diff --git a/blockdag/blocknode.go b/blockdag/blocknode.go
index 7e1ee6ef3..4ed64992b 100644
--- a/blockdag/blocknode.go
+++ b/blockdag/blocknode.go
@@ -104,6 +104,7 @@ type blockNode struct {
 	hashMerkleRoot       *daghash.Hash
 	idMerkleRoot         *daghash.Hash
 	acceptedIDMerkleRoot *daghash.Hash
+	utxoCommitment       *daghash.Hash
 
 	// status is a bitfield representing the validation state of the block. The
 	// status field, unlike the other fields, may be written to and so should
@@ -132,6 +133,7 @@ func initBlockNode(node *blockNode, blockHeader *wire.BlockHeader, parents block
 		node.hashMerkleRoot = blockHeader.HashMerkleRoot
 		node.idMerkleRoot = blockHeader.IDMerkleRoot
 		node.acceptedIDMerkleRoot = blockHeader.AcceptedIDMerkleRoot
+		node.utxoCommitment = blockHeader.UTXOCommitment
 	} else {
 		node.hash = &daghash.ZeroHash
 	}
@@ -183,6 +185,7 @@ func (node *blockNode) Header() *wire.BlockHeader {
 		HashMerkleRoot:       node.hashMerkleRoot,
 		IDMerkleRoot:         node.idMerkleRoot,
 		AcceptedIDMerkleRoot: node.acceptedIDMerkleRoot,
+		UTXOCommitment:       node.utxoCommitment,
 		Timestamp:            time.Unix(node.timestamp, 0),
 		Bits:                 node.bits,
 		Nonce:                node.nonce,
diff --git a/blockdag/common_test.go b/blockdag/common_test.go
index 41f1f38c6..c0954d45e 100644
--- a/blockdag/common_test.go
+++ b/blockdag/common_test.go
@@ -207,6 +207,7 @@ func newTestNode(parents blockSet, blockVersion int32, bits uint32, timestamp ti
 		HashMerkleRoot:       &daghash.ZeroHash,
 		IDMerkleRoot:         &daghash.ZeroHash,
 		AcceptedIDMerkleRoot: &daghash.ZeroHash,
+		UTXOCommitment:       &daghash.ZeroHash,
 	}
 	return newBlockNode(header, parents, phantomK)
 }
diff --git a/blockdag/dag_test.go b/blockdag/dag_test.go
index 3e3b56494..755665634 100644
--- a/blockdag/dag_test.go
+++ b/blockdag/dag_test.go
@@ -192,10 +192,10 @@ func TestHaveBlock(t *testing.T) {
 		{hash: dagconfig.SimNetParams.GenesisHash.String(), want: true},
 
 		// Block 3b should be present (as a second child of Block 2).
-		{hash: "3a81c2f7064370dddaeaf7bc7e4d282702cefb2b6e11c84942c3791c76cdd3e8", want: true},
+		{hash: "0a20af2fa5ce154a60faca96e9fa125fc52e0ca8f98484708d0413203626edaf", want: true},
 
 		// Block 100000 should be present (as an orphan).
-		{hash: "746deb238f38dfc82ea2e1dbd85c079ceb581fc2912aae37d6c3675a12545df4", want: true},
+		{hash: "18bcf45b8c0dbccd7690a728f3486c6d5fc84971688f89f4554297b6a278e554", want: true},
 
 		// Random hashes should not be available.
 		{hash: "123", want: false},
@@ -558,6 +558,7 @@ func chainedNodes(parents blockSet, numNodes int) []*blockNode {
 			IDMerkleRoot:         &daghash.ZeroHash,
 			HashMerkleRoot:       &daghash.ZeroHash,
 			AcceptedIDMerkleRoot: &daghash.ZeroHash,
+			UTXOCommitment:       &daghash.ZeroHash,
 		}
 		header.ParentHashes = tips.hashes()
 		nodes[i] = newBlockNode(&header, tips, dagconfig.SimNetParams.K)
@@ -908,6 +909,7 @@ func TestValidateFeeTransaction(t *testing.T) {
 				HashMerkleRoot:       BuildHashMerkleTreeStore(utilTxs).Root(),
 				IDMerkleRoot:         BuildIDMerkleTreeStore(utilTxs).Root(),
 				AcceptedIDMerkleRoot: &daghash.ZeroHash,
+				UTXOCommitment:       &daghash.ZeroHash,
 			},
 			Transactions: transactions,
 		}
diff --git a/blockdag/dagio.go b/blockdag/dagio.go
index 359cf727f..d4ac0a636 100644
--- a/blockdag/dagio.go
+++ b/blockdag/dagio.go
@@ -625,6 +625,7 @@ func (dag *BlockDAG) deserializeBlockNode(blockRow []byte) (*blockNode, error) {
 		hashMerkleRoot:       header.HashMerkleRoot,
 		idMerkleRoot:         header.IDMerkleRoot,
 		acceptedIDMerkleRoot: header.AcceptedIDMerkleRoot,
+		utxoCommitment:       header.UTXOCommitment,
 	}
 
 	node.children = newSet()
diff --git a/blockdag/example_test.go b/blockdag/example_test.go
index 70154f423..994c12071 100644
--- a/blockdag/example_test.go
+++ b/blockdag/example_test.go
@@ -67,5 +67,5 @@ func ExampleBlockDAG_ProcessBlock() {
 	fmt.Printf("Block accepted. Is it an orphan?: %v", isOrphan)
 
 	// Output:
-	// Failed to process block: already have block 4aa46622896ef2f0c59aaff0c05f87984a3e640a8e79f9167f4c1b959fd14706
+	// Failed to process block: already have block 5804d0207bdbfd88dd035271fab95944585eb57017b0709d5a0a10a7edb37795
 }
diff --git a/blockdag/testdata/blk_0_to_4.dat b/blockdag/testdata/blk_0_to_4.dat
index 596084971..ed95364c7 100644
Binary files a/blockdag/testdata/blk_0_to_4.dat and b/blockdag/testdata/blk_0_to_4.dat differ
diff --git a/blockdag/testdata/blk_3A.dat b/blockdag/testdata/blk_3A.dat
index 58310bd73..2f4308f3f 100644
Binary files a/blockdag/testdata/blk_3A.dat and b/blockdag/testdata/blk_3A.dat differ
diff --git a/blockdag/testdata/blk_3B.dat b/blockdag/testdata/blk_3B.dat
index c76b58251..551991afc 100644
Binary files a/blockdag/testdata/blk_3B.dat and b/blockdag/testdata/blk_3B.dat differ
diff --git a/blockdag/testdata/blk_3C.dat b/blockdag/testdata/blk_3C.dat
index 0eb9ecae6..a41f63b89 100644
Binary files a/blockdag/testdata/blk_3C.dat and b/blockdag/testdata/blk_3C.dat differ
diff --git a/blockdag/testdata/blk_3D.dat b/blockdag/testdata/blk_3D.dat
index aad54f5e7..a91601f5d 100644
Binary files a/blockdag/testdata/blk_3D.dat and b/blockdag/testdata/blk_3D.dat differ
diff --git a/blockdag/validate_test.go b/blockdag/validate_test.go
index 5ebcc2f02..c19c5f158 100644
--- a/blockdag/validate_test.go
+++ b/blockdag/validate_test.go
@@ -234,6 +234,12 @@ func TestCheckBlockSanity(t *testing.T) {
 				0x4e, 0x06, 0xba, 0x64, 0xd7, 0x61, 0xda, 0x25,
 				0x1a, 0x0e, 0x21, 0xd4, 0x64, 0x49, 0x02, 0xa2,
 			},
+			UTXOCommitment: &daghash.Hash{
+				0x80, 0xf7, 0x00, 0xe3, 0x16, 0x3d, 0x04, 0x95,
+				0x5b, 0x7e, 0xaf, 0x84, 0x7e, 0x1b, 0x6b, 0x06,
+				0x4e, 0x06, 0xba, 0x64, 0xd7, 0x61, 0xda, 0x25,
+				0x1a, 0x0e, 0x21, 0xd4, 0x64, 0x49, 0x02, 0xa2,
+			},
 			Timestamp: time.Unix(0x5cd18053, 0),
 			Bits:      0x207fffff,
 			Nonce:     0x0,
@@ -520,7 +526,7 @@ func TestCheckSerializedHeight(t *testing.T) {
 		msgTx := coinbaseTx.Copy()
 		msgTx.TxIn[0].SignatureScript = test.sigScript
 
