From 3da9db414180a7ed9a23da1732ebeff613c72fa5 Mon Sep 17 00:00:00 2001
From: mban259 <mban259@users.noreply.github.com>
Date: Sun, 28 Apr 2019 19:29:00 +0900
Subject: [PATCH 1/9] Add IsProofOfStake

---
 src/chainparams.h    |  8 ++++++++
 src/policy/stake.cpp | 11 +++++++++++
 src/policy/stake.h   |  2 ++
 3 files changed, 21 insertions(+)

diff --git a/src/chainparams.h b/src/chainparams.h
index 722e52ff40f5..f073a3749088 100644
--- a/src/chainparams.h
+++ b/src/chainparams.h
@@ -25,6 +25,12 @@ struct CCheckpointData {
     MapCheckpoints mapCheckpoints;
 };
 
+typedef std::map<uint256, uint32_t> MapPoSNonce;
+
+struct CPoSNonceData {
+    MapPoSNonce mapPoSNonce;
+};
+
 /**
  * Holds various statistics on transactions within a chain. Used to estimate
  * verification progress during chain sync.
@@ -80,6 +86,7 @@ class CChainParams
     const std::vector<SeedSpec6>& FixedSeeds() const { return vFixedSeeds; }
     const CCheckpointData& Checkpoints() const { return checkpointData; }
     const ChainTxData& TxData() const { return chainTxData; }
+    const CPoSNonceData& NonceData() const { return nonceData; }
     void UpdateVersionBitsParameters(Consensus::DeploymentPos d, int64_t nStartTime, int64_t nTimeout);
 protected:
     CChainParams() {}
@@ -99,6 +106,7 @@ class CChainParams
     bool fMineBlocksOnDemand;
     CCheckpointData checkpointData;
     ChainTxData chainTxData;
+    CPoSNonceData nonceData;
     bool m_fallback_fee_enabled;
 };
 
diff --git a/src/policy/stake.cpp b/src/policy/stake.cpp
index 843fd942f159..ddaaef45384b 100644
--- a/src/policy/stake.cpp
+++ b/src/policy/stake.cpp
@@ -13,6 +13,7 @@
 #include <script/standard.h>
 #include <stdio.h>
 #include <key_io.h>
+#include <chainparams.h>
 
 bool AddressesEqual(const CScript& a, const CScript& b)
 {
@@ -40,3 +41,13 @@ bool AddressesEqual(const CScript& a, const CScript& b)
     //printf("a = %s b = %s\n", EncodeDestination(aAddress).c_str(), EncodeDestination(bAddress).c_str());
     return aAddress == bAddress;
 }
+
+bool IsProofOfStake(const CBlockHeader& block)
+{
+    if(block.nNonce == 0){
+        return true;
+    }
+    const MapPoSNonce& map = Params().NonceData().mapPoSNonce;
+    auto itr = map.find(block.GetHash());
+    return itr != map.end();
+}
\ No newline at end of file
diff --git a/src/policy/stake.h b/src/policy/stake.h
index 1cd286eeb1f1..8bdbe4f4f5a4 100644
--- a/src/policy/stake.h
+++ b/src/policy/stake.h
@@ -10,4 +10,6 @@
 
 bool AddressesEqual(const CScript& a, const CScript& b);
 
+bool IsProofOfStake(const CBlockHeader& block);
+
 #endif //BITCOIN_POLICY_STAKE_H

From c981540b8807883ce01cc823b6a559ca1428429d Mon Sep 17 00:00:00 2001
From: mban259 <mban259@users.noreply.github.com>
Date: Sun, 28 Apr 2019 19:38:02 +0900
Subject: [PATCH 2/9] Set nNonce of PoW Block

---
 src/rpc/mining.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index bfd88d22a8e9..c34d450f8504 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -127,6 +127,7 @@ UniValue generateBlocks(std::shared_ptr<CReserveScript> coinbaseScript, int nGen
         if (!pblocktemplate.get())
             throw JSONRPCError(RPC_INTERNAL_ERROR, "Couldn't create new block");
         CBlock *pblock = &pblocktemplate->block;
+        pblock->nNonce = 1;
         {
             LOCK(cs_main);
             IncrementExtraNonce(pblock, chainActive.Tip(), nExtraNonce);

