diff --git a/Gopkg.lock b/Gopkg.lock
index d4514ef2..8f6edc08 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -363,7 +363,7 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:f1f1df1e19d55a1ef1f0a63633191e7d2a99993c0a17f945c0b9ebd16b17871b"
+  digest = "1:5e778214d472b6d2ad4d544d293d1478d9b222db8ffc6079623fbe3e58e1841e"
   name = "github.com/smallstep/nosql"
   packages = [
     ".",
@@ -373,7 +373,7 @@
     "mysql",
   ]
   pruneopts = "UT"
-  revision = "5a355c598075a346d9ca9b50ec10e3f86ac66148"
+  revision = "b66b34823456721912ba037126e92414690c07d6"
 
 [[projects]]
   branch = "master"
diff --git a/authority/authority.go b/authority/authority.go
index aad8c3e2..5497dc2d 100644
--- a/authority/authority.go
+++ b/authority/authority.go
@@ -22,7 +22,6 @@ type Authority struct {
 	intermediateIdentity *x509util.Identity
 	validateOnce         bool
 	certificates         *sync.Map
-	ottMap               *sync.Map
 	startTime            time.Time
 	provisioners         *provisioner.Collection
 	db                   db.AuthDB
@@ -40,7 +39,6 @@ func New(config *Config) (*Authority, error) {
 	var a = &Authority{
 		config:       config,
 		certificates: new(sync.Map),
-		ottMap:       new(sync.Map),
 		provisioners: provisioner.NewCollection(config.getAudiences()),
 	}
 	if err := a.init(); err != nil {
@@ -58,8 +56,8 @@ func (a *Authority) init() error {
 
 	var err error
 
-	// Initialize step-ca Database if defined in configuration.
-	// If a.config.DB is nil then a noopDB will be returned.
+	// Initialize step-ca Database.
+	// If a.config.DB is nil then a simple, barebones in memory DB will be used.
 	if a.db, err = db.New(a.config.DB); err != nil {
 		return err
 	}
diff --git a/authority/authorize.go b/authority/authorize.go
index 62152d09..bf4ce15f 100644
--- a/authority/authorize.go
+++ b/authority/authorize.go
@@ -4,18 +4,12 @@ import (
 	"crypto/x509"
 	"net/http"
 	"strings"
-	"time"
 
 	"github.com/pkg/errors"
 	"github.com/smallstep/certificates/authority/provisioner"
 	"github.com/smallstep/cli/jose"
 )
 
