diff --git a/CHANGELOG_PENDING.md b/CHANGELOG_PENDING.md
index 84254d818..acc10379a 100644
--- a/CHANGELOG_PENDING.md
+++ b/CHANGELOG_PENDING.md
@@ -77,6 +77,13 @@ program](https://hackerone.com/tendermint).
   - [libs/common] \#4237 Move byte functions from `libs/common` into pkg `bytes`
   - [libs/common] \#4237 Move throttletimer functions from `libs/common` into pkg `timer`
   - [libs/common] \#4237 Move tempfile functions from `libs/common` into pkg `tempfile`
+  - [libs/common] \#4240 Move os functions from `libs/common` into pkg `os`
+  - [libs/common] \#4240 Move net functions from `libs/common` into pkg `net`
+  - [libs/common] \#4240 Move mathematical functions and types out of `libs/common` to `math` pkg
+  - [libs/common] \#4240 Move string functions out of `libs/common` to `strings` pkg
+  - [libs/common] \#4240 Move async functions out of `libs/common` to `async` pkg
+  - [libs/common] \#4240 Move bit functions out of `libs/common` to `bits` pkg
+  - [libs/common] \#4240 Move cmap functions out of `libs/common` to `cmap` pkg
 
 
 - Blockchain Protocol
diff --git a/abci/client/grpc_client.go b/abci/client/grpc_client.go
index 514e27533..f853a4254 100644
--- a/abci/client/grpc_client.go
+++ b/abci/client/grpc_client.go
@@ -10,7 +10,7 @@ import (
 	"google.golang.org/grpc"
 
 	"github.com/tendermint/tendermint/abci/types"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 	"github.com/tendermint/tendermint/libs/service"
 )
 
@@ -41,7 +41,7 @@ func NewGRPCClient(addr string, mustConnect bool) *grpcClient {
 }
 
 func dialerFunc(ctx context.Context, addr string) (net.Conn, error) {
-	return cmn.Connect(addr)
+	return tmnet.Connect(addr)
 }
 
 func (cli *grpcClient) OnStart() error {
diff --git a/abci/client/socket_client.go b/abci/client/socket_client.go
index a3d07ff0a..2e765119b 100644
--- a/abci/client/socket_client.go
+++ b/abci/client/socket_client.go
@@ -12,7 +12,7 @@ import (
 	"time"
 
 	"github.com/tendermint/tendermint/abci/types"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 	"github.com/tendermint/tendermint/libs/service"
 	"github.com/tendermint/tendermint/libs/timer"
 )
@@ -62,7 +62,7 @@ func (cli *socketClient) OnStart() error {
 	var conn net.Conn
 RETRY_LOOP:
 	for {
-		conn, err = cmn.Connect(cli.addr)
+		conn, err = tmnet.Connect(cli.addr)
 		if err != nil {
 			if cli.mustConnect {
 				return err
diff --git a/abci/cmd/abci-cli/abci-cli.go b/abci/cmd/abci-cli/abci-cli.go
index 3f283e9bd..d5a9aca27 100644
--- a/abci/cmd/abci-cli/abci-cli.go
+++ b/abci/cmd/abci-cli/abci-cli.go
@@ -11,8 +11,8 @@ import (
 
 	"github.com/spf13/cobra"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmos "github.com/tendermint/tendermint/libs/os"
 
 	abcicli "github.com/tendermint/tendermint/abci/client"
 	"github.com/tendermint/tendermint/abci/example/code"
@@ -640,7 +640,7 @@ func cmdCounter(cmd *cobra.Command, args []string) error {
 	}
 
 	// Stop upon receiving SIGTERM or CTRL-C.
-	cmn.TrapSignal(logger, func() {
+	tmos.TrapSignal(logger, func() {
 		// Cleanup
 		srv.Stop()
 	})
@@ -672,7 +672,7 @@ func cmdKVStore(cmd *cobra.Command, args []string) error {
 	}
 
 	// Stop upon receiving SIGTERM or CTRL-C.
-	cmn.TrapSignal(logger, func() {
+	tmos.TrapSignal(logger, func() {
 		// Cleanup
 		srv.Stop()
 	})
diff --git a/abci/example/example_test.go b/abci/example/example_test.go
index c96dd2778..d40976015 100644
--- a/abci/example/example_test.go
+++ b/abci/example/example_test.go
@@ -13,8 +13,8 @@ import (
 
 	"golang.org/x/net/context"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 
 	abcicli "github.com/tendermint/tendermint/abci/client"
 	"github.com/tendermint/tendermint/abci/example/code"
@@ -108,7 +108,7 @@ func testStream(t *testing.T, app types.Application) {
 // test grpc
 
 func dialerFunc(ctx context.Context, addr string) (net.Conn, error) {
-	return cmn.Connect(addr)
+	return tmnet.Connect(addr)
 }
 
 func testGRPCSync(t *testing.T, app types.ABCIApplicationServer) {
diff --git a/abci/server/grpc_server.go b/abci/server/grpc_server.go
index 0f8e42d7f..b953c404d 100644
--- a/abci/server/grpc_server.go
+++ b/abci/server/grpc_server.go
@@ -6,7 +6,7 @@ import (
 	"google.golang.org/grpc"
 
 	"github.com/tendermint/tendermint/abci/types"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 	"github.com/tendermint/tendermint/libs/service"
 )
 
@@ -23,7 +23,7 @@ type GRPCServer struct {
 
 // NewGRPCServer returns a new gRPC ABCI server
 func NewGRPCServer(protoAddr string, app types.ABCIApplicationServer) service.Service {
-	proto, addr := cmn.ProtocolAndAddress(protoAddr)
+	proto, addr := tmnet.ProtocolAndAddress(protoAddr)
 	s := &GRPCServer{
 		proto:    proto,
 		addr:     addr,
diff --git a/abci/server/socket_server.go b/abci/server/socket_server.go
index c69be3813..efb4d94e0 100644
--- a/abci/server/socket_server.go
+++ b/abci/server/socket_server.go
@@ -8,7 +8,7 @@ import (
 	"sync"
 
 	"github.com/tendermint/tendermint/abci/types"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 	"github.com/tendermint/tendermint/libs/service"
 )
 
@@ -30,7 +30,7 @@ type SocketServer struct {
 }
 
 func NewSocketServer(protoAddr string, app types.Application) service.Service {
-	proto, addr := cmn.ProtocolAndAddress(protoAddr)
+	proto, addr := tmnet.ProtocolAndAddress(protoAddr)
 	s := &SocketServer{
 		proto:    proto,
 		addr:     addr,
diff --git a/abci/tests/benchmarks/parallel/parallel.go b/abci/tests/benchmarks/parallel/parallel.go
index 78b69ed12..fe213313d 100644
--- a/abci/tests/benchmarks/parallel/parallel.go
+++ b/abci/tests/benchmarks/parallel/parallel.go
@@ -6,12 +6,12 @@ import (
 	"log"
 
 	"github.com/tendermint/tendermint/abci/types"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 )
 
 func main() {
 
-	conn, err := cmn.Connect("unix://test.sock")
+	conn, err := tmnet.Connect("unix://test.sock")
 	if err != nil {
 		log.Fatal(err.Error())
 	}
diff --git a/abci/tests/benchmarks/simple/simple.go b/abci/tests/benchmarks/simple/simple.go
index f3ac8a170..b18eaa580 100644
--- a/abci/tests/benchmarks/simple/simple.go
+++ b/abci/tests/benchmarks/simple/simple.go
@@ -8,12 +8,12 @@ import (
 	"reflect"
 
 	"github.com/tendermint/tendermint/abci/types"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 )
 
 func main() {
 
-	conn, err := cmn.Connect("unix://test.sock")
+	conn, err := tmnet.Connect("unix://test.sock")
 	if err != nil {
 		log.Fatal(err.Error())
 	}
diff --git a/blockchain/v1/reactor_fsm_test.go b/blockchain/v1/reactor_fsm_test.go
index 511664121..1d4b55418 100644
--- a/blockchain/v1/reactor_fsm_test.go
+++ b/blockchain/v1/reactor_fsm_test.go
@@ -6,8 +6,8 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	"github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/types"
@@ -736,7 +736,7 @@ func makeCorrectTransitionSequence(startingHeight int64, numBlocks int64, numPee
 			continue
 		}
 		if randomPeerHeights {
-			peerHeights[i] = int64(cmn.MaxInt(rand.RandIntn(int(numBlocks)), int(startingHeight)+1))
+			peerHeights[i] = int64(tmmath.MaxInt(rand.RandIntn(int(numBlocks)), int(startingHeight)+1))
 		} else {
 			peerHeights[i] = numBlocks
 		}
diff --git a/cmd/priv_val_server/main.go b/cmd/priv_val_server/main.go
index 22af6418f..813ce6b14 100644
--- a/cmd/priv_val_server/main.go
+++ b/cmd/priv_val_server/main.go
@@ -6,8 +6,9 @@ import (
 	"time"
 
 	"github.com/tendermint/tendermint/crypto/ed25519"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmnet "github.com/tendermint/tendermint/libs/net"
+	tmos "github.com/tendermint/tendermint/libs/os"
 
 	"github.com/tendermint/tendermint/privval"
 )
@@ -36,7 +37,7 @@ func main() {
 	pv := privval.LoadFilePV(*privValKeyPath, *privValStatePath)
 
 	var dialer privval.SocketDialer
-	protocol, address := cmn.ProtocolAndAddress(*addr)
+	protocol, address := tmnet.ProtocolAndAddress(*addr)
 	switch protocol {
 	case "unix":
 		dialer = privval.DialUnixFn(address)
@@ -57,7 +58,7 @@ func main() {
 	}
 
 	// Stop upon receiving SIGTERM or CTRL-C.
-	cmn.TrapSignal(logger, func() {
+	tmos.TrapSignal(logger, func() {
 		err := ss.Stop()
 		if err != nil {
 			panic(err)
diff --git a/cmd/tendermint/commands/gen_node_key.go b/cmd/tendermint/commands/gen_node_key.go
index 38dc5c66d..e9f1f8103 100644
--- a/cmd/tendermint/commands/gen_node_key.go
+++ b/cmd/tendermint/commands/gen_node_key.go
@@ -5,7 +5,7 @@ import (
 
 	"github.com/spf13/cobra"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/p2p"
 )
 
@@ -19,7 +19,7 @@ var GenNodeKeyCmd = &cobra.Command{
 
 func genNodeKey(cmd *cobra.Command, args []string) error {
 	nodeKeyFile := config.NodeKeyFile()
-	if cmn.FileExists(nodeKeyFile) {
+	if tmos.FileExists(nodeKeyFile) {
 		return fmt.Errorf("node key at %s already exists", nodeKeyFile)
 	}
 
diff --git a/cmd/tendermint/commands/init.go b/cmd/tendermint/commands/init.go
index 3d93ca3d1..c6903c388 100644
--- a/cmd/tendermint/commands/init.go
+++ b/cmd/tendermint/commands/init.go
@@ -5,7 +5,7 @@ import (
 
 	"github.com/spf13/cobra"
 	cfg "github.com/tendermint/tendermint/config"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/privval"
@@ -29,7 +29,7 @@ func initFilesWithConfig(config *cfg.Config) error {
 	privValKeyFile := config.PrivValidatorKeyFile()
 	privValStateFile := config.PrivValidatorStateFile()
 	var pv *privval.FilePV
-	if cmn.FileExists(privValKeyFile) {
+	if tmos.FileExists(privValKeyFile) {
 		pv = privval.LoadFilePV(privValKeyFile, privValStateFile)
 		logger.Info("Found private validator", "keyFile", privValKeyFile,
 			"stateFile", privValStateFile)
@@ -41,7 +41,7 @@ func initFilesWithConfig(config *cfg.Config) error {
 	}
 
 	nodeKeyFile := config.NodeKeyFile()
-	if cmn.FileExists(nodeKeyFile) {
+	if tmos.FileExists(nodeKeyFile) {
 		logger.Info("Found node key", "path", nodeKeyFile)
 	} else {
 		if _, err := p2p.LoadOrGenNodeKey(nodeKeyFile); err != nil {
@@ -52,7 +52,7 @@ func initFilesWithConfig(config *cfg.Config) error {
 
 	// genesis file
 	genFile := config.GenesisFile()
-	if cmn.FileExists(genFile) {
+	if tmos.FileExists(genFile) {
 		logger.Info("Found genesis file", "path", genFile)
 	} else {
 		genDoc := types.GenesisDoc{
diff --git a/cmd/tendermint/commands/lite.go b/cmd/tendermint/commands/lite.go
index 1cc82ab2e..a63daf20f 100644
--- a/cmd/tendermint/commands/lite.go
+++ b/cmd/tendermint/commands/lite.go
@@ -7,7 +7,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/lite/proxy"
 	rpcclient "github.com/tendermint/tendermint/rpc/client"
 )
@@ -65,7 +65,7 @@ func EnsureAddrHasSchemeOrDefaultToTCP(addr string) (string, error) {
 
 func runProxy(cmd *cobra.Command, args []string) error {
 	// Stop upon receiving SIGTERM or CTRL-C.
-	cmn.TrapSignal(logger, func() {
+	tmos.TrapSignal(logger, func() {
 		// TODO: close up shop
 	})
 
diff --git a/cmd/tendermint/commands/reset_priv_validator.go b/cmd/tendermint/commands/reset_priv_validator.go
index 4e8bde8b4..eef837c60 100644
--- a/cmd/tendermint/commands/reset_priv_validator.go
+++ b/cmd/tendermint/commands/reset_priv_validator.go
@@ -5,8 +5,8 @@ import (
 
 	"github.com/spf13/cobra"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/privval"
 )
 
@@ -58,7 +58,7 @@ func ResetAll(dbDir, addrBookFile, privValKeyFile, privValStateFile string, logg
 		logger.Error("Error removing all blockchain history", "dir", dbDir, "err", err)
 	}
 	// recreate the dbDir since the privVal state needs to live there
-	cmn.EnsureDir(dbDir, 0700)
+	tmos.EnsureDir(dbDir, 0700)
 	resetFilePV(privValKeyFile, privValStateFile, logger)
 }
 
diff --git a/cmd/tendermint/commands/root_test.go b/cmd/tendermint/commands/root_test.go
index 229385af9..a39f92d38 100644
--- a/cmd/tendermint/commands/root_test.go
+++ b/cmd/tendermint/commands/root_test.go
@@ -15,7 +15,7 @@ import (
 
 	cfg "github.com/tendermint/tendermint/config"
 	"github.com/tendermint/tendermint/libs/cli"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 )
 
 var (
@@ -140,7 +140,7 @@ func TestRootConfig(t *testing.T) {
 
 		// XXX: path must match cfg.defaultConfigPath
 		configFilePath := filepath.Join(defaultRoot, "config")
-		err := cmn.EnsureDir(configFilePath, 0700)
+		err := tmos.EnsureDir(configFilePath, 0700)
 		require.Nil(t, err)
 
