const std::string POOL{"pool"};
+const std::string PQKEY{"pqkey"};
+const std::string PQKEYMETA{"pqkeymeta"};
+const std::string PQHDCHAIN{"pqhdchain"};
 const std::string PURPOSE{"purpose"};
 const std::string SETTINGS{"settings"};
 const std::string TX{"tx"};
@@ -101,6 +105,11 @@ bool WalletBatch::WriteKeyMetadata(const CKeyMetadata& meta, const CPubKey& pubk
     return WriteIC(std::make_pair(DBKeys::KEYMETA, pubkey), meta, overwrite);
 }
 
+bool WalletBatch::WritePQKeyMetadata(const CKeyMetadata& meta, const uint256& key_id, const bool overwrite)
+{
+    return WriteIC(std::make_pair(DBKeys::PQKEYMETA, key_id), meta, overwrite);
+}
+
 bool WalletBatch::WriteKey(const CPubKey& vchPubKey, const CPrivKey& vchPrivKey, const CKeyMetadata& keyMeta)
 {
     if (!WriteKeyMetadata(keyMeta, vchPubKey, false)) {
@@ -142,6 +151,32 @@ bool WalletBatch::WriteCryptedKey(const CPubKey& vchPubKey,
     return true;
 }
 
+bool WalletBatch::WritePQKey(const uint256& key_id, OutputType type,
+                               const std::vector<unsigned char>& pubkey,
+                               const std::vector<unsigned char>& secret)
+{
+    return WriteIC(std::make_pair(DBKeys::PQKEY, key_id),
+                   PQKeyRecord{static_cast<uint8_t>(type), pubkey, secret}, false);
+}
+
+bool WalletBatch::WriteCryptedPQKey(const uint256& key_id, OutputType type,
+                                      const std::vector<unsigned char>& pubkey,
+                                      const std::vector<unsigned char>& crypted_secret)
+{
+    if (!WriteIC(std::make_pair(DBKeys::CRYPTED_PQKEY, key_id),
+                 PQKeyRecord{static_cast<uint8_t>(type), pubkey, crypted_secret}, false)) {
+        return false;
+    }
+
+    ErasePQKey(key_id);
+    return true;
+}
+
+bool WalletBatch::ErasePQKey(const uint256& key_id)
+{
+    return EraseIC(std::make_pair(DBKeys::PQKEY, key_id));
+}
+
 bool WalletBatch::WriteMasterKey(unsigned int nID, const CMasterKey& kMasterKey)
 {
     return WriteIC(std::make_pair(DBKeys::MASTER_KEY, nID), kMasterKey, true);
@@ -477,6 +512,52 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
                 return false;
             }
             wss.fIsEncrypted = true;
+        } else if (strType == DBKeys::PQKEY) {
+            uint256 key_id;
+            ssKey >> key_id;
+
+            PQKeyRecord record;
+            ssValue >> record;
+
+            const OutputType type = static_cast<OutputType>(record.type);
+            if (type != OutputType::MLDSA && type != OutputType::SLHDSA) {
+                strErr = "Error reading wallet database: invalid PQ key type";
+                return false;
+            }
+
+            if (!pwallet->GetOrCreateLegacyScriptPubKeyMan()->LoadPQKey(
+                    key_id, type, record.pubkey, record.secret)) {
+                strErr = "Error reading wallet database: LegacyScriptPubKeyMan::LoadPQKey failed";
+                return false;
+            }
+            wss.nKeys++;
+        } else if (strType == DBKeys::CRYPTED_PQKEY) {
+            uint256 key_id;
+            ssKey >> key_id;
+
+            PQKeyRecord record;
+            ssValue >> record;
+
+            const OutputType type = static_cast<OutputType>(record.type);
+            if (type != OutputType::MLDSA && type != OutputType::SLHDSA) {
+                strErr = "Error reading wallet database: invalid encrypted PQ key type";
+                return false;
+            }
+
+            if (!pwallet->GetOrCreateLegacyScriptPubKeyMan()->LoadCryptedPQKey(
+                    key_id, type, record.pubkey, record.secret)) {
+                strErr = "Error reading wallet database: LegacyScriptPubKeyMan::LoadCryptedPQKey failed";
+                return false;
+            }
+            wss.nCKeys++;
+            wss.fIsEncrypted = true;
+        } else if (strType == DBKeys::PQKEYMETA) {
+            uint256 key_id;
+            ssKey >> key_id;
+            CKeyMetadata keyMeta;
+            ssValue >> keyMeta;
+            wss.nKeyMeta++;
+            pwallet->GetOrCreateLegacyScriptPubKeyMan()->LoadPQKeyMetadata(key_id, keyMeta);
         } else if (strType == DBKeys::KEYMETA) {
             CPubKey vchPubKey;
             ssKey >> vchPubKey;
@@ -589,6 +670,10 @@ ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue,
             CHDChain chain;
             ssValue >> chain;
             pwallet->GetOrCreateLegacyScriptPubKeyMan()->LoadHDChain(chain);
+        } else if (strType == DBKeys::PQHDCHAIN) {
+            PQHDChain chain;
+            ssValue >> chain;
+            pwallet->GetOrCreateLegacyScriptPubKeyMan()->LoadPQHDChain(chain);
         } else if (strType == DBKeys::OLD_KEY) {
             strErr = "Found unsupported 'wkey' record, try loading with version 0.18";
             return false;
@@ -732,7 +817,11 @@ bool ReadKeyValue(CWallet* pwallet, CDataStream& ssKey, CDataStream& ssValue, st
 bool WalletBatch::IsKeyType(const std::string& strType)
 {
     return (strType == DBKeys::KEY ||
-            strType == DBKeys::MASTER_KEY || strType == DBKeys::CRYPTED_KEY);
+            strType == DBKeys::MASTER_KEY ||
+            strType == DBKeys::CRYPTED_KEY ||
+            strType == DBKeys::PQKEY ||
+            strType == DBKeys::CRYPTED_PQKEY ||
+            strType == DBKeys::PQKEYMETA);
 }
 