-type idUsed struct {
-	UsedAt  int64  `json:"ua,omitempty"`
-	Subject string `json:"sub,omitempty"`
-}
-
 // Claims extends jose.Claims with step attributes.
 type Claims struct {
 	jose.Claims
@@ -72,10 +66,12 @@ func (a *Authority) authorizeToken(ott string) (provisioner.Interface, error) {
 		reuseKey = claims.Nonce
 	}
 	if reuseKey != "" {
-		if _, ok := a.ottMap.LoadOrStore(reuseKey, &idUsed{
-			UsedAt:  time.Now().Unix(),
-			Subject: claims.Subject,
-		}); ok {
+		ok, err := a.db.UseToken(reuseKey, ott)
+		if err != nil {
+			return nil, &apiError{errors.Wrap(err, "authorizeToken: failed when checking if token already used"),
+				http.StatusInternalServerError, errContext}
+		}
+		if !ok {
 			return nil, &apiError{errors.Errorf("authorizeToken: token already used"), http.StatusUnauthorized, errContext}
 		}
 	}
diff --git a/authority/authorize_test.go b/authority/authorize_test.go
index 90365655..368e9807 100644
--- a/authority/authorize_test.go
+++ b/authority/authorize_test.go
@@ -117,7 +117,7 @@ func TestAuthority_authorizeToken(t *testing.T) {
 					http.StatusUnauthorized, context{"ott": raw}},
 			}
 		},
-		"ok": func(t *testing.T) *authorizeTest {
+		"ok/simpledb": func(t *testing.T) *authorizeTest {
 			cl := jwt.Claims{
 				Subject:   "test.smallstep.com",
 				Issuer:    validIssuer,
@@ -133,9 +133,8 @@ func TestAuthority_authorizeToken(t *testing.T) {
 				ott:  raw,
 			}
 		},
-		"fail/token-already-used": func(t *testing.T) *authorizeTest {
+		"fail/simpledb/token-already-used": func(t *testing.T) *authorizeTest {
 			_a := testAuthority(t)
-
 			cl := jwt.Claims{
 				Subject:   "test.smallstep.com",
 				Issuer:    validIssuer,
@@ -155,6 +154,79 @@ func TestAuthority_authorizeToken(t *testing.T) {
 					http.StatusUnauthorized, context{"ott": raw}},
 			}
 		},
+		"ok/mockNoSQLDB": func(t *testing.T) *authorizeTest {
+			_a := testAuthority(t)
+			_a.db = &MockAuthDB{
+				useToken: func(id, tok string) (bool, error) {
+					return true, nil
+				},
+			}
+
+			cl := jwt.Claims{
+				Subject:   "test.smallstep.com",
+				Issuer:    validIssuer,
+				NotBefore: jwt.NewNumericDate(now),
+				Expiry:    jwt.NewNumericDate(now.Add(time.Minute)),
+				Audience:  validAudience,
+				ID:        "43",
+			}
+			raw, err := jwt.Signed(sig).Claims(cl).CompactSerialize()
+			assert.FatalError(t, err)
+			return &authorizeTest{
+				auth: _a,
+				ott:  raw,
+			}
+		},
+		"fail/mockNoSQLDB/error": func(t *testing.T) *authorizeTest {
+			_a := testAuthority(t)
+			_a.db = &MockAuthDB{
+				useToken: func(id, tok string) (bool, error) {
+					return false, errors.New("force")
+				},
+			}
+
+			cl := jwt.Claims{
+				Subject:   "test.smallstep.com",
+				Issuer:    validIssuer,
+				NotBefore: jwt.NewNumericDate(now),
+				Expiry:    jwt.NewNumericDate(now.Add(time.Minute)),
+				Audience:  validAudience,
+				ID:        "43",
+			}
+			raw, err := jwt.Signed(sig).Claims(cl).CompactSerialize()
+			assert.FatalError(t, err)
+			return &authorizeTest{
+				auth: _a,
+				ott:  raw,
+				err: &apiError{errors.New("authorizeToken: failed when checking if token already used: force"),
+					http.StatusInternalServerError, context{"ott": raw}},
+			}
+		},
+		"fail/mockNoSQLDB/token-already-used": func(t *testing.T) *authorizeTest {
+			_a := testAuthority(t)
+			_a.db = &MockAuthDB{
+				useToken: func(id, tok string) (bool, error) {
+					return false, nil
+				},
+			}
+
+			cl := jwt.Claims{
+				Subject:   "test.smallstep.com",
+				Issuer:    validIssuer,
+				NotBefore: jwt.NewNumericDate(now),
+				Expiry:    jwt.NewNumericDate(now.Add(time.Minute)),
+				Audience:  validAudience,
+				ID:        "43",
+			}
+			raw, err := jwt.Signed(sig).Claims(cl).CompactSerialize()
+			assert.FatalError(t, err)
+			return &authorizeTest{
+				auth: _a,
+				ott:  raw,
+				err: &apiError{errors.New("authorizeToken: token already used"),
+					http.StatusUnauthorized, context{"ott": raw}},
+			}
+		},
 	}
 
 	for name, genTestCase := range tests {
diff --git a/authority/db_test.go b/authority/db_test.go
index b4e073f1..870a3984 100644
--- a/authority/db_test.go
+++ b/authority/db_test.go
@@ -13,6 +13,7 @@ type MockAuthDB struct {
 	isRevoked        func(string) (bool, error)
 	revoke           func(rci *db.RevokedCertificateInfo) error
 	storeCertificate func(crt *x509.Certificate) error
+	useToken         func(id, tok string) (bool, error)
 	shutdown         func() error
 }
 
@@ -33,6 +34,16 @@ func (m *MockAuthDB) IsRevoked(sn string) (bool, error) {
 	return m.ret1.(bool), m.err
 }
 