 		// write the non-defaults to a different path
diff --git a/cmd/tendermint/commands/run_node.go b/cmd/tendermint/commands/run_node.go
index 577706461..6d9f575d0 100644
--- a/cmd/tendermint/commands/run_node.go
+++ b/cmd/tendermint/commands/run_node.go
@@ -11,7 +11,7 @@ import (
 	"github.com/spf13/cobra"
 
 	cfg "github.com/tendermint/tendermint/config"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	nm "github.com/tendermint/tendermint/node"
 )
 
@@ -105,7 +105,7 @@ func NewRunNodeCmd(nodeProvider nm.Provider) *cobra.Command {
 			}
 
 			// Stop upon receiving SIGTERM or CTRL-C.
-			cmn.TrapSignal(logger, func() {
+			tmos.TrapSignal(logger, func() {
 				if n.IsRunning() {
 					n.Stop()
 				}
diff --git a/cmd/tendermint/commands/show_validator.go b/cmd/tendermint/commands/show_validator.go
index d76d21970..b0c673373 100644
--- a/cmd/tendermint/commands/show_validator.go
+++ b/cmd/tendermint/commands/show_validator.go
@@ -6,7 +6,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/privval"
 )
 
@@ -19,7 +19,7 @@ var ShowValidatorCmd = &cobra.Command{
 
 func showValidator(cmd *cobra.Command, args []string) error {
 	keyFilePath := config.PrivValidatorKeyFile()
-	if !cmn.FileExists(keyFilePath) {
+	if !tmos.FileExists(keyFilePath) {
 		return fmt.Errorf("private validator file %s does not exist", keyFilePath)
 	}
 
diff --git a/config/toml.go b/config/toml.go
index c561ecc69..609f1487a 100644
--- a/config/toml.go
+++ b/config/toml.go
@@ -7,7 +7,7 @@ import (
 	"path/filepath"
 	"text/template"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 )
 
 // DefaultDirPerm is the default permissions used when creating directories.
@@ -27,20 +27,20 @@ func init() {
 // EnsureRoot creates the root, config, and data directories if they don't exist,
 // and panics if it fails.
 func EnsureRoot(rootDir string) {
-	if err := cmn.EnsureDir(rootDir, DefaultDirPerm); err != nil {
+	if err := tmos.EnsureDir(rootDir, DefaultDirPerm); err != nil {
 		panic(err.Error())
 	}
-	if err := cmn.EnsureDir(filepath.Join(rootDir, defaultConfigDir), DefaultDirPerm); err != nil {
+	if err := tmos.EnsureDir(filepath.Join(rootDir, defaultConfigDir), DefaultDirPerm); err != nil {
 		panic(err.Error())
 	}
-	if err := cmn.EnsureDir(filepath.Join(rootDir, defaultDataDir), DefaultDirPerm); err != nil {
+	if err := tmos.EnsureDir(filepath.Join(rootDir, defaultDataDir), DefaultDirPerm); err != nil {
 		panic(err.Error())
 	}
 
 	configFilePath := filepath.Join(rootDir, defaultConfigFilePath)
 
 	// Write default config file if missing.
-	if !cmn.FileExists(configFilePath) {
+	if !tmos.FileExists(configFilePath) {
 		writeDefaultConfigFile(configFilePath)
 	}
 }
@@ -59,7 +59,7 @@ func WriteConfigFile(configFilePath string, config *Config) {
 		panic(err)
 	}
 
-	cmn.MustWriteFile(configFilePath, buffer.Bytes(), 0644)
+	tmos.MustWriteFile(configFilePath, buffer.Bytes(), 0644)
 }
 
 // Note: any changes to the comments/variables/mapstructure
@@ -413,10 +413,10 @@ func ResetTestRootWithChainID(testName string, chainID string) *Config {
 		panic(err)
 	}
 	// ensure config and data subdirs are created
-	if err := cmn.EnsureDir(filepath.Join(rootDir, defaultConfigDir), DefaultDirPerm); err != nil {
+	if err := tmos.EnsureDir(filepath.Join(rootDir, defaultConfigDir), DefaultDirPerm); err != nil {
 		panic(err)
 	}
-	if err := cmn.EnsureDir(filepath.Join(rootDir, defaultDataDir), DefaultDirPerm); err != nil {
+	if err := tmos.EnsureDir(filepath.Join(rootDir, defaultDataDir), DefaultDirPerm); err != nil {
 		panic(err)
 	}
 
@@ -427,19 +427,19 @@ func ResetTestRootWithChainID(testName string, chainID string) *Config {
 	privStateFilePath := filepath.Join(rootDir, baseConfig.PrivValidatorState)
 
 	// Write default config file if missing.
-	if !cmn.FileExists(configFilePath) {
+	if !tmos.FileExists(configFilePath) {
 		writeDefaultConfigFile(configFilePath)
 	}
-	if !cmn.FileExists(genesisFilePath) {
+	if !tmos.FileExists(genesisFilePath) {
 		if chainID == "" {
 			chainID = "tendermint_test"
 		}
 		testGenesis := fmt.Sprintf(testGenesisFmt, chainID)
-		cmn.MustWriteFile(genesisFilePath, []byte(testGenesis), 0644)
+		tmos.MustWriteFile(genesisFilePath, []byte(testGenesis), 0644)
 	}
 	// we always overwrite the priv val
-	cmn.MustWriteFile(privKeyFilePath, []byte(testPrivValidatorKey), 0644)
-	cmn.MustWriteFile(privStateFilePath, []byte(testPrivValidatorState), 0644)
+	tmos.MustWriteFile(privKeyFilePath, []byte(testPrivValidatorKey), 0644)
+	tmos.MustWriteFile(privStateFilePath, []byte(testPrivValidatorState), 0644)
 
 	config := TestConfig().SetRoot(rootDir)
 	return config
diff --git a/consensus/common_test.go b/consensus/common_test.go
index 9f5cac40b..c6cd18193 100644
--- a/consensus/common_test.go
+++ b/consensus/common_test.go
@@ -23,8 +23,8 @@ import (
 	cfg "github.com/tendermint/tendermint/config"
 	cstypes "github.com/tendermint/tendermint/consensus/types"
 	tmbytes "github.com/tendermint/tendermint/libs/bytes"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	tmpubsub "github.com/tendermint/tendermint/libs/pubsub"
 	mempl "github.com/tendermint/tendermint/mempool"
 	"github.com/tendermint/tendermint/p2p"
@@ -50,7 +50,7 @@ var consensusReplayConfig *cfg.Config
 var ensureTimeout = time.Millisecond * 100
 
 func ensureDir(dir string, mode os.FileMode) {
-	if err := cmn.EnsureDir(dir, mode); err != nil {
+	if err := tmos.EnsureDir(dir, mode); err != nil {
 		panic(err)
 	}
 }
diff --git a/consensus/reactor.go b/consensus/reactor.go
index 8af2abaff..40868ff9d 100644
--- a/consensus/reactor.go
+++ b/consensus/reactor.go
@@ -10,7 +10,7 @@ import (
 
 	amino "github.com/tendermint/go-amino"
 	cstypes "github.com/tendermint/tendermint/consensus/types"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	"github.com/tendermint/tendermint/libs/bits"
 	tmevents "github.com/tendermint/tendermint/libs/events"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/p2p"
@@ -262,7 +262,7 @@ func (conR *Reactor) Receive(chID byte, src p2p.Peer, msgBytes []byte) {
 			}
 			// Respond with a VoteSetBitsMessage showing which votes we have.
 			// (and consequently shows which we don't have)
-			var ourVotes *cmn.BitArray
+			var ourVotes *bits.BitArray
 			switch msg.Type {
 			case types.PrevoteType:
 				ourVotes = votes.Prevotes(msg.Round).BitArrayByBlockID(msg.BlockID)
@@ -336,7 +336,7 @@ func (conR *Reactor) Receive(chID byte, src p2p.Peer, msgBytes []byte) {
 			cs.mtx.Unlock()
 
 			if height == msg.Height {
-				var ourVotes *cmn.BitArray
+				var ourVotes *bits.BitArray
 				switch msg.Type {
 				case types.PrevoteType:
 					ourVotes = votes.Prevotes(msg.Round).BitArrayByBlockID(msg.BlockID)
@@ -998,7 +998,7 @@ func (ps *PeerState) SetHasProposal(proposal *types.Proposal) {
 	}
 
 	ps.PRS.ProposalBlockPartsHeader = proposal.BlockID.PartsHeader
-	ps.PRS.ProposalBlockParts = cmn.NewBitArray(proposal.BlockID.PartsHeader.Total)
+	ps.PRS.ProposalBlockParts = bits.NewBitArray(proposal.BlockID.PartsHeader.Total)
 	ps.PRS.ProposalPOLRound = proposal.POLRound
 	ps.PRS.ProposalPOL = nil // Nil until ProposalPOLMessage received.
 }
@@ -1013,7 +1013,7 @@ func (ps *PeerState) InitProposalBlockParts(partsHeader types.PartSetHeader) {
 	}
 
 	ps.PRS.ProposalBlockPartsHeader = partsHeader
-	ps.PRS.ProposalBlockParts = cmn.NewBitArray(partsHeader.Total)
+	ps.PRS.ProposalBlockParts = bits.NewBitArray(partsHeader.Total)
 }
 
 // SetHasProposalBlockPart sets the given block part index as known for the peer.
@@ -1072,7 +1072,7 @@ func (ps *PeerState) PickVoteToSend(votes types.VoteSetReader) (vote *types.Vote
 	return nil, false
 }
 
-func (ps *PeerState) getVoteBitArray(height int64, round int, votesType types.SignedMsgType) *cmn.BitArray {
+func (ps *PeerState) getVoteBitArray(height int64, round int, votesType types.SignedMsgType) *bits.BitArray {
 	if !types.IsVoteTypeValid(votesType) {
 		return nil
 	}
@@ -1143,7 +1143,7 @@ func (ps *PeerState) ensureCatchupCommitRound(height int64, round int, numValida
 	if round == ps.PRS.Round {
 		ps.PRS.CatchupCommit = ps.PRS.Precommits
 	} else {
-		ps.PRS.CatchupCommit = cmn.NewBitArray(numValidators)
+		ps.PRS.CatchupCommit = bits.NewBitArray(numValidators)
 	}
 }
 
@@ -1160,20 +1160,20 @@ func (ps *PeerState) EnsureVoteBitArrays(height int64, numValidators int) {
 func (ps *PeerState) ensureVoteBitArrays(height int64, numValidators int) {
 	if ps.PRS.Height == height {
 		if ps.PRS.Prevotes == nil {
-			ps.PRS.Prevotes = cmn.NewBitArray(numValidators)
+			ps.PRS.Prevotes = bits.NewBitArray(numValidators)
 		}
 		if ps.PRS.Precommits == nil {
-			ps.PRS.Precommits = cmn.NewBitArray(numValidators)
+			ps.PRS.Precommits = bits.NewBitArray(numValidators)
 		}
 		if ps.PRS.CatchupCommit == nil {
-			ps.PRS.CatchupCommit = cmn.NewBitArray(numValidators)
+			ps.PRS.CatchupCommit = bits.NewBitArray(numValidators)
 		}
 		if ps.PRS.ProposalPOL == nil {
-			ps.PRS.ProposalPOL = cmn.NewBitArray(numValidators)
+			ps.PRS.ProposalPOL = bits.NewBitArray(numValidators)
 		}
 	} else if ps.PRS.Height == height+1 {
 		if ps.PRS.LastCommit == nil {
-			ps.PRS.LastCommit = cmn.NewBitArray(numValidators)
+			ps.PRS.LastCommit = bits.NewBitArray(numValidators)
 		}
 	}
 }
@@ -1343,7 +1343,7 @@ func (ps *PeerState) ApplyHasVoteMessage(msg *HasVoteMessage) {
 // `ourVotes` is a BitArray of votes we have for msg.BlockID
 // NOTE: if ourVotes is nil (e.g. msg.Height < rs.Height),
 // we conservatively overwrite ps's votes w/ msg.Votes.
-func (ps *PeerState) ApplyVoteSetBitsMessage(msg *VoteSetBitsMessage, ourVotes *cmn.BitArray) {
+func (ps *PeerState) ApplyVoteSetBitsMessage(msg *VoteSetBitsMessage, ourVotes *bits.BitArray) {
 	ps.mtx.Lock()
 	defer ps.mtx.Unlock()
 
@@ -1456,7 +1456,7 @@ type NewValidBlockMessage struct {
 	Height           int64
 	Round            int
 	BlockPartsHeader types.PartSetHeader
-	BlockParts       *cmn.BitArray
+	BlockParts       *bits.BitArray
 	IsCommit         bool
 }
 
@@ -1514,7 +1514,7 @@ func (m *ProposalMessage) String() string {
 type ProposalPOLMessage struct {
 	Height           int64
 	ProposalPOLRound int
-	ProposalPOL      *cmn.BitArray
+	ProposalPOL      *bits.BitArray
 }
 
 // ValidateBasic performs basic validation.
@@ -1656,7 +1656,7 @@ type VoteSetBitsMessage struct {
 	Round   int
 	Type    types.SignedMsgType
 	BlockID types.BlockID
-	Votes   *cmn.BitArray
+	Votes   *bits.BitArray
 }
 