From a03a2bc3fa2445d57694871e46a55bdbe6e772d1 Mon Sep 17 00:00:00 2001
From: mban259 <mban259@users.noreply.github.com>
Date: Sun, 28 Apr 2019 20:59:53 +0900
Subject: [PATCH 3/9] Add IsProofOfStake in CheckBlockHeader

---
 src/validation.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/validation.cpp b/src/validation.cpp
index b6f8d4e0045c..e0cfc307a7fb 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3231,7 +3231,7 @@ static bool FindUndoPos(CValidationState &state, int nFile, CDiskBlockPos &pos,
 static bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW = true)
 {
     // Check proof of work matches claimed amount
-    if (fCheckPOW && !CheckProofOfWork(block.GetHash(), block.nBits, consensusParams))
+    if (fCheckPOW && !IsProofOfStake(block) && !CheckProofOfWork(block.GetHash(), block.nBits, consensusParams))
         return state.DoS(50, false, REJECT_INVALID, "high-hash", false, "proof of work failed");
 
     return true;

From ef4a407da8412367b94621aa488f12363e0fb07b Mon Sep 17 00:00:00 2001
From: mban259 <mban259@users.noreply.github.com>
Date: Sun, 28 Apr 2019 21:18:48 +0900
Subject: [PATCH 4/9] Add spam filter

---
 src/net_processing.cpp | 104 +++++++++++++++++++++++++++++++++++++++--
 src/validation.cpp     |   8 +++-
 src/validation.h       |   2 +-
 3 files changed, 109 insertions(+), 5 deletions(-)

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index a4b0fdd6cc06..57b6f21fdbeb 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -181,6 +181,91 @@ struct CBlockReject {
     uint256 hashBlock;
 };
 
+class CNodeHeaders
+{
+public:
+    CNodeHeaders():
+        maxSize(0),
+        maxAvg(0)
+    {
+        maxSize = COINBASE_MATURITY;
+        maxAvg = 10;
+    }
+
+    bool addHeaders(const CBlockIndex *pindexFirst, const CBlockIndex *pindexLast)
+    {
+        if(pindexFirst && pindexLast)
+        {
+            // Get the begin block index
+            int nBegin = pindexFirst->nHeight;
+
+            // Get the end block index
+            int nEnd = pindexLast->nHeight;
+
+            for(int point = nBegin; point<= nEnd; point++)
+            {
+                addPoint(point);
+            }
+
+            return true;
+        }
+
+        return false;
+    }
+
+    bool updateState(CValidationState& state, bool ret)
+    {
+        // No headers
+        size_t size = points.size();
+        if(size == 0)
+            return true;
+
+        // Compute the number of the received headers
+        size_t nHeaders = 0;
+        for(auto point : points)
+        {
+            nHeaders += point.second;
+        }
+
+        // Compute the average value per height
+        double nAvgValue = (double)nHeaders / size;
+
+        // Ban the node if try to spam
+        bool banNode = (nAvgValue >= 1.5 * maxAvg && size >= maxAvg) ||
+                       (nAvgValue >= maxAvg && nHeaders >= maxSize) ||
+                       (nHeaders >= maxSize * 3);
+        if(banNode)
+        {
+            return state.DoS(100, false, REJECT_INVALID, "header-spam", false, "ban node for sending spam");
+        }
+
+        return ret;
+    }
+
+private:
+    void addPoint(int height)
+    {
+        // Erace the last element in the list
+        if(points.size() == maxSize)
+        {
+            points.erase(points.begin());
+        }
+
+        // Add the point to the list
+        int occurrence = 0;
+        auto mi = points.find(height);
+        if (mi != points.end())
+            occurrence = (*mi).second;
+        occurrence++;
+        points[height] = occurrence;
+    }
+
+private:
+    std::map<int,int> points;
+    size_t maxSize;
+    size_t maxAvg;
+};
+
 /**
  * Maintain validation-specific state about nodes, protected by cs_main, instead
  * by CNode's own locks. This simplifies asynchronous operation, where
@@ -270,6 +355,8 @@ struct CNodeState {
 
     ChainSyncTimeoutState m_chain_sync;
 
+    CNodeHeaders headers;
+
     //! Time of last new block announcement
     int64_t m_last_block_announcement;
 
@@ -310,7 +397,18 @@ static CNodeState *State(NodeId pnode) EXCLUSIVE_LOCKS_REQUIRED(cs_main) {
     return &it->second;
 }
 
