diff --git a/clientapi/routing/routing.go b/clientapi/routing/routing.go
index 9fe882376..c6be8939d 100644
--- a/clientapi/routing/routing.go
+++ b/clientapi/routing/routing.go
@@ -65,7 +65,7 @@ func Setup(
 	userInteractiveAuth := auth.NewUserInteractive(accountDB.GetAccountByPassword, cfg)
 
 	unstableFeatures := map[string]bool{
-		"org.matrix.e2e_cross_signing": true,
+		//"org.matrix.e2e_cross_signing": true,
 	}
 	for _, msc := range cfg.MSCs.MSCs {
 		unstableFeatures["org.matrix."+msc] = true
diff --git a/keyserver/storage/postgres/cross_signing_keys_table.go b/keyserver/storage/postgres/cross_signing_keys_table.go
index 8f3f7054e..63ad93035 100644
--- a/keyserver/storage/postgres/cross_signing_keys_table.go
+++ b/keyserver/storage/postgres/cross_signing_keys_table.go
@@ -23,13 +23,14 @@ import (
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 	"github.com/matrix-org/dendrite/keyserver/api"
 	"github.com/matrix-org/dendrite/keyserver/storage/tables"
+	"github.com/matrix-org/dendrite/keyserver/types"
 	"github.com/matrix-org/gomatrixserverlib"
 )
 
 var crossSigningKeysSchema = `
 CREATE TABLE IF NOT EXISTS keyserver_cross_signing_keys (
     user_id TEXT NOT NULL,
-	key_type TEXT NOT NULL,
+	key_type SMALLINT NOT NULL,
 	key_data TEXT NOT NULL,
 	PRIMARY KEY (user_id, key_type)
 );
@@ -74,11 +75,15 @@ func (s *crossSigningKeysStatements) SelectCrossSigningKeysForUser(
 	defer internal.CloseAndLogIfError(ctx, rows, "selectCrossSigningKeysForUserStmt: rows.close() failed")
 	r = api.CrossSigningKeyMap{}
 	for rows.Next() {
-		var keyType gomatrixserverlib.CrossSigningKeyPurpose
+		var keyTypeInt int16
 		var keyData gomatrixserverlib.Base64Bytes
-		if err := rows.Scan(&keyType, &keyData); err != nil {
+		if err := rows.Scan(&keyTypeInt, &keyData); err != nil {
 			return nil, err
 		}
+		keyType, ok := types.KeyTypeIntToPurpose[keyTypeInt]
+		if !ok {
+			return nil, fmt.Errorf("unknown key purpose int %d", keyTypeInt)
+		}
 		r[keyType] = keyData
 	}
 	return
@@ -87,7 +92,11 @@ func (s *crossSigningKeysStatements) SelectCrossSigningKeysForUser(
 func (s *crossSigningKeysStatements) UpsertCrossSigningKeysForUser(
 	ctx context.Context, txn *sql.Tx, userID string, keyType gomatrixserverlib.CrossSigningKeyPurpose, keyData gomatrixserverlib.Base64Bytes,
 ) error {
-	if _, err := sqlutil.TxStmt(txn, s.upsertCrossSigningKeysForUserStmt).ExecContext(ctx, userID, keyType, keyData); err != nil {
+	keyTypeInt, ok := types.KeyTypePurposeToInt[keyType]
+	if !ok {
+		return fmt.Errorf("unknown key purpose %q", keyType)
+	}
+	if _, err := sqlutil.TxStmt(txn, s.upsertCrossSigningKeysForUserStmt).ExecContext(ctx, userID, keyTypeInt, keyData); err != nil {
 		return fmt.Errorf("s.upsertCrossSigningKeysForUserStmt: %w", err)
 	}
 	return nil
diff --git a/keyserver/storage/sqlite3/cross_signing_keys_table.go b/keyserver/storage/sqlite3/cross_signing_keys_table.go
index 03b26d3c7..5aac9cac9 100644
--- a/keyserver/storage/sqlite3/cross_signing_keys_table.go
+++ b/keyserver/storage/sqlite3/cross_signing_keys_table.go
@@ -23,13 +23,14 @@ import (
 	"github.com/matrix-org/dendrite/internal/sqlutil"
 	"github.com/matrix-org/dendrite/keyserver/api"
 	"github.com/matrix-org/dendrite/keyserver/storage/tables"
+	"github.com/matrix-org/dendrite/keyserver/types"
 	"github.com/matrix-org/gomatrixserverlib"
 )
 
