diff --git a/vendor/github.com/coreos/etcd/auth/doc.go b/vendor/github.com/coreos/etcd/auth/doc.go
new file mode 100644
index 0000000..72741a1
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/auth/doc.go
@@ -0,0 +1,16 @@
+// Copyright 2016 The etcd Authors
+//
+// 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
+//
+//     http://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.
+
+// Package auth provides client role authentication for accessing keys in etcd.
+package auth
diff --git a/vendor/github.com/coreos/etcd/auth/jwt.go b/vendor/github.com/coreos/etcd/auth/jwt.go
new file mode 100644
index 0000000..99b2d6b
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/auth/jwt.go
@@ -0,0 +1,139 @@
+// Copyright 2017 The etcd Authors
+//
+// 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
+//
+//     http://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.
+
+package auth
+
+import (
+	"context"
+	"crypto/rsa"
+	"io/ioutil"
+
+	jwt "github.com/dgrijalva/jwt-go"
+)
+
+type tokenJWT struct {
+	signMethod string
+	signKey    *rsa.PrivateKey
+	verifyKey  *rsa.PublicKey
+}
+
+func (t *tokenJWT) enable()                         {}
+func (t *tokenJWT) disable()                        {}
+func (t *tokenJWT) invalidateUser(string)           {}
+func (t *tokenJWT) genTokenPrefix() (string, error) { return "", nil }
+
+func (t *tokenJWT) info(ctx context.Context, token string, rev uint64) (*AuthInfo, bool) {
+	// rev isn't used in JWT, it is only used in simple token
+	var (
+		username string
+		revision uint64
+	)
+
+	parsed, err := jwt.Parse(token, func(token *jwt.Token) (interface{}, error) {
+		return t.verifyKey, nil
+	})
+
+	switch err.(type) {
+	case nil:
+		if !parsed.Valid {
+			plog.Warningf("invalid jwt token: %s", token)
+			return nil, false
+		}
+
+		claims := parsed.Claims.(jwt.MapClaims)
+
+		username = claims["username"].(string)
+		revision = uint64(claims["revision"].(float64))
+	default:
+		plog.Warningf("failed to parse jwt token: %s", err)
+		return nil, false
+	}
+
+	return &AuthInfo{Username: username, Revision: revision}, true
+}
+
+func (t *tokenJWT) assign(ctx context.Context, username string, revision uint64) (string, error) {
+	// Future work: let a jwt token include permission information would be useful for
+	// permission checking in proxy side.
+	tk := jwt.NewWithClaims(jwt.GetSigningMethod(t.signMethod),
+		jwt.MapClaims{
+			"username": username,
+			"revision": revision,
+		})
+
+	token, err := tk.SignedString(t.signKey)
+	if err != nil {
+		plog.Debugf("failed to sign jwt token: %s", err)
+		return "", err
+	}
+
+	plog.Debugf("jwt token: %s", token)
+
+	return token, err
+}
+
+func prepareOpts(opts map[string]string) (jwtSignMethod, jwtPubKeyPath, jwtPrivKeyPath string, err error) {
+	for k, v := range opts {
+		switch k {
+		case "sign-method":
+			jwtSignMethod = v
+		case "pub-key":
+			jwtPubKeyPath = v
+		case "priv-key":
+			jwtPrivKeyPath = v
+		default:
+			plog.Errorf("unknown token specific option: %s", k)
+			return "", "", "", ErrInvalidAuthOpts
+		}
+	}
+	if len(jwtSignMethod) == 0 {
+		return "", "", "", ErrInvalidAuthOpts
+	}
+	return jwtSignMethod, jwtPubKeyPath, jwtPrivKeyPath, nil
+}
+
+func newTokenProviderJWT(opts map[string]string) (*tokenJWT, error) {
+	jwtSignMethod, jwtPubKeyPath, jwtPrivKeyPath, err := prepareOpts(opts)
+	if err != nil {
+		return nil, ErrInvalidAuthOpts
+	}
+
+	t := &tokenJWT{}
+
+	t.signMethod = jwtSignMethod
+
+	verifyBytes, err := ioutil.ReadFile(jwtPubKeyPath)
+	if err != nil {
+		plog.Errorf("failed to read public key (%s) for jwt: %s", jwtPubKeyPath, err)
+		return nil, err
+	}
+	t.verifyKey, err = jwt.ParseRSAPublicKeyFromPEM(verifyBytes)
+	if err != nil {
+		plog.Errorf("failed to parse public key (%s): %s", jwtPubKeyPath, err)
+		return nil, err
+	}
+
+	signBytes, err := ioutil.ReadFile(jwtPrivKeyPath)
+	if err != nil {
+		plog.Errorf("failed to read private key (%s) for jwt: %s", jwtPrivKeyPath, err)
+		return nil, err
+	}
+	t.signKey, err = jwt.ParseRSAPrivateKeyFromPEM(signBytes)
+	if err != nil {
+		plog.Errorf("failed to parse private key (%s): %s", jwtPrivKeyPath, err)
+		return nil, err
+	}
+
+	return t, nil
+}
diff --git a/vendor/github.com/coreos/etcd/auth/nop.go b/vendor/github.com/coreos/etcd/auth/nop.go
new file mode 100644
index 0000000..d437874
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/auth/nop.go
@@ -0,0 +1,35 @@
+// Copyright 2018 The etcd Authors
+//
+// 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
+//
+//     http://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.
+
+package auth
+
+import (
+	"context"
+)
+
+type tokenNop struct{}
+
+func (t *tokenNop) enable()                         {}
+func (t *tokenNop) disable()                        {}
+func (t *tokenNop) invalidateUser(string)           {}
+func (t *tokenNop) genTokenPrefix() (string, error) { return "", nil }
+func (t *tokenNop) info(ctx context.Context, token string, rev uint64) (*AuthInfo, bool) {
+	return nil, false
+}
+func (t *tokenNop) assign(ctx context.Context, username string, revision uint64) (string, error) {
+	return "", ErrAuthFailed
+}
+func newTokenProviderNop() (*tokenNop, error) {
+	return &tokenNop{}, nil
+}
diff --git a/vendor/github.com/coreos/etcd/auth/range_perm_cache.go b/vendor/github.com/coreos/etcd/auth/range_perm_cache.go
new file mode 100644
index 0000000..691b65b
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/auth/range_perm_cache.go
@@ -0,0 +1,133 @@
+// Copyright 2016 The etcd Authors
+//
+// 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
+//
+//     http://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.
