Merge #1002: [PoS] Time Protocol v2

4ea0476 [Consensus] Fix difficulty adjustment on first block of timeproto V2 (random-zebra)
c254df6 [P2P] Do not store more than 200 timedata samples. (random-zebra)
8ca3979 [Tests] (squashed) few regtest fixes (random-zebra)
3487e58 [PoS] Fix Stake maturity-check and mapHashedBlocks time (random-zebra)
55aeecd [Core] raise nTargetTimespan_V2 to 30 minutes (random-zebra)
79bdc83 [Core] Restore CheckBlock checks before previous block check (random-zebra)
3bb0c0a [PoS] Don't use chainActive.Tip() as prevIndex when creating new blocks (random-zebra)
55faec1 [Performance] Kernel, methods using object reference instead of copy the object. (furszy)
4afcba5 [PoS] Don't allow consecutive blocks within the same time slot (random-zebra)
c97e998 [PoS] StakeV1: iterate the time backwards. (random-zebra)
59cd3af [PoS] reduce difficulty by a factor 16 on nBlockTimeProtocolV2 (random-zebra)
3447dfb [Core] Make bnProofOfStakeLimit_V2 16 times v1 limit (random-zebra)
0bcf0c1 [PoS] Keep v1 miner until hard-fork (random-zebra)
ec45670 [Core] Guard the transition to v2 time protocol in MinPastBlockTime rule (random-zebra)
fee5f5c [PoS] set nTargetTimespan_V2 to 15 minutes (60 time slots) (random-zebra)
ca2b035 [PoS] Set target spacing to 60 seconds (random-zebra)
0578b0a [PoS] Adjust FutureBlockTimeDrift to 15 secs granularity (random-zebra)
dd71075 [Core] Set time granularity to 15 (instead of 16) (random-zebra)
8c3546f [Consensus] Change difficulty computation for V2 time protocol (random-zebra)
f892e45 [Core/PoS] Enforce timestamp mask in miner (random-zebra)
cdaf818 [Core] Define new Past Time Limit and enforce masked time (random-zebra)
bcb5836 [Core] Define new Future Time Drift (random-zebra)
159eda9 [Cleanup] Remove unused function CheckCoinStakeTimestamp (random-zebra)
9773c09 [Core] Add timestamp mask to chainparams (random-zebra)
1d8fb33 [COPY] Update missing headers (random-zebra)
6f09121 [Consensus] Add placeholder block height for Time Protocol V2 (random-zebra)

Pull request description:

  Main changes:

  - **granularity**: 15 secs, instead of 1
  - **future limit**: adjustedTime + 14 secs (current timeslot) instead of 3 mins
  - **past limit**: prevBlock time
  - **target timespan**: 15 mins (instead of 40)

ACKs for top commit:
  furszy:
    Great, ACK 4ea0476
  Mrs-X:
    ACK 4ea0476

Tree-SHA512: a365297ba169f78ad1c30cc2f318dce09d6e98038a43d35c645814923829e793147e7fdbcbb3f701878a1f5f4892f468f19451fcacc25973db63c92c02e40aa1

COPYING

@@ -1,5 +1,8 @@
 Copyright (c) 2009-2015 Bitcoin Developers
 Copyright (c) 2014-2015 Dash Developers
+Copyright (c) 2011-2013 The PPCoin developers
+Copyright (c) 2013-2014 The NovaCoin Developers
+Copyright (c) 2014-2018 The BlackCoin Developers
 Copyright (c) 2015-2019 PIVX Developers
 
 Permission is hereby granted, free of charge, to any person obtaining a copy

contrib/devtools/copyright_header.py

@@ -121,6 +121,9 @@ def compile_copyright_regex(copyright_style, year_style, name):
     "The Dash Core developers\n",
     "The PIVX developers\n",
     "The PPCoin developers\n",
+    "The NovaCoin Developers",
+    "The BlackCoin Developers\n",
+    "The Blackcoin More developers\n",
 ]
 
 DOMINANT_STYLE_COMPILED = {}

src/chain.h

@@ -1,5 +1,8 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2014 The Bitcoin developers
+// Copyright (c) 2011-2013 The PPCoin developers
+// Copyright (c) 2013-2014 The NovaCoin Developers
+// Copyright (c) 2014-2018 The BlackCoin Developers
 // Copyright (c) 2015-2019 The PIVX developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
@@ -10,6 +13,7 @@
 #include "chainparams.h"
 #include "pow.h"
 #include "primitives/block.h"
+#include "timedata.h"
 #include "tinyformat.h"
 #include "uint256.h"
 #include "util.h"
@@ -339,6 +343,27 @@ class CBlockIndex
         return pbegin[(pend - pbegin) / 2];
     }
 