 // ValidateBasic performs basic validation.
diff --git a/consensus/reactor_test.go b/consensus/reactor_test.go
index c0e05ee5f..fb4927754 100644
--- a/consensus/reactor_test.go
+++ b/consensus/reactor_test.go
@@ -20,8 +20,8 @@ import (
 	cfg "github.com/tendermint/tendermint/config"
 	cstypes "github.com/tendermint/tendermint/consensus/types"
 	"github.com/tendermint/tendermint/crypto/tmhash"
+	"github.com/tendermint/tendermint/libs/bits"
 	"github.com/tendermint/tendermint/libs/bytes"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
 	mempl "github.com/tendermint/tendermint/mempool"
 	"github.com/tendermint/tendermint/p2p"
@@ -712,11 +712,11 @@ func TestNewValidBlockMessageValidateBasic(t *testing.T) {
 			"blockParts bit array size 1 not equal to BlockPartsHeader.Total 2",
 		},
 		{
-			func(msg *NewValidBlockMessage) { msg.BlockPartsHeader.Total = 0; msg.BlockParts = cmn.NewBitArray(0) },
+			func(msg *NewValidBlockMessage) { msg.BlockPartsHeader.Total = 0; msg.BlockParts = bits.NewBitArray(0) },
 			"empty blockParts",
 		},
 		{
-			func(msg *NewValidBlockMessage) { msg.BlockParts = cmn.NewBitArray(types.MaxBlockPartsCount + 1) },
+			func(msg *NewValidBlockMessage) { msg.BlockParts = bits.NewBitArray(types.MaxBlockPartsCount + 1) },
 			"blockParts bit array size 1602 not equal to BlockPartsHeader.Total 1",
 		},
 	}
@@ -730,7 +730,7 @@ func TestNewValidBlockMessageValidateBasic(t *testing.T) {
 				BlockPartsHeader: types.PartSetHeader{
 					Total: 1,
 				},
-				BlockParts: cmn.NewBitArray(1),
+				BlockParts: bits.NewBitArray(1),
 			}
 
 			tc.malleateFn(msg)
@@ -750,8 +750,8 @@ func TestProposalPOLMessageValidateBasic(t *testing.T) {
 		{func(msg *ProposalPOLMessage) {}, ""},
 		{func(msg *ProposalPOLMessage) { msg.Height = -1 }, "negative Height"},
 		{func(msg *ProposalPOLMessage) { msg.ProposalPOLRound = -1 }, "negative ProposalPOLRound"},
-		{func(msg *ProposalPOLMessage) { msg.ProposalPOL = cmn.NewBitArray(0) }, "empty ProposalPOL bit array"},
-		{func(msg *ProposalPOLMessage) { msg.ProposalPOL = cmn.NewBitArray(types.MaxVotesCount + 1) },
+		{func(msg *ProposalPOLMessage) { msg.ProposalPOL = bits.NewBitArray(0) }, "empty ProposalPOL bit array"},
+		{func(msg *ProposalPOLMessage) { msg.ProposalPOL = bits.NewBitArray(types.MaxVotesCount + 1) },
 			"ProposalPOL bit array is too big: 10001, max: 10000"},
 	}
 
@@ -761,7 +761,7 @@ func TestProposalPOLMessageValidateBasic(t *testing.T) {
 			msg := &ProposalPOLMessage{
 				Height:           1,
 				ProposalPOLRound: 1,
-				ProposalPOL:      cmn.NewBitArray(1),
+				ProposalPOL:      bits.NewBitArray(1),
 			}
 
 			tc.malleateFn(msg)
@@ -906,7 +906,7 @@ func TestVoteSetBitsMessageValidateBasic(t *testing.T) {
 				},
 			}
 		}, "wrong BlockID: wrong PartsHeader: negative Total"},
-		{func(msg *VoteSetBitsMessage) { msg.Votes = cmn.NewBitArray(types.MaxVotesCount + 1) },
+		{func(msg *VoteSetBitsMessage) { msg.Votes = bits.NewBitArray(types.MaxVotesCount + 1) },
 			"votes bit array is too big: 10001, max: 10000"},
 	}
 
@@ -917,7 +917,7 @@ func TestVoteSetBitsMessageValidateBasic(t *testing.T) {
 				Height:  1,
 				Round:   0,
 				Type:    0x01,
-				Votes:   cmn.NewBitArray(1),
+				Votes:   bits.NewBitArray(1),
 				BlockID: types.BlockID{},
 			}
 
diff --git a/consensus/replay_file.go b/consensus/replay_file.go
index 9477f9c4c..b8b8c51da 100644
--- a/consensus/replay_file.go
+++ b/consensus/replay_file.go
@@ -13,8 +13,8 @@ import (
 	dbm "github.com/tendermint/tm-db"
 
 	cfg "github.com/tendermint/tendermint/config"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/mock"
 	"github.com/tendermint/tendermint/proxy"
 	sm "github.com/tendermint/tendermint/state"
@@ -35,7 +35,7 @@ func RunReplayFile(config cfg.BaseConfig, csConfig *cfg.ConsensusConfig, console
 	consensusState := newConsensusStateForReplay(config, csConfig)
 
 	if err := consensusState.ReplayFile(csConfig.WalFile(), console); err != nil {
-		cmn.Exit(fmt.Sprintf("Error during consensus replay: %v", err))
+		tmos.Exit(fmt.Sprintf("Error during consensus replay: %v", err))
 	}
 }
 
@@ -180,9 +180,9 @@ func (pb *playback) replayConsoleLoop() int {
 		bufReader := bufio.NewReader(os.Stdin)
 		line, more, err := bufReader.ReadLine()
 		if more {
-			cmn.Exit("input is too long")
+			tmos.Exit("input is too long")
 		} else if err != nil {
-			cmn.Exit(err.Error())
+			tmos.Exit(err.Error())
 		}
 
 		tokens := strings.Split(string(line), " ")
@@ -217,7 +217,7 @@ func (pb *playback) replayConsoleLoop() int {
 
 			newStepSub, err := pb.cs.eventBus.Subscribe(ctx, subscriber, types.EventQueryNewRoundStep)
 			if err != nil {
-				cmn.Exit(fmt.Sprintf("failed to subscribe %s to %v", subscriber, types.EventQueryNewRoundStep))
+				tmos.Exit(fmt.Sprintf("failed to subscribe %s to %v", subscriber, types.EventQueryNewRoundStep))
 			}
 			defer pb.cs.eventBus.Unsubscribe(ctx, subscriber, types.EventQueryNewRoundStep)
 
@@ -284,11 +284,11 @@ func newConsensusStateForReplay(config cfg.BaseConfig, csConfig *cfg.ConsensusCo
 	stateDB := dbm.NewDB("state", dbType, config.DBDir())
 	gdoc, err := sm.MakeGenesisDocFromFile(config.GenesisFile())
 	if err != nil {
-		cmn.Exit(err.Error())
+		tmos.Exit(err.Error())
 	}
 	state, err := sm.MakeGenesisState(gdoc)
 	if err != nil {
-		cmn.Exit(err.Error())
+		tmos.Exit(err.Error())
 	}
 
 	// Create proxyAppConn connection (consensus, mempool, query)
@@ -296,19 +296,19 @@ func newConsensusStateForReplay(config cfg.BaseConfig, csConfig *cfg.ConsensusCo
 	proxyApp := proxy.NewAppConns(clientCreator)
 	err = proxyApp.Start()
 	if err != nil {
-		cmn.Exit(fmt.Sprintf("Error starting proxy app conns: %v", err))
+		tmos.Exit(fmt.Sprintf("Error starting proxy app conns: %v", err))
 	}
 
 	eventBus := types.NewEventBus()
 	if err := eventBus.Start(); err != nil {
-		cmn.Exit(fmt.Sprintf("Failed to start event bus: %v", err))
+		tmos.Exit(fmt.Sprintf("Failed to start event bus: %v", err))
 	}
 
 	handshaker := NewHandshaker(stateDB, state, blockStore, gdoc)
 	handshaker.SetEventBus(eventBus)
 	err = handshaker.Handshake(proxyApp)
 	if err != nil {
-		cmn.Exit(fmt.Sprintf("Error on handshake: %v", err))
+		tmos.Exit(fmt.Sprintf("Error on handshake: %v", err))
 	}
 
 	mempool, evpool := mock.Mempool{}, sm.MockEvidencePool{}
diff --git a/consensus/state.go b/consensus/state.go
index f7395cba7..6cf9ab3da 100644
--- a/consensus/state.go
+++ b/consensus/state.go
@@ -10,9 +10,9 @@ import (
 
 	"github.com/pkg/errors"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/fail"
 	"github.com/tendermint/tendermint/libs/log"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/libs/service"
 	tmtime "github.com/tendermint/tendermint/types/time"
 
@@ -1434,7 +1434,7 @@ func (cs *State) finalizeCommit(height int64) {
 		block)
 	if err != nil {
 		cs.Logger.Error("Error on ApplyBlock. Did the application crash? Please restart tendermint", "err", err)
-		err := cmn.Kill()
+		err := tmos.Kill()
 		if err != nil {
 			cs.Logger.Error("Failed to kill this process - please do so manually", "err", err)
 		}
diff --git a/consensus/types/peer_round_state.go b/consensus/types/peer_round_state.go
index 41b5bd81b..937f597fe 100644
--- a/consensus/types/peer_round_state.go
+++ b/consensus/types/peer_round_state.go
@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"time"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	"github.com/tendermint/tendermint/libs/bits"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -23,21 +23,21 @@ type PeerRoundState struct {
 	// True if peer has proposal for this round
 	Proposal                 bool                `json:"proposal"`
 	ProposalBlockPartsHeader types.PartSetHeader `json:"proposal_block_parts_header"` //
-	ProposalBlockParts       *cmn.BitArray       `json:"proposal_block_parts"`        //
+	ProposalBlockParts       *bits.BitArray      `json:"proposal_block_parts"`        //
 	ProposalPOLRound         int                 `json:"proposal_pol_round"`          // Proposal's POL round. -1 if none.
 
 	// nil until ProposalPOLMessage received.
-	ProposalPOL     *cmn.BitArray `json:"proposal_pol"`
-	Prevotes        *cmn.BitArray `json:"prevotes"`          // All votes peer has for this round
-	Precommits      *cmn.BitArray `json:"precommits"`        // All precommits peer has for this round
-	LastCommitRound int           `json:"last_commit_round"` // Round of commit for last height. -1 if none.
-	LastCommit      *cmn.BitArray `json:"last_commit"`       // All commit precommits of commit for last height.
+	ProposalPOL     *bits.BitArray `json:"proposal_pol"`
+	Prevotes        *bits.BitArray `json:"prevotes"`          // All votes peer has for this round
+	Precommits      *bits.BitArray `json:"precommits"`        // All precommits peer has for this round
+	LastCommitRound int            `json:"last_commit_round"` // Round of commit for last height. -1 if none.
+	LastCommit      *bits.BitArray `json:"last_commit"`       // All commit precommits of commit for last height.
 
 	// Round that we have commit for. Not necessarily unique. -1 if none.
 	CatchupCommitRound int `json:"catchup_commit_round"`
 
 	// All commit precommits peer has for this height & CatchupCommitRound
-	CatchupCommit *cmn.BitArray `json:"catchup_commit"`
+	CatchupCommit *bits.BitArray `json:"catchup_commit"`
 }
 
 // String returns a string representation of the PeerRoundState
diff --git a/consensus/wal.go b/consensus/wal.go
index c00df13e7..64f04fee0 100644
--- a/consensus/wal.go
+++ b/consensus/wal.go
@@ -12,8 +12,8 @@ import (
 
 	amino "github.com/tendermint/go-amino"
 	auto "github.com/tendermint/tendermint/libs/autofile"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/libs/service"
 	"github.com/tendermint/tendermint/types"
 	tmtime "github.com/tendermint/tendermint/types/time"
@@ -94,7 +94,7 @@ var _ WAL = &baseWAL{}
 // NewWAL returns a new write-ahead logger based on `baseWAL`, which implements
 // WAL. It's flushed and synced to disk every 2s and once when stopped.
 func NewWAL(walFile string, groupOptions ...func(*auto.Group)) (*baseWAL, error) {
-	err := cmn.EnsureDir(filepath.Dir(walFile), 0700)
+	err := tmos.EnsureDir(filepath.Dir(walFile), 0700)
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to ensure WAL directory is in place")
 	}
diff --git a/docs/app-dev/abci-cli.md b/docs/app-dev/abci-cli.md
index 20f1b70c2..a72dc220f 100644
--- a/docs/app-dev/abci-cli.md
+++ b/docs/app-dev/abci-cli.md
@@ -93,7 +93,7 @@ func cmdKVStore(cmd *cobra.Command, args []string) error {
     }
 
     // Stop upon receiving SIGTERM or CTRL-C.
-    cmn.TrapSignal(logger, func() {
+    tmos.TrapSignal(logger, func() {
         // Cleanup
         srv.Stop()
     })
@@ -244,7 +244,7 @@ func cmdCounter(cmd *cobra.Command, args []string) error {
     }
 
     // Stop upon receiving SIGTERM or CTRL-C.
-    cmn.TrapSignal(logger, func() {
+    tmos.TrapSignal(logger, func() {
         // Cleanup
         srv.Stop()
     })
diff --git a/libs/common/async.go b/libs/async/async.go
similarity index 99%
rename from libs/common/async.go
rename to libs/async/async.go
index 7f9c4e872..e2487661a 100644
--- a/libs/common/async.go
+++ b/libs/async/async.go
@@ -1,4 +1,4 @@
-package common
+package async
 
 import (
 	"sync/atomic"
diff --git a/libs/common/async_test.go b/libs/async/async_test.go
similarity index 99%
rename from libs/common/async_test.go
rename to libs/async/async_test.go
index 276fe886e..ed85827b8 100644
--- a/libs/common/async_test.go
+++ b/libs/async/async_test.go
@@ -1,4 +1,4 @@
-package common
+package async
 
 import (
 	"fmt"
diff --git a/libs/autofile/autofile_test.go b/libs/autofile/autofile_test.go
index 921a317e9..664264cdc 100644
--- a/libs/autofile/autofile_test.go
+++ b/libs/autofile/autofile_test.go
@@ -9,7 +9,7 @@ import (
 
 	"github.com/stretchr/testify/require"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 )
 
 func TestSIGHUP(t *testing.T) {
@@ -49,10 +49,10 @@ func TestSIGHUP(t *testing.T) {
 	require.NoError(t, err)
 
