From 28a62b60df3f57eaad1d946b75a1af6f3f7b15e7 Mon Sep 17 00:00:00 2001
From: jl777 <jameslee777@yahoo.com>
Date: Tue, 12 Jun 2018 05:46:21 -1100
Subject: [PATCH] Deterministic RNG for notary mining

---
 src/miner.cpp | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/miner.cpp b/src/miner.cpp
index 35eb8e4d3..07e4a7a16 100644
--- a/src/miner.cpp
+++ b/src/miner.cpp
@@ -112,6 +112,7 @@ extern std::string NOTARY_PUBKEY,ASSETCHAINS_OVERRIDE_PUBKEY;
 
 extern uint8_t NOTARY_PUBKEY33[33],ASSETCHAINS_OVERRIDE_PUBKEY33[33];
 uint32_t Mining_start,Mining_height;
+int32_t My_notaryid = -1;
 int32_t komodo_chosennotary(int32_t *notaryidp,int32_t height,uint8_t *pubkey33,uint32_t timestamp);
 int32_t komodo_pax_opreturn(int32_t height,uint8_t *opret,int32_t maxsize);
 //uint64_t komodo_paxtotal();
@@ -472,13 +473,21 @@ CBlockTemplate* CreateNewBlock(const CScript& scriptPubKeyIn,int32_t gpucount)
         }
         pblock->nSolution.clear();
         pblocktemplate->vTxSigOps[0] = GetLegacySigOpCount(pblock->vtx[0]);
-        if ( ASSETCHAINS_SYMBOL[0] == 0 && NOTARY_PUBKEY33[0] != 0 )
+        if ( ASSETCHAINS_SYMBOL[0] == 0 && NOTARY_PUBKEY33[0] != 0 && My_notaryid >= 0 )
         {
+            uint32_t r;
             CMutableTransaction txNotary = CreateNewContextualCMutableTransaction(Params().GetConsensus(), chainActive.Height() + 1);
             if ( pblock->nTime < pindexPrev->nTime+60 )
                 pblock->nTime = pindexPrev->nTime + 60;
             if ( gpucount < 33 )
-                pblock->nTime += (rand() % (33 - gpucount)*(33 - gpucount));
+            {
+                uint8_t tmpbuffer[40]; int32_t n=0; bits256 randvals;
+                memcpy(&tmpbuffer[n],&My_notaryid,sizeof(My_notaryid)), n += sizeof(My_notaryid);
+                memcpy(&tmpbuffer[n],&Mining_height,sizeof(Mining_height)), n += sizeof(Mining_height);
+                memcpy(&tmpbuffer[n],&pblock->hashPrevBlock,sizeof(pblock->hashPrevBlock)), n += sizeof(pblock->hashPrevBlock);
+                vcalc_sha256(0,randvals.bytes,tmpbuffer,n);
+                pblock->nTime += (randvals.uints[0] % (33 - gpucount)*(33 - gpucount));
+            }
             if ( komodo_notaryvin(txNotary,NOTARY_PUBKEY33) > 0 )
             {
                 CAmount txfees = 5000;
@@ -729,7 +738,8 @@ void static BitcoinMiner()
             break;
     }
     komodo_chosennotary(&notaryid,chainActive.Tip()->nHeight,NOTARY_PUBKEY33,(uint32_t)chainActive.Tip()->GetBlockTime());
-    
+    if ( notaryid != My_notaryid )
+        My_notaryid = notaryid;
     std::string solver;
     //if ( notaryid >= 0 || ASSETCHAINS_SYMBOL[0] != 0 )
     solver = "tromp";