-		msgBlock := wire.NewMsgBlock(wire.NewBlockHeader(1, []*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0))
+		msgBlock := wire.NewMsgBlock(wire.NewBlockHeader(1, []*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0))
 		msgBlock.AddTransaction(msgTx)
 		block := util.NewBlock(msgBlock)
 		block.SetHeight(test.wantHeight)
@@ -627,7 +633,12 @@ func TestValidateParents(t *testing.T) {
 	b := generateNode(a)
 	c := generateNode(genesisNode)
 
-	fakeBlockHeader := &wire.BlockHeader{IDMerkleRoot: &daghash.ZeroHash, HashMerkleRoot: &daghash.ZeroHash, AcceptedIDMerkleRoot: &daghash.ZeroHash}
+	fakeBlockHeader := &wire.BlockHeader{
+		IDMerkleRoot:         &daghash.ZeroHash,
+		HashMerkleRoot:       &daghash.ZeroHash,
+		AcceptedIDMerkleRoot: &daghash.ZeroHash,
+		UTXOCommitment:       &daghash.ZeroHash,
+	}
 
 	// Check direct parents relation
 	err := validateParents(fakeBlockHeader, setFromSlice(a, b))
@@ -771,9 +782,10 @@ var Block100000 = wire.MsgBlock{
 			0x81, 0xb8, 0xa0, 0x68, 0x77, 0xc4, 0x02, 0x1e,
 			0x3c, 0xb1, 0x16, 0x8f, 0x5f, 0x6b, 0x45, 0x87,
 		},
-		Timestamp: time.Unix(0x5c404bc3, 0),
-		Bits:      0x207fffff,
-		Nonce:     0xdffffffffffffff9,
+		UTXOCommitment: &daghash.ZeroHash,
+		Timestamp:      time.Unix(0x5c404bc3, 0),
+		Bits:           0x207fffff,
+		Nonce:          0xdffffffffffffff9,
 	},
 	Transactions: []*wire.MsgTx{
 		{
@@ -1068,6 +1080,12 @@ var BlockWithWrongTxOrder = wire.MsgBlock{
 			0x0b, 0x79, 0xf5, 0x29, 0x6d, 0x1c, 0xaa, 0x90,
 			0x2f, 0x01, 0xd4, 0x83, 0x9b, 0x2a, 0x04, 0x5e,
 		},
+		UTXOCommitment: &daghash.Hash{
+			0x00, 0x69, 0x2d, 0x16, 0xb5, 0xd7, 0xe4, 0xf3,
+			0xcd, 0xc7, 0xc9, 0xaf, 0xfb, 0xd2, 0x1b, 0x85,
+			0x0b, 0x79, 0xf5, 0x29, 0x6d, 0x1c, 0xaa, 0x90,
+			0x2f, 0x01, 0xd4, 0x83, 0x9b, 0x2a, 0x04, 0x5e,
+		},
 		Timestamp: time.Unix(0x5cd16eaa, 0),
 		Bits:      0x207fffff,
 		Nonce:     0x2,
diff --git a/dagconfig/genesis.go b/dagconfig/genesis.go
index e0972644a..377ae551c 100644
--- a/dagconfig/genesis.go
+++ b/dagconfig/genesis.go
@@ -41,10 +41,10 @@ var genesisCoinbaseTx = wire.NewNativeMsgTx(1, genesisTxIns, genesisTxOuts)
 // genesisHash is the hash of the first block in the block chain for the main
 // network (genesis block).
 var genesisHash = daghash.Hash([daghash.HashSize]byte{
-	0x06, 0x47, 0xd1, 0x9f, 0x95, 0x1b, 0x4c, 0x7f,
-	0x16, 0xf9, 0x79, 0x8e, 0x0a, 0x64, 0x3e, 0x4a,
-	0x98, 0x87, 0x5f, 0xc0, 0xf0, 0xaf, 0x9a, 0xc5,
-	0xf0, 0xf2, 0x6e, 0x89, 0x22, 0x66, 0xa4, 0x4a,
+	0x95, 0x77, 0xb3, 0xed, 0xa7, 0x10, 0x0a, 0x5a,
+	0x9d, 0x70, 0xb0, 0x17, 0x70, 0xb5, 0x5e, 0x58,
+	0x44, 0x59, 0xb9, 0xfa, 0x71, 0x52, 0x03, 0xdd,
+	0x88, 0xfd, 0xdb, 0x7b, 0x20, 0xd0, 0x04, 0x58,
 })
 
 // genesisMerkleRoot is the hash of the first transaction in the genesis block
@@ -65,9 +65,10 @@ var genesisBlock = wire.MsgBlock{
 		HashMerkleRoot:       &genesisMerkleRoot,
 		IDMerkleRoot:         &genesisMerkleRoot,
 		AcceptedIDMerkleRoot: &daghash.Hash{},
-		Timestamp:            time.Unix(0x5cd00a98, 0),
+		UTXOCommitment:       &daghash.Hash{},
+		Timestamp:            time.Unix(0x5cd83da0, 0),
 		Bits:                 0x207fffff,
-		Nonce:                0x0,
+		Nonce:                0x1,
 	},
 	Transactions: []*wire.MsgTx{genesisCoinbaseTx},
 }
@@ -118,10 +119,10 @@ var devNetGenesisCoinbaseTx = genesisCoinbaseTx
 // devGenesisHash is the hash of the first block in the block chain for the development
 // network (genesis block).
 var devNetGenesisHash = daghash.Hash([daghash.HashSize]byte{
-	0x90, 0x9c, 0x51, 0x90, 0x39, 0x02, 0x5e, 0x11,
-	0x52, 0xa6, 0x54, 0xff, 0xc8, 0x40, 0xdf, 0x67,
-	0x2a, 0xe8, 0x20, 0x72, 0xed, 0x6a, 0x5e, 0x3f,
-	0xf4, 0x8e, 0xf8, 0xdb, 0x02, 0x02, 0x00, 0x00,
+	0x53, 0x68, 0x95, 0xd4, 0xf7, 0xc7, 0x3b, 0x94,
+	0x64, 0xfa, 0x98, 0xc7, 0xcb, 0x92, 0x53, 0x71,
+	0x5e, 0x14, 0xd1, 0x83, 0x01, 0xd4, 0x1e, 0x17,
+	0xd4, 0xc4, 0xd3, 0x50, 0xa7, 0x64, 0x00, 0x00,
 })
 
 // devNetGenesisMerkleRoot is the hash of the first transaction in the genesis block
@@ -137,9 +138,10 @@ var devNetGenesisBlock = wire.MsgBlock{
 		HashMerkleRoot:       &devNetGenesisMerkleRoot,
 		IDMerkleRoot:         &devNetGenesisMerkleRoot,
 		AcceptedIDMerkleRoot: &daghash.Hash{},
-		Timestamp:            time.Unix(0x5cd00a98, 0),
+		UTXOCommitment:       &daghash.Hash{},
+		Timestamp:            time.Unix(0x5cd83da0, 0),
 		Bits:                 0x1e7fffff,
-		Nonce:                0x2f0e8,
+		Nonce:                0xfe2a,
 	},
 	Transactions: []*wire.MsgTx{devNetGenesisCoinbaseTx},
 }
diff --git a/dagconfig/genesis_test.go b/dagconfig/genesis_test.go
index 9de5ea864..b3eddfff0 100644
--- a/dagconfig/genesis_test.go
+++ b/dagconfig/genesis_test.go
@@ -133,9 +133,13 @@ var genesisBlockBytes = []byte{
 	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-	0x00, 0x00, 0x00, 0x00, 0x00, 0x98, 0x0a, 0xd0,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0xa0, 0x3d, 0xd8,
 	0x5c, 0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0x7f,
-	0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x01, 0x01, 0x00, 0x00, 0x00, 0x01, 0x00,
 	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
diff --git a/database/example_test.go b/database/example_test.go
index 93b1afcd1..b5cc906af 100644
--- a/database/example_test.go
+++ b/database/example_test.go
@@ -175,5 +175,5 @@ func Example_blockStorageAndRetrieval() {
 	fmt.Printf("Serialized block size: %d bytes\n", len(loadedBlockBytes))
 
