diff --git a/benches/state_res_bench.rs b/benches/state_res_bench.rs
index b543de02..dc8696c6 100644
--- a/benches/state_res_bench.rs
+++ b/benches/state_res_bench.rs
@@ -90,7 +90,7 @@ fn resolve_deeper_event_set(c: &mut Criterion) {
             inner.get(&event_id("PA")).unwrap(),
         ]
         .iter()
-        .map(|ev| ((ev.kind(), ev.state_key()), ev.event_id().clone()))
+        .map(|ev| ((ev.kind(), ev.state_key().unwrap()), ev.event_id().clone()))
         .collect::<StateMap<_>>();
 
         let state_set_b = [
@@ -103,7 +103,7 @@ fn resolve_deeper_event_set(c: &mut Criterion) {
             inner.get(&event_id("PA")).unwrap(),
         ]
         .iter()
-        .map(|ev| ((ev.kind(), ev.state_key()), ev.event_id().clone()))
+        .map(|ev| ((ev.kind(), ev.state_key().unwrap()), ev.event_id().clone()))
         .collect::<StateMap<_>>();
 
         b.iter(|| {
@@ -220,12 +220,12 @@ impl TestStore<event::StateEvent> {
 
         let state_at_bob = [&create_event, &alice_mem, &join_rules, &bob_mem]
             .iter()
-            .map(|e| ((e.kind(), e.state_key()), e.event_id().clone()))
+            .map(|e| ((e.kind(), e.state_key().unwrap()), e.event_id().clone()))
             .collect::<StateMap<_>>();
 
         let state_at_charlie = [&create_event, &alice_mem, &join_rules, &charlie_mem]
             .iter()
-            .map(|e| ((e.kind(), e.state_key()), e.event_id().clone()))
+            .map(|e| ((e.kind(), e.state_key().unwrap()), e.event_id().clone()))
             .collect::<StateMap<_>>();
 
         let expected = [
@@ -236,7 +236,7 @@ impl TestStore<event::StateEvent> {
             &charlie_mem,
         ]
         .iter()
-        .map(|e| ((e.kind(), e.state_key()), e.event_id().clone()))
+        .map(|e| ((e.kind(), e.state_key().unwrap()), e.event_id().clone()))
         .collect::<StateMap<_>>();
 
         (state_at_bob, state_at_charlie, expected)
diff --git a/src/event_auth.rs b/src/event_auth.rs
index e3b6df2e..4f2d95bf 100644
--- a/src/event_auth.rs
+++ b/src/event_auth.rs
@@ -23,36 +23,39 @@ pub fn auth_types_for_event(
     sender: &UserId,
     state_key: Option<String>,
     content: serde_json::Value,
-) -> Vec<(EventType, Option<String>)> {
+) -> Vec<(EventType, String)> {
     if kind == &EventType::RoomCreate {
         return vec![];
     }
 
     let mut auth_types = vec![
-        (EventType::RoomPowerLevels, Some("".to_string())),
-        (EventType::RoomMember, Some(sender.to_string())),
-        (EventType::RoomCreate, Some("".to_string())),
+        (EventType::RoomPowerLevels, "".to_string()),
+        (EventType::RoomMember, sender.to_string()),
+        (EventType::RoomCreate, "".to_string()),
     ];
 
     if kind == &EventType::RoomMember {
-        if let Ok(content) = serde_json::from_value::<room::member::MemberEventContent>(content) {
-            if [MembershipState::Join, MembershipState::Invite].contains(&content.membership) {
-                let key = (EventType::RoomJoinRules, Some("".into()));
+        if let Some(state_key) = state_key {
+            if let Ok(content) = serde_json::from_value::<room::member::MemberEventContent>(content)
+            {
+                if [MembershipState::Join, MembershipState::Invite].contains(&content.membership) {
+                    let key = (EventType::RoomJoinRules, "".to_string());
+                    if !auth_types.contains(&key) {
+                        auth_types.push(key)
+                    }
+                }
+
+                let key = (EventType::RoomMember, state_key);
                 if !auth_types.contains(&key) {
                     auth_types.push(key)
                 }
-            }
 
-            let key = (EventType::RoomMember, state_key);
-            if !auth_types.contains(&key) {
-                auth_types.push(key)
-            }
-
-            if content.membership == MembershipState::Invite {
-                if let Some(t_id) = content.third_party_invite {
-                    let key = (EventType::RoomThirdPartyInvite, Some(t_id.signed.token));
-                    if !auth_types.contains(&key) {
-                        auth_types.push(key)
+                if content.membership == MembershipState::Invite {
+                    if let Some(t_id) = content.third_party_invite {
+                        let key = (EventType::RoomThirdPartyInvite, t_id.signed.token);
+                        if !auth_types.contains(&key) {
+                            auth_types.push(key)
+                        }
                     }
                 }
             }
@@ -157,7 +160,7 @@ pub fn auth_check<E: Event>(
 
