feat: serialize on the stack

src/bls/bls.h

@@ -123,6 +123,14 @@ public:
         cachedHash.SetNull();
     }
 
+    std::array<uint8_t, SerSize> ToBytes(const bool specificLegacyScheme) const
+    {
+        if (!fValid) {
+            return std::array<uint8_t, SerSize>{};
+        }
+        return impl.SerializeToArray(specificLegacyScheme);
+    }
+
     std::vector<uint8_t> ToByteVector(const bool specificLegacyScheme) const
     {
         if (!fValid) {
@@ -131,9 +139,9 @@ public:
         return impl.Serialize(specificLegacyScheme);
     }
 
-    std::vector<uint8_t> ToByteVector() const
+    std::array<uint8_t, SerSize> ToBytes() const
     {
-        return ToByteVector(bls::bls_legacy_scheme.load());
+        return ToBytes(bls::bls_legacy_scheme.load());
     }
 
     const uint256& GetHash() const
@@ -167,7 +175,7 @@ public:
     template <typename Stream>
     inline void Serialize(Stream& s, const bool specificLegacyScheme) const
     {
-        s.write(AsBytes(Span{ToByteVector(specificLegacyScheme).data(), SerSize}));
+        s.write(AsBytes(Span{ToBytes(specificLegacyScheme)}));
     }
 
     template <typename Stream>
@@ -206,7 +214,7 @@ public:
 
     inline bool CheckMalleable(Span<uint8_t> vecBytes, const bool specificLegacyScheme) const
     {
-        if (memcmp(vecBytes.data(), ToByteVector(specificLegacyScheme).data(), SerSize)) {
+        if (memcmp(vecBytes.data(), ToBytes(specificLegacyScheme).data(), SerSize)) {
             // TODO not sure if this is actually possible with the BLS libs. I'm assuming here that somewhere deep inside
             // these libs masking might happen, so that 2 different binary representations could result in the same object
             // representation
@@ -222,7 +230,7 @@ public:
 
     inline std::string ToString(const bool specificLegacyScheme) const
     {
-        std::vector<uint8_t> buf = ToByteVector(specificLegacyScheme);
+        auto buf = ToBytes(specificLegacyScheme);
         return HexStr(buf);
     }
 
@@ -245,10 +253,12 @@ struct CBLSIdImplicit : public uint256
         memcpy(instance.begin(), buffer, sizeof(CBLSIdImplicit));
         return instance;
     }
-    [[nodiscard]] std::vector<uint8_t> Serialize(const bool fLegacy) const
+    [[nodiscard]] std::vector<uint8_t> SerializeToVec(const bool fLegacy) const
     {
         return {begin(), end()};
     }
+    [[nodiscard]] std::array<uint8_t, WIDTH> Serialize(const bool fLegacy) const { return m_data; }
+    [[nodiscard]] std::array<uint8_t, WIDTH> SerializeToArray(const bool fLegacy) const { return Serialize(fLegacy); }
 };
 
 class CBLSId : public CBLSWrapper<CBLSIdImplicit, BLS_CURVE_ID_SIZE, CBLSId>
@@ -381,7 +391,7 @@ class CBLSLazyWrapper
 private:
     mutable std::mutex mutex;
 
-    mutable std::vector<uint8_t> vecBytes;
+    mutable std::array<uint8_t, BLSObject::SerSize> vecBytes{};
     mutable bool bufValid{false};
     mutable bool bufLegacyScheme{true};
 
@@ -392,7 +402,6 @@ private:
 
 public:
     CBLSLazyWrapper() :
-            vecBytes(BLSObject::SerSize, 0),
             bufLegacyScheme(bls::bls_legacy_scheme.load())
     {}
 