 	// Output:
-	// Serialized block size: 225 bytes
+	// Serialized block size: 257 bytes
 }
diff --git a/database/ffldb/blockio_test.go b/database/ffldb/blockio_test.go
index e1e3acd18..6cd6ba618 100644
--- a/database/ffldb/blockio_test.go
+++ b/database/ffldb/blockio_test.go
@@ -16,7 +16,7 @@ import (
 
 func TestDeleteFile(t *testing.T) {
 	testBlock := util.NewBlock(wire.NewMsgBlock(
-		wire.NewBlockHeader(1, []*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0)))
+		wire.NewBlockHeader(1, []*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0)))
 
 	tests := []struct {
 		fileNum     uint32
@@ -69,7 +69,7 @@ func TestDeleteFile(t *testing.T) {
 // and makes sure no panic occurs, as well as ensures the writeCursor was updated correctly.
 func TestHandleRollbackErrors(t *testing.T) {
 	testBlock := util.NewBlock(wire.NewMsgBlock(
-		wire.NewBlockHeader(1, []*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0)))
+		wire.NewBlockHeader(1, []*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0)))
 
 	testBlockSize := uint32(testBlock.MsgBlock().SerializeSize())
 	tests := []struct {
diff --git a/database/ffldb/db_test.go b/database/ffldb/db_test.go
index ab1f2d768..cf0c4a8c0 100644
--- a/database/ffldb/db_test.go
+++ b/database/ffldb/db_test.go
@@ -553,7 +553,7 @@ func TestForEachBucket(t *testing.T) {
 // TestStoreBlockErrors tests all error-cases in *tx.StoreBlock().
 // The non-error-cases are tested in the more general tests.
 func TestStoreBlockErrors(t *testing.T) {
-	testBlock := util.NewBlock(wire.NewMsgBlock(wire.NewBlockHeader(1, []*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0)))
+	testBlock := util.NewBlock(wire.NewMsgBlock(wire.NewBlockHeader(1, []*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0)))
 
 	tests := []struct {
 		name        string
@@ -716,7 +716,7 @@ func TestWritePendingAndCommitErrors(t *testing.T) {
 	rollbackCalled = false
 	err = pdb.Update(func(dbTx database.Tx) error {
 		return dbTx.StoreBlock(util.NewBlock(wire.NewMsgBlock(
-			wire.NewBlockHeader(1, []*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0))))
+			wire.NewBlockHeader(1, []*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0))))
 	})
 	if err == nil {
 		t.Errorf("No error returned when blockIdx.Put() should have returned an error")
diff --git a/database/testdata/blocks1-256.bz2 b/database/testdata/blocks1-256.bz2
index fd7350607..ad970d813 100644
Binary files a/database/testdata/blocks1-256.bz2 and b/database/testdata/blocks1-256.bz2 differ
diff --git a/database/testdata/generator.go b/database/testdata/generator.go
index fa65f221b..4a0ea45b6 100644
--- a/database/testdata/generator.go
+++ b/database/testdata/generator.go
@@ -49,6 +49,7 @@ func generateBlock(parent *wire.MsgBlock) *wire.MsgBlock {
 			HashMerkleRoot:       &genesisMerkleRoot,
 			IDMerkleRoot:         &daghash.ZeroHash,
 			AcceptedIDMerkleRoot: &daghash.ZeroHash,
+			UTXOCommitment:       &daghash.ZeroHash,
 			Timestamp:            time.Unix(0x5b28c4c8, 0), // 2018-06-19 08:54:32 +0000 UTC
 			Bits:                 0x2e00ffff,               // 503382015 [000000ffff000000000000000000000000000000000000000000000000000000]
 			Nonce:                0xc0192550,               // 2148484547
diff --git a/integration/rpctest/blockgen.go b/integration/rpctest/blockgen.go
index 2ae73007b..25a31d6d9 100644
--- a/integration/rpctest/blockgen.go
+++ b/integration/rpctest/blockgen.go
@@ -191,6 +191,7 @@ func CreateBlock(parentBlock *util.Block, inclusionTxs []*util.Tx,
 		HashMerkleRoot:       hashMerkleTree.Root(),
 		IDMerkleRoot:         idMerkleTree.Root(),
 		AcceptedIDMerkleRoot: &daghash.ZeroHash,
+		UTXOCommitment:       &daghash.ZeroHash,
 		Timestamp:            ts,
 		Bits:                 net.PowLimitBits,
 	}
diff --git a/mempool/estimatefee_test.go b/mempool/estimatefee_test.go
index a6c48fd34..d2fc6f471 100644
--- a/mempool/estimatefee_test.go
+++ b/mempool/estimatefee_test.go
@@ -70,7 +70,12 @@ func (eft *estimateFeeTester) newBlock(txs []*wire.MsgTx) {
 	eft.height++
 
 	block := util.NewBlock(&wire.MsgBlock{
-		Header:       wire.BlockHeader{IDMerkleRoot: &daghash.ZeroHash, HashMerkleRoot: &daghash.ZeroHash, AcceptedIDMerkleRoot: &daghash.ZeroHash},
+		Header: wire.BlockHeader{
+			IDMerkleRoot:         &daghash.ZeroHash,
+			HashMerkleRoot:       &daghash.ZeroHash,
+			AcceptedIDMerkleRoot: &daghash.ZeroHash,
+			UTXOCommitment:       &daghash.ZeroHash,
+		},
 		Transactions: txs,
 	})
 	block.SetHeight(eft.height)
diff --git a/mining/mining.go b/mining/mining.go
index 191930684..48da9c140 100644
--- a/mining/mining.go
+++ b/mining/mining.go
@@ -660,6 +660,7 @@ func (g *BlkTmplGenerator) NewBlockTemplate(payToAddress util.Address) (*BlockTe
 		HashMerkleRoot:       hashMerkleTree.Root(),
 		IDMerkleRoot:         idMerkleTree.Root(),
 		AcceptedIDMerkleRoot: &daghash.ZeroHash,
+		UTXOCommitment:       &daghash.ZeroHash,
 		Timestamp:            ts,
 		Bits:                 reqDifficulty,
 	}
diff --git a/mining/simulator/mineloop.go b/mining/simulator/mineloop.go
index 64a40193f..6774480f7 100644
--- a/mining/simulator/mineloop.go
+++ b/mining/simulator/mineloop.go
@@ -37,7 +37,7 @@ func parseBlock(template *btcjson.GetBlockTemplateResult) (*util.Block, error) {
 	bits := uint32(bitsInt64)
 