 DBErrors WalletBatch::LoadWallet(CWallet* pwallet)
@@ -851,6 +940,26 @@ DBErrors WalletBatch::LoadWallet(CWallet* pwallet)
     if (result != DBErrors::LOAD_OK)
         return result;
 
+    // Reconcile the post-quantum HD derivation state after all wallet
+    // database records have been loaded.
+    if (LegacyScriptPubKeyMan* legacy_spkm = pwallet->GetLegacyScriptPubKeyMan()) {
+        std::string pq_error;
+        if (!legacy_spkm->ReconcilePQHDChain(*this, pq_error)) {
+            pwallet->WalletLogPrintf("Error reconciling post-quantum HD chain: %s\n", pq_error);
+            return DBErrors::CORRUPT;
+        }
+    }
+
+    // Reconcile the post-quantum HD derivation state after all wallet
+    // database records have been loaded.
+    if (LegacyScriptPubKeyMan* legacy_spkm = pwallet->GetLegacyScriptPubKeyMan()) {
+        std::string pq_error;
+        if (!legacy_spkm->ReconcilePQHDChain(*this, pq_error)) {
+            pwallet->WalletLogPrintf("Error reconciling post-quantum HD chain: %s\n", pq_error);
+            return DBErrors::CORRUPT;
+        }
+    }
+
     // Last client version to open this wallet, was previously the file version number
     int last_client = CLIENT_VERSION;
     m_batch->Read(DBKeys::VERSION, last_client);
@@ -1048,6 +1157,11 @@ bool WalletBatch::WriteHDChain(const CHDChain& chain)
     return WriteIC(DBKeys::HDCHAIN, chain);
 }
 
