Use random beacon as salt when computing sigchain miner

Signed-off-by: Yilun <[email protected]>
nknorg · Jul 22, 2021 · a4a4559 · a4a4559
1 parent 89eaaa6
commit a4a4559
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Showing 3 changed files with 14 additions and 4 deletions.
diff --git a/chain/blockvalidator.go b/chain/blockvalidator.go
@@ -295,7 +295,7 @@ func GetNextBlockSigner(height uint32, timestamp int64) ([]byte, []byte, pb.Winn
 				return nil, nil, 0, err
 			}
 
-			publicKey, chordID, err = sigChain.GetMiner(height)
+			publicKey, chordID, err = sigChain.GetMiner(height, header.UnsignedHeader.RandomBeacon)
 			if err != nil {
 				return nil, nil, 0, err
 			}

diff --git a/config/config.go b/config/config.go
@@ -220,6 +220,10 @@ var (
 		heights: []uint32{2633000, 0},
 		values:  []int32{10, 0},
 	}
+	SigChainMinerSalt = HeightDependentBool{
+		heights: []uint32{2900000, 0},
+		values:  []bool{true, false},
+	}
 )
 
 var (

diff --git a/pb/sigchain.go b/pb/sigchain.go
@@ -201,7 +201,7 @@ func (sc *SigChain) GetSignerIndex(pubkey []byte) (int, error) {
 	return idx, err
 }
 
-func (sc *SigChain) GetMiner(height uint32) ([]byte, []byte, error) {
+func (sc *SigChain) GetMiner(height uint32, randomBeacon []byte) ([]byte, []byte, error) {
 	if !sc.IsComplete() {
 		return nil, nil, errors.New("sigchain is not complete")
 	}
@@ -235,15 +235,21 @@ func (sc *SigChain) GetMiner(height uint32) ([]byte, []byte, error) {
 		return nil, nil, err
 	}
 
+	h := sigHash
+	if config.SigChainMinerSalt.GetValueAtHeight(height) {
+		hs := sha256.Sum256(append(sigHash, randomBeacon...))
+		h = hs[:]
+	}
+
 	x := big.NewInt(0)
-	x.SetBytes(sigHash)
+	x.SetBytes(h)
 	y := big.NewInt(int64(elemLen))
 	newIndex := big.NewInt(0)
 	newIndex.Mod(x, y)
 
 	originalIndex := minerElems[newIndex.Int64()].index
 	if originalIndex == 0 {
-		return sc.SrcPubkey, sc.Elems[0].Id, nil
+		return nil, nil, errors.New("invalid miner index")
 	}
 
 	return sc.Elems[originalIndex-1].NextPubkey, sc.Elems[originalIndex].Id, nil