@@ -410,7 +419,6 @@ public:
         if (r.bufValid) {
             vecBytes = r.vecBytes;
         } else {
-            vecBytes.resize(BLSObject::SerSize);
             std::fill(vecBytes.begin(), vecBytes.end(), 0);
         }
         objInitialized = r.objInitialized;
@@ -433,10 +441,9 @@ public:
     {
         std::unique_lock<std::mutex> l(mutex);
         if (!objInitialized && !bufValid) {
-            vecBytes.resize(BLSObject::SerSize);
             std::fill(vecBytes.begin(), vecBytes.end(), 0);
         } else if (!bufValid || (bufLegacyScheme != specificLegacyScheme)) {
-            vecBytes = obj.ToByteVector(specificLegacyScheme);
+            vecBytes = obj.ToBytes(specificLegacyScheme);
             bufValid = true;
             bufLegacyScheme = specificLegacyScheme;
             hash.SetNull();
@@ -518,11 +525,10 @@ public:
     {
         std::unique_lock<std::mutex> l(mutex);
         if (!objInitialized && !bufValid) {
-            vecBytes.resize(BLSObject::SerSize);
             std::fill(vecBytes.begin(), vecBytes.end(), 0);
             hash.SetNull();
         } else if (!bufValid) {
-            vecBytes = obj.ToByteVector(bufLegacyScheme);
+            vecBytes = obj.ToBytes(bufLegacyScheme);
             bufValid = true;
             hash.SetNull();
         }

src/bls/bls_ies.cpp

@@ -49,8 +49,7 @@ bool CBLSIESEncryptedBlob::Encrypt(size_t idx, const CBLSPublicKey& peerPubKey,
         return false;
     }
 
-    std::vector<unsigned char> symKey = pk.ToByteVector();
+    auto symKey = pk.ToBytes();
-    symKey.resize(32);
 
     uint256 iv = GetIV(idx);
     return EncryptBlob(plainTextData, dataSize, data, symKey.data(), iv.begin());
@@ -63,10 +62,9 @@ bool CBLSIESEncryptedBlob::Decrypt(size_t idx, const CBLSSecretKey& secretKey, C
         return false;
     }
 
-    std::vector<unsigned char> symKey = pk.ToByteVector();
-    symKey.resize(32);
-
     uint256 iv = GetIV(idx);
+    auto symKey = pk.ToBytes();
+
     return DecryptBlob(data.data(), data.size(), decryptedDataRet, symKey.data(), iv.begin());
 }
 
@@ -117,8 +115,7 @@ bool CBLSIESMultiRecipientBlobs::Encrypt(size_t idx, const CBLSPublicKey& recipi
         return false;
     }
 
-    std::vector<uint8_t> symKey = pk.ToByteVector();
+    auto symKey = pk.ToBytes();
-    symKey.resize(32);
 
     return EncryptBlob(blob.data(), blob.size(), blobs[idx], symKey.data(), ivVector[idx].begin());
 }
@@ -134,13 +131,11 @@ bool CBLSIESMultiRecipientBlobs::Decrypt(size_t idx, const CBLSSecretKey& sk, Bl
         return false;
     }
 
-    std::vector<uint8_t> symKey = pk.ToByteVector();
-    symKey.resize(32);
-
     uint256 iv = ivSeed;
     for (size_t i = 0; i < idx; i++) {
         iv = ::SerializeHash(iv);
     }
+    auto symKey = pk.ToBytes();
 
     return DecryptBlob(blobs[idx].data(), blobs[idx].size(), blobRet, symKey.data(), iv.begin());
 }

src/coinjoin/coinjoin.cpp

@@ -55,7 +55,7 @@ bool CCoinJoinQueue::Sign(const CActiveMasternodeManager& mn_activeman)
     if (!sig.IsValid()) {
         return false;
     }
-    vchSig = sig.ToByteVector(false);
+    vchSig = sig.ToBytes(false);
 
     return true;
 }
@@ -94,7 +94,7 @@ bool CCoinJoinBroadcastTx::Sign(const CActiveMasternodeManager& mn_activeman)
     if (!sig.IsValid()) {
         return false;
     }
-    vchSig = sig.ToByteVector(false);
+    vchSig = sig.ToBytes(false);
 
     return true;
 }

src/coinjoin/coinjoin.h

@@ -7,6 +7,7 @@
 
 #include <coinjoin/common.h>
 
+#include <bls/bls.h>
 #include <core_io.h>
 #include <netaddress.h>
 #include <primitives/block.h>
@@ -183,7 +184,7 @@ public:
     uint256 m_protxHash;
     int64_t nTime{0};
     bool fReady{false}; //ready for submit
-    std::vector<unsigned char> vchSig;
+    std::array<unsigned char, BLS_CURVE_SIG_SIZE> vchSig;
     // memory only
     bool fTried{false};
 