     // 3. If event does not have m.room.create in auth_events reject
     if auth_events
-        .get(&(EventType::RoomCreate, Some("".into())))
+        .get(&(EventType::RoomCreate, "".to_string()))
         .is_none()
     {
         log::warn!("no m.room.create event in auth chain");
@@ -172,12 +175,6 @@ pub fn auth_check<E: Event>(
         log::info!("starting m.room.aliases check");
         // [synapse] adds `&& room_version` "special case aliases auth"
 
-        // [synapse]
-        // if event.state_key.unwrap().is_empty() {
-        //     log::warn!("state_key must be non-empty");
-        //     return Ok(false); // and be non-empty state_key (point to a user_id)
-        // }
-
         // If sender's domain doesn't matches state_key, reject
         if incoming_event.state_key() != Some(incoming_event.sender().server_name().to_string()) {
             log::warn!("state_key does not match sender");
@@ -190,6 +187,13 @@ pub fn auth_check<E: Event>(
 
     if incoming_event.kind() == EventType::RoomMember {
         log::info!("starting m.room.member check");
+        let state_key = match incoming_event.state_key() {
+            None => {
+                log::warn!("no statekey in member event");
+                return Ok(false);
+            }
+            Some(s) => s,
+        };
 
         if serde_json::from_value::<room::member::MemberEventContent>(incoming_event.content())
             .is_err()
@@ -199,7 +203,7 @@ pub fn auth_check<E: Event>(
         }
 
         if !valid_membership_change(
-            incoming_event.state_key().as_deref(),
+            &state_key,
             incoming_event.sender(),
             incoming_event.content(),
             prev_event,
@@ -279,19 +283,13 @@ pub fn auth_check<E: Event>(
 /// this is generated by calling `auth_types_for_event` with the membership event and
 /// the current State.
 pub fn valid_membership_change<E: Event>(
-    user_state_key: Option<&str>,
+    state_key: &str,
     user_sender: &UserId,
     content: serde_json::Value,
     prev_event: Option<Arc<E>>,
     current_third_party_invite: Option<Arc<E>>,
     auth_events: &StateMap<Arc<E>>,
 ) -> Result<bool> {
-    let state_key = if let Some(s) = user_state_key {
-        s
-    } else {
-        return Err(Error::InvalidPdu("State event requires state_key".into()));
-    };
-
     let content = serde_json::from_value::<room::member::MemberEventContent>(content)?;
 
     let target_membership = content.membership;
@@ -299,7 +297,7 @@ pub fn valid_membership_change<E: Event>(
     let target_user_id =
         UserId::try_from(state_key).map_err(|e| Error::ConversionError(format!("{}", e)))?;
 
-    let key = (EventType::RoomMember, Some(user_sender.to_string()));
+    let key = (EventType::RoomMember, user_sender.to_string());
     let sender = auth_events.get(&key);
     let sender_membership =
         sender.map_or(Ok::<_, Error>(member::MembershipState::Leave), |pdu| {
@@ -309,7 +307,7 @@ pub fn valid_membership_change<E: Event>(
             )
         })?;
 
-    let key = (EventType::RoomMember, Some(target_user_id.to_string()));
+    let key = (EventType::RoomMember, target_user_id.to_string());
     let current = auth_events.get(&key);
     let current_membership =
         current.map_or(Ok::<_, Error>(member::MembershipState::Leave), |pdu| {
@@ -319,7 +317,7 @@ pub fn valid_membership_change<E: Event>(
             )
         })?;
 
-    let key = (EventType::RoomPowerLevels, Some("".into()));
+    let key = (EventType::RoomPowerLevels, "".into());
     let power_levels = auth_events.get(&key).map_or_else(
         || Ok::<_, Error>(power_levels::PowerLevelsEventContent::default()),
         |power_levels| {
@@ -351,7 +349,7 @@ pub fn valid_membership_change<E: Event>(
         Some,
     );
 
-    let key = (EventType::RoomJoinRules, Some("".into()));
+    let key = (EventType::RoomJoinRules, "".into());
     let join_rules_event = auth_events.get(&key);
     let mut join_rules = JoinRule::Invite;
     if let Some(jr) = join_rules_event {
@@ -430,7 +428,7 @@ pub fn check_event_sender_in_room<E: Event>(
     sender: &UserId,
     auth_events: &StateMap<Arc<E>>,
 ) -> Option<bool> {
-    let mem = auth_events.get(&(EventType::RoomMember, Some(sender.to_string())))?;
+    let mem = auth_events.get(&(EventType::RoomMember, sender.to_string()))?;
     Some(
         serde_json::from_value::<room::member::MemberEventContent>(mem.content())
             .ok()?
@@ -442,7 +440,7 @@ pub fn check_event_sender_in_room<E: Event>(
 /// Is the user allowed to send a specific event based on the rooms power levels. Does the event
 /// have the correct userId as it's state_key if it's not the "" state_key.
 pub fn can_send_event<E: Event>(event: &Arc<E>, auth_events: &StateMap<Arc<E>>) -> bool {
-    let ple = auth_events.get(&(EventType::RoomPowerLevels, Some("".into())));
+    let ple = auth_events.get(&(EventType::RoomPowerLevels, "".into()));
 
