Merge remote-tracking branch 'origin/develop' into dev/adr_secp_signatures

2026-06-06 22:32:37 +00:00 · 2018-08-02 23:25:14 -07:00
parent 3d5d254932 2487210414
commit b3a3c8a192
37 changed files with 1553 additions and 687 deletions
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -147,7 +147,7 @@ jobs:
            for pkg in $(go list github.com/tendermint/tendermint/... | circleci tests split --split-by=timings); do
              id=$(basename "$pkg")

-              GOCACHE=off go test -v -timeout 5m -race -coverprofile=/tmp/workspace/profiles/$id.out -covermode=atomic "$pkg" | tee "/tmp/logs/$id-$RANDOM.log"
+              GOCACHE=off go test -timeout 5m -race -coverprofile=/tmp/workspace/profiles/$id.out -covermode=atomic "$pkg" | tee "/tmp/logs/$id-$RANDOM.log"
            done
      - persist_to_workspace:
          root: /tmp/workspace
--- a/CHANGELOG_PENDING.md
+++ b/CHANGELOG_PENDING.md
@@ -7,6 +7,7 @@ BREAKING CHANGES:
 - [tools] Removed `make ensure_deps` in favor of `make get_vendor_deps`
 - [p2p] Remove salsa and ripemd primitives, in favor of using chacha as a stream cipher, and hkdf
 - [abci] Changed time format from int64 to google.protobuf.Timestamp
+- [abci] Changed Validators to LastCommitInfo in RequestBeginBlock

 FEATURES:
 - [tools] Added `make check_dep`
@@ -19,7 +20,9 @@ IMPROVEMENTS:
    - only process one block at a time to avoid starving
 - [crypto] Switch hkdfchachapoly1305 to xchachapoly1305
 - [common] bit array functions which take in another parameter are now thread safe
+- [p2p] begin connecting to peers as soon a seed node provides them to you ([#2093](https://github.com/tendermint/tendermint/issues/2093))

 BUG FIXES:
+- [common] Safely handle cases where atomic write files already exist [#2109](https://github.com/tendermint/tendermint/issues/2109)
 - [privval] fix a deadline for accepting new connections in socket private
  validator.
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ develop   | [![CircleCI](https://circleci.com/gh/tendermint/tendermint/tree/deve
 Tendermint Core is Byzantine Fault Tolerant (BFT) middleware that takes a state transition machine - written in any programming language -
 and securely replicates it on many machines.

-For protocol details, see [the specification](/docs/spec).
+For protocol details, see [the specification](/docs/spec). For a consensus proof and detailed protocol analysis checkout our recent paper, "[The latest gossip on BFT consensus](https://arxiv.org/abs/1807.04938)".

 ## A Note on Production Readiness

--- a/abci/README.md
+++ b/abci/README.md
@@ -29,7 +29,7 @@ The two guides to focus on are the `Application Development Guide` and `Using AB
 To compile the protobuf file, run:

 ```
-make protoc
+cd $GOPATH/src/github.com/tendermint/tendermint/; make protoc_abci
 ```

 See `protoc --help` and [the Protocol Buffers site](https://developers.google.com/protocol-buffers)
--- a/abci/types/types.pb.go
+++ b/abci/types/types.pb.go
--- a/abci/types/types.proto
+++ b/abci/types/types.proto
@@ -71,10 +71,11 @@ message RequestQuery {
  bool prove = 4;
 }

+// NOTE: validators here have empty pubkeys.
 message RequestBeginBlock {
  bytes hash = 1;
  Header header = 2 [(gogoproto.nullable)=false];
-  repeated SigningValidator validators = 3  [(gogoproto.nullable)=false];
+  LastCommitInfo last_commit_info = 3 [(gogoproto.nullable)=false];
  repeated Evidence byzantine_validators = 4 [(gogoproto.nullable)=false];
 }

@@ -203,14 +204,14 @@ message ConsensusParams {
  BlockGossip block_gossip = 3;
 }

-// BlockSize contain limits on the block size.
+// BlockSize contains limits on the block size.
 message BlockSize {
  int32 max_bytes = 1;
  int32 max_txs = 2;
  int64 max_gas = 3;
 }

-// TxSize contain limits on the tx size.
+// TxSize contains limits on the tx size.
 message TxSize {
  int32 max_bytes = 1;
  int64 max_gas = 2;
@@ -223,6 +224,11 @@ message BlockGossip {
  int32 block_part_size_bytes = 1;
 }

+message LastCommitInfo {
+  int32 commit_round = 1;
+  repeated SigningValidator validators = 2 [(gogoproto.nullable)=false];
+}
+
 //----------------------------------------
 // Blockchain Types

--- a/abci/types/typespb_test.go
+++ b/abci/types/typespb_test.go
@@ -1646,6 +1646,62 @@ func TestBlockGossipMarshalTo(t *testing.T) {
 	}
 }

+func TestLastCommitInfoProto(t *testing.T) {
+	seed := time.Now().UnixNano()
+	popr := math_rand.New(math_rand.NewSource(seed))
+	p := NewPopulatedLastCommitInfo(popr, false)
+	dAtA, err := github_com_gogo_protobuf_proto.Marshal(p)
+	if err != nil {
+		t.Fatalf("seed = %d, err = %v", seed, err)
+	}
+	msg := &LastCommitInfo{}
+	if err := github_com_gogo_protobuf_proto.Unmarshal(dAtA, msg); err != nil {
+		t.Fatalf("seed = %d, err = %v", seed, err)
+	}
+	littlefuzz := make([]byte, len(dAtA))
+	copy(littlefuzz, dAtA)
+	for i := range dAtA {
+		dAtA[i] = byte(popr.Intn(256))
+	}
+	if !p.Equal(msg) {
+		t.Fatalf("seed = %d, %#v !Proto %#v", seed, msg, p)
+	}
+	if len(littlefuzz) > 0 {
+		fuzzamount := 100
+		for i := 0; i < fuzzamount; i++ {
+			littlefuzz[popr.Intn(len(littlefuzz))] = byte(popr.Intn(256))
+			littlefuzz = append(littlefuzz, byte(popr.Intn(256)))
+		}
+		// shouldn't panic
+		_ = github_com_gogo_protobuf_proto.Unmarshal(littlefuzz, msg)
+	}
+}
+
+func TestLastCommitInfoMarshalTo(t *testing.T) {
+	seed := time.Now().UnixNano()
+	popr := math_rand.New(math_rand.NewSource(seed))
+	p := NewPopulatedLastCommitInfo(popr, false)
+	size := p.Size()
+	dAtA := make([]byte, size)
+	for i := range dAtA {
+		dAtA[i] = byte(popr.Intn(256))
+	}
+	_, err := p.MarshalTo(dAtA)
+	if err != nil {
+		t.Fatalf("seed = %d, err = %v", seed, err)
+	}
+	msg := &LastCommitInfo{}
+	if err := github_com_gogo_protobuf_proto.Unmarshal(dAtA, msg); err != nil {
+		t.Fatalf("seed = %d, err = %v", seed, err)
+	}
+	for i := range dAtA {
+		dAtA[i] = byte(popr.Intn(256))
+	}
+	if !p.Equal(msg) {
+		t.Fatalf("seed = %d, %#v !Proto %#v", seed, msg, p)
+	}
+}
+
 func TestHeaderProto(t *testing.T) {
 	seed := time.Now().UnixNano()
 	popr := math_rand.New(math_rand.NewSource(seed))
@@ -2448,6 +2504,24 @@ func TestBlockGossipJSON(t *testing.T) {
 		t.Fatalf("seed = %d, %#v !Json Equal %#v", seed, msg, p)
 	}
 }
+func TestLastCommitInfoJSON(t *testing.T) {
+	seed := time.Now().UnixNano()
+	popr := math_rand.New(math_rand.NewSource(seed))
+	p := NewPopulatedLastCommitInfo(popr, true)
+	marshaler := github_com_gogo_protobuf_jsonpb.Marshaler{}
+	jsondata, err := marshaler.MarshalToString(p)
+	if err != nil {
+		t.Fatalf("seed = %d, err = %v", seed, err)
+	}
+	msg := &LastCommitInfo{}
+	err = github_com_gogo_protobuf_jsonpb.UnmarshalString(jsondata, msg)
+	if err != nil {
+		t.Fatalf("seed = %d, err = %v", seed, err)
+	}
+	if !p.Equal(msg) {
+		t.Fatalf("seed = %d, %#v !Json Equal %#v", seed, msg, p)
+	}
+}
 func TestHeaderJSON(t *testing.T) {
 	seed := time.Now().UnixNano()
 	popr := math_rand.New(math_rand.NewSource(seed))
@@ -3350,6 +3424,34 @@ func TestBlockGossipProtoCompactText(t *testing.T) {
 	}
 }

+func TestLastCommitInfoProtoText(t *testing.T) {
+	seed := time.Now().UnixNano()
+	popr := math_rand.New(math_rand.NewSource(seed))
+	p := NewPopulatedLastCommitInfo(popr, true)
+	dAtA := github_com_gogo_protobuf_proto.MarshalTextString(p)
+	msg := &LastCommitInfo{}
+	if err := github_com_gogo_protobuf_proto.UnmarshalText(dAtA, msg); err != nil {
+		t.Fatalf("seed = %d, err = %v", seed, err)
+	}
+	if !p.Equal(msg) {
+		t.Fatalf("seed = %d, %#v !Proto %#v", seed, msg, p)
+	}
+}
+
+func TestLastCommitInfoProtoCompactText(t *testing.T) {
+	seed := time.Now().UnixNano()
+	popr := math_rand.New(math_rand.NewSource(seed))
+	p := NewPopulatedLastCommitInfo(popr, true)
+	dAtA := github_com_gogo_protobuf_proto.CompactTextString(p)
+	msg := &LastCommitInfo{}
+	if err := github_com_gogo_protobuf_proto.UnmarshalText(dAtA, msg); err != nil {
+		t.Fatalf("seed = %d, err = %v", seed, err)
+	}
+	if !p.Equal(msg) {
+		t.Fatalf("seed = %d, %#v !Proto %#v", seed, msg, p)
+	}
+}
+
 func TestHeaderProtoText(t *testing.T) {
 	seed := time.Now().UnixNano()
 	popr := math_rand.New(math_rand.NewSource(seed))
@@ -4128,6 +4230,28 @@ func TestBlockGossipSize(t *testing.T) {
 	}
 }

+func TestLastCommitInfoSize(t *testing.T) {
+	seed := time.Now().UnixNano()
+	popr := math_rand.New(math_rand.NewSource(seed))
+	p := NewPopulatedLastCommitInfo(popr, true)
+	size2 := github_com_gogo_protobuf_proto.Size(p)
+	dAtA, err := github_com_gogo_protobuf_proto.Marshal(p)
+	if err != nil {
+		t.Fatalf("seed = %d, err = %v", seed, err)
+	}
+	size := p.Size()
+	if len(dAtA) != size {
+		t.Errorf("seed = %d, size %v != marshalled size %v", seed, size, len(dAtA))
+	}
+	if size2 != size {
+		t.Errorf("seed = %d, size %v != before marshal proto.Size %v", seed, size, size2)
+	}
+	size3 := github_com_gogo_protobuf_proto.Size(p)
+	if size3 != size {
+		t.Errorf("seed = %d, size %v != after marshal proto.Size %v", seed, size, size3)
+	}
+}
+
 func TestHeaderSize(t *testing.T) {
 	seed := time.Now().UnixNano()
 	popr := math_rand.New(math_rand.NewSource(seed))
--- a/blockchain/reactor.go
+++ b/blockchain/reactor.go
@@ -109,9 +109,6 @@ func (bcR *BlockchainReactor) SetLogger(l log.Logger) {