 	// Both files should exist
-	if body := cmn.MustReadFile(name + "_old"); string(body) != "Line 1\nLine 2\n" {
+	if body := tmos.MustReadFile(name + "_old"); string(body) != "Line 1\nLine 2\n" {
 		t.Errorf("unexpected body %s", body)
 	}
-	if body := cmn.MustReadFile(name); string(body) != "Line 3\nLine 4\n" {
+	if body := tmos.MustReadFile(name); string(body) != "Line 3\nLine 4\n" {
 		t.Errorf("unexpected body %s", body)
 	}
 }
diff --git a/libs/autofile/cmd/logjack.go b/libs/autofile/cmd/logjack.go
index 20002eff3..ca970ffa2 100644
--- a/libs/autofile/cmd/logjack.go
+++ b/libs/autofile/cmd/logjack.go
@@ -9,7 +9,7 @@ import (
 	"strings"
 
 	auto "github.com/tendermint/tendermint/libs/autofile"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 )
 
 const Version = "0.0.1"
@@ -41,7 +41,7 @@ func (fmtLogger) Info(msg string, keyvals ...interface{}) {
 
 func main() {
 	// Stop upon receiving SIGTERM or CTRL-C.
-	cmn.TrapSignal(fmtLogger{}, func() {
+	tmos.TrapSignal(fmtLogger{}, func() {
 		fmt.Println("logjack shutting down")
 	})
 
diff --git a/libs/autofile/group_test.go b/libs/autofile/group_test.go
index 2029e56dc..381740be6 100644
--- a/libs/autofile/group_test.go
+++ b/libs/autofile/group_test.go
@@ -9,14 +9,14 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/libs/rand"
 )
 
 func createTestGroupWithHeadSizeLimit(t *testing.T, headSizeLimit int64) *Group {
 	testID := rand.RandStr(12)
 	testDir := "_test_" + testID
-	err := cmn.EnsureDir(testDir, 0700)
+	err := tmos.EnsureDir(testDir, 0700)
 	require.NoError(t, err, "Error creating dir")
 
 	headPath := testDir + "/myfile"
diff --git a/libs/common/bit_array.go b/libs/bits/bit_array.go
similarity index 97%
rename from libs/common/bit_array.go
rename to libs/bits/bit_array.go
index 08bc0ee85..0894802d3 100644
--- a/libs/common/bit_array.go
+++ b/libs/bits/bit_array.go
@@ -1,4 +1,4 @@
-package common
+package bits
 
 import (
 	"encoding/binary"
@@ -7,6 +7,7 @@ import (
 	"strings"
 	"sync"
 
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	"github.com/tendermint/tendermint/libs/rand"
 )
 
@@ -121,8 +122,8 @@ func (bA *BitArray) Or(o *BitArray) *BitArray {
 	}
 	bA.mtx.Lock()
 	o.mtx.Lock()
-	c := bA.copyBits(MaxInt(bA.Bits, o.Bits))
-	smaller := MinInt(len(bA.Elems), len(o.Elems))
+	c := bA.copyBits(tmmath.MaxInt(bA.Bits, o.Bits))
+	smaller := tmmath.MinInt(len(bA.Elems), len(o.Elems))
 	for i := 0; i < smaller; i++ {
 		c.Elems[i] |= o.Elems[i]
 	}
@@ -148,7 +149,7 @@ func (bA *BitArray) And(o *BitArray) *BitArray {
 }
 
 func (bA *BitArray) and(o *BitArray) *BitArray {
-	c := bA.copyBits(MinInt(bA.Bits, o.Bits))
+	c := bA.copyBits(tmmath.MinInt(bA.Bits, o.Bits))
 	for i := 0; i < len(c.Elems); i++ {
 		c.Elems[i] &= o.Elems[i]
 	}
@@ -190,7 +191,7 @@ func (bA *BitArray) Sub(o *BitArray) *BitArray {
 	// If o is longer, those bits are ignored.
 	// If bA is longer, then skipping those iterations is equivalent
 	// to right padding with 0's
-	smaller := MinInt(len(bA.Elems), len(o.Elems))
+	smaller := tmmath.MinInt(len(bA.Elems), len(o.Elems))
 	for i := 0; i < smaller; i++ {
 		// &^ is and not in golang
 		c.Elems[i] &^= o.Elems[i]
diff --git a/libs/common/bit_array_test.go b/libs/bits/bit_array_test.go
similarity index 99%
rename from libs/common/bit_array_test.go
rename to libs/bits/bit_array_test.go
index ee88bb6ca..3f26efd0c 100644
--- a/libs/common/bit_array_test.go
+++ b/libs/bits/bit_array_test.go
@@ -1,4 +1,4 @@
-package common
+package bits
 
 import (
 	"bytes"
diff --git a/libs/common/cmap.go b/libs/cmap/cmap.go
similarity index 98%
rename from libs/common/cmap.go
rename to libs/cmap/cmap.go
index d87adb762..da2275d7d 100644
--- a/libs/common/cmap.go
+++ b/libs/cmap/cmap.go
@@ -1,4 +1,4 @@
-package common
+package cmap
 
 import "sync"
 
diff --git a/libs/common/cmap_test.go b/libs/cmap/cmap_test.go
similarity index 98%
rename from libs/common/cmap_test.go
rename to libs/cmap/cmap_test.go
index 373057cb9..b6ea0117d 100644
--- a/libs/common/cmap_test.go
+++ b/libs/cmap/cmap_test.go
@@ -1,4 +1,4 @@
-package common
+package cmap
 
 import (
 	"fmt"
diff --git a/libs/common/LICENSE b/libs/common/LICENSE
deleted file mode 100644
index 8a142a71b..000000000
--- a/libs/common/LICENSE
+++ /dev/null
@@ -1,193 +0,0 @@
-Tendermint Go-Common
-Copyright (C) 2015 Tendermint
-
-
-
-                                 Apache License
-                           Version 2.0, January 2004
-                        https://www.apache.org/licenses/
-
-   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-
-   1. Definitions.
-
-      "License" shall mean the terms and conditions for use, reproduction,
-      and distribution as defined by Sections 1 through 9 of this document.
-
-      "Licensor" shall mean the copyright owner or entity authorized by
-      the copyright owner that is granting the License.
-
-      "Legal Entity" shall mean the union of the acting entity and all
-      other entities that control, are controlled by, or are under common
-      control with that entity. For the purposes of this definition,
-      "control" means (i) the power, direct or indirect, to cause the
-      direction or management of such entity, whether by contract or
-      otherwise, or (ii) ownership of fifty percent (50%) or more of the
-      outstanding shares, or (iii) beneficial ownership of such entity.
-
-      "You" (or "Your") shall mean an individual or Legal Entity
-      exercising permissions granted by this License.
-
-      "Source" form shall mean the preferred form for making modifications,
-      including but not limited to software source code, documentation
-      source, and configuration files.
-
-      "Object" form shall mean any form resulting from mechanical
-      transformation or translation of a Source form, including but
-      not limited to compiled object code, generated documentation,
-      and conversions to other media types.
-
-      "Work" shall mean the work of authorship, whether in Source or
-      Object form, made available under the License, as indicated by a
-      copyright notice that is included in or attached to the work
-      (an example is provided in the Appendix below).
-
-      "Derivative Works" shall mean any work, whether in Source or Object
-      form, that is based on (or derived from) the Work and for which the
-      editorial revisions, annotations, elaborations, or other modifications
-      represent, as a whole, an original work of authorship. For the purposes
-      of this License, Derivative Works shall not include works that remain
-      separable from, or merely link (or bind by name) to the interfaces of,
-      the Work and Derivative Works thereof.
-
-      "Contribution" shall mean any work of authorship, including
-      the original version of the Work and any modifications or additions
-      to that Work or Derivative Works thereof, that is intentionally
-      submitted to Licensor for inclusion in the Work by the copyright owner
-      or by an individual or Legal Entity authorized to submit on behalf of
-      the copyright owner. For the purposes of this definition, "submitted"
-      means any form of electronic, verbal, or written communication sent
-      to the Licensor or its representatives, including but not limited to
-      communication on electronic mailing lists, source code control systems,
-      and issue tracking systems that are managed by, or on behalf of, the
-      Licensor for the purpose of discussing and improving the Work, but
-      excluding communication that is conspicuously marked or otherwise
-      designated in writing by the copyright owner as "Not a Contribution."
-
-      "Contributor" shall mean Licensor and any individual or Legal Entity
-      on behalf of whom a Contribution has been received by Licensor and
-      subsequently incorporated within the Work.
-
-   2. Grant of Copyright License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
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-      copyright license to reproduce, prepare Derivative Works of,
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-          wherever such third-party notices normally appear. The contents
-          of the NOTICE file are for informational purposes only and
-          do not modify the License. You may add Your own attribution
-          notices within Derivative Works that You distribute, alongside
-          or as an addendum to the NOTICE text from the Work, provided
-          that such additional attribution notices cannot be construed
-          as modifying the License.
-
-      You may add Your own copyright statement to Your modifications and
-      may provide additional or different license terms and conditions
-      for use, reproduction, or distribution of Your modifications, or
-      for any such Derivative Works as a whole, provided Your use,
-      reproduction, and distribution of the Work otherwise complies with
-      the conditions stated in this License.
-
-   5. Submission of Contributions. Unless You explicitly state otherwise,
-      any Contribution intentionally submitted for inclusion in the Work
-      by You to the Licensor shall be under the terms and conditions of
-      this License, without any additional terms or conditions.
-      Notwithstanding the above, nothing herein shall supersede or modify
-      the terms of any separate license agreement you may have executed
-      with Licensor regarding such Contributions.
-
-   6. Trademarks. This License does not grant permission to use the trade
-      names, trademarks, service marks, or product names of the Licensor,
-      except as required for reasonable and customary use in describing the
-      origin of the Work and reproducing the content of the NOTICE file.
-
-   7. Disclaimer of Warranty. Unless required by applicable law or
-      agreed to in writing, Licensor provides the Work (and each
-      Contributor provides its Contributions) on an "AS IS" BASIS,
-      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-      implied, including, without limitation, any warranties or conditions
-      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
-      PARTICULAR PURPOSE. You are solely responsible for determining the
-      appropriateness of using or redistributing the Work and assume any
-      risks associated with Your exercise of permissions under this License.
-
-   8. Limitation of Liability. In no event and under no legal theory,
-      whether in tort (including negligence), contract, or otherwise,
-      unless required by applicable law (such as deliberate and grossly
-      negligent acts) or agreed to in writing, shall any Contributor be
-      liable to You for damages, including any direct, indirect, special,
-      incidental, or consequential damages of any character arising as a
-      result of this License or out of the use or inability to use the
-      Work (including but not limited to damages for loss of goodwill,
-      work stoppage, computer failure or malfunction, or any and all
-      other commercial damages or losses), even if such Contributor
-      has been advised of the possibility of such damages.
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-   9. Accepting Warranty or Additional Liability. While redistributing
-      the Work or Derivative Works thereof, You may choose to offer,
-      and charge a fee for, acceptance of support, warranty, indemnity,
-      or other liability obligations and/or rights consistent with this
-      License. However, in accepting such obligations, You may act only
-      on Your own behalf and on Your sole responsibility, not on behalf
-      of any other Contributor, and only if You agree to indemnify,
-      defend, and hold each Contributor harmless for any liability
-      incurred by, or claims asserted against, such Contributor by reason
-      of your accepting any such warranty or additional liability.
-
-   END OF TERMS AND CONDITIONS
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       https://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
diff --git a/libs/common/fraction.go b/libs/math/fraction.go
similarity index 96%
rename from libs/common/fraction.go
rename to libs/math/fraction.go
index b5b46e791..dca8a8e79 100644
--- a/libs/common/fraction.go
+++ b/libs/math/fraction.go
@@ -1,4 +1,4 @@
-package common
+package math
 
 import "fmt"
 
diff --git a/libs/common/math.go b/libs/math/math.go
similarity index 96%
rename from libs/common/math.go
rename to libs/math/math.go
index ae91f2058..cf567a97a 100644
--- a/libs/common/math.go
+++ b/libs/math/math.go
@@ -1,4 +1,4 @@
-package common
+package math
 
 func MaxInt64(a, b int64) int64 {
 	if a > b {
diff --git a/libs/common/net.go b/libs/net/net.go
similarity index 98%
rename from libs/common/net.go
rename to libs/net/net.go
index c7fff4cc3..fa85256fa 100644
--- a/libs/common/net.go
+++ b/libs/net/net.go
@@ -1,4 +1,4 @@
-package common
+package net
 
 import (
 	"net"
diff --git a/libs/common/net_test.go b/libs/net/net_test.go
similarity index 97%
rename from libs/common/net_test.go
rename to libs/net/net_test.go
index 38d2ae82d..38cd58f6a 100644
--- a/libs/common/net_test.go
+++ b/libs/net/net_test.go
@@ -1,4 +1,4 @@
-package common
+package net
 
 import (
 	"testing"
diff --git a/libs/common/os.go b/libs/os/os.go
similarity index 99%
rename from libs/common/os.go
rename to libs/os/os.go
index 4b25653ae..b56726c94 100644
--- a/libs/common/os.go
+++ b/libs/os/os.go
@@ -1,4 +1,4 @@
-package common
+package os
 
 import (
 	"fmt"
diff --git a/libs/common/string.go b/libs/strings/string.go
similarity index 99%
rename from libs/common/string.go
rename to libs/strings/string.go
index 4f8a8f20d..466759233 100644
--- a/libs/common/string.go
+++ b/libs/strings/string.go
@@ -1,4 +1,4 @@
-package common
+package strings
 
 import (
 	"fmt"
diff --git a/libs/common/string_test.go b/libs/strings/string_test.go
similarity index 99%
rename from libs/common/string_test.go
rename to libs/strings/string_test.go
index 35b6fafc7..1ec7b0d56 100644
--- a/libs/common/string_test.go
+++ b/libs/strings/string_test.go
@@ -1,4 +1,4 @@
-package common
+package strings
 
 import (
 	"testing"
diff --git a/lite2/client.go b/lite2/client.go
index db1e494a1..64c5b9452 100644
--- a/lite2/client.go
+++ b/lite2/client.go
@@ -7,8 +7,8 @@ import (
 
 	"github.com/pkg/errors"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	"github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/lite2/provider"
 	"github.com/tendermint/tendermint/lite2/store"
@@ -70,7 +70,7 @@ func SequentialVerification() Option {
 // which must sign the new header in order for us to trust it. NOTE this only
 // applies to non-adjusted headers. For adjusted headers, sequential
 // verification is used.
-func SkippingVerification(trustLevel cmn.Fraction) Option {
+func SkippingVerification(trustLevel tmmath.Fraction) Option {
 	if err := ValidateTrustLevel(trustLevel); err != nil {
 		panic(err)
 	}
@@ -97,7 +97,7 @@ type Client struct {
 	chainID          string
 	trustingPeriod   time.Duration // see TrustOptions.Period
 	verificationMode mode
-	trustLevel       cmn.Fraction
+	trustLevel       tmmath.Fraction
 
 	// Primary provider of new headers.
 	primary provider.Provider
diff --git a/lite2/verifier.go b/lite2/verifier.go
index 1ab1ef144..3737dbbf6 100644
--- a/lite2/verifier.go
+++ b/lite2/verifier.go
@@ -6,14 +6,14 @@ import (
 