 	// parse rest of block
-	msgBlock := wire.NewMsgBlock(wire.NewBlockHeader(template.Version, parentHashes, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, uint32(bits), 0))
+	msgBlock := wire.NewMsgBlock(wire.NewBlockHeader(template.Version, parentHashes, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, uint32(bits), 0))
 
 	for i, txResult := range append([]btcjson.GetBlockTemplateResultTx{*template.CoinbaseTxn}, template.Transactions...) {
 		reader := hex.NewDecoder(strings.NewReader(txResult.Data))
diff --git a/peer/peer_test.go b/peer/peer_test.go
index 551c28375..2bb8bddee 100644
--- a/peer/peer_test.go
+++ b/peer/peer_test.go
@@ -494,7 +494,7 @@ func TestPeerListeners(t *testing.T) {
 		{
 			"OnBlock",
 			wire.NewMsgBlock(wire.NewBlockHeader(1,
-				[]*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 1, 1)),
+				[]*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 1, 1)),
 		},
 		{
 			"OnInv",
@@ -560,7 +560,7 @@ func TestPeerListeners(t *testing.T) {
 		{
 			"OnMerkleBlock",
 			wire.NewMsgMerkleBlock(wire.NewBlockHeader(1,
-				[]*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 1, 1)),
+				[]*daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 1, 1)),
 		},
 		// only one version message is allowed
 		// only one verack message is allowed
diff --git a/util/block_test.go b/util/block_test.go
index 73a944c33..d922bda4f 100644
--- a/util/block_test.go
+++ b/util/block_test.go
@@ -38,7 +38,7 @@ func TestBlock(t *testing.T) {
 	}
 
 	// Hash for block 100,000.
-	wantHashStr := "c4bb55d2eaae7c7505b199097ef163ab940aa41228bbdb6f8b6d8a5b71bc432c"
+	wantHashStr := "df1b3cc747f665f36df84bdaa54a9ea695fbe12e102156fc1fc61d89366bc2d7"
 	wantHash, err := daghash.NewHashFromStr(wantHashStr)
 	if err != nil {
 		t.Errorf("NewHashFromStr: %v", err)
@@ -147,10 +147,10 @@ func TestBlock(t *testing.T) {
 
 	// Transaction offsets and length for the transaction in Block100000.
 	wantTxLocs := []wire.TxLoc{
-		{TxStart: 186, TxLen: 163},
-		{TxStart: 349, TxLen: 287},
-		{TxStart: 636, TxLen: 285},
-		{TxStart: 921, TxLen: 253},
+		{TxStart: 218, TxLen: 163},
+		{TxStart: 381, TxLen: 287},
+		{TxStart: 668, TxLen: 285},
+		{TxStart: 953, TxLen: 253},
 	}
 
 	// Ensure the transaction location information is accurate.
@@ -259,7 +259,7 @@ func TestBlockErrors(t *testing.T) {
 	}
 
 	// Truncate the block byte buffer to force errors.
-	shortBytes := block100000Bytes[:186]
+	shortBytes := block100000Bytes[:218]
 	_, err = util.NewBlockFromBytes(shortBytes)
 	if err != io.EOF {
 		t.Errorf("NewBlockFromBytes: did not get expected error - "+
@@ -337,6 +337,12 @@ var Block100000 = wire.MsgBlock{
 			0x66, 0x57, 0xa9, 0x25, 0x2a, 0xac, 0xd5, 0xc0,
 			0xb2, 0x94, 0x09, 0x96, 0xec, 0xff, 0x95, 0x22,
 		},
+		UTXOCommitment: &daghash.Hash{
+			0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C,
+			0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+			0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+			0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
+		},
 		Timestamp: time.Unix(1529483563, 0), // 2018-06-20 08:32:43 +0000 UTC
 		Bits:      0x1e00ffff,               // 503382015
 		Nonce:     0x000ae53f,               // 714047
diff --git a/util/bloom/filter_test.go b/util/bloom/filter_test.go
index 283568486..92c10c08a 100644
--- a/util/bloom/filter_test.go
+++ b/util/bloom/filter_test.go
@@ -543,6 +543,10 @@ func TestFilterInsertP2PubKeyOnly(t *testing.T) {
 		0x3C, 0xE3, 0x70, 0xD9, 0x5F, 0x09, 0x3B, 0xC7, 0xE3, 0x67, 0x11, // AcceptedIDMerkleRoot
 		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63, 0x65, 0x9C, 0x79,
 		0x7B, 0x3C, 0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+		0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C, // UTXOCommitment
+		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 		0x76, 0x38, 0x1B, 0x4D, 0x00, 0x00, 0x00, 0x00, // Time
 		0x4C, 0x86, 0x04, 0x1B, // Bits
 		0x55, 0x4B, 0x85, 0x29, 0x00, 0x00, 0x00, 0x00, // Fake Nonce. TODO: (Ori) Replace to a real nonce
diff --git a/util/bloom/merkleblock_test.go b/util/bloom/merkleblock_test.go
index e707fe8df..f7ff2d1dd 100644
--- a/util/bloom/merkleblock_test.go
+++ b/util/bloom/merkleblock_test.go
@@ -31,6 +31,10 @@ func TestMerkleBlock3(t *testing.T) {
 		0x3C, 0xE3, 0x70, 0xD9, 0x5F, 0x09, 0x3B, 0xC7, 0xE3, 0x67, 0x11, // AcceptedIDMerkleRoot
 		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63, 0x65, 0x9C, 0x79,
 		0x7B, 0x3C, 0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+		0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C, // UTXOCommitment
+		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 		0x67, 0x29, 0x1B, 0x4D, 0x00, 0x00, 0x00, 0x00, //Time
 		0x4C, 0x86, 0x04, 0x1B, // Bits
 		0x8F, 0xA4, 0x5D, 0x63, 0x00, 0x00, 0x00, 0x00, // Fake Nonce. TODO: (Ori) Replace to a real nonce
@@ -88,7 +92,11 @@ func TestMerkleBlock3(t *testing.T) {
 		0xd9, 0x5f, 0x09, 0x3b, 0xc7, 0xe3, 0x67, 0x11,
 		0x7f, 0x16, 0xc5, 0x96, 0x2e, 0x8b, 0xd9, 0x63,
 		0x65, 0x9c, 0x79, 0x7b, 0x3c, 0x30, 0xc1, 0xf8,
-		0xfd, 0xd0, 0xd9, 0x72, 0x87, 0x67, 0x29, 0x1b,
+		0xfd, 0xd0, 0xd9, 0x72, 0x87, 0x10, 0x3b, 0xc7,
+		0xe3, 0x67, 0x11, 0x7b, 0x3c, 0x30, 0xc1, 0xf8,
+		0xfd, 0xd0, 0xd9, 0x72, 0x87, 0x7f, 0x16, 0xc5,
+		0x96, 0x2e, 0x8b, 0xd9, 0x63, 0x65, 0x9c, 0x79,
+		0x3c, 0xe3, 0x70, 0xd9, 0x5f, 0x67, 0x29, 0x1b,
 		0x4d, 0x00, 0x00, 0x00, 0x00, 0x4c, 0x86, 0x04,
 		0x1b, 0x8f, 0xa4, 0x5d, 0x63, 0x00, 0x00, 0x00,
 		0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0xe2, 0x03,
diff --git a/wire/bench_test.go b/wire/bench_test.go
index 9449172ee..f5298ed48 100644
--- a/wire/bench_test.go
+++ b/wire/bench_test.go
@@ -426,7 +426,7 @@ func BenchmarkDecodeHeaders(b *testing.B) {
 			}
 			parentHashes[i] = hash
 		}
-		m.AddBlockHeader(NewBlockHeader(1, parentHashes, hash, hash, hash, 0, uint64(i)))
+		m.AddBlockHeader(NewBlockHeader(1, parentHashes, hash, hash, hash, hash, 0, uint64(i)))
 	}
 