+    int64_t MaxFutureBlockTime() const
+    {
+        return GetAdjustedTime() + Params().FutureBlockTimeDrift(nHeight+1);
+    }
+
+    int64_t MinPastBlockTime() const
+    {
+        // Time Protocol v1: pindexPrev->MedianTimePast + 1
+        if (!Params().IsTimeProtocolV2(nHeight+1))
+            return GetMedianTimePast();
+
+        // on the transition from Time Protocol v1 to v2
+        // pindexPrev->nTime might be in the future (up to the allowed drift)
+        // so we allow the nBlockTimeProtocolV2 to be at most (180-14) seconds earlier than previous block
+        if (nHeight + 1 == Params().BlockStartTimeProtocolV2())
+            return GetBlockTime() - Params().FutureBlockTimeDrift(nHeight) + Params().FutureBlockTimeDrift(nHeight + 1);
+
+        // Time Protocol v2: pindexPrev->nTime
+        return GetBlockTime();
+    }
+
     bool IsProofOfWork() const
     {
         return !(nFlags & BLOCK_PROOF_OF_STAKE);

src/chainparams.cpp

@@ -121,17 +121,35 @@ libzerocoin::ZerocoinParams* CChainParams::Zerocoin_Params(bool useModulusV1) co
 bool CChainParams::HasStakeMinAgeOrDepth(const int contextHeight, const uint32_t contextTime,
         const int utxoFromBlockHeight, const uint32_t utxoFromBlockTime) const
 {
-    if (NetworkID() == CBaseChainParams::REGTEST)
-        return true;
-
-    // before stake modifier V2, the age required was 60 * 60 (1 hour) / not required on regtest
+    // before stake modifier V2, the age required was 60 * 60 (1 hour). Not required for regtest
     if (!IsStakeModifierV2(contextHeight))
-        return (utxoFromBlockTime + 3600 <= contextTime);
+        return NetworkID() == CBaseChainParams::REGTEST || (utxoFromBlockTime + nStakeMinAge <= contextTime);
 
     // after stake modifier V2, we require the utxo to be nStakeMinDepth deep in the chain
     return (contextHeight - utxoFromBlockHeight >= nStakeMinDepth);
 }
 
+int CChainParams::FutureBlockTimeDrift(const int nHeight) const
+{
+    if (IsTimeProtocolV2(nHeight))
+        // PoS (TimeV2): 14 seconds
+        return TimeSlotLength() - 1;
+
+    // PoS (TimeV1): 3 minutes
+    // PoW: 2 hours
+    return (nHeight > LAST_POW_BLOCK()) ? nFutureTimeDriftPoS : nFutureTimeDriftPoW;
+}
+
+bool CChainParams::IsValidBlockTimeStamp(const int64_t nTime, const int nHeight) const
+{
+    // Before time protocol V2, blocks can have arbitrary timestamps
+    if (!IsTimeProtocolV2(nHeight))
+        return true;
+
+    // Time protocol v2 requires time in slots
+    return (nTime % TimeSlotLength()) == 0;
+}
+
 class CMainParams : public CChainParams
 {
 public:
@@ -151,20 +169,27 @@ 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) >> 20; // 60/4 = 15 ==> use 2**4 higher limit
         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 = 1 * 60;                        // 1 minute
+        nTargetTimespan = 40 * 60;                      // 40 minutes
+        nTimeSlotLength = 15;                           // 15 seconds
+        nTargetTimespan_V2 = 2 * nTimeSlotLength * 60;  // 30 minutes
         nMaturity = 100;
+        nStakeMinAge = 60 * 60;                         // 1 hour
         nStakeMinDepth = 600;
         nFutureTimeDriftPoW = 7200;
         nFutureTimeDriftPoS = 180;
         nMasternodeCountDrift = 20;
         nMaxMoneyOut = 21000000 * COIN;
         nMinColdStakingAmount = 1 * COIN;
+        nTimeSlotLength = 15;           // 15 seconds
 
         /** Height or Time Based Activations **/
         nLastPOWBlock = 259200;
@@ -185,12 +210,13 @@ class CMainParams : public CChainParams
         nRejectOldSporkKey = 1569538800; //!> Fully reject old spork key after Thursday, September 26, 2019 11:00:00 PM GMT
         nBlockStakeModifierlV2 = 1967000;
         nBIP65ActivationHeight = 1808634;
+        nBlockTimeProtocolV2 = 2967000;
 
         // Public coin spend enforcement
         nPublicZCSpends = 1880000;
 
         // New P2P messages signatures
-        nBlockEnforceNewMessageSignatures = 2967000;
+        nBlockEnforceNewMessageSignatures = nBlockTimeProtocolV2;
 
         // Fake Serial Attack
         nFakeSerialBlockheightEnd = 1686229;
@@ -304,7 +330,6 @@ 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
@@ -326,12 +351,13 @@ class CTestNetParams : public CMainParams
         nRejectOldSporkKey = 1569538800; //!> Reject old spork key after Thursday, September 26, 2019 11:00:00 PM GMT
         nBlockStakeModifierlV2 = 1214000;
         nBIP65ActivationHeight = 851019;
+        nBlockTimeProtocolV2 = 2214000;
 
         // Public coin spend enforcement
         nPublicZCSpends = 1106100;
 
         // New P2P messages signatures
-        nBlockEnforceNewMessageSignatures = 2214000;
+        nBlockEnforceNewMessageSignatures = nBlockTimeProtocolV2;
 