+func (m *MockAuthDB) UseToken(id, tok string) (bool, error) {
+	if m.useToken != nil {
+		return m.useToken(id, tok)
+	}
+	if m.ret1 == nil {
+		return false, m.err
+	}
+	return m.ret1.(bool), m.err
+}
+
 func (m *MockAuthDB) Revoke(rci *db.RevokedCertificateInfo) error {
 	if m.revoke != nil {
 		return m.revoke(rci)
diff --git a/authority/tls_test.go b/authority/tls_test.go
index ea2c4063..142eedde 100644
--- a/authority/tls_test.go
+++ b/authority/tls_test.go
@@ -592,7 +592,6 @@ func TestRevoke(t *testing.T) {
 	tests := map[string]func() test{
 		"error/token/authorizeRevoke error": func() test {
 			a := testAuthority(t)
-			a.db = new(db.NoopDB)
 			ctx := getCtx()
 			ctx["ott"] = "foo"
 			return test{
@@ -609,8 +608,6 @@ func TestRevoke(t *testing.T) {
 		},
 		"error/nil-db": func() test {
 			a := testAuthority(t)
-			a.db = new(db.NoopDB)
-
 			cl := jwt.Claims{
 				Subject:   "sn",
 				Issuer:    validIssuer,
@@ -640,7 +637,12 @@ func TestRevoke(t *testing.T) {
 		},
 		"error/db-revoke": func() test {
 			a := testAuthority(t)
-			a.db = &MockAuthDB{err: errors.New("force")}
+			a.db = &MockAuthDB{
+				useToken: func(id, tok string) (bool, error) {
+					return true, nil
+				},
+				err: errors.New("force"),
+			}
 
 			cl := jwt.Claims{
 				Subject:   "sn",
@@ -671,7 +673,12 @@ func TestRevoke(t *testing.T) {
 		},
 		"error/already-revoked": func() test {
 			a := testAuthority(t)
-			a.db = &MockAuthDB{err: db.ErrAlreadyExists}
+			a.db = &MockAuthDB{
+				useToken: func(id, tok string) (bool, error) {
+					return true, nil
+				},
+				err: db.ErrAlreadyExists,
+			}
 
 			cl := jwt.Claims{
 				Subject:   "sn",
@@ -702,7 +709,11 @@ func TestRevoke(t *testing.T) {
 		},
 		"ok/token": func() test {
 			a := testAuthority(t)
-			a.db = &MockAuthDB{}
+			a.db = &MockAuthDB{
+				useToken: func(id, tok string) (bool, error) {
+					return true, nil
+				},
+			}
 
 			cl := jwt.Claims{
 				Subject:   "sn",
diff --git a/db/db.go b/db/db.go
index 886c3ef7..0494c1ac 100644
--- a/db/db.go
+++ b/db/db.go
@@ -10,8 +10,9 @@ import (
 )
 
 var (
-	revokedCertsTable = []byte("revoked_x509_certs")
 	certsTable        = []byte("x509_certs")
+	revokedCertsTable = []byte("revoked_x509_certs")
+	usedOTTTable      = []byte("used_ott")
 )
 
 // ErrAlreadyExists can be returned if the DB attempts to set a key that has
@@ -31,6 +32,7 @@ type AuthDB interface {
 	IsRevoked(sn string) (bool, error)
 	Revoke(rci *RevokedCertificateInfo) error
 	StoreCertificate(crt *x509.Certificate) error
+	UseToken(id, tok string) (bool, error)
 	Shutdown() error
 }
 
@@ -43,7 +45,7 @@ type DB struct {
 // New returns a new database client that implements the AuthDB interface.
 func New(c *Config) (AuthDB, error) {
 	if c == nil {
-		return new(NoopDB), nil
+		return newSimpleDB(c)
 	}
 
 	db, err := nosql.New(c.Type, c.DataSource, nosql.WithDatabase(c.Database),
@@ -126,6 +128,23 @@ func (db *DB) StoreCertificate(crt *x509.Certificate) error {
 	return nil
 }
 