 	// Serialize it so the bytes are available to test the decode below.
@@ -572,7 +572,7 @@ func BenchmarkDecodeMerkleBlock(b *testing.B) {
 	if err != nil {
 		b.Fatalf("NewHashFromStr: unexpected error: %v", err)
 	}
-	m.Header = *NewBlockHeader(1, []*daghash.Hash{hash}, hash, hash, hash, 0, uint64(10000))
+	m.Header = *NewBlockHeader(1, []*daghash.Hash{hash}, hash, hash, hash, hash, 0, uint64(10000))
 	for i := 0; i < 105; i++ {
 		hash, err := daghash.NewHashFromStr(fmt.Sprintf("%x", i))
 		if err != nil {
diff --git a/wire/blockheader.go b/wire/blockheader.go
index cc064e482..540c4a02f 100644
--- a/wire/blockheader.go
+++ b/wire/blockheader.go
@@ -16,10 +16,10 @@ import (
 // not including the list of parent block headers.
 // Version 4 bytes + Timestamp 8 bytes + Bits 4 bytes + Nonce 8 bytes +
 // + NumParentBlocks 1 byte + HashMerkleRoot hash + IDMerkleRoot hash +
-// + AcceptedIDMerkleRoot hash.
+// + AcceptedIDMerkleRoot hash + UTXOCommitment hash.
 // To get total size of block header len(ParentHashes) * daghash.HashSize should be
 // added to this value
-const BaseBlockHeaderPayload = 25 + 3*(daghash.HashSize)
+const BaseBlockHeaderPayload = 25 + 4*(daghash.HashSize)
 
 // MaxNumParentBlocks is the maximum number of parent blocks a block can reference.
 // Currently set to 255 as the maximum number NumParentBlocks can be due to it being a byte
@@ -48,6 +48,9 @@ type BlockHeader struct {
 	// accepted form the block.Blues
 	AcceptedIDMerkleRoot *daghash.Hash
 
+	// UTXOCommitment is an ECMH UTXO commitment to the block UTXO.
+	UTXOCommitment *daghash.Hash
+
 	// Time the block was created.
 	Timestamp time.Time
 
@@ -127,6 +130,7 @@ func (h *BlockHeader) SerializeSize() int {
 // block with defaults or calclulated values for the remaining fields.
 func NewBlockHeader(version int32, parentHashes []*daghash.Hash, hashMerkleRoot *daghash.Hash,
 	idMerkleRoot *daghash.Hash, acceptedIDMerkleRoot *daghash.Hash,
+	utxoCommitment *daghash.Hash,
 	bits uint32, nonce uint64) *BlockHeader {
 
 	// Limit the timestamp to one second precision since the protocol
@@ -137,6 +141,7 @@ func NewBlockHeader(version int32, parentHashes []*daghash.Hash, hashMerkleRoot
 		HashMerkleRoot:       hashMerkleRoot,
 		IDMerkleRoot:         idMerkleRoot,
 		AcceptedIDMerkleRoot: acceptedIDMerkleRoot,
+		UTXOCommitment:       utxoCommitment,
 		Timestamp:            time.Unix(time.Now().Unix(), 0),
 		Bits:                 bits,
 		Nonce:                nonce,
@@ -165,8 +170,9 @@ func readBlockHeader(r io.Reader, pver uint32, bh *BlockHeader) error {
 	bh.HashMerkleRoot = &daghash.Hash{}
 	bh.IDMerkleRoot = &daghash.Hash{}
 	bh.AcceptedIDMerkleRoot = &daghash.Hash{}
+	bh.UTXOCommitment = &daghash.Hash{}
 	return readElements(r, bh.HashMerkleRoot, bh.IDMerkleRoot,
-		bh.AcceptedIDMerkleRoot, (*int64Time)(&bh.Timestamp),
+		bh.AcceptedIDMerkleRoot, bh.UTXOCommitment, (*int64Time)(&bh.Timestamp),
 		&bh.Bits, &bh.Nonce)
 }
 
@@ -184,5 +190,5 @@ func writeBlockHeader(w io.Writer, pver uint32, bh *BlockHeader) error {
 		}
 	}
 	return writeElements(w, bh.HashMerkleRoot, bh.IDMerkleRoot,
-		bh.AcceptedIDMerkleRoot, sec, bh.Bits, bh.Nonce)
+		bh.AcceptedIDMerkleRoot, bh.UTXOCommitment, sec, bh.Bits, bh.Nonce)
 }
diff --git a/wire/blockheader_test.go b/wire/blockheader_test.go
index 446cce2ca..9633d567b 100644
--- a/wire/blockheader_test.go
+++ b/wire/blockheader_test.go
@@ -29,7 +29,7 @@ func TestBlockHeader(t *testing.T) {
 	acceptedIDMerkleRoot := exampleAcceptedIDMerkleRoot
 	bits := uint32(0x1d00ffff)
 	bh := NewBlockHeader(1, hashes, merkleHash, idMerkleRoot,
-		acceptedIDMerkleRoot, bits, nonce)
+		acceptedIDMerkleRoot, exampleUTXOCommitment, bits, nonce)
 
 	// Ensure we get the same data back out.
 	if !reflect.DeepEqual(bh.ParentHashes, hashes) {
@@ -64,6 +64,7 @@ func TestBlockHeaderWire(t *testing.T) {
 		HashMerkleRoot:       mainNetGenesisMerkleRoot,
 		IDMerkleRoot:         exampleIDMerkleRoot,
 		AcceptedIDMerkleRoot: exampleAcceptedIDMerkleRoot,
+		UTXOCommitment:       exampleUTXOCommitment,
 		Timestamp:            time.Unix(0x495fab29, 0), // 2009-01-03 12:15:05 -0600 CST
 		Bits:                 bits,
 		Nonce:                nonce,
@@ -93,6 +94,10 @@ func TestBlockHeaderWire(t *testing.T) {
 		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
 		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
 		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
+		0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C, // UTXOCommitment
+		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 		0x29, 0xab, 0x5f, 0x49, 0x00, 0x00, 0x00, 0x00, // Timestamp
 		0xff, 0xff, 0x00, 0x1d, // Bits
 		0xf3, 0xe0, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, // Fake Nonce. TODO: (Ori) Replace to a real nonce
@@ -180,6 +185,7 @@ func TestBlockHeaderSerialize(t *testing.T) {
 		HashMerkleRoot:       mainNetGenesisMerkleRoot,
 		IDMerkleRoot:         exampleIDMerkleRoot,
 		AcceptedIDMerkleRoot: exampleAcceptedIDMerkleRoot,
+		UTXOCommitment:       exampleUTXOCommitment,
 		Timestamp:            time.Unix(0x495fab29, 0), // 2009-01-03 12:15:05 -0600 CST
 		Bits:                 bits,
 		Nonce:                nonce,
@@ -209,6 +215,10 @@ func TestBlockHeaderSerialize(t *testing.T) {
 		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
 		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
 		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
+		0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C, // UTXOCommitment
+		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 		0x29, 0xab, 0x5f, 0x49, 0x00, 0x00, 0x00, 0x00, // Timestamp
 		0xff, 0xff, 0x00, 0x1d, // Bits
 		0xf3, 0xe0, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, // Fake Nonce. TODO: (Ori) Replace to a real nonce
@@ -269,6 +279,7 @@ func TestBlockHeaderSerializeSize(t *testing.T) {
 		HashMerkleRoot:       mainNetGenesisMerkleRoot,
 		IDMerkleRoot:         mainNetGenesisMerkleRoot,
 		AcceptedIDMerkleRoot: &daghash.ZeroHash,
+		UTXOCommitment:       &daghash.ZeroHash,
 		Timestamp:            timestamp,
 		Bits:                 bits,
 		Nonce:                nonce,
@@ -280,6 +291,7 @@ func TestBlockHeaderSerializeSize(t *testing.T) {
 		HashMerkleRoot:       mainNetGenesisMerkleRoot,
 		IDMerkleRoot:         mainNetGenesisMerkleRoot,
 		AcceptedIDMerkleRoot: &daghash.ZeroHash,
+		UTXOCommitment:       &daghash.ZeroHash,
 		Timestamp:            timestamp,
 		Bits:                 bits,
 		Nonce:                nonce,
@@ -289,10 +301,10 @@ func TestBlockHeaderSerializeSize(t *testing.T) {
 		size int          // Expected serialized size
 	}{
 		// Block with no transactions.
-		{genesisBlockHdr, 121},
+		{genesisBlockHdr, 153},
 