+
+package auth
+
+import (
+	"github.com/coreos/etcd/auth/authpb"
+	"github.com/coreos/etcd/mvcc/backend"
+	"github.com/coreos/etcd/pkg/adt"
+)
+
+func getMergedPerms(tx backend.BatchTx, userName string) *unifiedRangePermissions {
+	user := getUser(tx, userName)
+	if user == nil {
+		plog.Errorf("invalid user name %s", userName)
+		return nil
+	}
+
+	readPerms := &adt.IntervalTree{}
+	writePerms := &adt.IntervalTree{}
+
+	for _, roleName := range user.Roles {
+		role := getRole(tx, roleName)
+		if role == nil {
+			continue
+		}
+
+		for _, perm := range role.KeyPermission {
+			var ivl adt.Interval
+			var rangeEnd []byte
+
+			if len(perm.RangeEnd) != 1 || perm.RangeEnd[0] != 0 {
+				rangeEnd = perm.RangeEnd
+			}
+
+			if len(perm.RangeEnd) != 0 {
+				ivl = adt.NewBytesAffineInterval(perm.Key, rangeEnd)
+			} else {
+				ivl = adt.NewBytesAffinePoint(perm.Key)
+			}
+
+			switch perm.PermType {
+			case authpb.READWRITE:
+				readPerms.Insert(ivl, struct{}{})
+				writePerms.Insert(ivl, struct{}{})
+
+			case authpb.READ:
+				readPerms.Insert(ivl, struct{}{})
+
+			case authpb.WRITE:
+				writePerms.Insert(ivl, struct{}{})
+			}
+		}
+	}
+
+	return &unifiedRangePermissions{
+		readPerms:  readPerms,
+		writePerms: writePerms,
+	}
+}
+
+func checkKeyInterval(cachedPerms *unifiedRangePermissions, key, rangeEnd []byte, permtyp authpb.Permission_Type) bool {
+	if len(rangeEnd) == 1 && rangeEnd[0] == 0 {
+		rangeEnd = nil
+	}
+
+	ivl := adt.NewBytesAffineInterval(key, rangeEnd)
+	switch permtyp {
+	case authpb.READ:
+		return cachedPerms.readPerms.Contains(ivl)
+	case authpb.WRITE:
+		return cachedPerms.writePerms.Contains(ivl)
+	default:
+		plog.Panicf("unknown auth type: %v", permtyp)
+	}
+	return false
+}
+
+func checkKeyPoint(cachedPerms *unifiedRangePermissions, key []byte, permtyp authpb.Permission_Type) bool {
+	pt := adt.NewBytesAffinePoint(key)
+	switch permtyp {
+	case authpb.READ:
+		return cachedPerms.readPerms.Intersects(pt)
+	case authpb.WRITE:
+		return cachedPerms.writePerms.Intersects(pt)
+	default:
+		plog.Panicf("unknown auth type: %v", permtyp)
+	}
+	return false
+}
+
+func (as *authStore) isRangeOpPermitted(tx backend.BatchTx, userName string, key, rangeEnd []byte, permtyp authpb.Permission_Type) bool {
+	// assumption: tx is Lock()ed
+	_, ok := as.rangePermCache[userName]
+	if !ok {
+		perms := getMergedPerms(tx, userName)
+		if perms == nil {
+			plog.Errorf("failed to create a unified permission of user %s", userName)
+			return false
+		}
+		as.rangePermCache[userName] = perms
+	}
+
+	if len(rangeEnd) == 0 {
+		return checkKeyPoint(as.rangePermCache[userName], key, permtyp)
+	}
+
+	return checkKeyInterval(as.rangePermCache[userName], key, rangeEnd, permtyp)
+}
+
+func (as *authStore) clearCachedPerm() {
+	as.rangePermCache = make(map[string]*unifiedRangePermissions)
+}
+
+func (as *authStore) invalidateCachedPerm(userName string) {
+	delete(as.rangePermCache, userName)
+}
+
+type unifiedRangePermissions struct {
+	readPerms  *adt.IntervalTree
+	writePerms *adt.IntervalTree
+}
diff --git a/vendor/github.com/coreos/etcd/auth/simple_token.go b/vendor/github.com/coreos/etcd/auth/simple_token.go
new file mode 100644
index 0000000..ac55ad7
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/auth/simple_token.go
@@ -0,0 +1,223 @@
+// Copyright 2016 The etcd Authors
+//
+// 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
+//
+//     http://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.
+
+package auth
+
+// CAUTION: This randum number based token mechanism is only for testing purpose.
+// JWT based mechanism will be added in the near future.
+
+import (
+	"context"
+	"crypto/rand"
+	"fmt"
+	"math/big"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+const (
+	letters                  = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	defaultSimpleTokenLength = 16
+)
+
+// var for testing purposes
+var (
+	simpleTokenTTL           = 5 * time.Minute
+	simpleTokenTTLResolution = 1 * time.Second
+)
+
+type simpleTokenTTLKeeper struct {
+	tokens          map[string]time.Time
+	donec           chan struct{}
+	stopc           chan struct{}
+	deleteTokenFunc func(string)
+	mu              *sync.Mutex
+}
+
+func (tm *simpleTokenTTLKeeper) stop() {
+	select {
+	case tm.stopc <- struct{}{}:
+	case <-tm.donec:
+	}
+	<-tm.donec
+}
+
+func (tm *simpleTokenTTLKeeper) addSimpleToken(token string) {
+	tm.tokens[token] = time.Now().Add(simpleTokenTTL)
+}
+
+func (tm *simpleTokenTTLKeeper) resetSimpleToken(token string) {
+	if _, ok := tm.tokens[token]; ok {
+		tm.tokens[token] = time.Now().Add(simpleTokenTTL)
+	}
+}
+
+func (tm *simpleTokenTTLKeeper) deleteSimpleToken(token string) {
+	delete(tm.tokens, token)
+}
+
+func (tm *simpleTokenTTLKeeper) run() {
+	tokenTicker := time.NewTicker(simpleTokenTTLResolution)
+	defer func() {
+		tokenTicker.Stop()
+		close(tm.donec)
+	}()
+	for {
+		select {
+		case <-tokenTicker.C:
+			nowtime := time.Now()
+			tm.mu.Lock()
+			for t, tokenendtime := range tm.tokens {
+				if nowtime.After(tokenendtime) {
+					tm.deleteTokenFunc(t)
+					delete(tm.tokens, t)
+				}
+			}
+			tm.mu.Unlock()
+		case <-tm.stopc:
+			return
+		}
+	}
+}
+
+type tokenSimple struct {
+	indexWaiter       func(uint64) <-chan struct{}
+	simpleTokenKeeper *simpleTokenTTLKeeper
+	simpleTokensMu    sync.Mutex
+	simpleTokens      map[string]string // token -> username
+}
+
+func (t *tokenSimple) genTokenPrefix() (string, error) {
+	ret := make([]byte, defaultSimpleTokenLength)
+
+	for i := 0; i < defaultSimpleTokenLength; i++ {
+		bInt, err := rand.Int(rand.Reader, big.NewInt(int64(len(letters))))
+		if err != nil {
+			return "", err
+		}
+
+		ret[i] = letters[bInt.Int64()]
+	}
+
+	return string(ret), nil
+}
+