 // OnStart implements cmn.Service.
 func (bcR *BlockchainReactor) OnStart() error {
-	if err := bcR.BaseReactor.OnStart(); err != nil {
-		return err
-	}
 	if bcR.fastSync {
 		err := bcR.pool.Start()
 		if err != nil {
@@ -124,7 +121,6 @@ func (bcR *BlockchainReactor) OnStart() error {

 // OnStop implements cmn.Service.
 func (bcR *BlockchainReactor) OnStop() {
-	bcR.BaseReactor.OnStop()
 	bcR.pool.Stop()
 }

--- a/consensus/common_test.go
+++ b/consensus/common_test.go
@@ -17,14 +17,14 @@ import (
 	bc "github.com/tendermint/tendermint/blockchain"
 	cfg "github.com/tendermint/tendermint/config"
 	cstypes "github.com/tendermint/tendermint/consensus/types"
+	cmn "github.com/tendermint/tendermint/libs/common"
+	dbm "github.com/tendermint/tendermint/libs/db"
+	"github.com/tendermint/tendermint/libs/log"
 	mempl "github.com/tendermint/tendermint/mempool"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/privval"
 	sm "github.com/tendermint/tendermint/state"
 	"github.com/tendermint/tendermint/types"
-	cmn "github.com/tendermint/tendermint/libs/common"
-	dbm "github.com/tendermint/tendermint/libs/db"
-	"github.com/tendermint/tendermint/libs/log"

 	"github.com/tendermint/tendermint/abci/example/counter"
 	"github.com/tendermint/tendermint/abci/example/kvstore"
@@ -378,8 +378,11 @@ func randConsensusNetWithPeers(nValidators, nPeers int, testName string, tickerF
 		if i < nValidators {
 			privVal = privVals[i]
 		} else {
-			_, tempFilePath := cmn.Tempfile("priv_validator_")
-			privVal = privval.GenFilePV(tempFilePath)
+			tempFile, err := ioutil.TempFile("", "priv_validator_")
+			if err != nil {
+				panic(err)
+			}
+			privVal = privval.GenFilePV(tempFile.Name())
 		}

 		app := appFunc()
@@ -429,7 +432,7 @@ func randGenesisDoc(numValidators int, randPower bool, minPower int64) (*types.G
 func randGenesisState(numValidators int, randPower bool, minPower int64) (sm.State, []types.PrivValidator) {
 	genDoc, privValidators := randGenesisDoc(numValidators, randPower, minPower)
 	s0, _ := sm.MakeGenesisState(genDoc)
-	db := dbm.NewMemDB()
+	db := dbm.NewMemDB() // remove this ?
 	sm.SaveState(db, s0)
 	return s0, privValidators
 }
--- a/consensus/reactor.go
+++ b/consensus/reactor.go
@@ -58,9 +58,6 @@ func NewConsensusReactor(consensusState *ConsensusState, fastSync bool) *Consens
 // broadcasted to other peers and starting state if we're not in fast sync.
 func (conR *ConsensusReactor) OnStart() error {
 	conR.Logger.Info("ConsensusReactor ", "fastSync", conR.FastSync())
-	if err := conR.BaseReactor.OnStart(); err != nil {
-		return err
-	}

 	conR.subscribeToBroadcastEvents()

@@ -77,7 +74,6 @@ func (conR *ConsensusReactor) OnStart() error {
 // OnStop implements BaseService by unsubscribing from events and stopping
 // state.
 func (conR *ConsensusReactor) OnStop() {
-	conR.BaseReactor.OnStop()
 	conR.unsubscribeFromBroadcastEvents()
 	conR.conS.Stop()
 	if !conR.FastSync() {
--- a/consensus/reactor_test.go
+++ b/consensus/reactor_test.go
@@ -4,15 +4,21 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"path"
 	"runtime"
 	"runtime/pprof"
 	"sync"
 	"testing"
 	"time"

+	abcicli "github.com/tendermint/tendermint/abci/client"
 	"github.com/tendermint/tendermint/abci/example/kvstore"
+	abci "github.com/tendermint/tendermint/abci/types"
+	bc "github.com/tendermint/tendermint/blockchain"
 	cmn "github.com/tendermint/tendermint/libs/common"
+	dbm "github.com/tendermint/tendermint/libs/db"
 	"github.com/tendermint/tendermint/libs/log"
+	mempl "github.com/tendermint/tendermint/mempool"
 	sm "github.com/tendermint/tendermint/state"

 	cfg "github.com/tendermint/tendermint/config"
@@ -94,49 +100,118 @@ func TestReactorBasic(t *testing.T) {

 // Ensure we can process blocks with evidence
 func TestReactorWithEvidence(t *testing.T) {
-	N := 4
-	css := randConsensusNet(N, "consensus_reactor_test", newMockTickerFunc(true), newCounter)
-	evpool := mockEvidencePool{
-		t:  t,
-		ev: []types.Evidence{types.NewMockGoodEvidence(1, 1, []byte("somone"))},
+	nValidators := 4
+	testName := "consensus_reactor_test"
+	tickerFunc := newMockTickerFunc(true)
+	appFunc := newCounter
+
+	// heed the advice from https://www.sandimetz.com/blog/2016/1/20/the-wrong-abstraction
+	// to unroll unwieldy abstractions. Here we duplicate the code from:
+	// css := randConsensusNet(N, "consensus_reactor_test", newMockTickerFunc(true), newCounter)
+
+	genDoc, privVals := randGenesisDoc(nValidators, false, 30)
+	css := make([]*ConsensusState, nValidators)
+	logger := consensusLogger()
+	for i := 0; i < nValidators; i++ {
+		stateDB := dbm.NewMemDB() // each state needs its own db
+		state, _ := sm.LoadStateFromDBOrGenesisDoc(stateDB, genDoc)
+		thisConfig := ResetConfig(cmn.Fmt("%s_%d", testName, i))
+		ensureDir(path.Dir(thisConfig.Consensus.WalFile()), 0700) // dir for wal
+		app := appFunc()
+		vals := types.TM2PB.Validators(state.Validators)
+		app.InitChain(abci.RequestInitChain{Validators: vals})
+
+		pv := privVals[i]
+		// duplicate code from:
+		// css[i] = newConsensusStateWithConfig(thisConfig, state, privVals[i], app)
+
+		blockDB := dbm.NewMemDB()
+		blockStore := bc.NewBlockStore(blockDB)
+
+		// one for mempool, one for consensus
+		mtx := new(sync.Mutex)
+		proxyAppConnMem := abcicli.NewLocalClient(mtx, app)
+		proxyAppConnCon := abcicli.NewLocalClient(mtx, app)
+
+		// Make Mempool
+		mempool := mempl.NewMempool(thisConfig.Mempool, proxyAppConnMem, 0)
+		mempool.SetLogger(log.TestingLogger().With("module", "mempool"))
+		if thisConfig.Consensus.WaitForTxs() {
+			mempool.EnableTxsAvailable()
+		}
+
+		// mock the evidence pool
+		// everyone includes evidence of another double signing
+		vIdx := (i + 1) % nValidators
+		evpool := newMockEvidencePool(privVals[vIdx].GetAddress())
+
+		// Make ConsensusState
+		blockExec := sm.NewBlockExecutor(stateDB, log.TestingLogger(), proxyAppConnCon, mempool, evpool)
+		cs := NewConsensusState(thisConfig.Consensus, state, blockExec, blockStore, mempool, evpool)
+		cs.SetLogger(log.TestingLogger().With("module", "consensus"))
+		cs.SetPrivValidator(pv)
+
+		eventBus := types.NewEventBus()
+		eventBus.SetLogger(log.TestingLogger().With("module", "events"))
+		eventBus.Start()
+		cs.SetEventBus(eventBus)
+
+		cs.SetTimeoutTicker(tickerFunc())
+		cs.SetLogger(logger.With("validator", i, "module", "consensus"))
+
+		css[i] = cs
 	}
-	for i := 0; i < N; i++ {
-		css[i].evpool = evpool
-	}
-	reactors, eventChans, eventBuses := startConsensusNet(t, css, N)
+
+	reactors, eventChans, eventBuses := startConsensusNet(t, css, nValidators)
 	defer stopConsensusNet(log.TestingLogger(), reactors, eventBuses)
-	// wait till everyone makes the first new block
-	timeoutWaitGroup(t, N, func(j int) {
-		<-eventChans[j]
+
+	// wait till everyone makes the first new block with no evidence
+	timeoutWaitGroup(t, nValidators, func(j int) {
+		blockI := <-eventChans[j]
+		block := blockI.(types.EventDataNewBlock).Block
+		assert.True(t, len(block.Evidence.Evidence) == 0)
 	}, css)

 	// second block should have evidence
-	timeoutWaitGroup(t, N, func(j int) {
-		<-eventChans[j]
+	timeoutWaitGroup(t, nValidators, func(j int) {
+		blockI := <-eventChans[j]
+		block := blockI.(types.EventDataNewBlock).Block
+		assert.True(t, len(block.Evidence.Evidence) > 0)
 	}, css)
 }

+// mock evidence pool returns no evidence for block 1,
+// and returnes one piece for all higher blocks. The one piece
+// is for a given validator at block 1.
 type mockEvidencePool struct {
 	height int
 	ev     []types.Evidence
-	t      *testing.T
 }

-func (m mockEvidencePool) PendingEvidence() []types.Evidence {
+func newMockEvidencePool(val []byte) *mockEvidencePool {
+	return &mockEvidencePool{
+		ev: []types.Evidence{types.NewMockGoodEvidence(1, 1, val)},
+	}
+}
+
+func (m *mockEvidencePool) PendingEvidence() []types.Evidence {
 	if m.height > 0 {
 		return m.ev
 	}
 	return nil
 }
-func (m mockEvidencePool) AddEvidence(types.Evidence) error { return nil }
-func (m mockEvidencePool) Update(block *types.Block, state sm.State) {
-	m.height += 1
-
+func (m *mockEvidencePool) AddEvidence(types.Evidence) error { return nil }
+func (m *mockEvidencePool) Update(block *types.Block, state sm.State) {
 	if m.height > 0 {
-		require.True(m.t, len(block.Evidence.Evidence) > 0)
+		if len(block.Evidence.Evidence) == 0 {
+			panic("block has no evidence")
+		}
 	}
+	m.height += 1
 }

+//------------------------------------
+
 // Ensure a testnet sends proposal heartbeats and makes blocks when there are txs
 func TestReactorProposalHeartbeats(t *testing.T) {
 	N := 4
--- a/docs/app-dev/abci-spec.md
+++ b/docs/app-dev/abci-spec.md
@@ -160,9 +160,8 @@ See below for more details on the message types and how they are used.
 - **Request**:
  - `Hash ([]byte)`: The block's hash. This can be derived from the
    block header.
-  - `Header (struct{})`: The block header
-  - `Validators ([]SigningValidator)`: List of validators in the current validator
-    set and whether or not they signed a vote in the LastCommit
+  - `Header (struct{})`: The block header.
+  - `LastCommitInfo (LastCommitInfo)`: Info about the last commit.
  - `ByzantineValidators ([]Evidence)`: List of evidence of
    validators that acted maliciously
 - **Response**:
@@ -171,8 +170,9 @@ See below for more details on the message types and how they are used.
  - Signals the beginning of a new block. Called prior to
    any DeliverTxs.
  - The header is expected to at least contain the Height.
-  - The `Validators` and `ByzantineValidators` can be used to
-    determine rewards and punishments for the validators.
+  - The `LastCommitInfo` and `ByzantineValidators` can be used to determine
+    rewards and punishments for the validators. NOTE validators here do not
+    include pubkeys.