+// UseToken returns true if we were able to successfully store the token for
+// for the first time, false otherwise.
+func (db *DB) UseToken(id, tok string) (bool, error) {
+	// If the error is `Not Found` then the certificate has not been revoked.
+	// Any other error should be propagated to the caller.
+	_, found, err := db.LoadOrStore(usedOTTTable, []byte(id), []byte(tok))
+	switch {
+	case err != nil:
+		return false, errors.Wrapf(err, "error LoadOrStore-ing token %s/%s",
+			string(usedOTTTable), id)
+	case found:
+		return false, nil
+	default:
+		return true, nil
+	}
+}
+
 // Shutdown sends a shutdown message to the database.
 func (db *DB) Shutdown() error {
 	if db.isUp {
diff --git a/db/db_test.go b/db/db_test.go
index c2b16d57..c5dbe4fe 100644
--- a/db/db_test.go
+++ b/db/db_test.go
@@ -20,6 +20,17 @@ type MockNoSQLDB struct {
 	del         func(bucket, key []byte) error
 	list        func(bucket []byte) ([]*database.Entry, error)
 	update      func(tx *database.Tx) error
+	loadOrStore func(bucket, key, value []byte) ([]byte, bool, error)
+}
+
+func (m *MockNoSQLDB) LoadOrStore(bucket, key, value []byte) ([]byte, bool, error) {
+	if m.get != nil {
+		return m.loadOrStore(bucket, key, value)
+	}
+	if m.ret1 == nil {
+		return nil, false, m.err
+	}
+	return m.ret1.([]byte), m.ret2.(bool), m.err
 }
 