@@ -243,7 +244,7 @@ public:
     CTransactionRef tx;
     COutPoint masternodeOutpoint;
     uint256 m_protxHash;
-    std::vector<unsigned char> vchSig;
+    std::array<unsigned char, BLS_CURVE_SIG_SIZE> vchSig;
     int64_t sigTime{0};
     CCoinJoinBroadcastTx() :
         tx(MakeTransactionRef(CMutableTransaction{}))

src/llmq/dkgsession.cpp

@@ -1016,12 +1016,12 @@ void CDKGSession::SendCommitment(CDKGPendingMessages& pendingMessages, PeerManag
 
     if (lieType == 3) {
         const bool is_bls_legacy = bls::bls_legacy_scheme.load();
-        std::vector<uint8_t> buf = qc.sig.ToByteVector(is_bls_legacy);
+        auto buf = qc.sig.ToBytes(is_bls_legacy);
         buf[5]++;
         qc.sig.SetByteVector(buf, is_bls_legacy);
     } else if (lieType == 4) {
         const bool is_bls_legacy = bls::bls_legacy_scheme.load();
-        std::vector<uint8_t> buf = qc.quorumSig.ToByteVector(is_bls_legacy);
+        auto buf = qc.quorumSig.ToBytes(is_bls_legacy);
         buf[5]++;
         qc.quorumSig.SetByteVector(buf, is_bls_legacy);
     }

src/serialize.h

@@ -820,6 +820,9 @@ template<typename Stream, unsigned int N, typename T> inline void Unserialize(St
 template<typename Stream, typename T, typename A> inline void Serialize(Stream& os, const std::vector<T, A>& v);
 template<typename Stream, typename T, typename A> inline void Unserialize(Stream& is, std::vector<T, A>& v);
 
+template <typename Stream, typename T, std::size_t N> void Serialize(Stream& os, const std::array<T, N>& a);
+template <typename Stream, typename T, std::size_t N> void Unserialize(Stream& is, std::array<T, N>& a);
+
 /**
  * pair
  */
@@ -1051,6 +1054,54 @@ void Unserialize(Stream& is, std::vector<T, A>& v)
     }
 }
 
+/**
+ * array
+ */
+template <typename Stream, typename T, std::size_t N>
+void Serialize(Stream& os, const std::array<T, N>& a)
+{
+    if constexpr (std::is_same_v<T, unsigned char>) {
+        // Directly write the byte data without writing the size
+        if (!a.empty()) {
+            os.write(MakeByteSpan(a));
+        }
+    }
+    else if constexpr (std::is_same_v<T, bool>) {
+        // Serialize each bool individually
+        for (const bool& elem : a) {
+            ::Serialize(os, elem);
+        }
+    }
+    else {
+        // Serialize each element using the default Serialize function
+        for (const T& elem : a) {
+            ::Serialize(os, elem);
+        }
+    }
+}
+
+template <typename Stream, typename T, std::size_t N>
+void Unserialize(Stream& is, std::array<T, N>& a)
+{
+    if constexpr (std::is_same_v<T, unsigned char>) {
+        // Directly read the byte data without reading the size
+        if (N > 0) {
+            is.read(AsWritableBytes(Span{a}));
+        }
+    }
+    else if constexpr (std::is_same_v<T, bool>) {
+        // Unserialize each bool individually
+        for (bool& elem : a) {
+            ::Unserialize(is, elem);
+        }
+    }
+    else {
+        // Unserialize each element using the default Unserialize function
+        for (T& elem : a) {
+            ::Unserialize(is, elem);
+        }
+    }
+}
 
 /**
  * pair