 ### CheckTx

@@ -326,3 +326,10 @@ See below for more details on the message types and how they are used.
    It is the proposer's local time when block was created.
  - `TotalVotingPower (int64)`: Total voting power of the validator set at
    height `Height`
+
+### LastCommitInfo
+
+- **Fields**:
+  - `CommitRound (int32)`: Commit round.
+  - `Validators ([]SigningValidator)`: List of validators in the current
+    validator set and whether or not they signed a vote.
--- a/docs/app-dev/app-development.md
+++ b/docs/app-dev/app-development.md
@@ -365,14 +365,14 @@ ResponseBeginBlock requestBeginBlock(RequestBeginBlock req) {

 ### EndBlock

-The EndBlock request can be used to run some code at the end of every
-block. Additionally, the response may contain a list of validators,
-which can be used to update the validator set. To add a new validator or
-update an existing one, simply include them in the list returned in the
-EndBlock response. To remove one, include it in the list with a `power`
-equal to `0`. Tendermint core will take care of updating the validator
-set. Note the change in voting power must be strictly less than 1/3 per
-block if you want a light client to be able to prove the transition
+The EndBlock request can be used to run some code at the end of every block.
+Additionally, the response may contain a list of validators, which can be used
+to update the validator set. To add a new validator or update an existing one,
+simply include them in the list returned in the EndBlock response. To remove
+one, include it in the list with a `power` equal to `0`. Validator's `address`
+field can be left empty. Tendermint core will take care of updating the
+validator set. Note the change in voting power must be strictly less than 1/3
+per block if you want a light client to be able to prove the transition
 externally. See the [light client
 docs](https://godoc.org/github.com/tendermint/tendermint/lite#hdr-How_We_Track_Validators)
 for details on how it tracks validators.
--- a/docs/architecture/adr-015-crypto-encoding.md
+++ b/docs/architecture/adr-015-crypto-encoding.md
@@ -0,0 +1,80 @@
+# ADR 015: Crypto encoding 
+
+## Context
+
+We must standardize our method for encoding public keys and signatures on chain. 
+Currently we amino encode the public keys and signatures.
+The reason we are using amino here is primarily due to ease of support in
+parsing for other languages.
+We don't need its upgradability properties in cryptosystems, as a change in
+the crypto that requires adapting the encoding, likely warrants being deemed
+a new cryptosystem.
+(I.e. using new public parameters)
+
+## Decision
+
+### Public keys
+
+For public keys, we will continue to use amino encoding on the canonical
+representation of the pubkey.
+(Canonical as defined by the cryptosystem itself)
+This has two significant drawbacks.
+Amino encoding is less space-efficient, due to requiring support for upgradability.
+Amino encoding support requires forking protobuf and adding this new interface support
+option in the langauge of choice.
+
+The reason for continuing to use amino however is that people can create code
+more easily in languages that already have an up to date amino library.
+It is possible that this will change in the future, if it is deemed that
+requiring amino for interacting with tendermint cryptography is unneccessary.
+
+The arguments for space efficiency here are refuted on the basis that there are
+far more egregious wastages of space in the SDK.
+The space requirement of the public keys doesn't cause many problems beyond
+increasing the space attached to each validator / account.
+
+The alternative to using amino here would be for us to create an enum type.
+Switching to just an enum type is worthy of investigation post-launch.
+For referrence, part of amino encoding interfaces is basically a 4 byte enum
+type definition.
+Enum types would just change that 4 bytes to be a varuint, and it would remove
+the protobuf overhead, but it would be hard to integrate into the existing API.
+
+### Signatures
+
+Signatures should be switched to be `[]byte`.
+Spatial efficiency in the signatures is quite important,
+as it directly affects the gas cost of every transaction,
+and the throughput of the chain.
+Signatures don't need to encode what type they are for (unlike public keys)
+since public keys must already be known.
+Therefore we can validate the signature without needing to encode its type.
+
+When placed in state, signatures will still be amino encoded, but it will be the
+primitive type `[]byte` getting encoded.
+
+#### Ed25519
+Use the canonical representation for signatures.
+
+#### Secp256k1
+There isn't a clear canonical representation here.
+Signatures have two elements `r,s`.
+We should encode these bytes as `r || s`, where `r` and `s` are both exactly
+32 bytes long.
+This is basically Ethereum's encoding, but without the leading recovery bit.
+
+## Status
+
+Proposed. The signature section seems to be agreed upon for the most part.
+Needs decision on Enum types.
+
+## Consequences
+
+### Positive
+* More space efficient signatures
+
+### Negative
+* We have an amino dependency for cryptography.
+
+### Neutral
+* No change to public keys
--- a/docs/spec/blockchain/blockchain.md
+++ b/docs/spec/blockchain/blockchain.md
@@ -52,7 +52,8 @@ type Header struct {
    // application
    ResultsHash         []byte  // SimpleMerkle of []abci.Result from prevBlock
    AppHash             []byte  // Arbitrary state digest
-    ValidatorsHash      []byte  // SimpleMerkle of the ValidatorSet
+    ValidatorsHash      []byte  // SimpleMerkle of the current ValidatorSet
+    NextValidatorsHash  []byte  // SimpleMerkle of the next ValidatorSet
    ConsensusParamsHash []byte  // SimpleMerkle of the ConsensusParams

    // consensus
@@ -160,9 +161,12 @@ We refer to certain globally available objects:
 `block` is the block under consideration,
 `prevBlock` is the `block` at the previous height,
 and `state` keeps track of the validator set, the consensus parameters
-and other results from the application.
+and other results from the application. At the point when `block` is the block under consideration,
+the current version of the `state` corresponds to the state 
+after executing transactions from the `prevBlock`. 
 Elements of an object are accessed as expected,
-ie. `block.Header`. See [here](https://github.com/tendermint/tendermint/blob/master/docs/spec/blockchain/state.md) for the definition of `state`.
+ie. `block.Header`. 
+See [here](https://github.com/tendermint/tendermint/blob/master/docs/spec/blockchain/state.md) for the definition of `state`.

 ### Header

@@ -278,7 +282,14 @@ block.ValidatorsHash == SimpleMerkleRoot(state.Validators)

 Simple Merkle root of the current validator set that is committing the block.
 This can be used to validate the `LastCommit` included in the next block.
-May be updated by the application.
+
+### NextValidatorsHash
+
+```go
+block.NextValidatorsHash == SimpleMerkleRoot(state.NextValidators)
+```
+Simple Merkle root of the next validator set that will be the validator set that commits the next block.
+Modifications to the validator set are defined by the application.

 ### ConsensusParamsHash

@@ -407,25 +418,20 @@ set (TODO). Execute is defined as:

 ```go
 Execute(s State, app ABCIApp, block Block) State {
-    TODO: just spell out ApplyBlock here
-    and remove ABCIResponses struct.
-    abciResponses := app.ApplyBlock(block)
+    // Fuction ApplyBlock executes block of transactions against the app and returns the new root hash of the app state,
+    // modifications to the validator set and the changes of the consensus parameters.
+    AppHash, ValidatorChanges, ConsensusParamChanges := app.ApplyBlock(block)

    return State{
        LastResults: abciResponses.DeliverTxResults,
-        AppHash: abciResponses.AppHash,
-        Validators: UpdateValidators(state.Validators, abciResponses.ValidatorChanges),
+        AppHash: AppHash,
        LastValidators: state.Validators,
-        ConsensusParams: UpdateConsensusParams(state.ConsensusParams, abci.Responses.ConsensusParamChanges),
+        Validators: state.NextValidators,
+        NextValidators: UpdateValidators(state.NextValidators, ValidatorChanges), 
+        ConsensusParams: UpdateConsensusParams(state.ConsensusParams, ConsensusParamChanges),
    }
 }

-type ABCIResponses struct {
-    DeliverTxResults        []Result
-    ValidatorChanges        []Validator
-    ConsensusParamChanges   ConsensusParams
-    AppHash                 []byte
-}
 ```


--- a/docs/spec/blockchain/state.md
+++ b/docs/spec/blockchain/state.md
@@ -3,7 +3,7 @@
 ## State

 The state contains information whose cryptographic digest is included in block headers, and thus is
-necessary for validating new blocks. For instance, the set of validators and the results of
+necessary for validating new blocks. For instance, the validators set and the results of
 transactions are never included in blocks, but their Merkle roots are - the state keeps track of them.

 Note that the `State` object itself is an implementation detail, since it is never
@@ -18,8 +18,9 @@ type State struct {
    LastResults []Result
    AppHash []byte

-    Validators []Validator
    LastValidators []Validator
+    Validators []Validator
+    NextValidators []Validator

    ConsensusParams ConsensusParams
 }
--- a/evidence/reactor.go
+++ b/evidence/reactor.go
@@ -44,11 +44,6 @@ func (evR *EvidenceReactor) SetLogger(l log.Logger) {
 	evR.evpool.SetLogger(l)
 }

-// OnStart implements cmn.Service
-func (evR *EvidenceReactor) OnStart() error {
-	return evR.BaseReactor.OnStart()
-}
-
 // GetChannels implements Reactor.
 // It returns the list of channels for this reactor.
 func (evR *EvidenceReactor) GetChannels() []*p2p.ChannelDescriptor {
--- a/libs/autofile/autofile_test.go
+++ b/libs/autofile/autofile_test.go
@@ -1,6 +1,7 @@
 package autofile

 import (
+	"io/ioutil"
 	"os"
 	"sync/atomic"
 	"syscall"
@@ -13,10 +14,14 @@ import (
 func TestSIGHUP(t *testing.T) {

 	// First, create an AutoFile writing to a tempfile dir
-	file, name := cmn.Tempfile("sighup_test")
-	if err := file.Close(); err != nil {
+	file, err := ioutil.TempFile("", "sighup_test")
+	if err != nil {
 		t.Fatalf("Error creating tempfile: %v", err)
 	}
+	if err := file.Close(); err != nil {
+		t.Fatalf("Error closing tempfile: %v", err)
+	}
+	name := file.Name()
 	// Here is the actual AutoFile
 	af, err := OpenAutoFile(name)
 	if err != nil {
--- a/libs/autofile/group_test.go
+++ b/libs/autofile/group_test.go
@@ -147,14 +147,13 @@ func TestSearch(t *testing.T) {