+func (t *tokenSimple) assignSimpleTokenToUser(username, token string) {
+	t.simpleTokensMu.Lock()
+	defer t.simpleTokensMu.Unlock()
+	if t.simpleTokenKeeper == nil {
+		return
+	}
+
+	_, ok := t.simpleTokens[token]
+	if ok {
+		plog.Panicf("token %s is alredy used", token)
+	}
+
+	t.simpleTokens[token] = username
+	t.simpleTokenKeeper.addSimpleToken(token)
+}
+
+func (t *tokenSimple) invalidateUser(username string) {
+	if t.simpleTokenKeeper == nil {
+		return
+	}
+	t.simpleTokensMu.Lock()
+	for token, name := range t.simpleTokens {
+		if strings.Compare(name, username) == 0 {
+			delete(t.simpleTokens, token)
+			t.simpleTokenKeeper.deleteSimpleToken(token)
+		}
+	}
+	t.simpleTokensMu.Unlock()
+}
+
+func (t *tokenSimple) enable() {
+	delf := func(tk string) {
+		if username, ok := t.simpleTokens[tk]; ok {
+			plog.Infof("deleting token %s for user %s", tk, username)
+			delete(t.simpleTokens, tk)
+		}
+	}
+	t.simpleTokenKeeper = &simpleTokenTTLKeeper{
+		tokens:          make(map[string]time.Time),
+		donec:           make(chan struct{}),
+		stopc:           make(chan struct{}),
+		deleteTokenFunc: delf,
+		mu:              &t.simpleTokensMu,
+	}
+	go t.simpleTokenKeeper.run()
+}
+
+func (t *tokenSimple) disable() {
+	t.simpleTokensMu.Lock()
+	tk := t.simpleTokenKeeper
+	t.simpleTokenKeeper = nil
+	t.simpleTokens = make(map[string]string) // invalidate all tokens
+	t.simpleTokensMu.Unlock()
+	if tk != nil {
+		tk.stop()
+	}
+}
+
+func (t *tokenSimple) info(ctx context.Context, token string, revision uint64) (*AuthInfo, bool) {
+	if !t.isValidSimpleToken(ctx, token) {
+		return nil, false
+	}
+	t.simpleTokensMu.Lock()
+	username, ok := t.simpleTokens[token]
+	if ok && t.simpleTokenKeeper != nil {
+		t.simpleTokenKeeper.resetSimpleToken(token)
+	}
+	t.simpleTokensMu.Unlock()
+	return &AuthInfo{Username: username, Revision: revision}, ok
+}
+
+func (t *tokenSimple) assign(ctx context.Context, username string, rev uint64) (string, error) {
+	// rev isn't used in simple token, it is only used in JWT
+	index := ctx.Value(AuthenticateParamIndex{}).(uint64)
+	simpleTokenPrefix := ctx.Value(AuthenticateParamSimpleTokenPrefix{}).(string)
+	token := fmt.Sprintf("%s.%d", simpleTokenPrefix, index)
+	t.assignSimpleTokenToUser(username, token)
+
+	return token, nil
+}
+
+func (t *tokenSimple) isValidSimpleToken(ctx context.Context, token string) bool {
+	splitted := strings.Split(token, ".")
+	if len(splitted) != 2 {
+		return false
+	}
+	index, err := strconv.Atoi(splitted[1])
+	if err != nil {
+		return false
+	}
+
+	select {
+	case <-t.indexWaiter(uint64(index)):
+		return true
+	case <-ctx.Done():
+	}
+
+	return false
+}
+
+func newTokenProviderSimple(indexWaiter func(uint64) <-chan struct{}) *tokenSimple {
+	return &tokenSimple{
+		simpleTokens: make(map[string]string),
+		indexWaiter:  indexWaiter,
+	}
+}
diff --git a/vendor/github.com/coreos/etcd/auth/store.go b/vendor/github.com/coreos/etcd/auth/store.go
new file mode 100644
index 0000000..d676cb5
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/auth/store.go
@@ -0,0 +1,1136 @@
+// Copyright 2016 The etcd Authors
+//
+// 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
+//
+//     http://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.
+
+package auth
+
+import (
+	"bytes"
+	"context"
+	"encoding/binary"
+	"errors"
+	"sort"
+	"strings"
+	"sync"
+	"sync/atomic"
+
+	"github.com/coreos/etcd/auth/authpb"
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
+	"github.com/coreos/etcd/mvcc/backend"
+
+	"github.com/coreos/pkg/capnslog"
+	"golang.org/x/crypto/bcrypt"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/peer"
+)
+
+var (
+	enableFlagKey = []byte("authEnabled")
+	authEnabled   = []byte{1}
+	authDisabled  = []byte{0}
+
+	revisionKey = []byte("authRevision")
+
+	authBucketName      = []byte("auth")
+	authUsersBucketName = []byte("authUsers")
+	authRolesBucketName = []byte("authRoles")
+
+	plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "auth")
+
+	ErrRootUserNotExist     = errors.New("auth: root user does not exist")
+	ErrRootRoleNotExist     = errors.New("auth: root user does not have root role")
+	ErrUserAlreadyExist     = errors.New("auth: user already exists")
+	ErrUserEmpty            = errors.New("auth: user name is empty")
+	ErrUserNotFound         = errors.New("auth: user not found")
+	ErrRoleAlreadyExist     = errors.New("auth: role already exists")
+	ErrRoleNotFound         = errors.New("auth: role not found")
+	ErrAuthFailed           = errors.New("auth: authentication failed, invalid user ID or password")
+	ErrPermissionDenied     = errors.New("auth: permission denied")
+	ErrRoleNotGranted       = errors.New("auth: role is not granted to the user")
+	ErrPermissionNotGranted = errors.New("auth: permission is not granted to the role")
+	ErrAuthNotEnabled       = errors.New("auth: authentication is not enabled")
+	ErrAuthOldRevision      = errors.New("auth: revision in header is old")
+	ErrInvalidAuthToken     = errors.New("auth: invalid auth token")
+	ErrInvalidAuthOpts      = errors.New("auth: invalid auth options")
+	ErrInvalidAuthMgmt      = errors.New("auth: invalid auth management")
+
+	// BcryptCost is the algorithm cost / strength for hashing auth passwords
+	BcryptCost = bcrypt.DefaultCost
+)
+
+const (
+	rootUser = "root"
+	rootRole = "root"
+
+	tokenTypeSimple = "simple"
+	tokenTypeJWT    = "jwt"
+
+	revBytesLen = 8
+)
+
+type AuthInfo struct {
+	Username string
+	Revision uint64
+}
+
+// AuthenticateParamIndex is used for a key of context in the parameters of Authenticate()
+type AuthenticateParamIndex struct{}
+
+// AuthenticateParamSimpleTokenPrefix is used for a key of context in the parameters of Authenticate()
+type AuthenticateParamSimpleTokenPrefix struct{}