 func (m *MockNoSQLDB) Get(bucket, key []byte) ([]byte, error) {
@@ -188,3 +199,66 @@ func TestRevoke(t *testing.T) {
 		})
 	}
 }
+
+func TestUseToken(t *testing.T) {
+	type result struct {
+		err error
+		ok  bool
+	}
+	tests := map[string]struct {
+		id, tok string
+		db      *DB
+		want    result
+	}{
+		"fail/force-LoadOrStore-error": {
+			id:  "id",
+			tok: "token",
+			db: &DB{&MockNoSQLDB{
+				loadOrStore: func(bucket, key, value []byte) ([]byte, bool, error) {
+					return nil, false, errors.New("force")
+				},
+			}, true},
+			want: result{
+				ok:  false,
+				err: errors.New("error LoadOrStore-ing token id/token"),
+			},
+		},
+		"fail/LoadOrStore-found": {
+			id:  "id",
+			tok: "token",
+			db: &DB{&MockNoSQLDB{
+				loadOrStore: func(bucket, key, value []byte) ([]byte, bool, error) {
+					return []byte("foo"), true, nil
+				},
+			}, true},
+			want: result{
+				ok: false,
+			},
+		},
+		"ok/LoadOrStore-not-found": {
+			id:  "id",
+			tok: "token",
+			db: &DB{&MockNoSQLDB{
+				loadOrStore: func(bucket, key, value []byte) ([]byte, bool, error) {
+					return nil, false, nil
+				},
+			}, true},
+			want: result{
+				ok: true,
+			},
+		},
+	}
+	for name, tc := range tests {
+		t.Run(name, func(t *testing.T) {
+			ok, err := tc.db.UseToken(tc.id, tc.tok)
+			if err != nil {
+				if assert.NotNil(t, tc.want.err) {
+					assert.HasPrefix(t, tc.want.err.Error(), err.Error())
+				}
+				assert.False(t, ok)
+			} else {
+				assert.True(t, ok)
+			}
+		})
+	}
+}
diff --git a/db/noop.go b/db/noop.go
deleted file mode 100644
index 356b7f42..00000000
--- a/db/noop.go
+++ /dev/null
@@ -1,38 +0,0 @@
-package db
-
-import (
-	"crypto/x509"
-
-	"github.com/pkg/errors"
-)
-
-// ErrNotImplemented is an error returned when an operation is Not Implemented.
-var ErrNotImplemented = errors.Errorf("not implemented")
-
-// NoopDB implements the DB interface with Noops
-type NoopDB int
-
-// Init noop
-func (n *NoopDB) Init(c *Config) (AuthDB, error) {
-	return n, nil
-}
-
-// IsRevoked noop
-func (n *NoopDB) IsRevoked(sn string) (bool, error) {
-	return false, nil
-}
-
-// Revoke returns a "NotImplemented" error.
-func (n *NoopDB) Revoke(rci *RevokedCertificateInfo) error {
-	return ErrNotImplemented
-}
-
-// StoreCertificate returns a "NotImplemented" error.
-func (n *NoopDB) StoreCertificate(crt *x509.Certificate) error {
-	return ErrNotImplemented
-}
-
-// Shutdown returns nil
-func (n *NoopDB) Shutdown() error {
-	return nil
-}
diff --git a/db/noop_test.go b/db/noop_test.go
deleted file mode 100644
index 564a586c..00000000
--- a/db/noop_test.go
+++ /dev/null
@@ -1,21 +0,0 @@
-package db
-
-import (
-	"testing"
-
-	"github.com/smallstep/assert"
-)
-
-func Test_noop(t *testing.T) {
-	db := new(NoopDB)
-
-	_db, err := db.Init(&Config{})
-	assert.FatalError(t, err)
-	assert.Equals(t, db, _db)
-
-	isRevoked, err := db.IsRevoked("foo")
-	assert.False(t, isRevoked)
-	assert.Nil(t, err)
-
-	assert.Equals(t, db.Revoke(&RevokedCertificateInfo{}), ErrNotImplemented)
-}
diff --git a/db/simple.go b/db/simple.go
new file mode 100644
index 00000000..657a518f
--- /dev/null
+++ b/db/simple.go
@@ -0,0 +1,63 @@
+package db
+
+import (
+	"crypto/x509"
+	"sync"
+	"time"
+
+	"github.com/pkg/errors"
+)
+
+// ErrNotImplemented is an error returned when an operation is Not Implemented.
+var ErrNotImplemented = errors.Errorf("not implemented")
+
+// SimpleDB is a barebones implementation of the DB interface. It is NOT an
+// in memory implementation of the DB, but rather the bare minimum of
+// functionality that the CA requires to operate securely.
+type SimpleDB struct {
+	usedTokens *sync.Map
+}
+
+func newSimpleDB(c *Config) (AuthDB, error) {
+	db := &SimpleDB{}
+	db.usedTokens = new(sync.Map)
+	return db, nil
+}
+
+// IsRevoked noop
+func (s *SimpleDB) IsRevoked(sn string) (bool, error) {
+	return false, nil
+}
+
+// Revoke returns a "NotImplemented" error.
+func (s *SimpleDB) Revoke(rci *RevokedCertificateInfo) error {
+	return ErrNotImplemented
+}
+
+// StoreCertificate returns a "NotImplemented" error.
+func (s *SimpleDB) StoreCertificate(crt *x509.Certificate) error {
+	return ErrNotImplemented
+}
+
+type usedToken struct {
+	UsedAt int64  `json:"ua,omitempty"`
+	Token  string `json:"tok,omitempty"`
+}
+
+// UseToken returns a "NotImplemented" error.
+func (s *SimpleDB) UseToken(id, tok string) (bool, error) {
+	if _, ok := s.usedTokens.LoadOrStore(id, &usedToken{
+		UsedAt: time.Now().Unix(),
+		Token:  tok,
+	}); ok {
+		// Token already exists in DB.
+		return false, nil
+	}
+	// Successfully stored token.
+	return true, nil
+}
+
+// Shutdown returns nil
+func (s *SimpleDB) Shutdown() error {
+	return nil
+}
diff --git a/db/simple_test.go b/db/simple_test.go
new file mode 100644
index 00000000..ad5aa70c
--- /dev/null
+++ b/db/simple_test.go
@@ -0,0 +1,37 @@
+package db
+
+import (
+	"testing"
+
+	"github.com/smallstep/assert"
+)
+
+func TestSimpleDB(t *testing.T) {
+	db, err := newSimpleDB(nil)
+	assert.FatalError(t, err)
+
+	// Revoke
+	assert.Equals(t, ErrNotImplemented, db.Revoke(nil))
+
+	// IsRevoked -- verify noop
+	isRevoked, err := db.IsRevoked("foo")
+	assert.False(t, isRevoked)
+	assert.Nil(t, err)
+
+	// StoreCertificate
+	assert.Equals(t, ErrNotImplemented, db.StoreCertificate(nil))
+
+	// UseToken
+	ok, err := db.UseToken("foo", "bar")
+	assert.True(t, ok)
+	assert.Nil(t, err)
+	ok, err = db.UseToken("foo", "cat")
+	assert.False(t, ok)
+	assert.Nil(t, err)
+
+	// Shutdown -- verify noop
+	assert.FatalError(t, db.Shutdown())
+	ok, err = db.UseToken("foo", "cat")
+	assert.False(t, ok)
+	assert.Nil(t, err)
+}