 	"github.com/pkg/errors"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	"github.com/tendermint/tendermint/types"
 )
 
 var (
 	// DefaultTrustLevel - new header can be trusted if at least one correct old
 	// validator signed it.
-	DefaultTrustLevel = cmn.Fraction{Numerator: 1, Denominator: 3}
+	DefaultTrustLevel = tmmath.Fraction{Numerator: 1, Denominator: 3}
 )
 
 func Verify(
@@ -24,7 +24,7 @@ func Verify(
 	h2Vals *types.ValidatorSet,
 	trustingPeriod time.Duration,
 	now time.Time,
-	trustLevel cmn.Fraction) error {
+	trustLevel tmmath.Fraction) error {
 
 	if err := ValidateTrustLevel(trustLevel); err != nil {
 		return err
@@ -106,7 +106,7 @@ func verifyNewHeaderAndVals(
 // ValidateTrustLevel checks that trustLevel is within the allowed range [1/3,
 // 1]. If not, it returns an error. 1/3 is the minimum amount of trust needed
 // which does not break the security model.
-func ValidateTrustLevel(lvl cmn.Fraction) error {
+func ValidateTrustLevel(lvl tmmath.Fraction) error {
 	if lvl.Numerator*3 < lvl.Denominator || // < 1/3
 		lvl.Numerator > lvl.Denominator || // > 1
 		lvl.Denominator == 0 {
diff --git a/lite2/verifier_test.go b/lite2/verifier_test.go
index 570253400..321e9bdc3 100644
--- a/lite2/verifier_test.go
+++ b/lite2/verifier_test.go
@@ -7,7 +7,7 @@ import (
 
 	"github.com/stretchr/testify/assert"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -249,23 +249,23 @@ func TestVerifyNonAdjustedHeaders(t *testing.T) {
 
 func TestValidateTrustLevel(t *testing.T) {
 	testCases := []struct {
-		lvl   cmn.Fraction
+		lvl   tmmath.Fraction
 		valid bool
 	}{
 		// valid
-		0: {cmn.Fraction{Numerator: 1, Denominator: 1}, true},
-		1: {cmn.Fraction{Numerator: 1, Denominator: 3}, true},
-		2: {cmn.Fraction{Numerator: 2, Denominator: 3}, true},
-		3: {cmn.Fraction{Numerator: 3, Denominator: 3}, true},
-		4: {cmn.Fraction{Numerator: 4, Denominator: 5}, true},
+		0: {tmmath.Fraction{Numerator: 1, Denominator: 1}, true},
+		1: {tmmath.Fraction{Numerator: 1, Denominator: 3}, true},
+		2: {tmmath.Fraction{Numerator: 2, Denominator: 3}, true},
+		3: {tmmath.Fraction{Numerator: 3, Denominator: 3}, true},
+		4: {tmmath.Fraction{Numerator: 4, Denominator: 5}, true},
 
 		// invalid
-		5:  {cmn.Fraction{Numerator: 6, Denominator: 5}, false},
-		6:  {cmn.Fraction{Numerator: -1, Denominator: 3}, false},
-		7:  {cmn.Fraction{Numerator: 0, Denominator: 1}, false},
-		8:  {cmn.Fraction{Numerator: -1, Denominator: -3}, false},
-		9:  {cmn.Fraction{Numerator: 0, Denominator: 0}, false},
-		10: {cmn.Fraction{Numerator: 1, Denominator: 0}, false},
+		5:  {tmmath.Fraction{Numerator: 6, Denominator: 5}, false},
+		6:  {tmmath.Fraction{Numerator: -1, Denominator: 3}, false},
+		7:  {tmmath.Fraction{Numerator: 0, Denominator: 1}, false},
+		8:  {tmmath.Fraction{Numerator: -1, Denominator: -3}, false},
+		9:  {tmmath.Fraction{Numerator: 0, Denominator: 0}, false},
+		10: {tmmath.Fraction{Numerator: 1, Denominator: 0}, false},
 	}
 
 	for _, tc := range testCases {
diff --git a/mempool/clist_mempool.go b/mempool/clist_mempool.go
index e2f6ba814..7732032a4 100644
--- a/mempool/clist_mempool.go
+++ b/mempool/clist_mempool.go
@@ -15,8 +15,9 @@ import (
 	cfg "github.com/tendermint/tendermint/config"
 	auto "github.com/tendermint/tendermint/libs/autofile"
 	"github.com/tendermint/tendermint/libs/clist"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmmath "github.com/tendermint/tendermint/libs/math"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/proxy"
 	"github.com/tendermint/tendermint/types"
@@ -135,7 +136,7 @@ func WithMetrics(metrics *Metrics) CListMempoolOption {
 // *not thread safe*
 func (mem *CListMempool) InitWAL() {
 	walDir := mem.config.WalDir()
-	err := cmn.EnsureDir(walDir, 0700)
+	err := tmos.EnsureDir(walDir, 0700)
 	if err != nil {
 		panic(errors.Wrap(err, "Error ensuring WAL dir"))
 	}
@@ -480,7 +481,7 @@ func (mem *CListMempool) ReapMaxBytesMaxGas(maxBytes, maxGas int64) types.Txs {
 	var totalGas int64
 	// TODO: we will get a performance boost if we have a good estimate of avg
 	// size per tx, and set the initial capacity based off of that.
-	// txs := make([]types.Tx, 0, cmn.MinInt(mem.txs.Len(), max/mem.avgTxSize))
+	// txs := make([]types.Tx, 0, tmmath.MinInt(mem.txs.Len(), max/mem.avgTxSize))
 	txs := make([]types.Tx, 0, mem.txs.Len())
 	for e := mem.txs.Front(); e != nil; e = e.Next() {
 		memTx := e.Value.(*mempoolTx)
@@ -517,7 +518,7 @@ func (mem *CListMempool) ReapMaxTxs(max int) types.Txs {
 		time.Sleep(time.Millisecond * 10)
 	}
 
-	txs := make([]types.Tx, 0, cmn.MinInt(mem.txs.Len(), max))
+	txs := make([]types.Tx, 0, tmmath.MinInt(mem.txs.Len(), max))
 	for e := mem.txs.Front(); e != nil && len(txs) <= max; e = e.Next() {
 		memTx := e.Value.(*mempoolTx)
 		txs = append(txs, memTx.tx)
diff --git a/p2p/conn/connection.go b/p2p/conn/connection.go
index f9c4ee1d6..1c2088636 100644
--- a/p2p/conn/connection.go
+++ b/p2p/conn/connection.go
@@ -16,9 +16,9 @@ import (
 	"github.com/pkg/errors"
 
 	amino "github.com/tendermint/go-amino"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	flow "github.com/tendermint/tendermint/libs/flowrate"
 	"github.com/tendermint/tendermint/libs/log"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	"github.com/tendermint/tendermint/libs/service"
 	"github.com/tendermint/tendermint/libs/timer"
 )
@@ -560,7 +560,7 @@ FOR_LOOP:
 		// Peek into bufConnReader for debugging
 		/*
 			if numBytes := c.bufConnReader.Buffered(); numBytes > 0 {
-				bz, err := c.bufConnReader.Peek(cmn.MinInt(numBytes, 100))
+				bz, err := c.bufConnReader.Peek(tmmath.MinInt(numBytes, 100))
 				if err == nil {
 					// return
 				} else {
@@ -818,14 +818,14 @@ func (ch *Channel) nextPacketMsg() PacketMsg {
 	packet := PacketMsg{}
 	packet.ChannelID = ch.desc.ID
 	maxSize := ch.maxPacketMsgPayloadSize
-	packet.Bytes = ch.sending[:cmn.MinInt(maxSize, len(ch.sending))]
+	packet.Bytes = ch.sending[:tmmath.MinInt(maxSize, len(ch.sending))]
 	if len(ch.sending) <= maxSize {
 		packet.EOF = byte(0x01)
 		ch.sending = nil
 		atomic.AddInt32(&ch.sendQueueSize, -1) // decrement sendQueueSize
 	} else {
 		packet.EOF = byte(0x00)
-		ch.sending = ch.sending[cmn.MinInt(maxSize, len(ch.sending)):]
+		ch.sending = ch.sending[tmmath.MinInt(maxSize, len(ch.sending)):]
 	}
 	return packet
 }
diff --git a/p2p/conn/secret_connection.go b/p2p/conn/secret_connection.go
index e26fd6943..d6b20186f 100644
--- a/p2p/conn/secret_connection.go
+++ b/p2p/conn/secret_connection.go
@@ -23,7 +23,7 @@ import (
 
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/ed25519"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	"github.com/tendermint/tendermint/libs/async"
 )
 
 // 4 + 1024 == 1028 total frame size
@@ -296,7 +296,7 @@ func genEphKeys() (ephPub, ephPriv *[32]byte) {
 func shareEphPubKey(conn io.ReadWriter, locEphPub *[32]byte) (remEphPub *[32]byte, err error) {
 
 	// Send our pubkey and receive theirs in tandem.
-	var trs, _ = cmn.Parallel(
+	var trs, _ = async.Parallel(
 		func(_ int) (val interface{}, abort bool, err error) {
 			var _, err1 = cdc.MarshalBinaryLengthPrefixedWriter(conn, locEphPub)
 			if err1 != nil {
@@ -401,7 +401,7 @@ type authSigMessage struct {
 func shareAuthSignature(sc io.ReadWriter, pubKey crypto.PubKey, signature []byte) (recvMsg authSigMessage, err error) {
 
 	// Send our info and receive theirs in tandem.
-	var trs, _ = cmn.Parallel(
+	var trs, _ = async.Parallel(
 		func(_ int) (val interface{}, abort bool, err error) {
 			var _, err1 = cdc.MarshalBinaryLengthPrefixedWriter(sc, authSigMessage{pubKey, signature})
 			if err1 != nil {
diff --git a/p2p/conn/secret_connection_test.go b/p2p/conn/secret_connection_test.go
index d6d85fd80..e4fa01af9 100644
--- a/p2p/conn/secret_connection_test.go
+++ b/p2p/conn/secret_connection_test.go
@@ -19,7 +19,8 @@ import (
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/ed25519"
 	"github.com/tendermint/tendermint/crypto/secp256k1"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	"github.com/tendermint/tendermint/libs/async"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/libs/rand"
 )
 
@@ -53,7 +54,7 @@ func makeSecretConnPair(tb testing.TB) (fooSecConn, barSecConn *SecretConnection
 	var barPubKey = barPrvKey.PubKey()
 
 	// Make connections from both sides in parallel.
-	var trs, ok = cmn.Parallel(
+	var trs, ok = async.Parallel(
 		func(_ int) (val interface{}, abort bool, err error) {
 			fooSecConn, err = MakeSecretConnection(fooConn, fooPrvKey)
 			if err != nil {
@@ -178,7 +179,7 @@ func TestSecretConnectionReadWrite(t *testing.T) {
 	}
 
 	// A helper that will run with (fooConn, fooWrites, fooReads) and vice versa
-	genNodeRunner := func(id string, nodeConn kvstoreConn, nodeWrites []string, nodeReads *[]string) cmn.Task {
+	genNodeRunner := func(id string, nodeConn kvstoreConn, nodeWrites []string, nodeReads *[]string) async.Task {
 		return func(_ int) (interface{}, bool, error) {
 			// Initiate cryptographic private key and secret connection trhough nodeConn.
 			nodePrvKey := ed25519.GenPrivKey()
@@ -188,7 +189,7 @@ func TestSecretConnectionReadWrite(t *testing.T) {
 				return nil, true, err
 			}
 			// In parallel, handle some reads and writes.
-			var trs, ok = cmn.Parallel(
+			var trs, ok = async.Parallel(
 				func(_ int) (interface{}, bool, error) {
 					// Node writes:
 					for _, nodeWrite := range nodeWrites {
@@ -241,7 +242,7 @@ func TestSecretConnectionReadWrite(t *testing.T) {
 	}
 
 	// Run foo & bar in parallel
-	var trs, ok = cmn.Parallel(
+	var trs, ok = async.Parallel(
 		genNodeRunner("foo", fooConn, fooWrites, &fooReads),
 		genNodeRunner("bar", barConn, barWrites, &barReads),
 	)
@@ -292,7 +293,7 @@ func TestDeriveSecretsAndChallengeGolden(t *testing.T) {
 	if *update {
 		t.Logf("Updating golden test vector file %s", goldenFilepath)
 		data := createGoldenTestVectors(t)
-		cmn.WriteFile(goldenFilepath, []byte(data), 0644)
+		tmos.WriteFile(goldenFilepath, []byte(data), 0644)
 	}
 	f, err := os.Open(goldenFilepath)
 	if err != nil {
diff --git a/p2p/key.go b/p2p/key.go
index 504cda75c..f4c9413ab 100644
--- a/p2p/key.go
+++ b/p2p/key.go
@@ -8,7 +8,7 @@ import (
 
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/ed25519"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 )
 
 // ID is a hex-encoded crypto.Address
@@ -47,7 +47,7 @@ func PubKeyToID(pubKey crypto.PubKey) ID {
 // LoadOrGenNodeKey attempts to load the NodeKey from the given filePath.
 // If the file does not exist, it generates and saves a new NodeKey.
 func LoadOrGenNodeKey(filePath string) (*NodeKey, error) {
-	if cmn.FileExists(filePath) {
+	if tmos.FileExists(filePath) {
 		nodeKey, err := LoadNodeKey(filePath)
 		if err != nil {
 			return nil, err
diff --git a/p2p/node_info.go b/p2p/node_info.go
index 5b72446fd..24d5e11e1 100644
--- a/p2p/node_info.go
+++ b/p2p/node_info.go
@@ -5,7 +5,7 @@ import (
 	"reflect"
 
 	"github.com/tendermint/tendermint/libs/bytes"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmstrings "github.com/tendermint/tendermint/libs/strings"
 	"github.com/tendermint/tendermint/version"
 )
 
@@ -130,7 +130,7 @@ func (info DefaultNodeInfo) Validate() error {
 
 	// Validate Version
 	if len(info.Version) > 0 &&
-		(!cmn.IsASCIIText(info.Version) || cmn.ASCIITrim(info.Version) == "") {
+		(!tmstrings.IsASCIIText(info.Version) || tmstrings.ASCIITrim(info.Version) == "") {
 
 		return fmt.Errorf("info.Version must be valid ASCII text without tabs, but got %v", info.Version)
 	}
@@ -149,7 +149,7 @@ func (info DefaultNodeInfo) Validate() error {
 	}
 
 	// Validate Moniker.
-	if !cmn.IsASCIIText(info.Moniker) || cmn.ASCIITrim(info.Moniker) == "" {
+	if !tmstrings.IsASCIIText(info.Moniker) || tmstrings.ASCIITrim(info.Moniker) == "" {
 		return fmt.Errorf("info.Moniker must be valid non-empty ASCII text without tabs, but got %v", info.Moniker)
 	}
 