+
+type AuthStore interface {
+	// AuthEnable turns on the authentication feature
+	AuthEnable() error
+
+	// AuthDisable turns off the authentication feature
+	AuthDisable()
+
+	// Authenticate does authentication based on given user name and password
+	Authenticate(ctx context.Context, username, password string) (*pb.AuthenticateResponse, error)
+
+	// Recover recovers the state of auth store from the given backend
+	Recover(b backend.Backend)
+
+	// UserAdd adds a new user
+	UserAdd(r *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error)
+
+	// UserDelete deletes a user
+	UserDelete(r *pb.AuthUserDeleteRequest) (*pb.AuthUserDeleteResponse, error)
+
+	// UserChangePassword changes a password of a user
+	UserChangePassword(r *pb.AuthUserChangePasswordRequest) (*pb.AuthUserChangePasswordResponse, error)
+
+	// UserGrantRole grants a role to the user
+	UserGrantRole(r *pb.AuthUserGrantRoleRequest) (*pb.AuthUserGrantRoleResponse, error)
+
+	// UserGet gets the detailed information of a users
+	UserGet(r *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error)
+
+	// UserRevokeRole revokes a role of a user
+	UserRevokeRole(r *pb.AuthUserRevokeRoleRequest) (*pb.AuthUserRevokeRoleResponse, error)
+
+	// RoleAdd adds a new role
+	RoleAdd(r *pb.AuthRoleAddRequest) (*pb.AuthRoleAddResponse, error)
+
+	// RoleGrantPermission grants a permission to a role
+	RoleGrantPermission(r *pb.AuthRoleGrantPermissionRequest) (*pb.AuthRoleGrantPermissionResponse, error)
+
+	// RoleGet gets the detailed information of a role
+	RoleGet(r *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error)
+
+	// RoleRevokePermission gets the detailed information of a role
+	RoleRevokePermission(r *pb.AuthRoleRevokePermissionRequest) (*pb.AuthRoleRevokePermissionResponse, error)
+
+	// RoleDelete gets the detailed information of a role
+	RoleDelete(r *pb.AuthRoleDeleteRequest) (*pb.AuthRoleDeleteResponse, error)
+
+	// UserList gets a list of all users
+	UserList(r *pb.AuthUserListRequest) (*pb.AuthUserListResponse, error)
+
+	// RoleList gets a list of all roles
+	RoleList(r *pb.AuthRoleListRequest) (*pb.AuthRoleListResponse, error)
+
+	// IsPutPermitted checks put permission of the user
+	IsPutPermitted(authInfo *AuthInfo, key []byte) error
+
+	// IsRangePermitted checks range permission of the user
+	IsRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error
+
+	// IsDeleteRangePermitted checks delete-range permission of the user
+	IsDeleteRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error
+
+	// IsAdminPermitted checks admin permission of the user
+	IsAdminPermitted(authInfo *AuthInfo) error
+
+	// GenTokenPrefix produces a random string in a case of simple token
+	// in a case of JWT, it produces an empty string
+	GenTokenPrefix() (string, error)
+
+	// Revision gets current revision of authStore
+	Revision() uint64
+
+	// CheckPassword checks a given pair of username and password is correct
+	CheckPassword(username, password string) (uint64, error)
+
+	// Close does cleanup of AuthStore
+	Close() error
+
+	// AuthInfoFromCtx gets AuthInfo from gRPC's context
+	AuthInfoFromCtx(ctx context.Context) (*AuthInfo, error)
+
+	// AuthInfoFromTLS gets AuthInfo from TLS info of gRPC's context
+	AuthInfoFromTLS(ctx context.Context) *AuthInfo
+
+	// WithRoot generates and installs a token that can be used as a root credential
+	WithRoot(ctx context.Context) context.Context
+
+	// HasRole checks that user has role
+	HasRole(user, role string) bool
+}
+
+type TokenProvider interface {
+	info(ctx context.Context, token string, revision uint64) (*AuthInfo, bool)
+	assign(ctx context.Context, username string, revision uint64) (string, error)
+	enable()
+	disable()
+
+	invalidateUser(string)
+	genTokenPrefix() (string, error)
+}
+
+type authStore struct {
+	// atomic operations; need 64-bit align, or 32-bit tests will crash
+	revision uint64
+
+	be        backend.Backend
+	enabled   bool
+	enabledMu sync.RWMutex
+
+	rangePermCache map[string]*unifiedRangePermissions // username -> unifiedRangePermissions
+
+	tokenProvider TokenProvider
+}
+
+func (as *authStore) AuthEnable() error {
+	as.enabledMu.Lock()
+	defer as.enabledMu.Unlock()
+	if as.enabled {
+		plog.Noticef("Authentication already enabled")
+		return nil
+	}
+	b := as.be
+	tx := b.BatchTx()
+	tx.Lock()
+	defer func() {
+		tx.Unlock()
+		b.ForceCommit()
+	}()
+
+	u := getUser(tx, rootUser)
+	if u == nil {
+		return ErrRootUserNotExist
+	}
+
+	if !hasRootRole(u) {
+		return ErrRootRoleNotExist
+	}
+
+	tx.UnsafePut(authBucketName, enableFlagKey, authEnabled)
+
+	as.enabled = true
+	as.tokenProvider.enable()
+
+	as.rangePermCache = make(map[string]*unifiedRangePermissions)
+
+	as.setRevision(getRevision(tx))
+
+	plog.Noticef("Authentication enabled")
+
+	return nil
+}
+
+func (as *authStore) AuthDisable() {
+	as.enabledMu.Lock()
+	defer as.enabledMu.Unlock()
+	if !as.enabled {
+		return
+	}
+	b := as.be
+	tx := b.BatchTx()
+	tx.Lock()
+	tx.UnsafePut(authBucketName, enableFlagKey, authDisabled)
+	as.commitRevision(tx)
+	tx.Unlock()
+	b.ForceCommit()
+
+	as.enabled = false
+	as.tokenProvider.disable()
+
+	plog.Noticef("Authentication disabled")
+}
+
+func (as *authStore) Close() error {
+	as.enabledMu.Lock()
+	defer as.enabledMu.Unlock()
+	if !as.enabled {
+		return nil
+	}
+	as.tokenProvider.disable()
+	return nil
+}
+
+func (as *authStore) Authenticate(ctx context.Context, username, password string) (*pb.AuthenticateResponse, error) {
+	if !as.isAuthEnabled() {
+		return nil, ErrAuthNotEnabled
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, username)
+	if user == nil {
+		return nil, ErrAuthFailed
+	}
+
+	// Password checking is already performed in the API layer, so we don't need to check for now.