 var crossSigningKeysSchema = `
 CREATE TABLE IF NOT EXISTS keyserver_cross_signing_keys (
     user_id TEXT NOT NULL,
-	key_type TEXT NOT NULL,
+	key_type INTEGER NOT NULL,
 	key_data TEXT NOT NULL,
 	PRIMARY KEY (user_id, key_type)
 );
@@ -73,11 +74,15 @@ func (s *crossSigningKeysStatements) SelectCrossSigningKeysForUser(
 	defer internal.CloseAndLogIfError(ctx, rows, "selectCrossSigningKeysForUserStmt: rows.close() failed")
 	r = api.CrossSigningKeyMap{}
 	for rows.Next() {
-		var keyType gomatrixserverlib.CrossSigningKeyPurpose
+		var keyTypeInt int16
 		var keyData gomatrixserverlib.Base64Bytes
-		if err := rows.Scan(&keyType, &keyData); err != nil {
+		if err := rows.Scan(&keyTypeInt, &keyData); err != nil {
 			return nil, err
 		}
+		keyType, ok := types.KeyTypeIntToPurpose[keyTypeInt]
+		if !ok {
+			return nil, fmt.Errorf("unknown key purpose int %d", keyTypeInt)
+		}
 		r[keyType] = keyData
 	}
 	return
@@ -86,7 +91,11 @@ func (s *crossSigningKeysStatements) SelectCrossSigningKeysForUser(
 func (s *crossSigningKeysStatements) UpsertCrossSigningKeysForUser(
 	ctx context.Context, txn *sql.Tx, userID string, keyType gomatrixserverlib.CrossSigningKeyPurpose, keyData gomatrixserverlib.Base64Bytes,
 ) error {
-	if _, err := sqlutil.TxStmt(txn, s.upsertCrossSigningKeysForUserStmt).ExecContext(ctx, userID, keyType, keyData); err != nil {
+	keyTypeInt, ok := types.KeyTypePurposeToInt[keyType]
+	if !ok {
+		return fmt.Errorf("unknown key purpose %q", keyType)
+	}
+	if _, err := sqlutil.TxStmt(txn, s.upsertCrossSigningKeysForUserStmt).ExecContext(ctx, userID, keyTypeInt, keyData); err != nil {
 		return fmt.Errorf("s.upsertCrossSigningKeysForUserStmt: %w", err)
 	}
 	return nil
diff --git a/keyserver/types/storage.go b/keyserver/types/storage.go
new file mode 100644
index 000000000..e5f914b62
--- /dev/null
+++ b/keyserver/types/storage.go
@@ -0,0 +1,33 @@
+// Copyright 2021 The Matrix.org Foundation C.I.C.
+//
+// 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 types
+
+import "github.com/matrix-org/gomatrixserverlib"
+
+// KeyTypePurposeToInt maps a purpose to an integer, which is used in the
+// database to reduce the amount of space taken up by this column.
+var KeyTypePurposeToInt = map[gomatrixserverlib.CrossSigningKeyPurpose]int16{
+	gomatrixserverlib.CrossSigningKeyPurposeMaster:      1,
+	gomatrixserverlib.CrossSigningKeyPurposeSelfSigning: 2,
+	gomatrixserverlib.CrossSigningKeyPurposeUserSigning: 3,
+}
+
+// KeyTypeIntToPurpose maps an integer to a purpose, which is used in the
+// database to reduce the amount of space taken up by this column.
+var KeyTypeIntToPurpose = map[int16]gomatrixserverlib.CrossSigningKeyPurpose{
+	1: gomatrixserverlib.CrossSigningKeyPurposeMaster,
+	2: gomatrixserverlib.CrossSigningKeyPurposeSelfSigning,
+	3: gomatrixserverlib.CrossSigningKeyPurposeUserSigning,
+}