diff --git a/federationapi/internal/perform.go b/federationapi/internal/perform.go
index 8e111c77d..03ef5ab16 100644
--- a/federationapi/internal/perform.go
+++ b/federationapi/internal/perform.go
@@ -170,6 +170,14 @@ func (r *FederationInternalAPI) performJoinUsingServer(
 		UserIDQuerier: func(roomID spec.RoomID, senderID spec.SenderID) (*spec.UserID, error) {
 			return r.rsAPI.QueryUserIDForSender(ctx, roomID, senderID)
 		},
+		SenderIDCreator: func(ctx context.Context, userID spec.UserID, roomID spec.RoomID) (spec.SenderID, error) {
+			key, err := r.rsAPI.GetOrCreateUserRoomPrivateKey(ctx, userID, roomID)
+			if err != nil {
+				return "", err
+			}
+
+			return spec.SenderID(spec.Base64Bytes(key).Encode()), nil
+		},
 	}
 	response, joinErr := gomatrixserverlib.PerformJoin(ctx, r, joinInput)
 
diff --git a/go.mod b/go.mod
index fbe8f4329..654efe58e 100644
--- a/go.mod
+++ b/go.mod
@@ -22,7 +22,7 @@ require (
 	github.com/matrix-org/dugong v0.0.0-20210921133753-66e6b1c67e2e
 	github.com/matrix-org/go-sqlite3-js v0.0.0-20220419092513-28aa791a1c91
 	github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530
-	github.com/matrix-org/gomatrixserverlib v0.0.0-20230614131217-2d6e6fab7500
+	github.com/matrix-org/gomatrixserverlib v0.0.0-20230614132606-ed482e9b7fee
 	github.com/matrix-org/pinecone v0.11.1-0.20230210171230-8c3b24f2649a
 	github.com/matrix-org/util v0.0.0-20221111132719-399730281e66
 	github.com/mattn/go-sqlite3 v1.14.16
diff --git a/go.sum b/go.sum
index 7085dca75..4fbd2ebb8 100644
--- a/go.sum
+++ b/go.sum
@@ -323,8 +323,8 @@ github.com/matrix-org/go-sqlite3-js v0.0.0-20220419092513-28aa791a1c91 h1:s7fexw
 github.com/matrix-org/go-sqlite3-js v0.0.0-20220419092513-28aa791a1c91/go.mod h1:e+cg2q7C7yE5QnAXgzo512tgFh1RbQLC0+jozuegKgo=
 github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530 h1:kHKxCOLcHH8r4Fzarl4+Y3K5hjothkVW5z7T1dUM11U=
 github.com/matrix-org/gomatrix v0.0.0-20220926102614-ceba4d9f7530/go.mod h1:/gBX06Kw0exX1HrwmoBibFA98yBk/jxKpGVeyQbff+s=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20230614131217-2d6e6fab7500 h1:/HrUyJl02nguDKl5VDpOpwkWuDHt3L+dc4TQNWFCr0E=
-github.com/matrix-org/gomatrixserverlib v0.0.0-20230614131217-2d6e6fab7500/go.mod h1:H9V9N3Uqn1bBJqYJNGK1noqtgJTaCEhtTdcH/mp50uU=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20230614132606-ed482e9b7fee h1:EKtDtgXag5GR3X9MTnPoTAyoh3pzowAWlxVQvFrYSQE=
+github.com/matrix-org/gomatrixserverlib v0.0.0-20230614132606-ed482e9b7fee/go.mod h1:H9V9N3Uqn1bBJqYJNGK1noqtgJTaCEhtTdcH/mp50uU=
 github.com/matrix-org/pinecone v0.11.1-0.20230210171230-8c3b24f2649a h1:awrPDf9LEFySxTLKYBMCiObelNx/cBuv/wzllvCCH3A=
 github.com/matrix-org/pinecone v0.11.1-0.20230210171230-8c3b24f2649a/go.mod h1:HchJX9oKMXaT2xYFs0Ha/6Zs06mxLU8k6F1ODnrGkeQ=
 github.com/matrix-org/util v0.0.0-20221111132719-399730281e66 h1:6z4KxomXSIGWqhHcfzExgkH3Z3UkIXry4ibJS4Aqz2Y=
diff --git a/roomserver/api/api.go b/roomserver/api/api.go
index 8e26854a1..e2dd5dd73 100644
--- a/roomserver/api/api.go
+++ b/roomserver/api/api.go
@@ -51,6 +51,7 @@ type RoomserverInternalAPI interface {
 	UserRoomserverAPI
 	FederationRoomserverAPI
 	QuerySenderIDAPI
+	UserRoomPrivateKeyCreator
 
 	// needed to avoid chicken and egg scenario when setting up the
 	// interdependencies between the roomserver and other input APIs
@@ -67,7 +68,9 @@ type RoomserverInternalAPI interface {
 		req *QueryAuthChainRequest,
 		res *QueryAuthChainResponse,
 	) error
+}
 
+type UserRoomPrivateKeyCreator interface {
 	// GetOrCreateUserRoomPrivateKey gets the user room key for the specified user. If no key exists yet, a new one is created.
 	GetOrCreateUserRoomPrivateKey(ctx context.Context, userID spec.UserID, roomID spec.RoomID) (ed25519.PrivateKey, error)
 }
@@ -228,6 +231,7 @@ type FederationRoomserverAPI interface {
 	QueryLatestEventsAndStateAPI
 	QueryBulkStateContentAPI
 	QuerySenderIDAPI
+	UserRoomPrivateKeyCreator
 
 	// QueryServerBannedFromRoom returns whether a server is banned from a room by server ACLs.
 	QueryServerBannedFromRoom(ctx context.Context, req *QueryServerBannedFromRoomRequest, res *QueryServerBannedFromRoomResponse) error