@@ -163,7 +163,7 @@ func (info DefaultNodeInfo) Validate() error {
 	}
 	// XXX: Should we be more strict about address formats?
 	rpcAddr := other.RPCAddress
-	if len(rpcAddr) > 0 && (!cmn.IsASCIIText(rpcAddr) || cmn.ASCIITrim(rpcAddr) == "") {
+	if len(rpcAddr) > 0 && (!tmstrings.IsASCIIText(rpcAddr) || tmstrings.ASCIITrim(rpcAddr) == "") {
 		return fmt.Errorf("info.Other.RPCAddress=%v must be valid ASCII text without tabs", rpcAddr)
 	}
 
diff --git a/p2p/peer.go b/p2p/peer.go
index 1454b1cc1..7a6d6f868 100644
--- a/p2p/peer.go
+++ b/p2p/peer.go
@@ -5,7 +5,7 @@ import (
 	"net"
 	"time"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	"github.com/tendermint/tendermint/libs/cmap"
 	"github.com/tendermint/tendermint/libs/log"
 	"github.com/tendermint/tendermint/libs/service"
 
@@ -111,7 +111,7 @@ type peer struct {
 	channels []byte
 
 	// User data
-	Data *cmn.CMap
+	Data *cmap.CMap
 
 	metrics       *Metrics
 	metricsTicker *time.Ticker
@@ -132,7 +132,7 @@ func newPeer(
 		peerConn:      pc,
 		nodeInfo:      nodeInfo,
 		channels:      nodeInfo.(DefaultNodeInfo).Channels, // TODO
-		Data:          cmn.NewCMap(),
+		Data:          cmap.NewCMap(),
 		metricsTicker: time.NewTicker(metricsTickerDuration),
 		metrics:       NopMetrics(),
 	}
diff --git a/p2p/pex/addrbook.go b/p2p/pex/addrbook.go
index 94576084c..b9dde58c2 100644
--- a/p2p/pex/addrbook.go
+++ b/p2p/pex/addrbook.go
@@ -15,7 +15,7 @@ import (
 	"time"
 
 	"github.com/tendermint/tendermint/crypto"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	tmrand "github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/libs/service"
 	"github.com/tendermint/tendermint/p2p"
@@ -345,10 +345,10 @@ func (a *addrBook) GetSelection() []*p2p.NetAddress {
 		return nil
 	}
 
-	numAddresses := cmn.MaxInt(
-		cmn.MinInt(minGetSelection, bookSize),
+	numAddresses := tmmath.MaxInt(
+		tmmath.MinInt(minGetSelection, bookSize),
 		bookSize*getSelectionPercent/100)
-	numAddresses = cmn.MinInt(maxGetSelection, numAddresses)
+	numAddresses = tmmath.MinInt(maxGetSelection, numAddresses)
 
 	// XXX: instead of making a list of all addresses, shuffling, and slicing a random chunk,
 	// could we just select a random numAddresses of indexes?
@@ -402,14 +402,14 @@ func (a *addrBook) GetSelectionWithBias(biasTowardsNewAddrs int) []*p2p.NetAddre
 		biasTowardsNewAddrs = 0
 	}
 
-	numAddresses := cmn.MaxInt(
-		cmn.MinInt(minGetSelection, bookSize),
+	numAddresses := tmmath.MaxInt(
+		tmmath.MinInt(minGetSelection, bookSize),
 		bookSize*getSelectionPercent/100)
-	numAddresses = cmn.MinInt(maxGetSelection, numAddresses)
+	numAddresses = tmmath.MinInt(maxGetSelection, numAddresses)
 
 	// number of new addresses that, if possible, should be in the beginning of the selection
 	// if there are no enough old addrs, will choose new addr instead.
-	numRequiredNewAdd := cmn.MaxInt(percentageOfNum(biasTowardsNewAddrs, numAddresses), numAddresses-a.nOld)
+	numRequiredNewAdd := tmmath.MaxInt(percentageOfNum(biasTowardsNewAddrs, numAddresses), numAddresses-a.nOld)
 	selection := a.randomPickAddresses(bucketTypeNew, numRequiredNewAdd)
 	selection = append(selection, a.randomPickAddresses(bucketTypeOld, numAddresses-len(selection))...)
 	return selection
diff --git a/p2p/pex/addrbook_test.go b/p2p/pex/addrbook_test.go
index 8d424224f..de9d09182 100644
--- a/p2p/pex/addrbook_test.go
+++ b/p2p/pex/addrbook_test.go
@@ -11,8 +11,8 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	"github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/p2p"
 )
@@ -483,8 +483,8 @@ func testAddrBookAddressSelection(t *testing.T, bookSize int) {
 		// There is at least one partition and at most three.
 		var (
 			k      = percentageOfNum(biasToSelectNewPeers, nAddrs)
-			expNew = cmn.MinInt(nNew, cmn.MaxInt(k, nAddrs-nBookOld))
-			expOld = cmn.MinInt(nOld, nAddrs-expNew)
+			expNew = tmmath.MinInt(nNew, tmmath.MaxInt(k, nAddrs-nBookOld))
+			expOld = tmmath.MinInt(nOld, nAddrs-expNew)
 		)
 
 		// Verify that the number of old and new addresses are as expected
diff --git a/p2p/pex/pex_reactor.go b/p2p/pex/pex_reactor.go
index 77235741a..e86ad2a5e 100644
--- a/p2p/pex/pex_reactor.go
+++ b/p2p/pex/pex_reactor.go
@@ -9,7 +9,8 @@ import (
 	"github.com/pkg/errors"
 
 	amino "github.com/tendermint/go-amino"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	"github.com/tendermint/tendermint/libs/cmap"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	"github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/libs/service"
 	"github.com/tendermint/tendermint/p2p"
@@ -85,8 +86,8 @@ type Reactor struct {
 	ensurePeersPeriod time.Duration // TODO: should go in the config
 
 	// maps to prevent abuse
-	requestsSent         *cmn.CMap // ID->struct{}: unanswered send requests
-	lastReceivedRequests *cmn.CMap // ID->time.Time: last time peer requested from us
+	requestsSent         *cmap.CMap // ID->struct{}: unanswered send requests
+	lastReceivedRequests *cmap.CMap // ID->time.Time: last time peer requested from us
 
 	seedAddrs []*p2p.NetAddress
 
@@ -131,8 +132,8 @@ func NewReactor(b AddrBook, config *ReactorConfig) *Reactor {
 		book:                 b,
 		config:               config,
 		ensurePeersPeriod:    defaultEnsurePeersPeriod,
-		requestsSent:         cmn.NewCMap(),
-		lastReceivedRequests: cmn.NewCMap(),
+		requestsSent:         cmap.NewCMap(),
+		lastReceivedRequests: cmap.NewCMap(),
 		crawlPeerInfos:       make(map[p2p.ID]crawlPeerInfo),
 	}
 	r.BaseReactor = *p2p.NewBaseReactor("Reactor", r)
@@ -452,7 +453,7 @@ func (r *Reactor) ensurePeers() {
 	// bias to prefer more vetted peers when we have fewer connections.
 	// not perfect, but somewhate ensures that we prioritize connecting to more-vetted
 	// NOTE: range here is [10, 90]. Too high ?
-	newBias := cmn.MinInt(out, 8)*10 + 10
+	newBias := tmmath.MinInt(out, 8)*10 + 10
 
 	toDial := make(map[p2p.ID]*p2p.NetAddress)
 	// Try maxAttempts times to pick numToDial addresses to dial
diff --git a/p2p/switch.go b/p2p/switch.go
index 587de39aa..4c14006d0 100644
--- a/p2p/switch.go
+++ b/p2p/switch.go
@@ -9,7 +9,7 @@ import (
 	"github.com/pkg/errors"
 
 	"github.com/tendermint/tendermint/config"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	"github.com/tendermint/tendermint/libs/cmap"
 	"github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/libs/service"
 	"github.com/tendermint/tendermint/p2p/conn"
@@ -74,8 +74,8 @@ type Switch struct {
 	chDescs      []*conn.ChannelDescriptor
 	reactorsByCh map[byte]Reactor
 	peers        *PeerSet
-	dialing      *cmn.CMap
-	reconnecting *cmn.CMap
+	dialing      *cmap.CMap
+	reconnecting *cmap.CMap
 	nodeInfo     NodeInfo // our node info
 	nodeKey      *NodeKey // our node privkey
 	addrBook     AddrBook
@@ -114,8 +114,8 @@ func NewSwitch(
 		chDescs:              make([]*conn.ChannelDescriptor, 0),
 		reactorsByCh:         make(map[byte]Reactor),
 		peers:                NewPeerSet(),
-		dialing:              cmn.NewCMap(),
-		reconnecting:         cmn.NewCMap(),
+		dialing:              cmap.NewCMap(),
+		reconnecting:         cmap.NewCMap(),
 		metrics:              NopMetrics(),
 		transport:            transport,
 		filterTimeout:        defaultFilterTimeout,
diff --git a/p2p/test_util.go b/p2p/test_util.go
index 7ef50235c..89c8015a5 100644
--- a/p2p/test_util.go
+++ b/p2p/test_util.go
@@ -9,8 +9,8 @@ import (
 
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/ed25519"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 	"github.com/tendermint/tendermint/libs/rand"
 
 	"github.com/tendermint/tendermint/config"
@@ -276,7 +276,7 @@ func testNodeInfoWithNetwork(id ID, name, network string) NodeInfo {
 }
 
 func getFreePort() int {
-	port, err := cmn.GetFreePort()
+	port, err := tmnet.GetFreePort()
 	if err != nil {
 		panic(err)
 	}
diff --git a/privval/file.go b/privval/file.go
index d77ec269d..c31e95a6a 100644
--- a/privval/file.go
+++ b/privval/file.go
@@ -10,7 +10,7 @@ import (
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/ed25519"
 	tmbytes "github.com/tendermint/tendermint/libs/bytes"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/libs/tempfile"
 	"github.com/tendermint/tendermint/types"
 	tmtime "github.com/tendermint/tendermint/types/time"
@@ -183,12 +183,12 @@ func LoadFilePVEmptyState(keyFilePath, stateFilePath string) *FilePV {
 func loadFilePV(keyFilePath, stateFilePath string, loadState bool) *FilePV {
 	keyJSONBytes, err := ioutil.ReadFile(keyFilePath)
 	if err != nil {
-		cmn.Exit(err.Error())
+		tmos.Exit(err.Error())
 	}
 	pvKey := FilePVKey{}
 	err = cdc.UnmarshalJSON(keyJSONBytes, &pvKey)
 	if err != nil {
-		cmn.Exit(fmt.Sprintf("Error reading PrivValidator key from %v: %v\n", keyFilePath, err))
+		tmos.Exit(fmt.Sprintf("Error reading PrivValidator key from %v: %v\n", keyFilePath, err))
 	}
 
 	// overwrite pubkey and address for convenience
@@ -200,11 +200,11 @@ func loadFilePV(keyFilePath, stateFilePath string, loadState bool) *FilePV {
 	if loadState {
 		stateJSONBytes, err := ioutil.ReadFile(stateFilePath)
 		if err != nil {
-			cmn.Exit(err.Error())
+			tmos.Exit(err.Error())
 		}
 		err = cdc.UnmarshalJSON(stateJSONBytes, &pvState)
 		if err != nil {
-			cmn.Exit(fmt.Sprintf("Error reading PrivValidator state from %v: %v\n", stateFilePath, err))
+			tmos.Exit(fmt.Sprintf("Error reading PrivValidator state from %v: %v\n", stateFilePath, err))
 		}
 	}
 
@@ -220,7 +220,7 @@ func loadFilePV(keyFilePath, stateFilePath string, loadState bool) *FilePV {
 // or else generates a new one and saves it to the filePaths.
 func LoadOrGenFilePV(keyFilePath, stateFilePath string) *FilePV {
 	var pv *FilePV
-	if cmn.FileExists(keyFilePath) {
+	if tmos.FileExists(keyFilePath) {
 		pv = LoadFilePV(keyFilePath, stateFilePath)
 	} else {
 		pv = GenFilePV(keyFilePath, stateFilePath)
diff --git a/privval/signer_listener_endpoint_test.go b/privval/signer_listener_endpoint_test.go
index 25cfd0877..3c5f6d599 100644
--- a/privval/signer_listener_endpoint_test.go
+++ b/privval/signer_listener_endpoint_test.go
@@ -9,8 +9,8 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/tendermint/tendermint/crypto/ed25519"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 	"github.com/tendermint/tendermint/libs/rand"
 	"github.com/tendermint/tendermint/types"
 )
@@ -134,7 +134,7 @@ func TestRetryConnToRemoteSigner(t *testing.T) {
 ///////////////////////////////////
 
 func newSignerListenerEndpoint(logger log.Logger, addr string, timeoutReadWrite time.Duration) *SignerListenerEndpoint {
-	proto, address := cmn.ProtocolAndAddress(addr)
+	proto, address := tmnet.ProtocolAndAddress(addr)
 
 	ln, err := net.Listen(proto, address)
 	logger.Info("SignerListener: Listening", "proto", proto, "address", address)
diff --git a/privval/socket_dialers.go b/privval/socket_dialers.go
index fb1f9477b..1945e7728 100644
--- a/privval/socket_dialers.go
+++ b/privval/socket_dialers.go
@@ -6,7 +6,7 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/tendermint/tendermint/crypto"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 	p2pconn "github.com/tendermint/tendermint/p2p/conn"
 )
 
@@ -22,7 +22,7 @@ type SocketDialer func() (net.Conn, error)
 // privKey for the authenticated encryption handshake.
 func DialTCPFn(addr string, timeoutReadWrite time.Duration, privKey crypto.PrivKey) SocketDialer {
 	return func() (net.Conn, error) {
-		conn, err := cmn.Connect(addr)
+		conn, err := tmnet.Connect(addr)
 		if err == nil {
 			deadline := time.Now().Add(timeoutReadWrite)
 			err = conn.SetDeadline(deadline)
diff --git a/privval/utils.go b/privval/utils.go
index 65368eb28..64f4f8c2f 100644
--- a/privval/utils.go
+++ b/privval/utils.go
@@ -7,8 +7,8 @@ import (
 	"github.com/pkg/errors"
 
 	"github.com/tendermint/tendermint/crypto/ed25519"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 )
 
 // IsConnTimeout returns a boolean indicating whether the error is known to
@@ -29,7 +29,7 @@ func IsConnTimeout(err error) bool {
 func NewSignerListener(listenAddr string, logger log.Logger) (*SignerListenerEndpoint, error) {
 	var listener net.Listener
 
