diff --git a/src/github.com/matrix-org/dendrite/common/threepid/checksignature.go b/src/github.com/matrix-org/dendrite/common/threepid/checksignature.go
deleted file mode 100644
index 18b5edb21..000000000
--- a/src/github.com/matrix-org/dendrite/common/threepid/checksignature.go
+++ /dev/null
@@ -1,75 +0,0 @@
-// Copyright 2017 Vector Creations Ltd
-//
-// 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 threepid
-
-import (
-	"encoding/json"
-	"errors"
-	"fmt"
-	"net/http"
-
-	"github.com/matrix-org/gomatrixserverlib"
-)
-
-// CheckIDServerSignatures iterates over the signatures of a requests.
-// If no signature can be found for the ID server's domain, returns an error, else
-// iterates over the signature for the said domain, retrieves the matching public
-// key, and verify it.
-// Returns nil if all the verifications succeeded.
-// Returns an error if something failed in the process.
-func CheckIDServerSignatures(idServer string, signatures map[string]map[string]string, marshalledBody []byte) error {
-	// TODO: Check if the domain is part of a list of trusted ID servers
-	idServerSignatures, ok := signatures[idServer]
-	if !ok {
-		return errors.New("No signature for domain " + idServer)
-	}
-
-	for keyID := range idServerSignatures {
-		pubKey, err := queryIDServerPubKey(idServer, keyID)
-		if err != nil {
-			return err
-		}
-		if err = gomatrixserverlib.VerifyJSON(idServer, gomatrixserverlib.KeyID(keyID), pubKey, marshalledBody); err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
-
-// queryIDServerPubKey requests a public key identified with a given ID to the
-// a given identity server and returns the matching base64-decoded public key.
-// Returns an error if the request couldn't be sent, if its body couldn't be parsed
-// or if the key couldn't be decoded from base64.
-func queryIDServerPubKey(idServerName string, keyID string) ([]byte, error) {
-	url := fmt.Sprintf("https://%s/_matrix/identity/api/v1/pubkey/%s", idServerName, keyID)
-	resp, err := http.Get(url)
-	if err != nil {
-		return nil, err
-	}
-
-	var pubKeyRes struct {
-		PublicKey gomatrixserverlib.Base64String `json:"public_key"`
-	}
-
-	if resp.StatusCode != http.StatusOK {
-		// TODO: Log the error supplied with the identity server?
-		errMsg := fmt.Sprintf("Couldn't retrieve key %s from server %s", keyID, idServerName)
-		return nil, errors.New(errMsg)
-	}
-
-	err = json.NewDecoder(resp.Body).Decode(&pubKeyRes)
-	return pubKeyRes.PublicKey, err
-}
diff --git a/src/github.com/matrix-org/dendrite/federationapi/writers/threepid.go b/src/github.com/matrix-org/dendrite/federationapi/writers/threepid.go
index 332adbe5e..b3569dd59 100644
--- a/src/github.com/matrix-org/dendrite/federationapi/writers/threepid.go
+++ b/src/github.com/matrix-org/dendrite/federationapi/writers/threepid.go
@@ -21,11 +21,9 @@ import (
 	"time"
 
 	"github.com/matrix-org/dendrite/clientapi/httputil"
-	"github.com/matrix-org/dendrite/clientapi/jsonerror"
 	"github.com/matrix-org/dendrite/clientapi/producers"
 	"github.com/matrix-org/dendrite/common"
 	"github.com/matrix-org/dendrite/common/config"
-	"github.com/matrix-org/dendrite/common/threepid"
 	"github.com/matrix-org/dendrite/roomserver/api"
 
 	"github.com/matrix-org/gomatrixserverlib"
@@ -79,29 +77,12 @@ func CreateInvitesFrom3PIDInvites(
 	}
 }
 
+// createInviteFrom3PIDInvite processes an invite provided by the identity server
+// and creates a m.room.member event (with "invite" membership) from it
 func createInviteFrom3PIDInvite(
 	req *http.Request, queryAPI api.RoomserverQueryAPI, cfg config.Dendrite,
 	inv invite,
 ) (*gomatrixserverlib.Event, *util.JSONResponse) {
-	// Check if the token was provided
-	if inv.Signed.Token == "" {
-		return nil, &util.JSONResponse{
-			Code: 400,
-			JSON: jsonerror.Unknown("Rejecting received notification of third-party invite without signed"),
-		}
-	}
-
-	// Check the signatures
-	marshalledSigned, err := json.Marshal(inv.Signed)
-	if err != nil {
-		resErr := httputil.LogThenError(req, err)
-		return nil, &resErr
-	}
-	if err := threepid.CheckIDServerSignatures("", inv.Signed.Signatures, marshalledSigned); err != nil {
-		resErr := httputil.LogThenError(req, err)
-		return nil, &resErr
-	}
-
 	// Build the event
 	builder := &gomatrixserverlib.EventBuilder{
 		Type:     "m.room.member",