 	// Now search for each number
 	for i := 0; i < 100; i++ {
-		t.Log("Testing for i", i)
 		gr, match, err := g.Search("INFO", makeSearchFunc(i))
-		require.NoError(t, err, "Failed to search for line")
-		assert.True(t, match, "Expected Search to return exact match")
+		require.NoError(t, err, "Failed to search for line, tc #%d", i)
+		assert.True(t, match, "Expected Search to return exact match, tc #%d", i)
 		line, err := gr.ReadLine()
-		require.NoError(t, err, "Failed to read line after search")
+		require.NoError(t, err, "Failed to read line after search, tc #%d", i)
 		if !strings.HasPrefix(line, fmt.Sprintf("INFO %v ", i)) {
-			t.Fatal("Failed to get correct line")
+			t.Fatalf("Failed to get correct line, tc #%d", i)
 		}
 		// Make sure we can continue to read from there.
 		cur := i + 1
@@ -165,16 +164,16 @@ func TestSearch(t *testing.T) {
 					// OK!
 					break
 				} else {
-					t.Fatal("Got EOF after the wrong INFO #")
+					t.Fatalf("Got EOF after the wrong INFO #, tc #%d", i)
 				}
 			} else if err != nil {
-				t.Fatal("Error reading line", err)
+				t.Fatalf("Error reading line, tc #%d, err:\n%s", i, err)
 			}
 			if !strings.HasPrefix(line, "INFO ") {
 				continue
 			}
 			if !strings.HasPrefix(line, fmt.Sprintf("INFO %v ", cur)) {
-				t.Fatalf("Unexpected INFO #. Expected %v got:\n%v", cur, line)
+				t.Fatalf("Unexpected INFO #. Expected %v got:\n%v, tc #%d", cur, line, i)
 			}
 			cur++
 		}
--- a/libs/common/os.go
+++ b/libs/common/os.go
@@ -8,7 +8,6 @@ import (
 	"os"
 	"os/exec"
 	"os/signal"
-	"path/filepath"
 	"strings"
 	"syscall"
 )
@@ -124,60 +123,6 @@ func MustWriteFile(filePath string, contents []byte, mode os.FileMode) {
 	}
 }

-// WriteFileAtomic creates a temporary file with data and the perm given and
-// swaps it atomically with filename if successful.
-func WriteFileAtomic(filename string, data []byte, perm os.FileMode) error {
-	var (
-		dir      = filepath.Dir(filename)
-		tempFile = filepath.Join(dir, "write-file-atomic-"+RandStr(32))
-		// Override in case it does exist, create in case it doesn't and force kernel
-		// flush, which still leaves the potential of lingering disk cache.
-		flag = os.O_WRONLY | os.O_CREATE | os.O_SYNC | os.O_TRUNC
-	)
-
-	f, err := os.OpenFile(tempFile, flag, perm)
-	if err != nil {
-		return err
-	}
-	// Clean up in any case. Defer stacking order is last-in-first-out.
-	defer os.Remove(f.Name())
-	defer f.Close()
-
-	if n, err := f.Write(data); err != nil {
-		return err
-	} else if n < len(data) {
-		return io.ErrShortWrite
-	}
-	// Close the file before renaming it, otherwise it will cause "The process 
-	// cannot access the file because it is being used by another process." on windows.
-	f.Close()
-
-	return os.Rename(f.Name(), filename)
-}
-
-//--------------------------------------------------------------------------------
-
-func Tempfile(prefix string) (*os.File, string) {
-	file, err := ioutil.TempFile("", prefix)
-	if err != nil {
-		PanicCrisis(err)
-	}
-	return file, file.Name()
-}
-
-func Tempdir(prefix string) (*os.File, string) {
-	tempDir := os.TempDir() + "/" + prefix + RandStr(12)
-	err := EnsureDir(tempDir, 0700)
-	if err != nil {
-		panic(Fmt("Error creating temp dir: %v", err))
-	}
-	dir, err := os.Open(tempDir)
-	if err != nil {
-		panic(Fmt("Error opening temp dir: %v", err))
-	}
-	return dir, tempDir
-}
-
 //--------------------------------------------------------------------------------

 func Prompt(prompt string, defaultValue string) (string, error) {
--- a/libs/common/os_test.go
+++ b/libs/common/os_test.go
@@ -1,52 +1,10 @@
 package common

 import (
-	"bytes"
-	"io/ioutil"
 	"os"
 	"testing"
 )

-func TestWriteFileAtomic(t *testing.T) {
-	var (
-		data             = []byte(RandStr(RandIntn(2048)))
-		old              = RandBytes(RandIntn(2048))
-		perm os.FileMode = 0600
-	)
-
-	f, err := ioutil.TempFile("/tmp", "write-atomic-test-")
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer os.Remove(f.Name())
-
-	if err = ioutil.WriteFile(f.Name(), old, 0664); err != nil {
-		t.Fatal(err)
-	}
-
-	if err = WriteFileAtomic(f.Name(), data, perm); err != nil {
-		t.Fatal(err)
-	}
-
-	rData, err := ioutil.ReadFile(f.Name())
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if !bytes.Equal(data, rData) {
-		t.Fatalf("data mismatch: %v != %v", data, rData)
-	}
-
-	stat, err := os.Stat(f.Name())
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if have, want := stat.Mode().Perm(), perm; have != want {
-		t.Errorf("have %v, want %v", have, want)
-	}
-}
-
 func TestGoPath(t *testing.T) {
 	// restore original gopath upon exit
 	path := os.Getenv("GOPATH")
--- a/libs/common/random.go
+++ b/libs/common/random.go
@@ -109,6 +109,10 @@ func RandInt63n(n int64) int64 {
 	return grand.Int63n(n)
 }

+func RandBool() bool {
+	return grand.Bool()
+}
+
 func RandFloat32() float32 {
 	return grand.Float32()
 }
@@ -274,6 +278,13 @@ func (r *Rand) Intn(n int) int {
 	return i
 }

+// Bool returns a uniformly random boolean
+func (r *Rand) Bool() bool {
+	// See https://github.com/golang/go/issues/23804#issuecomment-365370418
+	// for reasoning behind computing like this
+	return r.Int63()%2 == 0
+}
+
 // Perm returns a pseudo-random permutation of n integers in [0, n).
 func (r *Rand) Perm(n int) []int {
 	r.Lock()
--- a/libs/common/tempfile.go
+++ b/libs/common/tempfile.go
@@ -0,0 +1,128 @@
+package common
+
+import (
+	fmt "fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+const (
+	atomicWriteFilePrefix = "write-file-atomic-"
+	// Maximum number of atomic write file conflicts before we start reseeding
+	// (reduced from golang's default 10 due to using an increased randomness space)
+	atomicWriteFileMaxNumConflicts = 5
+	// Maximum number of attempts to make at writing the write file before giving up
+	// (reduced from golang's default 10000 due to using an increased randomness space)
+	atomicWriteFileMaxNumWriteAttempts = 1000
+	// LCG constants from Donald Knuth MMIX
+	// This LCG's has a period equal to 2**64
+	lcgA = 6364136223846793005
+	lcgC = 1442695040888963407
+	// Create in case it doesn't exist and force kernel
+	// flush, which still leaves the potential of lingering disk cache.
+	// Never overwrites files
+	atomicWriteFileFlag = os.O_WRONLY | os.O_CREATE | os.O_SYNC | os.O_TRUNC | os.O_EXCL
+)
+
+var (
+	atomicWriteFileRand   uint64
+	atomicWriteFileRandMu sync.Mutex
+)
+
+func writeFileRandReseed() uint64 {
+	// Scale the PID, to minimize the chance that two processes seeded at similar times
+	// don't get the same seed. Note that PID typically ranges in [0, 2**15), but can be
+	// up to 2**22 under certain configurations. We left bit-shift the PID by 20, so that
+	// a PID difference of one corresponds to a time difference of 2048 seconds.
+	// The important thing here is that now for a seed conflict, they would both have to be on
+	// the correct nanosecond offset, and second-based offset, which is much less likely than
+	// just a conflict with the correct nanosecond offset.
+	return uint64(time.Now().UnixNano() + int64(os.Getpid()<<20))
+}
+
+// Use a fast thread safe LCG for atomic write file names.
+// Returns a string corresponding to a 64 bit int.
+// If it was a negative int, the leading number is a 0.
+func randWriteFileSuffix() string {
+	atomicWriteFileRandMu.Lock()
+	r := atomicWriteFileRand
+	if r == 0 {
+		r = writeFileRandReseed()
+	}
+
+	// Update randomness according to lcg
+	r = r*lcgA + lcgC
+
+	atomicWriteFileRand = r
+	atomicWriteFileRandMu.Unlock()
+	// Can have a negative name, replace this in the following
+	suffix := strconv.Itoa(int(r))
+	if string(suffix[0]) == "-" {
+		// Replace first "-" with "0". This is purely for UI clarity,
+		// as otherwhise there would be two `-` in a row.
+		suffix = strings.Replace(suffix, "-", "0", 1)
+	}
+	return suffix
+}
+
+// WriteFileAtomic creates a temporary file with data and provided perm and
+// swaps it atomically with filename if successful.
+func WriteFileAtomic(filename string, data []byte, perm os.FileMode) (err error) {
+	// This implementation is inspired by the golang stdlibs method of creating
+	// tempfiles. Notable differences are that we use different flags, a 64 bit LCG
+	// and handle negatives differently.
+	// The core reason we can't use golang's TempFile is that we must write
+	// to the file synchronously, as we need this to persist to disk.
+	// We also open it in write-only mode, to avoid concerns that arise with read.
+	var (
+		dir = filepath.Dir(filename)
+		f   *os.File
+	)
+
+	nconflict := 0
+	// Limit the number of attempts to create a file. Something is seriously
+	// wrong if it didn't get created after 1000 attempts, and we don't want
+	// an infinite loop
+	i := 0
+	for ; i < atomicWriteFileMaxNumWriteAttempts; i++ {
+		name := filepath.Join(dir, atomicWriteFilePrefix+randWriteFileSuffix())
+		f, err = os.OpenFile(name, atomicWriteFileFlag, perm)
+		// If the file already exists, try a new file
+		if os.IsExist(err) {
+			// If the files exists too many times, start reseeding as we've
+			// likely hit another instances seed.
+			if nconflict++; nconflict > atomicWriteFileMaxNumConflicts {
+				atomicWriteFileRandMu.Lock()
+				atomicWriteFileRand = writeFileRandReseed()
+				atomicWriteFileRandMu.Unlock()
+			}
+			continue
+		} else if err != nil {
+			return err
+		}
+		break
+	}
+	if i == atomicWriteFileMaxNumWriteAttempts {
+		return fmt.Errorf("Could not create atomic write file after %d attempts", i)
+	}
+
+	// Clean up in any case. Defer stacking order is last-in-first-out.
+	defer os.Remove(f.Name())
+	defer f.Close()
+
+	if n, err := f.Write(data); err != nil {
+		return err
+	} else if n < len(data) {
+		return io.ErrShortWrite
+	}
+	// Close the file before renaming it, otherwise it will cause "The process
+	// cannot access the file because it is being used by another process." on windows.
+	f.Close()
+
+	return os.Rename(f.Name(), filename)
+}
--- a/libs/common/tempfile_test.go
+++ b/libs/common/tempfile_test.go
@@ -0,0 +1,138 @@
+package common
+
+// Need access to internal variables, so can't use _test package
+
+import (
+	"bytes"
+	fmt "fmt"
+	"io/ioutil"
+	"os"
+	testing "testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestWriteFileAtomic(t *testing.T) {
+	var (
+		data             = []byte(RandStr(RandIntn(2048)))
+		old              = RandBytes(RandIntn(2048))
+		perm os.FileMode = 0600
+	)
+
+	f, err := ioutil.TempFile("/tmp", "write-atomic-test-")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(f.Name())
+
+	if err = ioutil.WriteFile(f.Name(), old, 0664); err != nil {
+		t.Fatal(err)
+	}
+
+	if err = WriteFileAtomic(f.Name(), data, perm); err != nil {
+		t.Fatal(err)
+	}
+
+	rData, err := ioutil.ReadFile(f.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !bytes.Equal(data, rData) {
+		t.Fatalf("data mismatch: %v != %v", data, rData)
+	}
+
+	stat, err := os.Stat(f.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if have, want := stat.Mode().Perm(), perm; have != want {
+		t.Errorf("have %v, want %v", have, want)
+	}
+}
+
+// This tests atomic write file when there is a single duplicate file.
+// Expected behavior is for a new file to be created, and the original write file to be unaltered.
+func TestWriteFileAtomicDuplicateFile(t *testing.T) {
+	var (
+		defaultSeed    uint64 = 1
+		testString            = "This is a glorious test string"
+		expectedString        = "Did the test file's string appear here?"
+
+		fileToWrite = "/tmp/TestWriteFileAtomicDuplicateFile-test.txt"
+	)
+	// Create a file at the seed, and reset the seed.
+	atomicWriteFileRand = defaultSeed
+	firstFileRand := randWriteFileSuffix()
+	atomicWriteFileRand = defaultSeed
+	fname := "/tmp/" + atomicWriteFilePrefix + firstFileRand
+	f, err := os.OpenFile(fname, atomicWriteFileFlag, 0777)
+	defer os.Remove(fname)
+	// Defer here, in case there is a panic in WriteFileAtomic.
+	defer os.Remove(fileToWrite)
+
+	require.Nil(t, err)
+	f.WriteString(testString)
+	WriteFileAtomic(fileToWrite, []byte(expectedString), 0777)
+	// Check that the first atomic file was untouched
+	firstAtomicFileBytes, err := ioutil.ReadFile(fname)
+	require.Nil(t, err, "Error reading first atomic file")
+	require.Equal(t, []byte(testString), firstAtomicFileBytes, "First atomic file was overwritten")
+	// Check that the resultant file is correct
+	resultantFileBytes, err := ioutil.ReadFile(fileToWrite)
+	require.Nil(t, err, "Error reading resultant file")
+	require.Equal(t, []byte(expectedString), resultantFileBytes, "Written file had incorrect bytes")
+
+	// Check that the intermediate write file was deleted
+	// Get the second write files' randomness
+	atomicWriteFileRand = defaultSeed
+	_ = randWriteFileSuffix()
+	secondFileRand := randWriteFileSuffix()
+	_, err = os.Stat("/tmp/" + atomicWriteFilePrefix + secondFileRand)
+	require.True(t, os.IsNotExist(err), "Intermittent atomic write file not deleted")
+}
+
+// This tests atomic write file when there are many duplicate files.
+// Expected behavior is for a new file to be created under a completely new seed,
+// and the original write files to be unaltered.
+func TestWriteFileAtomicManyDuplicates(t *testing.T) {
+	var (
+		defaultSeed    uint64 = 2
+		testString            = "This is a glorious test string, from file %d"
+		expectedString        = "Did any of the test file's string appear here?"
+
+		fileToWrite = "/tmp/TestWriteFileAtomicDuplicateFile-test.txt"
+	)
+	// Initialize all of the atomic write files
+	atomicWriteFileRand = defaultSeed
+	for i := 0; i < atomicWriteFileMaxNumConflicts+2; i++ {
+		fileRand := randWriteFileSuffix()
+		fname := "/tmp/" + atomicWriteFilePrefix + fileRand
+		f, err := os.OpenFile(fname, atomicWriteFileFlag, 0777)
+		require.Nil(t, err)
+		f.WriteString(fmt.Sprintf(testString, i))
+		defer os.Remove(fname)
+	}
+
+	atomicWriteFileRand = defaultSeed
+	// Defer here, in case there is a panic in WriteFileAtomic.
+	defer os.Remove(fileToWrite)
+
+	WriteFileAtomic(fileToWrite, []byte(expectedString), 0777)
+	// Check that all intermittent atomic file were untouched
+	atomicWriteFileRand = defaultSeed
+	for i := 0; i < atomicWriteFileMaxNumConflicts+2; i++ {
+		fileRand := randWriteFileSuffix()
+		fname := "/tmp/" + atomicWriteFilePrefix + fileRand
+		firstAtomicFileBytes, err := ioutil.ReadFile(fname)
+		require.Nil(t, err, "Error reading first atomic file")
+		require.Equal(t, []byte(fmt.Sprintf(testString, i)), firstAtomicFileBytes,
+			"atomic write file %d was overwritten", i)
+	}
+
+	// Check that the resultant file is correct
+	resultantFileBytes, err := ioutil.ReadFile(fileToWrite)
+	require.Nil(t, err, "Error reading resultant file")
+	require.Equal(t, []byte(expectedString), resultantFileBytes, "Written file had incorrect bytes")
+}
--- a/libs/db/backend_test.go
+++ b/libs/db/backend_test.go
@@ -2,6 +2,7 @@ package db