 		// First block in the mainnet block DAG.
-		{baseBlockHdr, 185},
+		{baseBlockHdr, 217},
 	}
 
 	t.Logf("Running %d tests", len(tests))
diff --git a/wire/common_test.go b/wire/common_test.go
index 9bd7a876b..c1135a17f 100644
--- a/wire/common_test.go
+++ b/wire/common_test.go
@@ -56,6 +56,13 @@ var exampleAcceptedIDMerkleRoot = &daghash.Hash{
 	0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 }
 
+var exampleUTXOCommitment = &daghash.Hash{
+	0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C,
+	0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+	0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+	0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
+}
+
 // TestElementWire tests wire encode and decode for various element types.  This
 // is mainly to test the "fast" paths in readElement and writeElement which use
 // type assertions to avoid reflection when possible.
diff --git a/wire/message_test.go b/wire/message_test.go
index 455723034..4fad13c03 100644
--- a/wire/message_test.go
+++ b/wire/message_test.go
@@ -68,7 +68,7 @@ func TestMessage(t *testing.T) {
 	msgFilterAdd := NewMsgFilterAdd([]byte{0x01})
 	msgFilterClear := NewMsgFilterClear()
 	msgFilterLoad := NewMsgFilterLoad([]byte{0x01}, 10, 0, BloomUpdateNone)
-	bh := NewBlockHeader(1, []*daghash.Hash{mainNetGenesisHash, simNetGenesisHash}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0)
+	bh := NewBlockHeader(1, []*daghash.Hash{mainNetGenesisHash, simNetGenesisHash}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, &daghash.Hash{}, 0, 0)
 	msgMerkleBlock := NewMsgMerkleBlock(bh)
 	msgReject := NewMsgReject("block", RejectDuplicate, "duplicate block")
 	msgGetCFilters := NewMsgGetCFilters(GCSFilterExtended, 0, &daghash.Hash{})
@@ -91,7 +91,7 @@ func TestMessage(t *testing.T) {
 		{msgGetAddr, msgGetAddr, pver, MainNet, 26},
 		{msgAddr, msgAddr, pver, MainNet, 27},
 		{msgGetBlocks, msgGetBlocks, pver, MainNet, 61},
-		{msgBlock, msgBlock, pver, MainNet, 372},
+		{msgBlock, msgBlock, pver, MainNet, 404},
 		{msgInv, msgInv, pver, MainNet, 25},
 		{msgGetData, msgGetData, pver, MainNet, 25},
 		{msgNotFound, msgNotFound, pver, MainNet, 25},
@@ -107,7 +107,7 @@ func TestMessage(t *testing.T) {
 		{msgFilterAdd, msgFilterAdd, pver, MainNet, 26},
 		{msgFilterClear, msgFilterClear, pver, MainNet, 24},
 		{msgFilterLoad, msgFilterLoad, pver, MainNet, 35},
-		{msgMerkleBlock, msgMerkleBlock, pver, MainNet, 215},
+		{msgMerkleBlock, msgMerkleBlock, pver, MainNet, 247},
 		{msgReject, msgReject, pver, MainNet, 79},
 		{msgGetCFilters, msgGetCFilters, pver, MainNet, 65},
 		{msgGetCFHeaders, msgGetCFHeaders, pver, MainNet, 65},
diff --git a/wire/msgblock_test.go b/wire/msgblock_test.go
index dc2f0a736..34859e7ea 100644
--- a/wire/msgblock_test.go
+++ b/wire/msgblock_test.go
@@ -27,10 +27,11 @@ func TestBlock(t *testing.T) {
 	hashMerkleRoot := blockOne.Header.HashMerkleRoot
 	idMerkleRoot := blockOne.Header.IDMerkleRoot
 	acceptedIDMerkleRoot := blockOne.Header.AcceptedIDMerkleRoot
+	utxoCommitment := blockOne.Header.UTXOCommitment
 	bits := blockOne.Header.Bits
 	nonce := blockOne.Header.Nonce
 	bh := NewBlockHeader(1, parentHashes, hashMerkleRoot, idMerkleRoot,
-		acceptedIDMerkleRoot, bits, nonce)
+		acceptedIDMerkleRoot, utxoCommitment, bits, nonce)
 
 	// Ensure the command is expected value.
 	wantCmd := "block"
@@ -76,7 +77,7 @@ func TestBlock(t *testing.T) {
 // TestBlockHash tests the ability to generate the hash of a block accurately.
 func TestBlockHash(t *testing.T) {
 	// Block 1 hash.
-	hashStr := "d632f80af4f507bed094a424902e37cc4b1e447e4ede731f0f4b446edebaf381"
+	hashStr := "8a3a27a37c9e3342b4b38ae9ef29e59fe37b59618adafbf36a106b6d62f80654"
 	wantHash, err := daghash.NewHashFromStr(hashStr)
 	if err != nil {
 		t.Errorf("NewHashFromStr: %v", err)
@@ -224,16 +225,18 @@ func TestBlockWireErrors(t *testing.T) {
 		{&blockOne, blockOneBytes, pver, 101, io.ErrShortWrite, io.EOF},
 		// Force error in accepted ID merkle root.
 		{&blockOne, blockOneBytes, pver, 133, io.ErrShortWrite, io.EOF},
-		// Force error in timestamp.
+		// Force error in utxo commitment.
 		{&blockOne, blockOneBytes, pver, 165, io.ErrShortWrite, io.EOF},
+		// Force error in timestamp.
+		{&blockOne, blockOneBytes, pver, 197, io.ErrShortWrite, io.EOF},
 		// Force error in difficulty bits.
-		{&blockOne, blockOneBytes, pver, 173, io.ErrShortWrite, io.EOF},
+		{&blockOne, blockOneBytes, pver, 205, io.ErrShortWrite, io.EOF},
 		// Force error in header nonce.
-		{&blockOne, blockOneBytes, pver, 177, io.ErrShortWrite, io.EOF},
+		{&blockOne, blockOneBytes, pver, 209, io.ErrShortWrite, io.EOF},
 		// Force error in transaction count.
-		{&blockOne, blockOneBytes, pver, 185, io.ErrShortWrite, io.EOF},
+		{&blockOne, blockOneBytes, pver, 217, io.ErrShortWrite, io.EOF},
 		// Force error in transactions.
-		{&blockOne, blockOneBytes, pver, 186, io.ErrShortWrite, io.EOF},
+		{&blockOne, blockOneBytes, pver, 218, io.ErrShortWrite, io.EOF},
 	}
 
 	t.Logf("Running %d tests", len(tests))
@@ -350,16 +353,18 @@ func TestBlockSerializeErrors(t *testing.T) {
 		{&blockOne, blockOneBytes, 101, io.ErrShortWrite, io.EOF},
 		// Force error in accepted ID merkle root.
 		{&blockOne, blockOneBytes, 133, io.ErrShortWrite, io.EOF},
-		// Force error in timestamp.
+		// Force error in utxo commitment.
 		{&blockOne, blockOneBytes, 165, io.ErrShortWrite, io.EOF},
+		// Force error in timestamp.
+		{&blockOne, blockOneBytes, 197, io.ErrShortWrite, io.EOF},
 		// Force error in difficulty bits.
-		{&blockOne, blockOneBytes, 173, io.ErrShortWrite, io.EOF},
+		{&blockOne, blockOneBytes, 205, io.ErrShortWrite, io.EOF},
 		// Force error in header nonce.
-		{&blockOne, blockOneBytes, 177, io.ErrShortWrite, io.EOF},
+		{&blockOne, blockOneBytes, 209, io.ErrShortWrite, io.EOF},
 		// Force error in transaction count.
-		{&blockOne, blockOneBytes, 185, io.ErrShortWrite, io.EOF},
+		{&blockOne, blockOneBytes, 217, io.ErrShortWrite, io.EOF},
 		// Force error in transactions.
-		{&blockOne, blockOneBytes, 186, io.ErrShortWrite, io.EOF},
+		{&blockOne, blockOneBytes, 218, io.ErrShortWrite, io.EOF},
 	}
 
 	t.Logf("Running %d tests", len(tests))
@@ -431,6 +436,10 @@ func TestBlockOverflowErrors(t *testing.T) {
 				0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
 				0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
 				0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
+				0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C, // UTXOCommitment
+				0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+				0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+				0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 				0x61, 0xbc, 0x66, 0x49, 0x00, 0x00, 0x00, 0x00, // Timestamp
 				0xff, 0xff, 0x00, 0x1d, // Bits
 				0x01, 0xe3, 0x62, 0x99, 0x00, 0x00, 0x00, 0x00, // Fake Nonce. TODO: (Ori) Replace to a real nonce
@@ -483,7 +492,7 @@ func TestBlockSerializeSize(t *testing.T) {
 		size int       // Expected serialized size
 	}{
 		// Block with no transactions.
-		{noTxBlock, 186},
+		{noTxBlock, 218},
 