-static void UpdatePreferredDownload(CNode* node, CNodeState* state) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
+bool ProcessNetBlockHeaders(CNode* pfrom, const std::vector<CBlockHeader>& block, CValidationState& state, const CChainParams& chainparams, const CBlockIndex** ppindex = nullptr, CBlockHeader* first_invalid = nullptr)
+{
+    const CBlockIndex* pindexFirst = nullptr;
+    bool ret = ProcessNewBlockHeaders(block, state, chainparams, ppindex, first_invalid, &pindexFirst);
+    LOCK(cs_main);
+    CNodeState* nodestate = State(pfrom->GetId());
+    const CBlockIndex* pindexLast = ppindex == nullptr ? nullptr : *ppindex;
+    nodestate->headers.addHeaders(pindexFirst, pindexLast);
+    return nodestate->headers.updateState(state, ret);
+}
+
+void UpdatePreferredDownload(CNode* node, CNodeState* state) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
 {
     nPreferredDownload -= state->fPreferredDownload;
 
@@ -1409,7 +1507,7 @@ bool static ProcessHeadersMessage(CNode *pfrom, CConnman *connman, const std::ve
 
     CValidationState state;
     CBlockHeader first_invalid_header;
-    if (!ProcessNewBlockHeaders(headers, state, chainparams, &pindexLast, &first_invalid_header)) {
+    if (!ProcessNetBlockHeaders(pfrom, headers, state, chainparams, &pindexLast, &first_invalid_header)) {
         int nDoS;
         if (state.IsInvalid(nDoS)) {
             LOCK(cs_main);
@@ -2411,7 +2509,7 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
 
         const CBlockIndex *pindex = nullptr;
         CValidationState state;
-        if (!ProcessNewBlockHeaders({cmpctblock.header}, state, chainparams, &pindex)) {
+        if (!ProcessNetBlockHeaders(pfrom, {cmpctblock.header}, state, chainparams, &pindex)) {
             int nDoS;
             if (state.IsInvalid(nDoS)) {
                 if (nDoS > 0) {
diff --git a/src/validation.cpp b/src/validation.cpp
index e0cfc307a7fb..c57ae9462915 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3581,11 +3581,12 @@ bool CChainState::AcceptBlockHeader(const CBlockHeader& block, CValidationState&
 }
 
 // Exposed wrapper for AcceptBlockHeader
-bool ProcessNewBlockHeaders(const std::vector<CBlockHeader>& headers, CValidationState& state, const CChainParams& chainparams, const CBlockIndex** ppindex, CBlockHeader *first_invalid)
+bool ProcessNewBlockHeaders(const std::vector<CBlockHeader>& headers, CValidationState& state, const CChainParams& chainparams, const CBlockIndex** ppindex, CBlockHeader *first_invalid,  const CBlockIndex** pindexFirst)
 {
     if (first_invalid != nullptr) first_invalid->SetNull();
     {
         LOCK(cs_main);
+        bool bFirst = true;
         for (const CBlockHeader& header : headers) {
             CBlockIndex *pindex = nullptr; // Use a temp pindex instead of ppindex to avoid a const_cast
             if (!g_chainstate.AcceptBlockHeader(header, state, chainparams, &pindex)) {
@@ -3594,6 +3595,11 @@ bool ProcessNewBlockHeaders(const std::vector<CBlockHeader>& headers, CValidatio
             }
             if (ppindex) {
                 *ppindex = pindex;
+                if(bFirst && pindexFirst)
+                {
+                    *pindexFirst = pindex;
+                    bFirst = false;
+                }
             }
         }
     }
diff --git a/src/validation.h b/src/validation.h
index 6dab0a24318e..2d267c0fdb16 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -243,7 +243,7 @@ bool ProcessNewBlock(const CChainParams& chainparams, const std::shared_ptr<cons
  * @param[out] ppindex If set, the pointer will be set to point to the last new block index object for the given headers
  * @param[out] first_invalid First header that fails validation, if one exists
  */
-bool ProcessNewBlockHeaders(const std::vector<CBlockHeader>& block, CValidationState& state, const CChainParams& chainparams, const CBlockIndex** ppindex = nullptr, CBlockHeader* first_invalid = nullptr) LOCKS_EXCLUDED(cs_main);
+bool ProcessNewBlockHeaders(const std::vector<CBlockHeader>& block, CValidationState& state, const CChainParams& chainparams, const CBlockIndex** ppindex = nullptr, CBlockHeader* first_invalid = nullptr, const CBlockIndex** pindexFirst = nullptr) LOCKS_EXCLUDED(cs_main);
 