 import (
 	"fmt"
+	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
@@ -17,8 +18,8 @@ func cleanupDBDir(dir, name string) {

 func testBackendGetSetDelete(t *testing.T, backend DBBackendType) {
 	// Default
-	dir, dirname := cmn.Tempdir(fmt.Sprintf("test_backend_%s_", backend))
-	defer dir.Close()
+	dirname, err := ioutil.TempDir("", fmt.Sprintf("test_backend_%s_", backend))
+	require.Nil(t, err)
 	db := NewDB("testdb", backend, dirname)

 	// A nonexistent key should return nil, even if the key is empty
--- a/libs/db/common_test.go
+++ b/libs/db/common_test.go
@@ -2,12 +2,12 @@ package db

 import (
 	"fmt"
+	"io/ioutil"
 	"sync"
 	"testing"

 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	cmn "github.com/tendermint/tendermint/libs/common"
 )

 //----------------------------------------
@@ -61,9 +61,9 @@ func checkValuePanics(t *testing.T, itr Iterator) {
 }

 func newTempDB(t *testing.T, backend DBBackendType) (db DB) {
-	dir, dirname := cmn.Tempdir("db_common_test")
+	dirname, err := ioutil.TempDir("", "db_common_test")
+	require.Nil(t, err)
 	db = NewDB("testdb", backend, dirname)
-	dir.Close()
 	return db
 }

--- a/p2p/conn/secret_connection_test.go
+++ b/p2p/conn/secret_connection_test.go
@@ -1,8 +1,16 @@
 package conn

 import (
+	"bufio"
+	"encoding/hex"
+	"flag"
 	"fmt"
 	"io"
+	"log"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
 	"testing"

 	"github.com/stretchr/testify/assert"
@@ -208,6 +216,66 @@ func TestSecretConnectionReadWrite(t *testing.T) {