 		// First block in the mainnet block chain.
 		{&blockOne, len(blockOneBytes)},
@@ -509,6 +518,7 @@ var blockOne = MsgBlock{
 		HashMerkleRoot:       mainNetGenesisMerkleRoot,
 		IDMerkleRoot:         exampleIDMerkleRoot,
 		AcceptedIDMerkleRoot: exampleAcceptedIDMerkleRoot,
+		UTXOCommitment:       exampleUTXOCommitment,
 		Timestamp:            time.Unix(0x4966bc61, 0), // 2009-01-08 20:54:25 -0600 CST
 		Bits:                 0x1d00ffff,               // 486604799
 		Nonce:                0x9962e301,               // 2573394689
@@ -572,6 +582,10 @@ var blockOneBytes = []byte{
 	0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
 	0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
 	0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
+	0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C, // UTXOCommitment
+	0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+	0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+	0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 	0x61, 0xbc, 0x66, 0x49, 0x00, 0x00, 0x00, 0x00, // Timestamp
 	0xff, 0xff, 0x00, 0x1d, // Bits
 	0x01, 0xe3, 0x62, 0x99, 0x00, 0x00, 0x00, 0x00, // Fake Nonce. TODO: (Ori) Replace to a real nonce
@@ -608,5 +622,5 @@ var blockOneBytes = []byte{
 
 // Transaction location information for block one transactions.
 var blockOneTxLocs = []TxLoc{
-	{TxStart: 186, TxLen: 162},
+	{TxStart: 218, TxLen: 162},
 }
diff --git a/wire/msgheaders_test.go b/wire/msgheaders_test.go
index 60ba771ed..26205d1e0 100644
--- a/wire/msgheaders_test.go
+++ b/wire/msgheaders_test.go
@@ -29,7 +29,7 @@ func TestHeaders(t *testing.T) {
 	// Ensure max payload is expected value for latest protocol version.
 	// Num headers (varInt) + max allowed headers (header length + 1 byte
 	// for the number of transactions which is always 0).
-	wantPayload := uint32(16564009)
+	wantPayload := uint32(16628009)
 	maxPayload := msg.MaxPayloadLength(pver)
 	if maxPayload != wantPayload {
 		t.Errorf("MaxPayloadLength: wrong max payload length for "+
@@ -65,10 +65,11 @@ func TestHeadersWire(t *testing.T) {
 	hashMerkleRoot := blockOne.Header.HashMerkleRoot
 	idMerkleRoot := blockOne.Header.IDMerkleRoot
 	acceptedIDMerkleRoot := blockOne.Header.AcceptedIDMerkleRoot
+	utxoCommitment := blockOne.Header.UTXOCommitment
 	bits := uint32(0x1d00ffff)
 	nonce := uint64(0x9962e301)
 	bh := NewBlockHeader(1, hashes, hashMerkleRoot, idMerkleRoot,
-		acceptedIDMerkleRoot, bits, nonce)
+		acceptedIDMerkleRoot, utxoCommitment, bits, nonce)
 	bh.Version = blockOne.Header.Version
 	bh.Timestamp = blockOne.Header.Timestamp
 
@@ -105,6 +106,10 @@ func TestHeadersWire(t *testing.T) {
 		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
 		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
 		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
+		0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C, // UTXOCommitment
+		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 		0x61, 0xbc, 0x66, 0x49, 0x00, 0x00, 0x00, 0x00, // Timestamp
 		0xff, 0xff, 0x00, 0x1d, // Bits
 		0x01, 0xe3, 0x62, 0x99, 0x00, 0x00, 0x00, 0x00, // Fake Nonce. TODO: (Ori) Replace to a real nonce
@@ -175,10 +180,11 @@ func TestHeadersWireErrors(t *testing.T) {
 	hashMerkleRoot := blockOne.Header.HashMerkleRoot
 	idMerkleRoot := blockOne.Header.IDMerkleRoot
 	acceptedIDMerkleRoot := blockOne.Header.AcceptedIDMerkleRoot
+	utxoCommitment := blockOne.Header.UTXOCommitment
 	bits := uint32(0x1d00ffff)
 	nonce := uint64(0x9962e301)
 	bh := NewBlockHeader(1, hashes, hashMerkleRoot, idMerkleRoot,
-		acceptedIDMerkleRoot, bits, nonce)
+		acceptedIDMerkleRoot, utxoCommitment, bits, nonce)
 	bh.Version = blockOne.Header.Version
 	bh.Timestamp = blockOne.Header.Timestamp
 
@@ -205,6 +211,14 @@ func TestHeadersWireErrors(t *testing.T) {
 		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 		0x09, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C,
 		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+		0x09, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C, // AcceptedIDMerkleRoot
+		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
+		0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C, // UTXOCommitment
+		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 		0x61, 0xbc, 0x66, 0x49, 0x00, 0x00, 0x00, 0x00, // Timestamp
 		0xff, 0xff, 0x00, 0x1d, // Bits
 		0x01, 0xe3, 0x62, 0x99, 0x00, 0x00, 0x00, 0x00, // Fake Nonce. TODO: (Ori) Replace to a real nonce
@@ -225,7 +239,7 @@ func TestHeadersWireErrors(t *testing.T) {
 	// Intentionally invalid block header that has a transaction count used
 	// to force errors.
 	bhTrans := NewBlockHeader(1, hashes, hashMerkleRoot, idMerkleRoot,
-		acceptedIDMerkleRoot, bits, nonce)
+		acceptedIDMerkleRoot, utxoCommitment, bits, nonce)
 	bhTrans.Version = blockOne.Header.Version
 	bhTrans.Timestamp = blockOne.Header.Timestamp
 
@@ -255,6 +269,10 @@ func TestHeadersWireErrors(t *testing.T) {
 		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
 		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
 		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
+		0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C, // UTXOCommitment
+		0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+		0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+		0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 		0x61, 0xbc, 0x66, 0x49, 0x00, 0x00, 0x00, 0x00, // Timestamp
 		0xff, 0xff, 0x00, 0x1d, // Bits
 		0x01, 0xe3, 0x62, 0x99, 0x00, 0x00, 0x00, 0x00, // Fake Nonce. TODO: (Ori) Replace to a real nonce
@@ -277,7 +295,7 @@ func TestHeadersWireErrors(t *testing.T) {
 		// Force error with greater than max headers.
 		{maxHeaders, maxHeadersEncoded, pver, 3, wireErr, wireErr},
 		// Force error with number of transactions.
-		{transHeader, transHeaderEncoded, pver, 178, io.ErrShortWrite, io.EOF},
+		{transHeader, transHeaderEncoded, pver, 210, io.ErrShortWrite, io.EOF},
 		// Force error with included transactions.
 		{transHeader, transHeaderEncoded, pver, len(transHeaderEncoded), nil, wireErr},
 	}
diff --git a/wire/msgmerkleblock_test.go b/wire/msgmerkleblock_test.go
index d5c2bae24..26d8734bd 100644
--- a/wire/msgmerkleblock_test.go
+++ b/wire/msgmerkleblock_test.go
@@ -25,10 +25,11 @@ func TestMerkleBlock(t *testing.T) {
 	hashMerkleRoot := blockOne.Header.HashMerkleRoot
 	idMerkleRoot := blockOne.Header.IDMerkleRoot
 	acceptedIDMerkleRoot := blockOne.Header.AcceptedIDMerkleRoot
+	utxoCommitment := blockOne.Header.UTXOCommitment
 	bits := blockOne.Header.Bits
 	nonce := blockOne.Header.Nonce
 	bh := NewBlockHeader(1, parentHashes, hashMerkleRoot, idMerkleRoot,
-		acceptedIDMerkleRoot, bits, nonce)
+		acceptedIDMerkleRoot, utxoCommitment, bits, nonce)
 