+	// Staleness of password can be detected with OCC in the API layer, too.
+
+	token, err := as.tokenProvider.assign(ctx, username, as.Revision())
+	if err != nil {
+		return nil, err
+	}
+
+	plog.Debugf("authorized %s, token is %s", username, token)
+	return &pb.AuthenticateResponse{Token: token}, nil
+}
+
+func (as *authStore) CheckPassword(username, password string) (uint64, error) {
+	if !as.isAuthEnabled() {
+		return 0, ErrAuthNotEnabled
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, username)
+	if user == nil {
+		return 0, ErrAuthFailed
+	}
+
+	if bcrypt.CompareHashAndPassword(user.Password, []byte(password)) != nil {
+		plog.Noticef("authentication failed, invalid password for user %s", username)
+		return 0, ErrAuthFailed
+	}
+
+	return getRevision(tx), nil
+}
+
+func (as *authStore) Recover(be backend.Backend) {
+	enabled := false
+	as.be = be
+	tx := be.BatchTx()
+	tx.Lock()
+	_, vs := tx.UnsafeRange(authBucketName, enableFlagKey, nil, 0)
+	if len(vs) == 1 {
+		if bytes.Equal(vs[0], authEnabled) {
+			enabled = true
+		}
+	}
+
+	as.setRevision(getRevision(tx))
+
+	tx.Unlock()
+
+	as.enabledMu.Lock()
+	as.enabled = enabled
+	as.enabledMu.Unlock()
+}
+
+func (as *authStore) UserAdd(r *pb.AuthUserAddRequest) (*pb.AuthUserAddResponse, error) {
+	if len(r.Name) == 0 {
+		return nil, ErrUserEmpty
+	}
+
+	hashed, err := bcrypt.GenerateFromPassword([]byte(r.Password), BcryptCost)
+	if err != nil {
+		plog.Errorf("failed to hash password: %s", err)
+		return nil, err
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, r.Name)
+	if user != nil {
+		return nil, ErrUserAlreadyExist
+	}
+
+	newUser := &authpb.User{
+		Name:     []byte(r.Name),
+		Password: hashed,
+	}
+
+	putUser(tx, newUser)
+
+	as.commitRevision(tx)
+
+	plog.Noticef("added a new user: %s", r.Name)
+
+	return &pb.AuthUserAddResponse{}, nil
+}
+
+func (as *authStore) UserDelete(r *pb.AuthUserDeleteRequest) (*pb.AuthUserDeleteResponse, error) {
+	if as.enabled && strings.Compare(r.Name, rootUser) == 0 {
+		plog.Errorf("the user root must not be deleted")
+		return nil, ErrInvalidAuthMgmt
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, r.Name)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	delUser(tx, r.Name)
+
+	as.commitRevision(tx)
+
+	as.invalidateCachedPerm(r.Name)
+	as.tokenProvider.invalidateUser(r.Name)
+
+	plog.Noticef("deleted a user: %s", r.Name)
+
+	return &pb.AuthUserDeleteResponse{}, nil
+}
+
+func (as *authStore) UserChangePassword(r *pb.AuthUserChangePasswordRequest) (*pb.AuthUserChangePasswordResponse, error) {
+	// TODO(mitake): measure the cost of bcrypt.GenerateFromPassword()
+	// If the cost is too high, we should move the encryption to outside of the raft
+	hashed, err := bcrypt.GenerateFromPassword([]byte(r.Password), BcryptCost)
+	if err != nil {
+		plog.Errorf("failed to hash password: %s", err)
+		return nil, err
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, r.Name)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	updatedUser := &authpb.User{
+		Name:     []byte(r.Name),
+		Roles:    user.Roles,
+		Password: hashed,
+	}
+
+	putUser(tx, updatedUser)
+
+	as.commitRevision(tx)
+
+	as.invalidateCachedPerm(r.Name)
+	as.tokenProvider.invalidateUser(r.Name)
+
+	plog.Noticef("changed a password of a user: %s", r.Name)
+
+	return &pb.AuthUserChangePasswordResponse{}, nil
+}
+
+func (as *authStore) UserGrantRole(r *pb.AuthUserGrantRoleRequest) (*pb.AuthUserGrantRoleResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, r.User)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	if r.Role != rootRole {
+		role := getRole(tx, r.Role)
+		if role == nil {
+			return nil, ErrRoleNotFound
+		}
+	}
+
+	idx := sort.SearchStrings(user.Roles, r.Role)
+	if idx < len(user.Roles) && strings.Compare(user.Roles[idx], r.Role) == 0 {
+		plog.Warningf("user %s is already granted role %s", r.User, r.Role)
+		return &pb.AuthUserGrantRoleResponse{}, nil
+	}
+
+	user.Roles = append(user.Roles, r.Role)
+	sort.Strings(user.Roles)
+
+	putUser(tx, user)
+
+	as.invalidateCachedPerm(r.User)
+
+	as.commitRevision(tx)
+
+	plog.Noticef("granted role %s to user %s", r.Role, r.User)
+	return &pb.AuthUserGrantRoleResponse{}, nil
+}
+
+func (as *authStore) UserGet(r *pb.AuthUserGetRequest) (*pb.AuthUserGetResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	user := getUser(tx, r.Name)
+	tx.Unlock()
+
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	var resp pb.AuthUserGetResponse
+	resp.Roles = append(resp.Roles, user.Roles...)