 /** Check whether enough disk space is available for an incoming block */
 bool CheckDiskSpace(uint64_t nAdditionalBytes = 0, bool blocks_dir = false);

From 62ca8a6c1218acd483dc4d0efb714454dc696b57 Mon Sep 17 00:00:00 2001
From: mban259 <mban259@users.noreply.github.com>
Date: Mon, 29 Apr 2019 02:21:07 +0900
Subject: [PATCH 5/9] Parameterize header spam filter

---
 src/init.cpp           |  4 +++-
 src/net_processing.cpp | 18 +++++++++++-------
 src/net_processing.h   |  8 ++++++++
 3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/src/init.cpp b/src/init.cpp
index 4b386748040a..ddf34df71ec0 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -516,7 +516,9 @@ void SetupServerArgs()
     gArgs.AddArg("-rpcuser=<user>", "Username for JSON-RPC connections", false, OptionsCategory::RPC);
     gArgs.AddArg("-rpcworkqueue=<n>", strprintf("Set the depth of the work queue to service RPC calls (default: %d)", DEFAULT_HTTP_WORKQUEUE), true, OptionsCategory::RPC);
     gArgs.AddArg("-server", "Accept command line and JSON-RPC commands", false, OptionsCategory::RPC);
-
+    gArgs.AddArg("-headerspamfilter=<n>", strprintf(_("Use header spam filter (default: %u)"), DEFAULT_HEADER_SPAM_FILTER), false, OptionsCategory::NODE_RELAY);
+    gArgs.AddArg("-headerspamfiltermaxsize=<n>", strprintf(_("Maximum size of the list of indexes in the header spam filter (default: %u)"), DEFAULT_HEADER_SPAM_FILTER_MAX_SIZE), false, OptionsCategory::NODE_RELAY);
+    gArgs.AddArg("-headerspamfiltermaxavg=<n>", strprintf(_("Maximum average size of an index occurrence in the header spam filter (default: %u)"), DEFAULT_HEADER_SPAM_FILTER_MAX_AVG), false, OptionsCategory::NODE_RELAY);
 #if HAVE_DECL_DAEMON
     gArgs.AddArg("-daemon", "Run in the background as a daemon and accept commands", false, OptionsCategory::OPTIONS);
 #else
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 57b6f21fdbeb..aa45cf5d4b14 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -188,8 +188,8 @@ class CNodeHeaders
         maxSize(0),
         maxAvg(0)
     {
-        maxSize = COINBASE_MATURITY;
-        maxAvg = 10;
+        maxSize = gArgs.GetArg("-headerspamfiltermaxsize", DEFAULT_HEADER_SPAM_FILTER_MAX_SIZE);
+        maxAvg = gArgs.GetArg("-headerspamfiltermaxavg", DEFAULT_HEADER_SPAM_FILTER_MAX_AVG);
     }
 
     bool addHeaders(const CBlockIndex *pindexFirst, const CBlockIndex *pindexLast)
@@ -401,11 +401,15 @@ bool ProcessNetBlockHeaders(CNode* pfrom, const std::vector<CBlockHeader>& block
 {
     const CBlockIndex* pindexFirst = nullptr;
     bool ret = ProcessNewBlockHeaders(block, state, chainparams, ppindex, first_invalid, &pindexFirst);
-    LOCK(cs_main);
-    CNodeState* nodestate = State(pfrom->GetId());
-    const CBlockIndex* pindexLast = ppindex == nullptr ? nullptr : *ppindex;
-    nodestate->headers.addHeaders(pindexFirst, pindexLast);
-    return nodestate->headers.updateState(state, ret);
+    if(gArgs.GetBoolArg("-headerspamfilter", DEFAULT_HEADER_SPAM_FILTER))
+    {
+        LOCK(cs_main);
+        CNodeState *nodestate = State(pfrom->GetId());
+        const CBlockIndex *pindexLast = ppindex == nullptr ? nullptr : *ppindex;
+        nodestate->headers.addHeaders(pindexFirst, pindexLast);
+        return nodestate->headers.updateState(state, ret);
+    }
+    return ret;
 }
 
 void UpdatePreferredDownload(CNode* node, CNodeState* state) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
diff --git a/src/net_processing.h b/src/net_processing.h
index 7caefc80cab5..8252b4dd3ac8 100644
--- a/src/net_processing.h
+++ b/src/net_processing.h
@@ -9,6 +9,7 @@
 #include <net.h>
 #include <validationinterface.h>
 #include <consensus/params.h>
+#include <consensus/consensus.h>
 