+bool WalletBatch::WritePQHDChain(const PQHDChain& chain)
+{
+    return WriteIC(DBKeys::PQHDCHAIN, chain);
+}
+
 bool WalletBatch::WriteWalletFlags(const uint64_t flags)
 {
     return WriteIC(DBKeys::FLAGS, flags);
diff --git a/src/wallet/walletdb.h b/src/wallet/walletdb.h
index 5a87846..8a254c1 100644
--- a/src/wallet/walletdb.h
+++ b/src/wallet/walletdb.h
@@ -39,6 +39,7 @@ class CWallet;
 class CWalletTx;
 class uint160;
 class uint256;
+enum class OutputType;
 
 /** Error statuses for the wallet database */
 enum class DBErrors
@@ -51,6 +52,30 @@ enum class DBErrors
     NEED_REWRITE
 };
 
+struct PQKeyRecord
+{
+    uint8_t type;
+    std::vector<unsigned char> pubkey;
+    std::vector<unsigned char> secret;
+
+    SERIALIZE_METHODS(PQKeyRecord, obj)
+    {
+        READWRITE(obj.type, obj.pubkey, obj.secret);
+    }
+};
+
+struct PQHDChain
+{
+    uint32_t nMLDSAExternalCounter{0};
+    uint32_t nSLHDSAExternalCounter{0};
+    CKeyID seed_id;
+
+    SERIALIZE_METHODS(PQHDChain, obj)
+    {
+        READWRITE(obj.nMLDSAExternalCounter, obj.nSLHDSAExternalCounter, obj.seed_id);
+    }
+};
+
 namespace DBKeys {
 extern const std::string ACENTRY;
 extern const std::string ACTIVEEXTERNALSPK;
@@ -58,6 +83,7 @@ extern const std::string ACTIVEINTERNALSPK;
 extern const std::string BESTBLOCK;
 extern const std::string BESTBLOCK_NOMERKLE;
 extern const std::string CRYPTED_KEY;
+extern const std::string CRYPTED_PQKEY;
 extern const std::string CSCRIPT;
 extern const std::string DEFAULTKEY;
 extern const std::string DESTDATA;
@@ -71,6 +97,10 @@ extern const std::string NAME;
 extern const std::string OLD_KEY;
 extern const std::string ORDERPOSNEXT;
 extern const std::string POOL;
+extern const std::string PQKEY;
+extern const std::string PQKEYMETA;
+extern const std::string PQHDCHAIN;
+extern const std::string PQHDCHAIN;
 extern const std::string PURPOSE;
 extern const std::string SETTINGS;
 extern const std::string TX;
@@ -222,8 +252,12 @@ public:
     bool EraseTx(uint256 hash);
 
     bool WriteKeyMetadata(const CKeyMetadata& meta, const CPubKey& pubkey, const bool overwrite);
+    bool WritePQKeyMetadata(const CKeyMetadata& meta, const uint256& key_id, const bool overwrite);
     bool WriteKey(const CPubKey& vchPubKey, const CPrivKey& vchPrivKey, const CKeyMetadata &keyMeta);
     bool WriteCryptedKey(const CPubKey& vchPubKey, const std::vector<unsigned char>& vchCryptedSecret, const CKeyMetadata &keyMeta);
+    bool WritePQKey(const uint256& key_id, OutputType type, const std::vector<unsigned char>& pubkey, const std::vector<unsigned char>& secret);
+    bool WriteCryptedPQKey(const uint256& key_id, OutputType type, const std::vector<unsigned char>& pubkey, const std::vector<unsigned char>& crypted_secret);
+    bool ErasePQKey(const uint256& key_id);
     bool WriteMasterKey(unsigned int nID, const CMasterKey& kMasterKey);
 
     bool WriteCScript(const uint160& hash, const CScript& redeemScript);
@@ -266,6 +300,7 @@ public:
 
     //! write the hdchain model (external chain child index counter)
     bool WriteHDChain(const CHDChain& chain);
+    bool WritePQHDChain(const PQHDChain& chain);
 
     bool WriteWalletFlags(const uint64_t flags);
     //! Begin a new transaction