+	return &resp, nil
+}
+
+func (as *authStore) UserList(r *pb.AuthUserListRequest) (*pb.AuthUserListResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	users := getAllUsers(tx)
+	tx.Unlock()
+
+	resp := &pb.AuthUserListResponse{Users: make([]string, len(users))}
+	for i := range users {
+		resp.Users[i] = string(users[i].Name)
+	}
+	return resp, nil
+}
+
+func (as *authStore) UserRevokeRole(r *pb.AuthUserRevokeRoleRequest) (*pb.AuthUserRevokeRoleResponse, error) {
+	if as.enabled && strings.Compare(r.Name, rootUser) == 0 && strings.Compare(r.Role, rootRole) == 0 {
+		plog.Errorf("the role root must not be revoked from the user root")
+		return nil, ErrInvalidAuthMgmt
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, r.Name)
+	if user == nil {
+		return nil, ErrUserNotFound
+	}
+
+	updatedUser := &authpb.User{
+		Name:     user.Name,
+		Password: user.Password,
+	}
+
+	for _, role := range user.Roles {
+		if strings.Compare(role, r.Role) != 0 {
+			updatedUser.Roles = append(updatedUser.Roles, role)
+		}
+	}
+
+	if len(updatedUser.Roles) == len(user.Roles) {
+		return nil, ErrRoleNotGranted
+	}
+
+	putUser(tx, updatedUser)
+
+	as.invalidateCachedPerm(r.Name)
+
+	as.commitRevision(tx)
+
+	plog.Noticef("revoked role %s from user %s", r.Role, r.Name)
+	return &pb.AuthUserRevokeRoleResponse{}, nil
+}
+
+func (as *authStore) RoleGet(r *pb.AuthRoleGetRequest) (*pb.AuthRoleGetResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	var resp pb.AuthRoleGetResponse
+
+	role := getRole(tx, r.Role)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+	resp.Perm = append(resp.Perm, role.KeyPermission...)
+	return &resp, nil
+}
+
+func (as *authStore) RoleList(r *pb.AuthRoleListRequest) (*pb.AuthRoleListResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	roles := getAllRoles(tx)
+	tx.Unlock()
+
+	resp := &pb.AuthRoleListResponse{Roles: make([]string, len(roles))}
+	for i := range roles {
+		resp.Roles[i] = string(roles[i].Name)
+	}
+	return resp, nil
+}
+
+func (as *authStore) RoleRevokePermission(r *pb.AuthRoleRevokePermissionRequest) (*pb.AuthRoleRevokePermissionResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := getRole(tx, r.Role)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+
+	updatedRole := &authpb.Role{
+		Name: role.Name,
+	}
+
+	for _, perm := range role.KeyPermission {
+		if !bytes.Equal(perm.Key, []byte(r.Key)) || !bytes.Equal(perm.RangeEnd, []byte(r.RangeEnd)) {
+			updatedRole.KeyPermission = append(updatedRole.KeyPermission, perm)
+		}
+	}
+
+	if len(role.KeyPermission) == len(updatedRole.KeyPermission) {
+		return nil, ErrPermissionNotGranted
+	}
+
+	putRole(tx, updatedRole)
+
+	// TODO(mitake): currently single role update invalidates every cache
+	// It should be optimized.
+	as.clearCachedPerm()
+
+	as.commitRevision(tx)
+
+	plog.Noticef("revoked key %s from role %s", r.Key, r.Role)
+	return &pb.AuthRoleRevokePermissionResponse{}, nil
+}
+
+func (as *authStore) RoleDelete(r *pb.AuthRoleDeleteRequest) (*pb.AuthRoleDeleteResponse, error) {
+	if as.enabled && strings.Compare(r.Role, rootRole) == 0 {
+		plog.Errorf("the role root must not be deleted")
+		return nil, ErrInvalidAuthMgmt
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := getRole(tx, r.Role)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+
+	delRole(tx, r.Role)
+
+	users := getAllUsers(tx)
+	for _, user := range users {
+		updatedUser := &authpb.User{
+			Name:     user.Name,
+			Password: user.Password,
+		}
+
+		for _, role := range user.Roles {
+			if strings.Compare(role, r.Role) != 0 {
+				updatedUser.Roles = append(updatedUser.Roles, role)
+			}
+		}
+
+		if len(updatedUser.Roles) == len(user.Roles) {
+			continue
+		}
+
+		putUser(tx, updatedUser)
+
+		as.invalidateCachedPerm(string(user.Name))
+	}
+
+	as.commitRevision(tx)
+
+	plog.Noticef("deleted role %s", r.Role)
+	return &pb.AuthRoleDeleteResponse{}, nil
+}
+
+func (as *authStore) RoleAdd(r *pb.AuthRoleAddRequest) (*pb.AuthRoleAddResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := getRole(tx, r.Name)
+	if role != nil {
+		return nil, ErrRoleAlreadyExist
+	}
+
+	newRole := &authpb.Role{
+		Name: []byte(r.Name),
+	}
+
+	putRole(tx, newRole)
+
+	as.commitRevision(tx)
+
+	plog.Noticef("Role %s is created", r.Name)
+
+	return &pb.AuthRoleAddResponse{}, nil
+}
+
+func (as *authStore) authInfoFromToken(ctx context.Context, token string) (*AuthInfo, bool) {
+	return as.tokenProvider.info(ctx, token, as.Revision())
+}
+
+type permSlice []*authpb.Permission
+
+func (perms permSlice) Len() int {
+	return len(perms)
+}
+
+func (perms permSlice) Less(i, j int) bool {
+	return bytes.Compare(perms[i].Key, perms[j].Key) < 0
+}
+
+func (perms permSlice) Swap(i, j int) {
+	perms[i], perms[j] = perms[j], perms[i]
+}
+
+func (as *authStore) RoleGrantPermission(r *pb.AuthRoleGrantPermissionRequest) (*pb.AuthRoleGrantPermissionResponse, error) {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	role := getRole(tx, r.Name)
+	if role == nil {
+		return nil, ErrRoleNotFound
+	}
+
+	idx := sort.Search(len(role.KeyPermission), func(i int) bool {
+		return bytes.Compare(role.KeyPermission[i].Key, []byte(r.Perm.Key)) >= 0
+	})
+
+	if idx < len(role.KeyPermission) && bytes.Equal(role.KeyPermission[idx].Key, r.Perm.Key) && bytes.Equal(role.KeyPermission[idx].RangeEnd, r.Perm.RangeEnd) {
+		// update existing permission
+		role.KeyPermission[idx].PermType = r.Perm.PermType
+	} else {
+		// append new permission to the role
+		newPerm := &authpb.Permission{
+			Key:      []byte(r.Perm.Key),
+			RangeEnd: []byte(r.Perm.RangeEnd),
+			PermType: r.Perm.PermType,
+		}
+
+		role.KeyPermission = append(role.KeyPermission, newPerm)
+		sort.Sort(permSlice(role.KeyPermission))
+	}
+
+	putRole(tx, role)
+
+	// TODO(mitake): currently single role update invalidates every cache
+	// It should be optimized.