 }

+// Run go test -update from within this module
+// to update the golden test vector file
+var update = flag.Bool("update", false, "update .golden files")
+
+func TestDeriveSecretsAndChallengeGolden(t *testing.T) {
+	goldenFilepath := filepath.Join("testdata", t.Name()+".golden")
+	if *update {
+		t.Logf("Updating golden test vector file %s", goldenFilepath)
+		data := createGoldenTestVectors(t)
+		cmn.WriteFile(goldenFilepath, []byte(data), 0644)
+	}
+	f, err := os.Open(goldenFilepath)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer f.Close()
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		params := strings.Split(line, ",")
+		randSecretVector, err := hex.DecodeString(params[0])
+		require.Nil(t, err)
+		randSecret := new([32]byte)
+		copy((*randSecret)[:], randSecretVector)
+		locIsLeast, err := strconv.ParseBool(params[1])
+		require.Nil(t, err)
+		expectedRecvSecret, err := hex.DecodeString(params[2])
+		require.Nil(t, err)
+		expectedSendSecret, err := hex.DecodeString(params[3])
+		require.Nil(t, err)
+		expectedChallenge, err := hex.DecodeString(params[4])
+		require.Nil(t, err)
+
+		recvSecret, sendSecret, challenge := deriveSecretAndChallenge(randSecret, locIsLeast)
+		require.Equal(t, expectedRecvSecret, (*recvSecret)[:], "Recv Secrets aren't equal")
+		require.Equal(t, expectedSendSecret, (*sendSecret)[:], "Send Secrets aren't equal")
+		require.Equal(t, expectedChallenge, (*challenge)[:], "challenges aren't equal")
+	}
+}
+
+// Creates the data for a test vector file.
+// The file format is:
+// Hex(diffie_hellman_secret), loc_is_least, Hex(recvSecret), Hex(sendSecret), Hex(challenge)
+func createGoldenTestVectors(t *testing.T) string {
+	data := ""
+	for i := 0; i < 32; i++ {
+		randSecretVector := cmn.RandBytes(32)
+		randSecret := new([32]byte)
+		copy((*randSecret)[:], randSecretVector)
+		data += hex.EncodeToString((*randSecret)[:]) + ","
+		locIsLeast := cmn.RandBool()
+		data += strconv.FormatBool(locIsLeast) + ","
+		recvSecret, sendSecret, challenge := deriveSecretAndChallenge(randSecret, locIsLeast)
+		data += hex.EncodeToString((*recvSecret)[:]) + ","
+		data += hex.EncodeToString((*sendSecret)[:]) + ","
+		data += hex.EncodeToString((*challenge)[:]) + "\n"
+	}
+	return data
+}
+
 func BenchmarkSecretConnection(b *testing.B) {
 	b.StopTimer()
 	fooSecConn, barSecConn := makeSecretConnPair(b)
--- a/p2p/conn/testdata/TestDeriveSecretsAndChallengeGolden.golden
+++ b/p2p/conn/testdata/TestDeriveSecretsAndChallengeGolden.golden
@@ -0,0 +1,32 @@
+9fe4a5a73df12dbd8659b1d9280873fe993caefec6b0ebc2686dd65027148e03,true,80a83ad6afcb6f8175192e41973aed31dd75e3c106f813d986d9567a4865eb2f,96362a04f628a0666d9866147326898bb0847b8db8680263ad19e6336d4eed9e,2632c3fd20f456c5383ed16aa1d56dc7875a2b0fc0d5ff053c3ada8934098c69
+0716764b370d543fee692af03832c16410f0a56e4ddb79604ea093b10bb6f654,false,84f2b1e8658456529a2c324f46c3406c3c6fecd5fbbf9169f60bed8956a8b03d,cba357ae33d7234520d5742102a2a6cdb39b7db59c14a58fa8aadd310127630f,576643a8fcc1a4cf866db900f4a150dbe35d44a1b3ff36e4911565c3fa22fc32
+358dd73aae2c5b7b94b57f950408a3c681e748777ecab2063c8ca51a63588fa8,false,c2e2f664c8ee561af8e1e30553373be4ae23edecc8c6bd762d44b2afb7f2a037,d1563f428ac1c023c15d8082b2503157fe9ecbde4fb3493edd69ebc299b4970c,89fb6c6439b12fe11a4c604b8ad883f7dc76be33df590818fe5eb15ddb01face
+0958308bdb583e639dd399a98cd21077d834b4b5e30771275a5a73a62efcc7e0,false,523c0ae97039173566f7ab4b8f271d8d78feef5a432d618e58ced4f80f7c1696,c1b743401c6e4508e62b8245ea7c3252bbad082e10af10e80608084d63877977,d7c52adf12ebc69677aec4bd387b0c5a35570fe61cb7b8ae55f3ab14b1b79be0
+d93d134e72f58f177642ac30f36b2d3cd4720aa7e60feb1296411a9009cf4524,false,47a427bcc1ef6f0ce31dbf343bc8bbf49554b4dd1e2330fd97d0df23ecdbba10,73e23adb7801179349ecf9c8cdf64d71d64a9f1145ba6730e5d029f99eaf8840,a8fdcb77f591bfba7b8483aa15ae7b42054ba68625d51dec005896dfe910281f
+6104474c791cda24d952b356fb41a5d273c0ce6cc87d270b1701d0523cd5aa13,true,1cb4397b9e478430321af4647da2ccbef62ff8888542d31cca3f626766c8080f,673b23318826bd31ad1a4995c6e5095c4b092f5598aa0a96381a3e977bc0eaf9,4a25a25c5f75d6cc512f2ba8c1546e6263e9ef8269f0c046c37838cc66aa83e6
+8a6002503c15cab763e27c53fc449f6854a210c95cdd67e4466b0f2cb46b629c,false,f01ff06aef356c87f8d2646ff9ed8b855497c2ca00ea330661d84ef421a67e63,4f59bb23090010614877265a1597f1a142fa97b7208e1d554435763505f36f6a,1aadcb1c8b5993da102cebcb60c545b03197c98137064530840f45d917ad300e
+31a57c6b1fe33beb1f7ebbbfc06d58c4f307cd355b6f9753e58f3edec16c7559,false,13e126c4cb240349dccf0dc843977671d34a1daffd0517d06ed66b703344db22,d491431906a306af45ecf9f1977e32d7f65a79f5139f931760416de27554b687,5ea7e8e3d5a30503423341609d360d246b61a9159fc07f253a46e357977cd745
+71a3c79718b824627faeefdce887d9465b353bd962cc5e97c5b5dfedab457ef9,true,e2e8eea547dcee7eafa89ae41f48ab049beac24935fad75258924fd5273d23cb,45d2e839bf36a3616cbe8a9bdbd4e7b288bf5bf1e6e79c07995eb2b18eb2eaff,7ee50e0810bc9f98e56bc46de5da22d84b3efa52fe5d85db4b2344530ef17ed8
+2e9dba2eb4f9019c2628ff5899744469c26caf793636f30ddb76601751aee968,false,8bfc3b314e4468d4e19c9d28b7bfd5b5532263105273b0fe80801f6146313993,b77d2b223e27038f978ab87a725859f6995f903056bdbd594ab04f0b2cbad517,9032be49a9cbcd1de6fee332f8f24ebf545c05e0175b98c564e7d1e69630ae20
+81322b22c835efb26d78051f3a3840a9d01aa558c019ecfa26483b5c5535728c,true,61eacb7e9665e362ef492ef950cea58f8bc67434ab7ee5545139147adf395da4,0f600ef0c358cae938969f434c2ec0ce3be632fdf5246b7bb8ee3ff294036ecd,a7026b4c21fe225ecd775ae81249405c6f492882eb85f3f8e2232f11e515561e
+826b86c5e8cb4173ff2d05c48e3537140c5e0f26f7866bbcd4e57616806e1be2,true,ae44dabd077d227c8d898930a7705a2b785c8849121282106c045bb58b66eb36,24b2c1b1e2a9ebe387df6dfb9fbde6c681e4eeb0a33bb1c3df3789087f56ffe3,b37a64ea97431b25cb271c4c8435f6dd97118b35da57168f3c3c269920f7bbc1
+18b5a7b973d4b263072e69515c5b6ed22191c3d6e851aaba872904672f8344ec,true,ce402af2fb93b6ef18cd406f7c437d3cbfb09141b7a02116b1cfbabbf75ad84a,c86bdb1709ef0f4a31a818843660f83338b9db77e262bb7c6546138e51c6046b,11fcd8e59c4e7f6050d3cd332337db794ae31260c159e409af3ed8f4d6523bf4
+26d10c56872b72bb76ae7c7b3f074afb3d4a364e5e3f8c661be9b4f5a522ea75,true,1c9782a8485c4ecb13904ec551a7f9300ecd687abfbe63c91c7fd583f84a7a4d,ae3f4ccd0dfee8b514f67db2e923714d324935b9ae9e488d088ebb79569d8cc4,8139a3ab728b0e765e4d90549ab8eed7e1048a83267eafa7442208a7f627558a
+558838dfcfe94105c46a4ade4548e6c96271d33e6c752661356cc66024615bae,true,d5a38625be74177318072cf877f2427ce2327e9b58d2eb134d0ac52c9126572f,dead938f77007e3164b6eee4cd153433d03ca5d9ec64f41aa6b2d6a069edeeda,4a081a356361da429c564cf7ac8e217121bbe8c5ee5c9632bae0b7ddbe94f9d4
+f4a3f6a93a4827a59682fd8bf1a8e4fd9aaff01a337a86e1966c8fff0e746014,true,39a0aea2a8ac7f0524d63e395a25b98fc3844ed039f20b11058019dca2b3840f,6ff53243426ded506d22501ae0f989d9946b86a8bb2550d7ed6e90fdf41d0e7c,8784e728bf12f465ed20dc6f0e1d949a68e5795d4799536427a6f859547b7fd6
+1717020e1c4fca1b4926dba16671c0c04e4f19c621c646cb4525fa533b1c205c,false,b9a909767f3044608b4e314b149a729bef199f8311310e1ecd2072e5659b7194,7baf0ff4b980919cf545312f45234976f0b6c574aac5b772024f73248aad7538,99a18e1e4b039ef3777a8fdd0d9ffaccaf3b4523b6d26adacfe91cc5fcd9977e
+de769062be27b2a4248dd5be315960c8d231738417ece670c2d6a1c52877b59e,true,cc6c2086718b21813513894546e85766d34c754e81fd6a19c12fc322ffb9b1c3,5a7da7500191c65a5f1fbb2a6122717edc70ca0469baf2bbbd6ca8255b93c077,8c0d32091dc687f1399c754a617d224742726bece848b50c35b4db5f0469ace7
+7c5549f36767e02ebf49a4616467199459aa6932dcc091f182f822185659559a,true,d8335e606128b0c621ff6cda99dc62babf4a4436c574c5c478c20122712727d0,0a7c673cccd6f7fd4ed1673f7d0f2cb08961faced123ca901b74581d5bdc8b25,16ac1eb2a39384716c7d490272d87e76c10665fdb331e1883435de175ce4460e
+ecf8261ebda248dc7796f98987efe1b7be363a59037c9e61044490d08a077610,true,53def80fcdba01367c0ea36459b57409f59a771f57a8259b54f24785e5656b7d,90140870b3b1e84c9dcf7836eac0581b16fe0a40307619d267c6f871e1efce6a,c6d1836b66c1a722a377c7eb058995a0ef8711839c6d6a0cdd6ad1ff70f935a5
+21c0ef76ce0eae9391ceabfb08a861899db55ac4ccf010ed672599669c6938f2,false,8af5482cc015093f261d5b7ce87035dda41d8318b9960b52cca3e5f0d3f61808,f4d5338bcb57262e1034f01ed3858ca1e5d66a73f18588e72f3dc8c6a730be0c,7ba82c2820c95e3354d9a6ab4920ebcd7938ce19e25930fee58439246b0321b1
+05f3b66d6b0fe906137e60b4719083a2465106badedcdae3a4c91c46c5367340,false,e5c9e074e95c2896fa4093830e96e9cf159b8dcba2ead21f37237cf6e9a9aaa2,b3a0a50309b4ca23cd34363fd8df30e73ec4a275973986c2e11a53752eff0a3b,358a62056ff05f27185b9952d291c6346171937f6811cafbacddd82e17010f39
+fef0251cff7c5d1ba0514f1820a8265453365fd9f5bb8a92f955dc007a40e730,true,e35a0aff6e9060a39c15d276a1337f1948d0be0aef81fcd563a6783115b5283d,20a8efe83474253d70e5fd847df0cd26222cd39e9210687b68c0a23b73429108,2989fab4278b32f4f40dc02227ab30e10f62e15ab7aa7382da769b1d084e33df
+1b7bb172baa2753ec9c3e81a7a9b4c6ef10f9ed7afcafa975395f095eca63a54,false,a98257203987d0c4d260d8feef841466977276612e268b69b5ce4191af161b29,ea177a20d6c1f73f9667090568f9197943037d6586f7e2d6b7b81756fc71df5f,844eff318ef4c6ee45f158c1946ff999e40ffac70883ab6d6b90995f246e69a2
+5ee9b60a25753066d0ecc1155ca6afcc6b853ba558c9533c134a93b82e756856,true,9889460b95ca9545864a4a5194891b7d475362428d6d797532da10bf1fc92076,a7a96739abd8eceb6751afc98df68e29f7af16fbfda3d4710df9c35b6dcdb4d5,998326285c90a2ea2e1f6c6dac79530742645e3dd1b2b42a0733388a99cab81b
+a102613781872f88a949d82cb5efcc2e0f437010a950d71b87929ecb480af3b3,false,e099080a55b9b29ccecbbb0d91dbe49defcc217efd1de0588e0836ce5970d327,319293b8660a3cea9879487645ddadda72a5c60079c9154bb0dbb8a0c9cda79e,4d567f1b1a1b304347cf7b129e4c7a05aa57e2bbb8ea335db9e33d05fab12e4d
+1d4538180d06f37c43e8caa2d0d80aa7c5d701c8c3e31508704131427837f5cc,true,73afeeb46efc03d2b9f20fc271752528e52b8931287296a7e4367c96bccb32bd,59dc4b69d9ccf6f77715e47fb9bf454f1b90bbd05f1d2bbd07c7d6666f31c91f,ac59d735dfcdc3a0a4ce5a10f09dea8c6afd47de9c0308dc817e3789c8aee963
+e4c480af1b0e3487a331761f64eb3f020a2b8ffa25ad17e00f57aa7ec2c5e84d,true,1145e9f001c70d364e97fcdbc88a2a3d6aecdd975212923820f90a0b215f11f6,b802ac7ef21c8abaeae024c76e3fa70a2a82f73e0bb7c7fe76752ad1742af2e6,0a95876e30617e32ae25acd3af97c37dc075825f800def3f2bf3f68a268744e9
+3a7a83dd657dd6277bcfa957534f40d9b559039aad752066a8d7ed9a6d9c0ab5,false,f90a251ad2338b19cfee6a7965f6f5098136974abb99b3d24553fa6117384978,e422ed7567e5602731b3d980106d0546ef4a4da5eb7175d66a452df12d37bad2,b086bed71dfb6662cb10e2b4fb16a7c22394f488e822fc19697db6077f6caf6f
+273e8560c2b1734e863a6542bded7a6fcbfb49a12770bd8866d4863dceea3ae9,false,3b7849a362e7b7ba8c8b8a0cd00df5180604987dbda6c03f37d9a09fdb27fb28,e6cdf4d767df0f411e970da8dda6acd3c2c34ce63908d8a6dbf3715daa0318e4,359a4a39fbdffc808161a48a3ffbe77fc6a03ff52324c22510a42e46c08a6f22
+9b4f8702991be9569b6c0b07a2173104d41325017b27d68fa5af91cdab164c4d,true,598323677db11ece050289f31881ee8caacb59376c7182f9055708b2a4673f84,7675adc1264b6758beb097a991f766f62796f78c1cfa58a4de3d81c36434d3ae,d5d8d610ffd85b04cbe1c73ff5becd5917c513d9625b001f51d486d0dadcefe3
+e1a686ba0169eb97379ebf9d22e073819450ee5ad5f049c8e93016e8d2ec1430,false,ffe461e6075865cde2704aa148fd29bcf0af245803f446cb6153244f25617993,46df6c25fa0344e662490c4da0bddca626644e67e66705840ef08aae35c343fa,e9a56d75acad4272ab0c49ee5919a4e86e6c5695ef065704c1e592d4e7b41a10
--- a/p2p/pex/pex_reactor.go
+++ b/p2p/pex/pex_reactor.go
@@ -74,6 +74,8 @@ type PEXReactor struct {
 	requestsSent         *cmn.CMap // ID->struct{}: unanswered send requests
 	lastReceivedRequests *cmn.CMap // ID->time.Time: last time peer requested from us