 /** Default for -maxorphantx, maximum number of orphan transactions kept in memory */
 static const unsigned int DEFAULT_MAX_ORPHAN_TRANSACTIONS = 100;
@@ -17,6 +18,13 @@ static const unsigned int DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN = 100;
 /** Default for BIP61 (sending reject messages) */
 static constexpr bool DEFAULT_ENABLE_BIP61 = true;
 
+/** Default for -headerspamfilter, use header spam filter */
+static const bool DEFAULT_HEADER_SPAM_FILTER = true;
+/** Default for -headerspamfiltermaxsize, maximum size of the list of indexes in the header spam filter */
+static const unsigned int DEFAULT_HEADER_SPAM_FILTER_MAX_SIZE = COINBASE_MATURITY;
+/** Default for -headerspamfiltermaxavg, maximum average size of an index occurrence in the header spam filter */
+static const unsigned int DEFAULT_HEADER_SPAM_FILTER_MAX_AVG = 10;
+
 class PeerLogicValidation final : public CValidationInterface, public NetEventsInterface {
 private:
     CConnman* const connman;

From 5314781092515d82f0e52ef24c901a749b8eb4c0 Mon Sep 17 00:00:00 2001
From: Time Markov <time.markov@qtum.com>
Date: Mon, 22 Oct 2018 13:07:44 +0200
Subject: [PATCH 6/9] Update header filter for zero size

---
 src/net_processing.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index aa45cf5d4b14..753db13bd5c5 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -194,7 +194,7 @@ class CNodeHeaders
 
     bool addHeaders(const CBlockIndex *pindexFirst, const CBlockIndex *pindexLast)
     {
-        if(pindexFirst && pindexLast)
+        if(pindexFirst && pindexLast && maxSize && maxAvg)
         {
             // Get the begin block index
             int nBegin = pindexFirst->nHeight;
@@ -218,7 +218,7 @@ class CNodeHeaders
         // No headers
         size_t size = points.size();
         if(size == 0)
-            return true;
+            return ret;
 
         // Compute the number of the received headers
         size_t nHeaders = 0;

From e97a3953c304a9336c3462158298b50fc263b03c Mon Sep 17 00:00:00 2001
From: Time Markov <time.markov@qtum.com>
Date: Wed, 24 Oct 2018 09:15:35 +0200
Subject: [PATCH 7/9] Clear the points and ban the node

---
 src/net_processing.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 753db13bd5c5..3e54055ed4b6 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -236,6 +236,8 @@ class CNodeHeaders
                        (nHeaders >= maxSize * 3);
         if(banNode)
         {
+            // Clear the points and ban the node
+            points.clear();
             return state.DoS(100, false, REJECT_INVALID, "header-spam", false, "ban node for sending spam");
         }
 

From 89bb95cc2382662eca6e31fa5c45ea175f52a1b1 Mon Sep 17 00:00:00 2001
From: Time Markov <time.markov@qtum.com>
Date: Wed, 24 Oct 2018 12:57:45 +0200
Subject: [PATCH 8/9] Download block only when work greater

---
 src/net_processing.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 3e54055ed4b6..83ea3c38f2f8 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -619,7 +619,7 @@ static void FindNextBlocksToDownload(NodeId nodeid, unsigned int count, std::vec
     // Make sure pindexBestKnownBlock is up to date, we'll need it.
     ProcessBlockAvailability(nodeid);
 
-    if (state->pindexBestKnownBlock == nullptr || state->pindexBestKnownBlock->nChainWork < chainActive.Tip()->nChainWork || state->pindexBestKnownBlock->nChainWork < nMinimumChainWork) {
+    if (state->pindexBestKnownBlock == nullptr || state->pindexBestKnownBlock->nChainWork <= chainActive.Tip()->nChainWork || state->pindexBestKnownBlock->nChainWork < nMinimumChainWork) {
         // This peer has nothing interesting.
         return;
     }

From 3d9cf20b44e289c5d45012d881ab7d4243090146 Mon Sep 17 00:00:00 2001
From: mban259 <mban259@users.noreply.github.com>
Date: Mon, 29 Apr 2019 19:51:42 +0900
Subject: [PATCH 9/9] Remove IsProofOfStake

