[Consensus] Change difficulty computation for V2 time protocol

- 16 seconds granularity - 64 seconds blocktime - 16 minutes retargetting timespan - 2^(256-48)-1 target limit
PIVX-Project · Nov 20, 2019 · 8c3546f · 8c3546f
1 parent f892e45
commit 8c3546f
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Showing 4 changed files with 24 additions and 8 deletions.
diff --git a/src/chainparams.cpp b/src/chainparams.cpp
@@ -173,13 +173,18 @@ class CMainParams : public CChainParams
         vAlertPubKey = ParseHex("0000098d3ba6ba6e7423fa5cbd6a89e0a9a5348f88d332b44a5cb1a8b7ed2c1eaa335fc8dc4f012cb8241cc0bdafd6ca70c5f5448916e4e6f511bcd746ed57dc50");
         nDefaultPort = 51472;
         bnProofOfWorkLimit = ~uint256(0) >> 20; // PIVX starting difficulty is 1 / 2^12
+        bnProofOfStakeLimit = ~uint256(0) >> 24;
+        bnProofOfStakeLimit_V2 = ~uint256(0) >> 48;
         nSubsidyHalvingInterval = 210000;
         nMaxReorganizationDepth = 100;
         nEnforceBlockUpgradeMajority = 8100; // 75%
         nRejectBlockOutdatedMajority = 10260; // 95%
         nToCheckBlockUpgradeMajority = 10800; // Approximate expected amount of blocks in 7 days (1440*7.5)
         nMinerThreads = 0;
         nTargetSpacing = 1 * 60;        // 1 minute
+        nTargetSpacing_V2 = 64;         // 64 seconds
+        nTargetTimespan = 40 * 60;      // 40 minutes
+        nTargetTimespan_V2 = 16 * 60;   // 16 minutes
         nMaturity = 100;
         nStakeMinDepth = 600;
         nFutureTimeDriftPoW = 7200;
@@ -329,7 +334,6 @@ class CTestNetParams : public CMainParams
         nRejectBlockOutdatedMajority = 5472; // 95%
         nToCheckBlockUpgradeMajority = 5760; // 4 days
         nMinerThreads = 0;
-        nTargetSpacing = 1 * 60;  // PIVX: 1 minute
         nLastPOWBlock = 200;
         nPivxBadBlockTime = 1489001494; // Skip nBit validation of Block 259201 per PR #915
         nPivxBadBlocknBits = 0x1e0a20bd; // Skip nBit validation of Block 201 per PR #915
@@ -434,7 +438,6 @@ class CRegTestParams : public CTestNetParams
         nRejectBlockOutdatedMajority = 950;
         nToCheckBlockUpgradeMajority = 1000;
         nMinerThreads = 1;
-        nTargetSpacing = 1 * 60;        // PIVX: 1 minutes
         bnProofOfWorkLimit = ~uint256(0) >> 1;
         nLastPOWBlock = 250;
         nMaturity = 100;

diff --git a/src/chainparams.h b/src/chainparams.h
@@ -51,6 +51,7 @@ class CChainParams
     const std::vector<unsigned char>& AlertKey() const { return vAlertPubKey; }
     int GetDefaultPort() const { return nDefaultPort; }
     const uint256& ProofOfWorkLimit() const { return bnProofOfWorkLimit; }
+    const uint256& ProofOfStakeLimit(const bool fV2) const { return fV2 ? bnProofOfStakeLimit_V2 : bnProofOfStakeLimit; }
     int SubsidyHalvingInterval() const { return nSubsidyHalvingInterval; }
     /** Used to check majorities for block version upgrade */
     int EnforceBlockUpgradeMajority() const { return nEnforceBlockUpgradeMajority; }
@@ -73,7 +74,8 @@ class CChainParams
     bool SkipProofOfWorkCheck() const { return fSkipProofOfWorkCheck; }
     /** Make standard checks */
     bool RequireStandard() const { return fRequireStandard; }
-    int64_t TargetSpacing() const { return nTargetSpacing; }
+    int64_t TargetSpacing(const bool fV2 = true) const { return fV2 ? nTargetSpacing_V2 : nTargetSpacing; }
+    int64_t TargetTimespan(const bool fV2 = true) const { return fV2 ? nTargetTimespan_V2 : nTargetTimespan; }
 
     /** returns the coinbase maturity **/
     int COINBASE_MATURITY() const { return nMaturity; }
@@ -166,12 +168,17 @@ class CChainParams
     std::vector<unsigned char> vAlertPubKey;
     int nDefaultPort;
     uint256 bnProofOfWorkLimit;
+    uint256 bnProofOfStakeLimit;
+    uint256 bnProofOfStakeLimit_V2;
     int nMaxReorganizationDepth;
     int nSubsidyHalvingInterval;
     int nEnforceBlockUpgradeMajority;
     int nRejectBlockOutdatedMajority;
     int nToCheckBlockUpgradeMajority;
     int64_t nTargetSpacing;
+    int64_t nTargetSpacing_V2;
+    int64_t nTargetTimespan;
+    int64_t nTargetTimespan_V2;
     int nLastPOWBlock;
     int64_t nPivxBadBlockTime;
     unsigned int nPivxBadBlocknBits;

diff --git a/src/kernel.cpp b/src/kernel.cpp
@@ -261,7 +261,7 @@ bool GetKernelStakeModifier(uint256 hashBlockFrom, uint64_t& nStakeModifier, int
         return true;
     }
     const CBlockIndex* pindex = pindexFrom;
-    CBlockIndex* pindexNext = chainActive[pindex->nHeight + 1];;
+    CBlockIndex* pindexNext = chainActive[pindex->nHeight + 1];
 
     // loop to find the stake modifier later by a selection interval
     do {

diff --git a/src/pow.cpp b/src/pow.cpp
@@ -38,16 +38,22 @@ unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHead
     }
 
     if (pindexLast->nHeight >= Params().LAST_POW_BLOCK()) {
-        uint256 bnTargetLimit = (~uint256(0) >> 24);
-        int64_t nTargetSpacing = 60;
-        int64_t nTargetTimespan = 60 * 40;
+        const bool fTimeV2 = Params().IsTimeProtocolV2(pindexLast->nHeight+1);
+        const uint256 bnTargetLimit = Params().ProofOfStakeLimit(fTimeV2);
+        const int64_t nTargetSpacing = Params().TargetSpacing(fTimeV2);
+        const int64_t nTargetTimespan = Params().TargetTimespan(fTimeV2);
+
+        // on first block with V2 time protocol, return the limit
+        if (fTimeV2 && !Params().IsTimeProtocolV2(pindexLast->nHeight))
+            return bnTargetLimit.GetCompact();
 
         int64_t nActualSpacing = 0;
         if (pindexLast->nHeight != 0)
             nActualSpacing = pindexLast->GetBlockTime() - pindexLast->pprev->GetBlockTime();
-
         if (nActualSpacing < 0)
             nActualSpacing = 1;
+        if (fTimeV2 && nActualSpacing > nTargetSpacing*10)
+            nActualSpacing = nTargetSpacing*10;
 
         // ppcoin: target change every block
         // ppcoin: retarget with exponential moving toward target spacing