+	seedAddrs []*p2p.NetAddress
+
 	attemptsToDial sync.Map // address (string) -> {number of attempts (int), last time dialed (time.Time)}
 }

@@ -113,9 +115,6 @@ func NewPEXReactor(b AddrBook, config *PEXReactorConfig) *PEXReactor {

 // OnStart implements BaseService
 func (r *PEXReactor) OnStart() error {
-	if err := r.BaseReactor.OnStart(); err != nil {
-		return err
-	}
 	err := r.book.Start()
 	if err != nil && err != cmn.ErrAlreadyStarted {
 		return err
@@ -123,10 +122,13 @@ func (r *PEXReactor) OnStart() error {

 	// return err if user provided a bad seed address
 	// or a host name that we cant resolve
-	if err := r.checkSeeds(); err != nil {
+	seedAddrs, err := r.checkSeeds()
+	if err != nil {
 		return err
 	}

+	r.seedAddrs = seedAddrs
+
 	// Check if this node should run
 	// in seed/crawler mode
 	if r.config.SeedMode {
@@ -139,7 +141,6 @@ func (r *PEXReactor) OnStart() error {

 // OnStop implements BaseService
 func (r *PEXReactor) OnStop() {
-	r.BaseReactor.OnStop()
 	r.book.Stop()
 }

@@ -285,7 +286,6 @@ func (r *PEXReactor) RequestAddrs(p Peer) {
 // request for this peer and deletes the open request.
 // If there's no open request for the src peer, it returns an error.
 func (r *PEXReactor) ReceiveAddrs(addrs []*p2p.NetAddress, src Peer) error {
-
 	id := string(src.ID())
 	if !r.requestsSent.Has(id) {
 		return cmn.NewError("Received unsolicited pexAddrsMessage")
@@ -301,6 +301,13 @@ func (r *PEXReactor) ReceiveAddrs(addrs []*p2p.NetAddress, src Peer) error {

 		err := r.book.AddAddress(netAddr, srcAddr)
 		r.logErrAddrBook(err)
+
+		// If this address came from a seed node, try to connect to it without waiting.
+		for _, seedAddr := range r.seedAddrs {
+			if seedAddr.Equals(srcAddr) {
+				r.ensurePeers()
+			}
+		}
 	}
 	return nil
 }
@@ -472,18 +479,18 @@ func (r *PEXReactor) dialPeer(addr *p2p.NetAddress) {
 }

 // check seed addresses are well formed
-func (r *PEXReactor) checkSeeds() error {
+func (r *PEXReactor) checkSeeds() ([]*p2p.NetAddress, error) {
 	lSeeds := len(r.config.Seeds)
 	if lSeeds == 0 {
-		return nil
+		return nil, nil
 	}
-	_, errs := p2p.NewNetAddressStrings(r.config.Seeds)
+	netAddrs, errs := p2p.NewNetAddressStrings(r.config.Seeds)
 	for _, err := range errs {
 		if err != nil {
-			return err
+			return nil, err
 		}
 	}
-	return nil
+	return netAddrs, nil
 }

 // randomly dial seeds until we connect to one or exhaust them
@@ -492,13 +499,12 @@ func (r *PEXReactor) dialSeeds() {
 	if lSeeds == 0 {
 		return
 	}
-	seedAddrs, _ := p2p.NewNetAddressStrings(r.config.Seeds)

 	perm := cmn.RandPerm(lSeeds)
 	// perm := r.Switch.rng.Perm(lSeeds)
 	for _, i := range perm {
 		// dial a random seed
-		seedAddr := seedAddrs[i]
+		seedAddr := r.seedAddrs[i]
 		err := r.Switch.DialPeerWithAddress(seedAddr, false)
 		if err == nil {
 			return
--- a/p2p/pex/pex_reactor_test.go
+++ b/p2p/pex/pex_reactor_test.go
@@ -211,31 +211,26 @@ func TestPEXReactorUsesSeedsIfNeeded(t *testing.T) {
 	defer os.RemoveAll(dir) // nolint: errcheck

 	// 1. create seed
-	seed := p2p.MakeSwitch(
-		cfg,
-		0,
-		"127.0.0.1",
-		"123.123.123",
-		func(i int, sw *p2p.Switch) *p2p.Switch {
-			book := NewAddrBook(filepath.Join(dir, "addrbook0.json"), false)
-			book.SetLogger(log.TestingLogger())
-			sw.SetAddrBook(book)
-
-			sw.SetLogger(log.TestingLogger())
-
-			r := NewPEXReactor(book, &PEXReactorConfig{})
-			r.SetLogger(log.TestingLogger())
-			sw.AddReactor("pex", r)
-			return sw
-		},
-	)
-	seed.AddListener(
-		p2p.NewDefaultListener("tcp://"+seed.NodeInfo().ListenAddr, "", false, log.TestingLogger()),
-	)
+	seed := testCreateSeed(dir, 0, []*p2p.NetAddress{}, []*p2p.NetAddress{})
 	require.Nil(t, seed.Start())
 	defer seed.Stop()

 	// 2. create usual peer with only seed configured.
+	peer := testCreatePeerWithSeed(dir, 1, seed)
+	require.Nil(t, peer.Start())
+	defer peer.Stop()
+
+	// 3. check that the peer connects to seed immediately
+	assertPeersWithTimeout(t, []*p2p.Switch{peer}, 10*time.Millisecond, 3*time.Second, 1)
+}
+
+func TestConnectionSpeedForPeerReceivedFromSeed(t *testing.T) {
+	// directory to store address books
+	dir, err := ioutil.TempDir("", "pex_reactor")
+	require.Nil(t, err)
+	defer os.RemoveAll(dir) // nolint: errcheck
+
+	// 1. create peer
 	peer := p2p.MakeSwitch(
 		cfg,
 		1,
@@ -250,20 +245,34 @@ func TestPEXReactorUsesSeedsIfNeeded(t *testing.T) {

 			r := NewPEXReactor(
 				book,
-				&PEXReactorConfig{
-					Seeds: []string{seed.NodeInfo().NetAddress().String()},
-				},
+				&PEXReactorConfig{},
 			)
 			r.SetLogger(log.TestingLogger())
 			sw.AddReactor("pex", r)
 			return sw
 		},
 	)
+	peer.AddListener(
+		p2p.NewDefaultListener("tcp://"+peer.NodeInfo().ListenAddr, "", false, log.TestingLogger()),
+	)
 	require.Nil(t, peer.Start())
 	defer peer.Stop()

-	// 3. check that the peer connects to seed immediately
-	assertPeersWithTimeout(t, []*p2p.Switch{peer}, 10*time.Millisecond, 3*time.Second, 1)
+	// 2. Create seed which knows about the peer
+	seed := testCreateSeed(dir, 2, []*p2p.NetAddress{peer.NodeInfo().NetAddress()}, []*p2p.NetAddress{peer.NodeInfo().NetAddress()})
+	require.Nil(t, seed.Start())
+	defer seed.Stop()
+
+	// 3. create another peer with only seed configured.
+	secondPeer := testCreatePeerWithSeed(dir, 3, seed)
+	require.Nil(t, secondPeer.Start())
+	defer secondPeer.Stop()
+
+	// 4. check that the second peer connects to seed immediately
+	assertPeersWithTimeout(t, []*p2p.Switch{secondPeer}, 10*time.Millisecond, 3*time.Second, 1)
+
+	// 5. check that the second peer connects to the first peer immediately
+	assertPeersWithTimeout(t, []*p2p.Switch{secondPeer}, 10*time.Millisecond, 1*time.Second, 2)
 }

 func TestPEXReactorCrawlStatus(t *testing.T) {
@@ -401,6 +410,7 @@ func assertPeersWithTimeout(
 				outbound, inbound, _ := s.NumPeers()
 				if outbound+inbound < nPeers {
 					allGood = false
+					break
 				}
 			}
 			remaining -= checkPeriod
@@ -417,14 +427,77 @@ func assertPeersWithTimeout(
 				numPeersStr += fmt.Sprintf("%d => {outbound: %d, inbound: %d}, ", i, outbound, inbound)
 			}
 			t.Errorf(
-				"expected all switches to be connected to at least one peer (switches: %s)",
-				numPeersStr,
+				"expected all switches to be connected to at least %d peer(s) (switches: %s)",
+				nPeers, numPeersStr,
 			)
 			return
 		}
 	}
 }

+// Creates a seed which knows about the provided addresses / source address pairs.
+// Starting and stopping the seed is left to the caller
+func testCreateSeed(dir string, id int, knownAddrs, srcAddrs []*p2p.NetAddress) *p2p.Switch {
+	seed := p2p.MakeSwitch(
+		cfg,
+		id,
+		"127.0.0.1",
+		"123.123.123",
+		func(i int, sw *p2p.Switch) *p2p.Switch {
+			book := NewAddrBook(filepath.Join(dir, "addrbookSeed.json"), false)
+			book.SetLogger(log.TestingLogger())
+			for j := 0; j < len(knownAddrs); j++ {
+				book.AddAddress(knownAddrs[j], srcAddrs[j])
+				book.MarkGood(knownAddrs[j])
+			}
+			sw.SetAddrBook(book)
+
+			sw.SetLogger(log.TestingLogger())
+
+			r := NewPEXReactor(book, &PEXReactorConfig{})
+			r.SetLogger(log.TestingLogger())
+			sw.AddReactor("pex", r)
+			return sw
+		},
+	)
+	seed.AddListener(
+		p2p.NewDefaultListener("tcp://"+seed.NodeInfo().ListenAddr, "", false, log.TestingLogger()),
+	)
+	return seed
+}
+
+// Creates a peer which knows about the provided seed.
+// Starting and stopping the peer is left to the caller
+func testCreatePeerWithSeed(dir string, id int, seed *p2p.Switch) *p2p.Switch {
+	peer := p2p.MakeSwitch(
+		cfg,
+		id,
+		"127.0.0.1",
+		"123.123.123",
+		func(i int, sw *p2p.Switch) *p2p.Switch {
+			book := NewAddrBook(filepath.Join(dir, fmt.Sprintf("addrbook%d.json", id)), false)
+			book.SetLogger(log.TestingLogger())
+			sw.SetAddrBook(book)
+
+			sw.SetLogger(log.TestingLogger())
+
+			r := NewPEXReactor(
+				book,
+				&PEXReactorConfig{
+					Seeds: []string{seed.NodeInfo().NetAddress().String()},
+				},
+			)
+			r.SetLogger(log.TestingLogger())
+			sw.AddReactor("pex", r)
+			return sw
+		},
+	)
+	peer.AddListener(
+		p2p.NewDefaultListener("tcp://"+peer.NodeInfo().ListenAddr, "", false, log.TestingLogger()),
+	)
+	return peer
+}
+
 func createReactor(conf *PEXReactorConfig) (r *PEXReactor, book *addrBook) {
 	// directory to store address book
 	dir, err := ioutil.TempDir("", "pex_reactor")
--- a/privval/priv_validator_test.go
+++ b/privval/priv_validator_test.go
@@ -3,6 +3,7 @@ package privval
 import (
 	"encoding/base64"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"testing"
 	"time"
@@ -11,22 +12,22 @@ import (
 	"github.com/stretchr/testify/require"
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/ed25519"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/types"
 )

 func TestGenLoadValidator(t *testing.T) {
 	assert := assert.New(t)