 	// Ensure the command is expected value.
 	wantCmd := "merkleblock"
@@ -120,10 +121,11 @@ func TestMerkleBlockCrossProtocol(t *testing.T) {
 	hashMerkleRoot := blockOne.Header.HashMerkleRoot
 	idMerkleRoot := blockOne.Header.IDMerkleRoot
 	acceptedIDMerkleRoot := blockOne.Header.AcceptedIDMerkleRoot
+	utxoCommitment := blockOne.Header.UTXOCommitment
 	bits := blockOne.Header.Bits
 	nonce := blockOne.Header.Nonce
 	bh := NewBlockHeader(1, parentHashes, hashMerkleRoot, idMerkleRoot,
-		acceptedIDMerkleRoot, bits, nonce)
+		acceptedIDMerkleRoot, utxoCommitment, bits, nonce)
 
 	msg := NewMsgMerkleBlock(bh)
 
@@ -209,22 +211,24 @@ func TestMerkleBlockWireErrors(t *testing.T) {
 		{&merkleBlockOne, merkleBlockOneBytes, pver, 101, io.ErrShortWrite, io.EOF},
 		// Force error in accepted ID merkle root.
 		{&merkleBlockOne, merkleBlockOneBytes, pver, 133, io.ErrShortWrite, io.EOF},
-		// Force error in timestamp.
+		// Force error in utxo commitment.
 		{&merkleBlockOne, merkleBlockOneBytes, pver, 165, io.ErrShortWrite, io.EOF},
+		// Force error in timestamp.
+		{&merkleBlockOne, merkleBlockOneBytes, pver, 197, io.ErrShortWrite, io.EOF},
 		// Force error in difficulty bits.
-		{&merkleBlockOne, merkleBlockOneBytes, pver, 173, io.ErrShortWrite, io.EOF},
+		{&merkleBlockOne, merkleBlockOneBytes, pver, 205, io.ErrShortWrite, io.EOF},
 		// Force error in header nonce.
-		{&merkleBlockOne, merkleBlockOneBytes, pver, 177, io.ErrShortWrite, io.EOF},
+		{&merkleBlockOne, merkleBlockOneBytes, pver, 209, io.ErrShortWrite, io.EOF},
 		// Force error in transaction count.
-		{&merkleBlockOne, merkleBlockOneBytes, pver, 185, io.ErrShortWrite, io.EOF},
+		{&merkleBlockOne, merkleBlockOneBytes, pver, 217, io.ErrShortWrite, io.EOF},
 		// Force error in num hashes.
-		{&merkleBlockOne, merkleBlockOneBytes, pver, 189, io.ErrShortWrite, io.EOF},
+		{&merkleBlockOne, merkleBlockOneBytes, pver, 221, io.ErrShortWrite, io.EOF},
 		// Force error in hashes.
-		{&merkleBlockOne, merkleBlockOneBytes, pver, 190, io.ErrShortWrite, io.EOF},
-		// Force error in num flag bytes.
 		{&merkleBlockOne, merkleBlockOneBytes, pver, 222, io.ErrShortWrite, io.EOF},
+		// Force error in num flag bytes.
+		{&merkleBlockOne, merkleBlockOneBytes, pver, 254, io.ErrShortWrite, io.EOF},
 		// Force error in flag bytes.
-		{&merkleBlockOne, merkleBlockOneBytes, pver, 223, io.ErrShortWrite, io.EOF},
+		{&merkleBlockOne, merkleBlockOneBytes, pver, 255, io.ErrShortWrite, io.EOF},
 	}
 
 	t.Logf("Running %d tests", len(tests))
@@ -281,16 +285,17 @@ func TestMerkleBlockOverflowErrors(t *testing.T) {
 	// allowed tx hashes.
 	var buf bytes.Buffer
 	WriteVarInt(&buf, maxTxPerBlock+1)
-	numHashesOffset := 189
+	numHashesOffset := 221
 	exceedMaxHashes := make([]byte, numHashesOffset)
 	copy(exceedMaxHashes, merkleBlockOneBytes[:numHashesOffset])
+	spew.Dump(exceedMaxHashes)
 	exceedMaxHashes = append(exceedMaxHashes, buf.Bytes()...)
 
 	// Create bytes for a merkle block that claims to have more than the max
 	// allowed flag bytes.
 	buf.Reset()
 	WriteVarInt(&buf, maxFlagsPerMerkleBlock+1)
-	numFlagBytesOffset := 222
+	numFlagBytesOffset := 254
 	exceedMaxFlagBytes := make([]byte, numFlagBytesOffset)
 	copy(exceedMaxFlagBytes, merkleBlockOneBytes[:numFlagBytesOffset])
 	exceedMaxFlagBytes = append(exceedMaxFlagBytes, buf.Bytes()...)
@@ -334,6 +339,7 @@ var merkleBlockOne = MsgMerkleBlock{
 		},
 		IDMerkleRoot:         exampleIDMerkleRoot,
 		AcceptedIDMerkleRoot: exampleAcceptedIDMerkleRoot,
+		UTXOCommitment:       exampleUTXOCommitment,
 		Timestamp:            time.Unix(0x4966bc61, 0), // 2009-01-08 20:54:25 -0600 CST
 		Bits:                 0x1d00ffff,               // 486604799
 		Nonce:                0x9962e301,               // 2573394689
@@ -363,7 +369,7 @@ var merkleBlockOneBytes = []byte{
 	0x72, 0xff, 0x3d, 0x8e, 0xdb, 0xbb, 0x2d, 0xe0,
 	0xbf, 0xa6, 0x7b, 0x13, 0x97, 0x4b, 0xb9, 0x91,
 	0x0d, 0x11, 0x6d, 0x5c, 0xbd, 0x86, 0x3e, 0x68,
-	0x98, 0x20, 0x51, 0xfd, 0x1e, 0x4b, 0xa7, 0x44, // MerkleRoot
+	0x98, 0x20, 0x51, 0xfd, 0x1e, 0x4b, 0xa7, 0x44, // HashMerkleRoot
 	0xbb, 0xbe, 0x68, 0x0e, 0x1f, 0xee, 0x14, 0x67,
 	0x7b, 0xa1, 0xa3, 0xc3, 0x54, 0x0b, 0xf7, 0xb1,
 	0xcd, 0xb6, 0x06, 0xe8, 0x57, 0x23, 0x3e, 0x0e,
@@ -375,6 +381,10 @@ var merkleBlockOneBytes = []byte{
 	0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
 	0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
 	0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
+	0x10, 0x3B, 0xC7, 0xE3, 0x67, 0x11, 0x7B, 0x3C, // UTXOCommitment
+	0x30, 0xC1, 0xF8, 0xFD, 0xD0, 0xD9, 0x72, 0x87,
+	0x7F, 0x16, 0xC5, 0x96, 0x2E, 0x8B, 0xD9, 0x63,
+	0x65, 0x9C, 0x79, 0x3C, 0xE3, 0x70, 0xD9, 0x5F,
 	0x61, 0xbc, 0x66, 0x49, 0x00, 0x00, 0x00, 0x00, // Timestamp
 	0xff, 0xff, 0x00, 0x1d, // Bits
 	0x01, 0xe3, 0x62, 0x99, 0x00, 0x00, 0x00, 0x00, // Fake Nonce. TODO: (Ori) Replace to a real nonce