---
 src/chainparams.h    |  8 --------
 src/policy/stake.cpp | 11 -----------
 src/policy/stake.h   |  2 --
 src/rpc/mining.cpp   |  1 -
 src/validation.cpp   |  2 +-
 5 files changed, 1 insertion(+), 23 deletions(-)

diff --git a/src/chainparams.h b/src/chainparams.h
index f073a3749088..722e52ff40f5 100644
--- a/src/chainparams.h
+++ b/src/chainparams.h
@@ -25,12 +25,6 @@ struct CCheckpointData {
     MapCheckpoints mapCheckpoints;
 };
 
-typedef std::map<uint256, uint32_t> MapPoSNonce;
-
-struct CPoSNonceData {
-    MapPoSNonce mapPoSNonce;
-};
-
 /**
  * Holds various statistics on transactions within a chain. Used to estimate
  * verification progress during chain sync.
@@ -86,7 +80,6 @@ class CChainParams
     const std::vector<SeedSpec6>& FixedSeeds() const { return vFixedSeeds; }
     const CCheckpointData& Checkpoints() const { return checkpointData; }
     const ChainTxData& TxData() const { return chainTxData; }
-    const CPoSNonceData& NonceData() const { return nonceData; }
     void UpdateVersionBitsParameters(Consensus::DeploymentPos d, int64_t nStartTime, int64_t nTimeout);
 protected:
     CChainParams() {}
@@ -106,7 +99,6 @@ class CChainParams
     bool fMineBlocksOnDemand;
     CCheckpointData checkpointData;
     ChainTxData chainTxData;
-    CPoSNonceData nonceData;
     bool m_fallback_fee_enabled;
 };
 
diff --git a/src/policy/stake.cpp b/src/policy/stake.cpp
index ddaaef45384b..843fd942f159 100644
--- a/src/policy/stake.cpp
+++ b/src/policy/stake.cpp
@@ -13,7 +13,6 @@
 #include <script/standard.h>
 #include <stdio.h>
 #include <key_io.h>
-#include <chainparams.h>
 
 bool AddressesEqual(const CScript& a, const CScript& b)
 {
@@ -41,13 +40,3 @@ bool AddressesEqual(const CScript& a, const CScript& b)
     //printf("a = %s b = %s\n", EncodeDestination(aAddress).c_str(), EncodeDestination(bAddress).c_str());
     return aAddress == bAddress;
 }
-
-bool IsProofOfStake(const CBlockHeader& block)
-{
-    if(block.nNonce == 0){
-        return true;
-    }
-    const MapPoSNonce& map = Params().NonceData().mapPoSNonce;
-    auto itr = map.find(block.GetHash());
-    return itr != map.end();
-}
\ No newline at end of file
diff --git a/src/policy/stake.h b/src/policy/stake.h
index 8bdbe4f4f5a4..1cd286eeb1f1 100644
--- a/src/policy/stake.h
+++ b/src/policy/stake.h
@@ -10,6 +10,4 @@
 
 bool AddressesEqual(const CScript& a, const CScript& b);
 
-bool IsProofOfStake(const CBlockHeader& block);
-
 #endif //BITCOIN_POLICY_STAKE_H
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index c34d450f8504..bfd88d22a8e9 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -127,7 +127,6 @@ UniValue generateBlocks(std::shared_ptr<CReserveScript> coinbaseScript, int nGen
         if (!pblocktemplate.get())
             throw JSONRPCError(RPC_INTERNAL_ERROR, "Couldn't create new block");
         CBlock *pblock = &pblocktemplate->block;
-        pblock->nNonce = 1;
         {
             LOCK(cs_main);
             IncrementExtraNonce(pblock, chainActive.Tip(), nExtraNonce);
diff --git a/src/validation.cpp b/src/validation.cpp
index c57ae9462915..79125249539d 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -3231,7 +3231,7 @@ static bool FindUndoPos(CValidationState &state, int nFile, CDiskBlockPos &pos,
 static bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, const Consensus::Params& consensusParams, bool fCheckPOW = true)
 {
     // Check proof of work matches claimed amount
-    if (fCheckPOW && !IsProofOfStake(block) && !CheckProofOfWork(block.GetHash(), block.nBits, consensusParams))
+    if (fCheckPOW && !CheckProofOfWork(block.GetHash(), block.nBits, consensusParams))
         return state.DoS(50, false, REJECT_INVALID, "high-hash", false, "proof of work failed");
 
     return true;