-	_, tempFilePath := cmn.Tempfile("priv_validator_")
-	privVal := GenFilePV(tempFilePath)
+	tempFile, err := ioutil.TempFile("", "priv_validator_")
+	require.Nil(t, err)
+	privVal := GenFilePV(tempFile.Name())

 	height := int64(100)
 	privVal.LastHeight = height
 	privVal.Save()
 	addr := privVal.GetAddress()

-	privVal = LoadFilePV(tempFilePath)
+	privVal = LoadFilePV(tempFile.Name())
 	assert.Equal(addr, privVal.GetAddress(), "expected privval addr to be the same")
 	assert.Equal(height, privVal.LastHeight, "expected privval.LastHeight to have been saved")
 }
@@ -34,7 +35,9 @@ func TestGenLoadValidator(t *testing.T) {
 func TestLoadOrGenValidator(t *testing.T) {
 	assert := assert.New(t)

-	_, tempFilePath := cmn.Tempfile("priv_validator_")
+	tempFile, err := ioutil.TempFile("", "priv_validator_")
+	require.Nil(t, err)
+	tempFilePath := tempFile.Name()
 	if err := os.Remove(tempFilePath); err != nil {
 		t.Error(err)
 	}
@@ -91,8 +94,9 @@ func TestUnmarshalValidator(t *testing.T) {
 func TestSignVote(t *testing.T) {
 	assert := assert.New(t)

-	_, tempFilePath := cmn.Tempfile("priv_validator_")
-	privVal := GenFilePV(tempFilePath)
+	tempFile, err := ioutil.TempFile("", "priv_validator_")
+	require.Nil(t, err)
+	privVal := GenFilePV(tempFile.Name())

 	block1 := types.BlockID{[]byte{1, 2, 3}, types.PartSetHeader{}}
 	block2 := types.BlockID{[]byte{3, 2, 1}, types.PartSetHeader{}}
@@ -101,7 +105,7 @@ func TestSignVote(t *testing.T) {

 	// sign a vote for first time
 	vote := newVote(privVal.Address, 0, height, round, voteType, block1)
-	err := privVal.SignVote("mychainid", vote)
+	err = privVal.SignVote("mychainid", vote)
 	assert.NoError(err, "expected no error signing vote")

 	// try to sign the same vote again; should be fine
@@ -132,8 +136,9 @@ func TestSignVote(t *testing.T) {
 func TestSignProposal(t *testing.T) {
 	assert := assert.New(t)

-	_, tempFilePath := cmn.Tempfile("priv_validator_")
-	privVal := GenFilePV(tempFilePath)
+	tempFile, err := ioutil.TempFile("", "priv_validator_")
+	require.Nil(t, err)
+	privVal := GenFilePV(tempFile.Name())

 	block1 := types.PartSetHeader{5, []byte{1, 2, 3}}
 	block2 := types.PartSetHeader{10, []byte{3, 2, 1}}
@@ -141,7 +146,7 @@ func TestSignProposal(t *testing.T) {

 	// sign a proposal for first time
 	proposal := newProposal(height, round, block1)
-	err := privVal.SignProposal("mychainid", proposal)
+	err = privVal.SignProposal("mychainid", proposal)
 	assert.NoError(err, "expected no error signing proposal")

 	// try to sign the same proposal again; should be fine
@@ -170,8 +175,9 @@ func TestSignProposal(t *testing.T) {
 }

 func TestDifferByTimestamp(t *testing.T) {
-	_, tempFilePath := cmn.Tempfile("priv_validator_")
-	privVal := GenFilePV(tempFilePath)
+	tempFile, err := ioutil.TempFile("", "priv_validator_")
+	require.Nil(t, err)
+	privVal := GenFilePV(tempFile.Name())

 	block1 := types.PartSetHeader{5, []byte{1, 2, 3}}
 	height, round := int64(10), 1
--- a/rpc/core/status.go
+++ b/rpc/core/status.go
@@ -104,20 +104,11 @@ func Status() (*ctypes.ResultStatus, error) {
 	return result, nil
 }

-const consensusTimeout = time.Second
-
 func validatorAtHeight(h int64) *types.Validator {
-	lastBlockHeight, vals := getValidatorsWithTimeout(
-		consensusState,
-		consensusTimeout,
-	)
-
-	if lastBlockHeight == -1 {
-		return nil
-	}
-
 	privValAddress := pubKey.Address()

+	lastBlockHeight, vals := consensusState.GetValidators()
+
 	// if we're still at height h, search in the current validator set
 	if lastBlockHeight == h {
 		for _, val := range vals {
@@ -140,35 +131,3 @@ func validatorAtHeight(h int64) *types.Validator {

 	return nil
 }
-
-type validatorRetriever interface {
-	GetValidators() (int64, []*types.Validator)
-}
-
-// NOTE: Consensus might halt, but we still need to process RPC requests (at
-// least for endpoints whole output does not depend on consensus state).
-func getValidatorsWithTimeout(
-	vr validatorRetriever,
-	t time.Duration,
-) (int64, []*types.Validator) {
-	resultCh := make(chan struct {
-		lastBlockHeight int64
-		vals            []*types.Validator
-	})
-	go func() {
-		h, v := vr.GetValidators()
-		resultCh <- struct {
-			lastBlockHeight int64
-			vals            []*types.Validator
-		}{h, v}
-	}()
-	select {
-	case res := <-resultCh:
-		return res.lastBlockHeight, res.vals
-	case <-time.After(t):
-		if logger != nil {
-			logger.Error("Timed out querying validators from consensus", "timeout", t)
-		}
-		return -1, []*types.Validator{}
-	}
-}
--- a/rpc/core/status_test.go
+++ b/rpc/core/status_test.go
@@ -1,39 +0,0 @@
-package core
-
-import (
-	"testing"
-	"time"
-
-	"github.com/tendermint/tendermint/types"
-)
-
-func TestGetValidatorsWithTimeout(t *testing.T) {
-	height, vs := getValidatorsWithTimeout(
-		testValidatorReceiver{},
-		time.Millisecond,
-	)
-
-	if height != -1 {
-		t.Errorf("expected negative height")
-	}
-
-	if len(vs) != 0 {
-		t.Errorf("expected no validators")
-	}
-}
-
-type testValidatorReceiver struct{}
-
-func (tr testValidatorReceiver) GetValidators() (int64, []*types.Validator) {
-	vs := []*types.Validator{}
-
-	for i := 0; i < 3; i++ {
-		v, _ := types.RandValidator(true, 10)
-
-		vs = append(vs, v)
-	}
-
-	time.Sleep(time.Millisecond)
-
-	return 10, vs
-}
--- a/state/execution.go
+++ b/state/execution.go
@@ -188,9 +188,12 @@ func execBlockOnProxyApp(logger log.Logger, proxyAppConn proxy.AppConnConsensus,

 	// Begin block
 	_, err := proxyAppConn.BeginBlockSync(abci.RequestBeginBlock{
-		Hash:                block.Hash(),
-		Header:              types.TM2PB.Header(&block.Header),
-		Validators:          signVals,
+		Hash:   block.Hash(),
+		Header: types.TM2PB.Header(&block.Header),
+		LastCommitInfo: abci.LastCommitInfo{
+			CommitRound: int32(block.LastCommit.Round()),
+			Validators:  signVals,
+		},
 		ByzantineValidators: byzVals,
 	})
 	if err != nil {
@@ -245,7 +248,7 @@ func getBeginBlockValidatorInfo(block *types.Block, lastValSet *types.ValidatorS
 			vote = block.LastCommit.Precommits[i]
 		}
 		val := abci.SigningValidator{
-			Validator:       types.TM2PB.Validator(val),
+			Validator:       types.TM2PB.ValidatorWithoutPubKey(val),
 			SignedLastBlock: vote != nil,
 		}
 		signVals[i] = val
--- a/state/execution_test.go
+++ b/state/execution_test.go
@@ -293,7 +293,7 @@ func (app *testApp) Info(req abci.RequestInfo) (resInfo abci.ResponseInfo) {
 }

 func (app *testApp) BeginBlock(req abci.RequestBeginBlock) abci.ResponseBeginBlock {
-	app.Validators = req.Validators
+	app.Validators = req.LastCommitInfo.Validators
 	app.ByzantineValidators = req.ByzantineValidators
 	return abci.ResponseBeginBlock{}
 }
--- a/types/protobuf.go
+++ b/types/protobuf.go
@@ -50,6 +50,13 @@ func (tm2pb) Header(header *Header) abci.Header {
 	}
 }

+func (tm2pb) ValidatorWithoutPubKey(val *Validator) abci.Validator {
+	return abci.Validator{
+		Address: val.PubKey.Address(),
+		Power:   val.VotingPower,
+	}
+}
+
 // XXX: panics on unknown pubkey type
 func (tm2pb) Validator(val *Validator) abci.Validator {
 	return abci.Validator{
@@ -129,7 +136,7 @@ func (tm2pb) Evidence(ev Evidence, valSet *ValidatorSet, evTime time.Time) abci.

 	return abci.Evidence{
 		Type:             evType,
-		Validator:        TM2PB.Validator(val),
+		Validator:        TM2PB.ValidatorWithoutPubKey(val),
 		Height:           ev.Height(),
 		Time:             evTime,
 		TotalVotingPower: valSet.TotalVotingPower(),
--- a/types/protobuf_test.go
+++ b/types/protobuf_test.go
@@ -102,6 +102,9 @@ func TestABCIEvidence(t *testing.T) {
 	)

 	assert.Equal(t, "duplicate/vote", abciEv.Type)
+
+	// test we do not send pubkeys
+	assert.Empty(t, abciEv.Validator.PubKey)
 }

 type pubKeyEddie struct{}
@@ -120,3 +123,21 @@ func TestABCIValidatorFromPubKeyAndPower(t *testing.T) {
 	assert.Panics(t, func() { TM2PB.ValidatorFromPubKeyAndPower(nil, 10) })
 	assert.Panics(t, func() { TM2PB.ValidatorFromPubKeyAndPower(pubKeyEddie{}, 10) })
 }
+
+func TestABCIValidatorWithoutPubKey(t *testing.T) {
+	pkEd := ed25519.GenPrivKey().PubKey()
+
+	abciVal := TM2PB.ValidatorWithoutPubKey(&Validator{
+		Address:     pkEd.Address(),
+		PubKey:      pkEd,
+		VotingPower: 10,
+	})
+
+	// pubkey must be nil
+	tmValExpected := abci.Validator{
+		Address: pkEd.Address(),
+		Power:   10,
+	}
+
+	assert.Equal(t, tmValExpected, abciVal)
+}