+	as.clearCachedPerm()
+
+	as.commitRevision(tx)
+
+	plog.Noticef("role %s's permission of key %s is updated as %s", r.Name, r.Perm.Key, authpb.Permission_Type_name[int32(r.Perm.PermType)])
+
+	return &pb.AuthRoleGrantPermissionResponse{}, nil
+}
+
+func (as *authStore) isOpPermitted(userName string, revision uint64, key, rangeEnd []byte, permTyp authpb.Permission_Type) error {
+	// TODO(mitake): this function would be costly so we need a caching mechanism
+	if !as.isAuthEnabled() {
+		return nil
+	}
+
+	// only gets rev == 0 when passed AuthInfo{}; no user given
+	if revision == 0 {
+		return ErrUserEmpty
+	}
+
+	if revision < as.Revision() {
+		return ErrAuthOldRevision
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	defer tx.Unlock()
+
+	user := getUser(tx, userName)
+	if user == nil {
+		plog.Errorf("invalid user name %s for permission checking", userName)
+		return ErrPermissionDenied
+	}
+
+	// root role should have permission on all ranges
+	if hasRootRole(user) {
+		return nil
+	}
+
+	if as.isRangeOpPermitted(tx, userName, key, rangeEnd, permTyp) {
+		return nil
+	}
+
+	return ErrPermissionDenied
+}
+
+func (as *authStore) IsPutPermitted(authInfo *AuthInfo, key []byte) error {
+	return as.isOpPermitted(authInfo.Username, authInfo.Revision, key, nil, authpb.WRITE)
+}
+
+func (as *authStore) IsRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error {
+	return as.isOpPermitted(authInfo.Username, authInfo.Revision, key, rangeEnd, authpb.READ)
+}
+
+func (as *authStore) IsDeleteRangePermitted(authInfo *AuthInfo, key, rangeEnd []byte) error {
+	return as.isOpPermitted(authInfo.Username, authInfo.Revision, key, rangeEnd, authpb.WRITE)
+}
+
+func (as *authStore) IsAdminPermitted(authInfo *AuthInfo) error {
+	if !as.isAuthEnabled() {
+		return nil
+	}
+	if authInfo == nil {
+		return ErrUserEmpty
+	}
+
+	tx := as.be.BatchTx()
+	tx.Lock()
+	u := getUser(tx, authInfo.Username)
+	tx.Unlock()
+
+	if u == nil {
+		return ErrUserNotFound
+	}
+
+	if !hasRootRole(u) {
+		return ErrPermissionDenied
+	}
+
+	return nil
+}
+
+func getUser(tx backend.BatchTx, username string) *authpb.User {
+	_, vs := tx.UnsafeRange(authUsersBucketName, []byte(username), nil, 0)
+	if len(vs) == 0 {
+		return nil
+	}
+
+	user := &authpb.User{}
+	err := user.Unmarshal(vs[0])
+	if err != nil {
+		plog.Panicf("failed to unmarshal user struct (name: %s): %s", username, err)
+	}
+	return user
+}
+
+func getAllUsers(tx backend.BatchTx) []*authpb.User {
+	_, vs := tx.UnsafeRange(authUsersBucketName, []byte{0}, []byte{0xff}, -1)
+	if len(vs) == 0 {
+		return nil
+	}
+
+	users := make([]*authpb.User, len(vs))
+	for i := range vs {
+		user := &authpb.User{}
+		err := user.Unmarshal(vs[i])
+		if err != nil {
+			plog.Panicf("failed to unmarshal user struct: %s", err)
+		}
+		users[i] = user
+	}
+	return users
+}
+
+func putUser(tx backend.BatchTx, user *authpb.User) {
+	b, err := user.Marshal()
+	if err != nil {
+		plog.Panicf("failed to marshal user struct (name: %s): %s", user.Name, err)
+	}
+	tx.UnsafePut(authUsersBucketName, user.Name, b)
+}
+
+func delUser(tx backend.BatchTx, username string) {
+	tx.UnsafeDelete(authUsersBucketName, []byte(username))
+}
+
+func getRole(tx backend.BatchTx, rolename string) *authpb.Role {
+	_, vs := tx.UnsafeRange(authRolesBucketName, []byte(rolename), nil, 0)
+	if len(vs) == 0 {
+		return nil
+	}
+
+	role := &authpb.Role{}
+	err := role.Unmarshal(vs[0])
+	if err != nil {
+		plog.Panicf("failed to unmarshal role struct (name: %s): %s", rolename, err)
+	}
+	return role
+}
+
+func getAllRoles(tx backend.BatchTx) []*authpb.Role {
+	_, vs := tx.UnsafeRange(authRolesBucketName, []byte{0}, []byte{0xff}, -1)
+	if len(vs) == 0 {
+		return nil
+	}
+
+	roles := make([]*authpb.Role, len(vs))
+	for i := range vs {
+		role := &authpb.Role{}
+		err := role.Unmarshal(vs[i])
+		if err != nil {
+			plog.Panicf("failed to unmarshal role struct: %s", err)
+		}
+		roles[i] = role
+	}
+	return roles
+}
+
+func putRole(tx backend.BatchTx, role *authpb.Role) {
+	b, err := role.Marshal()
+	if err != nil {
+		plog.Panicf("failed to marshal role struct (name: %s): %s", role.Name, err)
+	}
+
+	tx.UnsafePut(authRolesBucketName, []byte(role.Name), b)
+}
+
+func delRole(tx backend.BatchTx, rolename string) {
+	tx.UnsafeDelete(authRolesBucketName, []byte(rolename))
+}
+
+func (as *authStore) isAuthEnabled() bool {
+	as.enabledMu.RLock()
+	defer as.enabledMu.RUnlock()
+	return as.enabled
+}
+
+func NewAuthStore(be backend.Backend, tp TokenProvider) *authStore {
+	tx := be.BatchTx()
+	tx.Lock()
+
+	tx.UnsafeCreateBucket(authBucketName)
+	tx.UnsafeCreateBucket(authUsersBucketName)
+	tx.UnsafeCreateBucket(authRolesBucketName)
+
+	enabled := false
+	_, vs := tx.UnsafeRange(authBucketName, enableFlagKey, nil, 0)
+	if len(vs) == 1 {
+		if bytes.Equal(vs[0], authEnabled) {
+			enabled = true
+		}
+	}
+
+	as := &authStore{
+		be:             be,
+		revision:       getRevision(tx),
+		enabled:        enabled,
+		rangePermCache: make(map[string]*unifiedRangePermissions),
+		tokenProvider:  tp,
+	}
+
+	if enabled {
+		as.tokenProvider.enable()
+	}
+
+	if as.Revision() == 0 {
+		as.commitRevision(tx)
+	}
+
+	tx.Unlock()
+	be.ForceCommit()
+
+	return as
+}
+
+func hasRootRole(u *authpb.User) bool {
+	// u.Roles is sorted in UserGrantRole(), so we can use binary search.