-	protocol, address := cmn.ProtocolAndAddress(listenAddr)
+	protocol, address := tmnet.ProtocolAndAddress(listenAddr)
 	ln, err := net.Listen(protocol, address)
 	if err != nil {
 		return nil, err
@@ -54,7 +54,7 @@ func NewSignerListener(listenAddr string, logger log.Logger) (*SignerListenerEnd
 
 // GetFreeLocalhostAddrPort returns a free localhost:port address
 func GetFreeLocalhostAddrPort() string {
-	port, err := cmn.GetFreePort()
+	port, err := tmnet.GetFreePort()
 	if err != nil {
 		panic(err)
 	}
diff --git a/rpc/client/rpc_test.go b/rpc/client/rpc_test.go
index e9b3a30c4..e0dba3f56 100644
--- a/rpc/client/rpc_test.go
+++ b/rpc/client/rpc_test.go
@@ -16,8 +16,8 @@ import (
 
 	"github.com/tendermint/tendermint/crypto/ed25519"
 	"github.com/tendermint/tendermint/crypto/tmhash"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	mempl "github.com/tendermint/tendermint/mempool"
 	"github.com/tendermint/tendermint/privval"
 	"github.com/tendermint/tendermint/rpc/client"
@@ -644,7 +644,7 @@ func testBatchedJSONRPCCalls(t *testing.T, c *client.HTTP) {
 	bresult2, ok := bresults[1].(*ctypes.ResultBroadcastTxCommit)
 	require.True(t, ok)
 	require.Equal(t, *bresult2, *r2)
-	apph := cmn.MaxInt64(bresult1.Height, bresult2.Height) + 1
+	apph := tmmath.MaxInt64(bresult1.Height, bresult2.Height) + 1
 
 	client.WaitForHeight(c, apph, nil)
 
diff --git a/rpc/core/blocks.go b/rpc/core/blocks.go
index 1a7ccd53e..5bcb3a05b 100644
--- a/rpc/core/blocks.go
+++ b/rpc/core/blocks.go
@@ -3,7 +3,7 @@ package core
 import (
 	"fmt"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	ctypes "github.com/tendermint/tendermint/rpc/core/types"
 	rpctypes "github.com/tendermint/tendermint/rpc/lib/types"
 	sm "github.com/tendermint/tendermint/state"
@@ -54,11 +54,11 @@ func filterMinMax(height, min, max, limit int64) (int64, int64, error) {
 	}
 
 	// limit max to the height
-	max = cmn.MinInt64(height, max)
+	max = tmmath.MinInt64(height, max)
 
 	// limit min to within `limit` of max
 	// so the total number of blocks returned will be `limit`
-	min = cmn.MaxInt64(min, max-limit+1)
+	min = tmmath.MaxInt64(min, max-limit+1)
 
 	if min > max {
 		return min, max, fmt.Errorf("min height %d can't be greater than max height %d", min, max)
diff --git a/rpc/core/consensus.go b/rpc/core/consensus.go
index 794fb113b..6a5a49e03 100644
--- a/rpc/core/consensus.go
+++ b/rpc/core/consensus.go
@@ -2,7 +2,7 @@ package core
 
 import (
 	cm "github.com/tendermint/tendermint/consensus"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	ctypes "github.com/tendermint/tendermint/rpc/core/types"
 	rpctypes "github.com/tendermint/tendermint/rpc/lib/types"
 	sm "github.com/tendermint/tendermint/state"
@@ -37,7 +37,7 @@ func Validators(ctx *rpctypes.Context, heightPtr *int64, page, perPage int) (*ct
 
 	skipCount := validateSkipCount(page, perPage)
 
-	v := validators.Validators[skipCount : skipCount+cmn.MinInt(perPage, totalCount-skipCount)]
+	v := validators.Validators[skipCount : skipCount+tmmath.MinInt(perPage, totalCount-skipCount)]
 
 	return &ctypes.ResultValidators{
 		BlockHeight: height,
diff --git a/rpc/core/tx.go b/rpc/core/tx.go
index cdc37f017..26d5364f4 100644
--- a/rpc/core/tx.go
+++ b/rpc/core/tx.go
@@ -3,7 +3,7 @@ package core
 import (
 	"fmt"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 
 	tmquery "github.com/tendermint/tendermint/libs/pubsub/query"
 	ctypes "github.com/tendermint/tendermint/rpc/core/types"
@@ -78,7 +78,7 @@ func TxSearch(ctx *rpctypes.Context, query string, prove bool, page, perPage int
 	}
 	skipCount := validateSkipCount(page, perPage)
 
-	apiResults := make([]*ctypes.ResultTx, cmn.MinInt(perPage, totalCount-skipCount))
+	apiResults := make([]*ctypes.ResultTx, tmmath.MinInt(perPage, totalCount-skipCount))
 	var proof types.TxProof
 	// if there's no tx in the results array, we don't need to loop through the apiResults array
 	for i := 0; i < len(apiResults); i++ {
diff --git a/rpc/grpc/client_server.go b/rpc/grpc/client_server.go
index 5967b8ac5..133eb53ff 100644
--- a/rpc/grpc/client_server.go
+++ b/rpc/grpc/client_server.go
@@ -6,7 +6,7 @@ import (
 	"golang.org/x/net/context"
 	"google.golang.org/grpc"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 )
 
 // Config is an gRPC server configuration.
@@ -34,5 +34,5 @@ func StartGRPCClient(protoAddr string) BroadcastAPIClient {
 }
 
 func dialerFunc(ctx context.Context, addr string) (net.Conn, error) {
-	return cmn.Connect(addr)
+	return tmnet.Connect(addr)
 }
diff --git a/rpc/lib/test/main.go b/rpc/lib/test/main.go
index 2e433b901..891f9388d 100644
--- a/rpc/lib/test/main.go
+++ b/rpc/lib/test/main.go
@@ -7,8 +7,8 @@ import (
 
 	amino "github.com/tendermint/go-amino"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	rpcserver "github.com/tendermint/tendermint/rpc/lib/server"
 	rpctypes "github.com/tendermint/tendermint/rpc/lib/types"
 )
@@ -33,13 +33,13 @@ func main() {
 	)
 
 	// Stop upon receiving SIGTERM or CTRL-C.
-	cmn.TrapSignal(logger, func() {})
+	tmos.TrapSignal(logger, func() {})
 
 	rpcserver.RegisterRPCFuncs(mux, routes, cdc, logger)
 	config := rpcserver.DefaultConfig()
 	listener, err := rpcserver.Listen("0.0.0.0:8008", config)
 	if err != nil {
-		cmn.Exit(err.Error())
+		tmos.Exit(err.Error())
 	}
 	rpcserver.StartHTTPServer(listener, mux, logger, config)
 }
diff --git a/rpc/test/helpers.go b/rpc/test/helpers.go
index 83ba2445f..32c465c2e 100644
--- a/rpc/test/helpers.go
+++ b/rpc/test/helpers.go
@@ -12,7 +12,7 @@ import (
 	"github.com/tendermint/tendermint/libs/log"
 
 	cfg "github.com/tendermint/tendermint/config"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmnet "github.com/tendermint/tendermint/libs/net"
 	nm "github.com/tendermint/tendermint/node"
 	"github.com/tendermint/tendermint/p2p"
 	"github.com/tendermint/tendermint/privval"
@@ -74,7 +74,7 @@ func makePathname() string {
 }
 
 func randPort() int {
-	port, err := cmn.GetFreePort()
+	port, err := tmnet.GetFreePort()
 	if err != nil {
 		panic(err)
 	}
diff --git a/state/store.go b/state/store.go
index b1a9c7f81..545718688 100644
--- a/state/store.go
+++ b/state/store.go
@@ -4,7 +4,8 @@ import (
 	"fmt"
 
 	abci "github.com/tendermint/tendermint/abci/types"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/types"
 	dbm "github.com/tendermint/tm-db"
 )
@@ -79,7 +80,7 @@ func loadState(db dbm.DB, key []byte) (state State) {
 	err := cdc.UnmarshalBinaryBare(buf, &state)
 	if err != nil {
 		// DATA HAS BEEN CORRUPTED OR THE SPEC HAS CHANGED
-		cmn.Exit(fmt.Sprintf(`LoadState: Data has been corrupted or its spec has changed:
+		tmos.Exit(fmt.Sprintf(`LoadState: Data has been corrupted or its spec has changed:
                 %v\n`, err))
 	}
 	// TODO: ensure that buf is completely read.
@@ -155,7 +156,7 @@ func LoadABCIResponses(db dbm.DB, height int64) (*ABCIResponses, error) {
 	err := cdc.UnmarshalBinaryBare(buf, abciResponses)
 	if err != nil {
 		// DATA HAS BEEN CORRUPTED OR THE SPEC HAS CHANGED
-		cmn.Exit(fmt.Sprintf(`LoadABCIResponses: Data has been corrupted or its spec has
+		tmos.Exit(fmt.Sprintf(`LoadABCIResponses: Data has been corrupted or its spec has
                 changed: %v\n`, err))
 	}
 	// TODO: ensure that buf is completely read.
@@ -213,7 +214,7 @@ func LoadValidators(db dbm.DB, height int64) (*types.ValidatorSet, error) {
 
 func lastStoredHeightFor(height, lastHeightChanged int64) int64 {
 	checkpointHeight := height - height%valSetCheckpointInterval
-	return cmn.MaxInt64(checkpointHeight, lastHeightChanged)
+	return tmmath.MaxInt64(checkpointHeight, lastHeightChanged)
 }
 
 // CONTRACT: Returned ValidatorsInfo can be mutated.
@@ -227,7 +228,7 @@ func loadValidatorsInfo(db dbm.DB, height int64) *ValidatorsInfo {
 	err := cdc.UnmarshalBinaryBare(buf, v)
 	if err != nil {
 		// DATA HAS BEEN CORRUPTED OR THE SPEC HAS CHANGED
-		cmn.Exit(fmt.Sprintf(`LoadValidators: Data has been corrupted or its spec has changed:
+		tmos.Exit(fmt.Sprintf(`LoadValidators: Data has been corrupted or its spec has changed:
                 %v\n`, err))
 	}
 	// TODO: ensure that buf is completely read.
@@ -304,7 +305,7 @@ func loadConsensusParamsInfo(db dbm.DB, height int64) *ConsensusParamsInfo {
 	err := cdc.UnmarshalBinaryBare(buf, paramsInfo)
 	if err != nil {
 		// DATA HAS BEEN CORRUPTED OR THE SPEC HAS CHANGED
-		cmn.Exit(fmt.Sprintf(`LoadConsensusParams: Data has been corrupted or its spec has changed:
+		tmos.Exit(fmt.Sprintf(`LoadConsensusParams: Data has been corrupted or its spec has changed:
                 %v\n`, err))
 	}
 	// TODO: ensure that buf is completely read.
diff --git a/state/txindex/kv/kv.go b/state/txindex/kv/kv.go
index 46365dafb..956af153e 100644
--- a/state/txindex/kv/kv.go
+++ b/state/txindex/kv/kv.go
@@ -13,8 +13,8 @@ import (
 
 	dbm "github.com/tendermint/tm-db"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/pubsub/query"
+	tmstring "github.com/tendermint/tendermint/libs/strings"
 	"github.com/tendermint/tendermint/state/txindex"
 	"github.com/tendermint/tendermint/types"
 )
@@ -91,7 +91,7 @@ func (txi *TxIndex) AddBatch(b *txindex.Batch) error {
 		txi.indexEvents(result, hash, storeBatch)
 
 		// index tx by height
-		if txi.indexAllEvents || cmn.StringInSlice(types.TxHeightKey, txi.compositeKeysToIndex) {
+		if txi.indexAllEvents || tmstring.StringInSlice(types.TxHeightKey, txi.compositeKeysToIndex) {
 			storeBatch.Set(keyForHeight(result), hash)
 		}
 
@@ -121,7 +121,7 @@ func (txi *TxIndex) Index(result *types.TxResult) error {
 	txi.indexEvents(result, hash, b)
 
 	// index tx by height
-	if txi.indexAllEvents || cmn.StringInSlice(types.TxHeightKey, txi.compositeKeysToIndex) {
+	if txi.indexAllEvents || tmstring.StringInSlice(types.TxHeightKey, txi.compositeKeysToIndex) {
 		b.Set(keyForHeight(result), hash)
 	}
 
@@ -150,7 +150,7 @@ func (txi *TxIndex) indexEvents(result *types.TxResult, hash []byte, store dbm.S
 			}
 
 			compositeTag := fmt.Sprintf("%s.%s", event.Type, string(attr.Key))
-			if txi.indexAllEvents || cmn.StringInSlice(compositeTag, txi.compositeKeysToIndex) {
+			if txi.indexAllEvents || tmstring.StringInSlice(compositeTag, txi.compositeKeysToIndex) {
 				store.Set(keyForEvent(compositeTag, attr.Value, result), hash)
 			}
 		}
diff --git a/tools/tm-monitor/main.go b/tools/tm-monitor/main.go
index bcabcf73e..7e4bffca2 100644
--- a/tools/tm-monitor/main.go
+++ b/tools/tm-monitor/main.go
@@ -6,8 +6,8 @@ import (
 	"os"
 	"strings"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	monitor "github.com/tendermint/tendermint/tools/tm-monitor/monitor"
 )
 
@@ -59,7 +59,7 @@ Examples:
 	}
 
 	// Stop upon receiving SIGTERM or CTRL-C.
-	cmn.TrapSignal(logger, func() {
+	tmos.TrapSignal(logger, func() {
 		if !noton {
 			ton.Stop()
 		}
diff --git a/tools/tm-signer-harness/internal/test_harness.go b/tools/tm-signer-harness/internal/test_harness.go
index 216cf6851..c489a2fd4 100644
--- a/tools/tm-signer-harness/internal/test_harness.go
+++ b/tools/tm-signer-harness/internal/test_harness.go
@@ -13,8 +13,9 @@ import (
 	"github.com/tendermint/tendermint/privval"
 	"github.com/tendermint/tendermint/state"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/log"
+	tmnet "github.com/tendermint/tendermint/libs/net"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -321,10 +322,10 @@ func (th *TestHarness) Shutdown(err error) {
 