         // Fake Serial Attack
         nFakeSerialBlockheightEnd = -1;
@@ -408,13 +434,14 @@ class CRegTestParams : public CTestNetParams
         nRejectBlockOutdatedMajority = 950;
         nToCheckBlockUpgradeMajority = 1000;
         nMinerThreads = 1;
-        nTargetSpacing = 1 * 60;        // PIVX: 1 minutes
         bnProofOfWorkLimit = ~uint256(0) >> 1;
         nLastPOWBlock = 250;
         nMaturity = 100;
+        nStakeMinAge = 0;
         nStakeMinDepth = 0;
+        nTimeSlotLength = 1;            // time not masked on RegNet
         nMasternodeCountDrift = 4;
-        nModifierUpdateBlock = 0; //approx Mon, 17 Apr 2017 04:00:00 GMT
+        nModifierUpdateBlock = 0;       //approx Mon, 17 Apr 2017 04:00:00 GMT
         nMaxMoneyOut = 43199500 * COIN;
         nZerocoinStartHeight = 300;
         nBlockZerocoinV2 = 300;
@@ -423,7 +450,8 @@ class CRegTestParams : public CTestNetParams
         nBlockRecalculateAccumulators = 999999999; //Trigger a recalculation of accumulators
         nBlockFirstFraudulent = 999999999; //First block that bad serials emerged
         nBlockLastGoodCheckpoint = 999999999; //Last valid accumulator checkpoint
-        nBlockStakeModifierlV2 = std::numeric_limits<int>::max(); // max integer value (never switch on regtest)
+        nBlockStakeModifierlV2 = 255;
+        nBlockTimeProtocolV2 = 999999999;
 
         // Public coin spend enforcement
         nPublicZCSpends = 350;

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; }
@@ -74,17 +75,22 @@ class CChainParams
     /** Make standard checks */
     bool RequireStandard() const { return fRequireStandard; }
     int64_t TargetSpacing() const { return nTargetSpacing; }
+    int64_t TargetTimespan(const bool fV2 = true) const { return fV2 ? nTargetTimespan_V2 : nTargetTimespan; }
 
     /** returns the coinbase maturity **/
     int COINBASE_MATURITY() const { return nMaturity; }
 
     /** returns the coinstake maturity (min depth required) **/
+    int COINSTAKE_MIN_AGE() const { return nStakeMinAge; }
     int COINSTAKE_MIN_DEPTH() const { return nStakeMinDepth; }
     bool HasStakeMinAgeOrDepth(const int contextHeight, const uint32_t contextTime, const int utxoFromBlockHeight, const uint32_t utxoFromBlockTime) const;
 
-    /** returns the max future time (and drift in seconds) allowed for a block in the future **/
-    int FutureBlockTimeDrift(const bool isPoS) const { return isPoS ? nFutureTimeDriftPoS : nFutureTimeDriftPoW; }
-    uint32_t MaxFutureBlockTime(uint32_t time, const bool isPoS) const { return time + FutureBlockTimeDrift(isPoS); }
+    /** Time Protocol V2 **/
+    int BlockStartTimeProtocolV2() const { return nBlockTimeProtocolV2; }
+    bool IsTimeProtocolV2(const int nHeight) const { return nHeight >= BlockStartTimeProtocolV2(); }
+    int TimeSlotLength() const { return nTimeSlotLength; }
+    int FutureBlockTimeDrift(const int nHeight) const;
+    bool IsValidBlockTimeStamp(const int64_t nTime, const int nHeight) const;
 
     CAmount MaxMoneyOut() const { return nMaxMoneyOut; }
     /** The masternode count that we will allow the see-saw reward payments to be off by */
@@ -164,20 +170,26 @@ 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 nTargetTimespan;
+    int64_t nTargetTimespan_V2;
     int nLastPOWBlock;
     int64_t nPivxBadBlockTime;
     unsigned int nPivxBadBlocknBits;
     int nMasternodeCountDrift;
     int nMaturity;
     int nStakeMinDepth;
+    int nStakeMinAge;
     int nFutureTimeDriftPoW;
     int nFutureTimeDriftPoS;
+    int nTimeSlotLength;
 
     int nModifierUpdateBlock;
     CAmount nMaxMoneyOut;
@@ -229,6 +241,7 @@ class CChainParams
     int nBlockDoubleAccumulated;
     int nPublicZCSpends;
     int nBlockStakeModifierlV2;
+    int nBlockTimeProtocolV2;
     int nBlockEnforceNewMessageSignatures;
 
     CAmount nMinColdStakingAmount;

src/init.cpp

@@ -1,6 +1,9 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2014 The Bitcoin developers
 // Copyright (c) 2014-2015 The Dash developers
+// Copyright (c) 2011-2013 The PPCoin developers
+// Copyright (c) 2013-2014 The NovaCoin Developers
+// Copyright (c) 2014-2018 The BlackCoin Developers
 // Copyright (c) 2015-2019 The PIVX developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.