+	idx := sort.SearchStrings(u.Roles, rootRole)
+	return idx != len(u.Roles) && u.Roles[idx] == rootRole
+}
+
+func (as *authStore) commitRevision(tx backend.BatchTx) {
+	atomic.AddUint64(&as.revision, 1)
+	revBytes := make([]byte, revBytesLen)
+	binary.BigEndian.PutUint64(revBytes, as.Revision())
+	tx.UnsafePut(authBucketName, revisionKey, revBytes)
+}
+
+func getRevision(tx backend.BatchTx) uint64 {
+	_, vs := tx.UnsafeRange(authBucketName, []byte(revisionKey), nil, 0)
+	if len(vs) != 1 {
+		// this can happen in the initialization phase
+		return 0
+	}
+
+	return binary.BigEndian.Uint64(vs[0])
+}
+
+func (as *authStore) setRevision(rev uint64) {
+	atomic.StoreUint64(&as.revision, rev)
+}
+
+func (as *authStore) Revision() uint64 {
+	return atomic.LoadUint64(&as.revision)
+}
+
+func (as *authStore) AuthInfoFromTLS(ctx context.Context) *AuthInfo {
+	peer, ok := peer.FromContext(ctx)
+	if !ok || peer == nil || peer.AuthInfo == nil {
+		return nil
+	}
+
+	tlsInfo := peer.AuthInfo.(credentials.TLSInfo)
+	for _, chains := range tlsInfo.State.VerifiedChains {
+		for _, chain := range chains {
+			cn := chain.Subject.CommonName
+			plog.Debugf("found common name %s", cn)
+
+			ai := &AuthInfo{
+				Username: cn,
+				Revision: as.Revision(),
+			}
+			md, ok := metadata.FromIncomingContext(ctx)
+			if !ok {
+				return nil
+			}
+
+			// gRPC-gateway proxy request to etcd server includes Grpcgateway-Accept
+			// header. The proxy uses etcd client server certificate. If the certificate
+			// has a CommonName we should never use this for authentication.
+			if gw := md["grpcgateway-accept"]; len(gw) > 0 {
+				plog.Warningf("ignoring common name in gRPC-gateway proxy request %s", ai.Username)
+				return nil
+			}
+			return ai
+		}
+	}
+
+	return nil
+}
+
+func (as *authStore) AuthInfoFromCtx(ctx context.Context) (*AuthInfo, error) {
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return nil, nil
+	}
+
+	//TODO(mitake|hexfusion) review unifying key names
+	ts, ok := md["token"]
+	if !ok {
+		ts, ok = md["authorization"]
+	}
+	if !ok {
+		return nil, nil
+	}
+
+	token := ts[0]
+	authInfo, uok := as.authInfoFromToken(ctx, token)
+	if !uok {
+		plog.Warningf("invalid auth token: %s", token)
+		return nil, ErrInvalidAuthToken
+	}
+
+	return authInfo, nil
+}
+
+func (as *authStore) GenTokenPrefix() (string, error) {
+	return as.tokenProvider.genTokenPrefix()
+}
+
+func decomposeOpts(optstr string) (string, map[string]string, error) {
+	opts := strings.Split(optstr, ",")
+	tokenType := opts[0]
+
+	typeSpecificOpts := make(map[string]string)
+	for i := 1; i < len(opts); i++ {
+		pair := strings.Split(opts[i], "=")
+
+		if len(pair) != 2 {
+			plog.Errorf("invalid token specific option: %s", optstr)
+			return "", nil, ErrInvalidAuthOpts
+		}
+
+		if _, ok := typeSpecificOpts[pair[0]]; ok {
+			plog.Errorf("invalid token specific option, duplicated parameters (%s): %s", pair[0], optstr)
+			return "", nil, ErrInvalidAuthOpts
+		}
+
+		typeSpecificOpts[pair[0]] = pair[1]
+	}
+
+	return tokenType, typeSpecificOpts, nil
+
+}
+
+func NewTokenProvider(tokenOpts string, indexWaiter func(uint64) <-chan struct{}) (TokenProvider, error) {
+	tokenType, typeSpecificOpts, err := decomposeOpts(tokenOpts)
+	if err != nil {
+		return nil, ErrInvalidAuthOpts
+	}
+
+	switch tokenType {
+	case tokenTypeSimple:
+		plog.Warningf("simple token is not cryptographically signed")
+		return newTokenProviderSimple(indexWaiter), nil
+
+	case tokenTypeJWT:
+		return newTokenProviderJWT(typeSpecificOpts)
+
+	case "":
+		return newTokenProviderNop()
+	default:
+		plog.Errorf("unknown token type: %s", tokenType)
+		return nil, ErrInvalidAuthOpts
+	}
+}
+
+func (as *authStore) WithRoot(ctx context.Context) context.Context {
+	if !as.isAuthEnabled() {
+		return ctx
+	}
+
+	var ctxForAssign context.Context
+	if ts, ok := as.tokenProvider.(*tokenSimple); ok && ts != nil {
+		ctx1 := context.WithValue(ctx, AuthenticateParamIndex{}, uint64(0))
+		prefix, err := ts.genTokenPrefix()
+		if err != nil {
+			plog.Errorf("failed to generate prefix of internally used token")
+			return ctx
+		}
+		ctxForAssign = context.WithValue(ctx1, AuthenticateParamSimpleTokenPrefix{}, prefix)
+	} else {
+		ctxForAssign = ctx
+	}
+
+	token, err := as.tokenProvider.assign(ctxForAssign, "root", as.Revision())
+	if err != nil {
+		// this must not happen
+		plog.Errorf("failed to assign token for lease revoking: %s", err)
+		return ctx
+	}
+
+	mdMap := map[string]string{
+		"token": token,
+	}
+	tokenMD := metadata.New(mdMap)
+
+	// use "mdIncomingKey{}" since it's called from local etcdserver
+	return metadata.NewIncomingContext(ctx, tokenMD)
+}
+
+func (as *authStore) HasRole(user, role string) bool {
+	tx := as.be.BatchTx()
+	tx.Lock()
+	u := getUser(tx, user)
+	tx.Unlock()
+
+	if u == nil {
+		plog.Warningf("tried to check user %s has role %s, but user %s doesn't exist", user, role, user)
+		return false
+	}
+
+	for _, r := range u.Roles {
+		if role == r {
+			return true
+		}
+	}
+
+	return false
+}