 // newTestHarnessListener creates our client instance which we will use for testing.
 func newTestHarnessListener(logger log.Logger, cfg TestHarnessConfig) (*privval.SignerListenerEndpoint, error) {
-	proto, addr := cmn.ProtocolAndAddress(cfg.BindAddr)
+	proto, addr := tmnet.ProtocolAndAddress(cfg.BindAddr)
 	if proto == "unix" {
 		// make sure the socket doesn't exist - if so, try to delete it
-		if cmn.FileExists(addr) {
+		if tmos.FileExists(addr) {
 			if err := os.Remove(addr); err != nil {
 				logger.Error("Failed to remove existing Unix domain socket", "addr", addr)
 				return nil, err
diff --git a/types/block.go b/types/block.go
index c67b9ade9..45cb8d827 100644
--- a/types/block.go
+++ b/types/block.go
@@ -12,8 +12,9 @@ import (
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/merkle"
 	"github.com/tendermint/tendermint/crypto/tmhash"
+	"github.com/tendermint/tendermint/libs/bits"
 	tmbytes "github.com/tendermint/tendermint/libs/bytes"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	"github.com/tendermint/tendermint/version"
 )
 
@@ -561,7 +562,7 @@ type Commit struct {
 	// NOTE: can't memoize in constructor because constructor isn't used for
 	// unmarshaling.
 	hash     tmbytes.HexBytes
-	bitArray *cmn.BitArray
+	bitArray *bits.BitArray
 }
 
 // NewCommit returns a new Commit.
@@ -645,9 +646,9 @@ func (commit *Commit) Size() int {
 
 // BitArray returns a BitArray of which validators voted for BlockID or nil in this commit.
 // Implements VoteSetReader.
-func (commit *Commit) BitArray() *cmn.BitArray {
+func (commit *Commit) BitArray() *bits.BitArray {
 	if commit.bitArray == nil {
-		commit.bitArray = cmn.NewBitArray(len(commit.Signatures))
+		commit.bitArray = bits.NewBitArray(len(commit.Signatures))
 		for i, commitSig := range commit.Signatures {
 			// TODO: need to check the BlockID otherwise we could be counting conflicts,
 			// not just the one with +2/3 !
@@ -829,7 +830,7 @@ func (data *Data) StringIndented(indent string) string {
 	if data == nil {
 		return "nil-Data"
 	}
-	txStrings := make([]string, cmn.MinInt(len(data.Txs), 21))
+	txStrings := make([]string, tmmath.MinInt(len(data.Txs), 21))
 	for i, tx := range data.Txs {
 		if i == 20 {
 			txStrings[i] = fmt.Sprintf("... (%v total)", len(data.Txs))
@@ -867,7 +868,7 @@ func (data *EvidenceData) StringIndented(indent string) string {
 	if data == nil {
 		return "nil-Evidence"
 	}
-	evStrings := make([]string, cmn.MinInt(len(data.Evidence), 21))
+	evStrings := make([]string, tmmath.MinInt(len(data.Evidence), 21))
 	for i, ev := range data.Evidence {
 		if i == 20 {
 			evStrings[i] = fmt.Sprintf("... (%v total)", len(data.Evidence))
diff --git a/types/block_test.go b/types/block_test.go
index d3454f54b..ba920f63f 100644
--- a/types/block_test.go
+++ b/types/block_test.go
@@ -17,8 +17,8 @@ import (
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/merkle"
 	"github.com/tendermint/tendermint/crypto/tmhash"
+	"github.com/tendermint/tendermint/libs/bits"
 	"github.com/tendermint/tendermint/libs/bytes"
-	cmn "github.com/tendermint/tendermint/libs/common"
 	tmrand "github.com/tendermint/tendermint/libs/rand"
 	tmtime "github.com/tendermint/tendermint/types/time"
 	"github.com/tendermint/tendermint/version"
@@ -221,7 +221,7 @@ func TestCommit(t *testing.T) {
 	}
 
 	require.NotNil(t, commit.BitArray())
-	assert.Equal(t, cmn.NewBitArray(10).Size(), commit.BitArray().Size())
+	assert.Equal(t, bits.NewBitArray(10).Size(), commit.BitArray().Size())
 
 	assert.Equal(t, voteSet.GetByIndex(0), commit.GetByIndex(0))
 	assert.True(t, commit.IsCommit())
diff --git a/types/genesis.go b/types/genesis.go
index a28bafdff..73a7847d8 100644
--- a/types/genesis.go
+++ b/types/genesis.go
@@ -11,7 +11,7 @@ import (
 
 	"github.com/tendermint/tendermint/crypto"
 	tmbytes "github.com/tendermint/tendermint/libs/bytes"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmos "github.com/tendermint/tendermint/libs/os"
 	tmtime "github.com/tendermint/tendermint/types/time"
 )
 
@@ -50,7 +50,7 @@ func (genDoc *GenesisDoc) SaveAs(file string) error {
 	if err != nil {
 		return err
 	}
-	return cmn.WriteFile(file, genDocBytes, 0644)
+	return tmos.WriteFile(file, genDocBytes, 0644)
 }
 
 // ValidatorHash returns the hash of the validator set contained in the GenesisDoc
diff --git a/types/params.go b/types/params.go
index 773ec7731..157c0447c 100644
--- a/types/params.go
+++ b/types/params.go
@@ -5,7 +5,7 @@ import (
 
 	abci "github.com/tendermint/tendermint/abci/types"
 	"github.com/tendermint/tendermint/crypto/tmhash"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmstrings "github.com/tendermint/tendermint/libs/strings"
 )
 
 const (
@@ -159,7 +159,7 @@ func (params *ConsensusParams) Hash() []byte {
 func (params *ConsensusParams) Equals(params2 *ConsensusParams) bool {
 	return params.Block == params2.Block &&
 		params.Evidence == params2.Evidence &&
-		cmn.StringSliceEqual(params.Validator.PubKeyTypes, params2.Validator.PubKeyTypes)
+		tmstrings.StringSliceEqual(params.Validator.PubKeyTypes, params2.Validator.PubKeyTypes)
 }
 
 // Update returns a copy of the params with updates from the non-zero fields of p2.
diff --git a/types/part_set.go b/types/part_set.go
index cdacc0083..51af767b8 100644
--- a/types/part_set.go
+++ b/types/part_set.go
@@ -9,8 +9,9 @@ import (
 	"github.com/pkg/errors"
 
 	"github.com/tendermint/tendermint/crypto/merkle"
+	"github.com/tendermint/tendermint/libs/bits"
 	tmbytes "github.com/tendermint/tendermint/libs/bytes"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 )
 
 var (
@@ -92,7 +93,7 @@ type PartSet struct {
 
 	mtx           sync.Mutex
 	parts         []*Part
-	partsBitArray *cmn.BitArray
+	partsBitArray *bits.BitArray
 	count         int
 }
 
@@ -103,11 +104,11 @@ func NewPartSetFromData(data []byte, partSize int) *PartSet {
 	total := (len(data) + partSize - 1) / partSize
 	parts := make([]*Part, total)
 	partsBytes := make([][]byte, total)
-	partsBitArray := cmn.NewBitArray(total)
+	partsBitArray := bits.NewBitArray(total)
 	for i := 0; i < total; i++ {
 		part := &Part{
 			Index: i,
-			Bytes: data[i*partSize : cmn.MinInt(len(data), (i+1)*partSize)],
+			Bytes: data[i*partSize : tmmath.MinInt(len(data), (i+1)*partSize)],
 		}
 		parts[i] = part
 		partsBytes[i] = part.Bytes
@@ -133,7 +134,7 @@ func NewPartSetFromHeader(header PartSetHeader) *PartSet {
 		total:         header.Total,
 		hash:          header.Hash,
 		parts:         make([]*Part, header.Total),
-		partsBitArray: cmn.NewBitArray(header.Total),
+		partsBitArray: bits.NewBitArray(header.Total),
 		count:         0,
 	}
 }
@@ -155,7 +156,7 @@ func (ps *PartSet) HasHeader(header PartSetHeader) bool {
 	return ps.Header().Equals(header)
 }
 
-func (ps *PartSet) BitArray() *cmn.BitArray {
+func (ps *PartSet) BitArray() *bits.BitArray {
 	ps.mtx.Lock()
 	defer ps.mtx.Unlock()
 	return ps.partsBitArray.Copy()
@@ -288,8 +289,8 @@ func (ps *PartSet) MarshalJSON() ([]byte, error) {
 	defer ps.mtx.Unlock()
 
 	return cdc.MarshalJSON(struct {
-		CountTotal    string        `json:"count/total"`
-		PartsBitArray *cmn.BitArray `json:"parts_bit_array"`
+		CountTotal    string         `json:"count/total"`
+		PartsBitArray *bits.BitArray `json:"parts_bit_array"`
 	}{
 		fmt.Sprintf("%d/%d", ps.Count(), ps.Total()),
 		ps.partsBitArray,
diff --git a/types/signable.go b/types/signable.go
index 72d2ea9ac..074654cc5 100644
--- a/types/signable.go
+++ b/types/signable.go
@@ -2,14 +2,14 @@ package types
 
 import (
 	"github.com/tendermint/tendermint/crypto/ed25519"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 )
 
 var (
 	// MaxSignatureSize is a maximum allowed signature size for the Proposal
 	// and Vote.
 	// XXX: secp256k1 does not have Size nor MaxSize defined.
-	MaxSignatureSize = cmn.MaxInt(ed25519.SignatureSize, 64)
+	MaxSignatureSize = tmmath.MaxInt(ed25519.SignatureSize, 64)
 )
 
 // Signable is an interface for all signable things.
diff --git a/types/validator_set.go b/types/validator_set.go
index 9796fe453..29859a48a 100644
--- a/types/validator_set.go
+++ b/types/validator_set.go
@@ -9,9 +9,8 @@ import (
 	"strings"
 
 	"github.com/pkg/errors"
-
 	"github.com/tendermint/tendermint/crypto/merkle"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 )
 
 const (
@@ -749,7 +748,7 @@ func (vals *ValidatorSet) VerifyFutureCommit(newSet *ValidatorSet, chainID strin
 // NOTE the given validators do not necessarily correspond to the validator set
 // for this commit, but there may be some intersection.
 func (vals *ValidatorSet) VerifyCommitTrusting(chainID string, blockID BlockID,
-	height int64, commit *Commit, trustLevel cmn.Fraction) error {
+	height int64, commit *Commit, trustLevel tmmath.Fraction) error {
 
 	if trustLevel.Numerator*3 < trustLevel.Denominator || // < 1/3
 		trustLevel.Numerator > trustLevel.Denominator { // > 1
diff --git a/types/validator_set_test.go b/types/validator_set_test.go
index 9cb6d6536..ce7556918 100644
--- a/types/validator_set_test.go
+++ b/types/validator_set_test.go
@@ -13,7 +13,7 @@ import (
 
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/ed25519"
-	cmn "github.com/tendermint/tendermint/libs/common"
+	tmmath "github.com/tendermint/tendermint/libs/math"
 	"github.com/tendermint/tendermint/libs/rand"
 	tmtime "github.com/tendermint/tendermint/types/time"
 )
@@ -1013,7 +1013,7 @@ func TestValSetUpdatesOrderIndependenceTestsExecute(t *testing.T) {
 
 		// perform at most 20 permutations on the updates and call UpdateWithChangeSet()
 		n := len(tt.updateVals)
-		maxNumPerms := cmn.MinInt(20, n*n)
+		maxNumPerms := tmmath.MinInt(20, n*n)
 		for j := 0; j < maxNumPerms; j++ {
 			// create a copy of original set and apply a random permutation of updates
 			valSetCopy := valSet.Copy()
diff --git a/types/vote_set.go b/types/vote_set.go
index d1e388dd2..82698fe51 100644
--- a/types/vote_set.go
+++ b/types/vote_set.go
@@ -8,7 +8,7 @@ import (
 
 	"github.com/pkg/errors"
 
-	cmn "github.com/tendermint/tendermint/libs/common"
+	"github.com/tendermint/tendermint/libs/bits"
 )
 
 const (
@@ -66,7 +66,7 @@ type VoteSet struct {
 	valSet        *ValidatorSet
 
 	mtx           sync.Mutex
-	votesBitArray *cmn.BitArray
+	votesBitArray *bits.BitArray
 	votes         []*Vote                // Primary votes to share
 	sum           int64                  // Sum of voting power for seen votes, discounting conflicts
 	maj23         *BlockID               // First 2/3 majority seen
@@ -85,7 +85,7 @@ func NewVoteSet(chainID string, height int64, round int, signedMsgType SignedMsg
 		round:         round,
 		signedMsgType: signedMsgType,
 		valSet:        valSet,
-		votesBitArray: cmn.NewBitArray(valSet.Size()),
+		votesBitArray: bits.NewBitArray(valSet.Size()),
 		votes:         make([]*Vote, valSet.Size()),
 		sum:           0,
 		maj23:         nil,
@@ -340,7 +340,7 @@ func (voteSet *VoteSet) SetPeerMaj23(peerID P2PID, blockID BlockID) error {
 }
 
 // Implements VoteSetReader.
-func (voteSet *VoteSet) BitArray() *cmn.BitArray {
+func (voteSet *VoteSet) BitArray() *bits.BitArray {
 	if voteSet == nil {
 		return nil
 	}
@@ -349,7 +349,7 @@ func (voteSet *VoteSet) BitArray() *cmn.BitArray {
 	return voteSet.votesBitArray.Copy()
 }
 
-func (voteSet *VoteSet) BitArrayByBlockID(blockID BlockID) *cmn.BitArray {
+func (voteSet *VoteSet) BitArrayByBlockID(blockID BlockID) *bits.BitArray {
 	if voteSet == nil {
 		return nil
 	}
@@ -580,16 +580,16 @@ func (voteSet *VoteSet) MakeCommit() *Commit {
 	2. A peer claims to have a 2/3 majority w/ blockKey (peerMaj23=true)
 */
 type blockVotes struct {
-	peerMaj23 bool          // peer claims to have maj23
-	bitArray  *cmn.BitArray // valIndex -> hasVote?
-	votes     []*Vote       // valIndex -> *Vote
-	sum       int64         // vote sum
+	peerMaj23 bool           // peer claims to have maj23
+	bitArray  *bits.BitArray // valIndex -> hasVote?
+	votes     []*Vote        // valIndex -> *Vote
+	sum       int64          // vote sum
 }
 
 func newBlockVotes(peerMaj23 bool, numValidators int) *blockVotes {
 	return &blockVotes{
 		peerMaj23: peerMaj23,
-		bitArray:  cmn.NewBitArray(numValidators),
+		bitArray:  bits.NewBitArray(numValidators),
 		votes:     make([]*Vote, numValidators),
 		sum:       0,
 	}
@@ -619,7 +619,7 @@ type VoteSetReader interface {
 	GetRound() int
 	Type() byte
 	Size() int
-	BitArray() *cmn.BitArray
+	BitArray() *bits.BitArray
 	GetByIndex(int) *Vote
 	IsCommit() bool
 }