     let event_type_power_level = get_send_level(&event.kind(), event.state_key(), ple);
     let user_level = get_user_power_level(&event.sender(), auth_events);
@@ -476,7 +474,10 @@ pub fn check_power_levels<E: Event>(
     power_event: &Arc<E>,
     auth_events: &StateMap<Arc<E>>,
 ) -> Option<bool> {
-    let key = (power_event.kind(), power_event.state_key());
+    let power_event_state_key = power_event
+        .state_key()
+        .expect("power events have state keys");
+    let key = (power_event.kind(), power_event_state_key);
     let current_state = if let Some(current_state) = auth_events.get(&key) {
         current_state
     } else {
@@ -620,7 +621,7 @@ fn get_deserialize_levels(
 
 /// Does the event redacting come from a user with enough power to redact the given event.
 pub fn check_redaction<E: Event>(
-    room_version: &RoomVersionId,
+    _room_version: &RoomVersionId,
     redaction_event: &Arc<E>,
     auth_events: &StateMap<Arc<E>>,
 ) -> Result<bool> {
@@ -639,18 +640,15 @@ pub fn check_redaction<E: Event>(
     // Servers should only apply redaction's to events where the sender's domains match,
     // or the sender of the redaction has the appropriate permissions per the power levels.
 
-    // version 1 check
-    if let RoomVersionId::Version1 = room_version {
-        // If the domain of the event_id of the event being redacted is the same as the domain of the event_id of the m.room.redaction, allow
-        if redaction_event.event_id().server_name()
-            == redaction_event
-                .redacts()
-                .as_ref()
-                .and_then(|id| id.server_name())
-        {
-            log::info!("redaction event allowed via room version 1 rules");
-            return Ok(true);
-        }
+    // If the domain of the event_id of the event being redacted is the same as the domain of the event_id of the m.room.redaction, allow
+    if redaction_event.event_id().server_name()
+        == redaction_event
+            .redacts()
+            .as_ref()
+            .and_then(|id| id.server_name())
+    {
+        log::info!("redaction event allowed via room version 1 rules");
+        return Ok(true);
     }
 
     Ok(false)
@@ -675,7 +673,7 @@ pub fn check_membership<E: Event>(member_event: Option<Arc<E>>, state: Membershi
 
 /// Can this room federate based on its m.room.create event.
 pub fn can_federate<E: Event>(auth_events: &StateMap<Arc<E>>) -> bool {
-    let creation_event = auth_events.get(&(EventType::RoomCreate, Some("".into())));
+    let creation_event = auth_events.get(&(EventType::RoomCreate, "".into()));
     if let Some(ev) = creation_event {
         if let Some(fed) = ev.content().get("m.federate") {
             fed == "true"
@@ -690,7 +688,7 @@ pub fn can_federate<E: Event>(auth_events: &StateMap<Arc<E>>) -> bool {
 /// Helper function to fetch a field, `name`, from a "m.room.power_level" event's content.
 /// or return `default` if no power level event is found or zero if no field matches `name`.
 pub fn get_named_level<E: Event>(auth_events: &StateMap<Arc<E>>, name: &str, default: i64) -> i64 {
-    let power_level_event = auth_events.get(&(EventType::RoomPowerLevels, Some("".into())));
+    let power_level_event = auth_events.get(&(EventType::RoomPowerLevels, "".into()));
     if let Some(pl) = power_level_event {
         // TODO do this the right way and deserialize
         if let Some(level) = pl.content().get(name) {
@@ -706,7 +704,7 @@ pub fn get_named_level<E: Event>(auth_events: &StateMap<Arc<E>>, name: &str, def
 /// Helper function to fetch a users default power level from a "m.room.power_level" event's `users`
 /// object.
 pub fn get_user_power_level<E: Event>(user_id: &UserId, auth_events: &StateMap<Arc<E>>) -> i64 {
-    if let Some(pl) = auth_events.get(&(EventType::RoomPowerLevels, Some("".into()))) {
+    if let Some(pl) = auth_events.get(&(EventType::RoomPowerLevels, "".into())) {
         if let Ok(content) =
             serde_json::from_value::<room::power_levels::PowerLevelsEventContent>(pl.content())
         {
@@ -720,7 +718,7 @@ pub fn get_user_power_level<E: Event>(user_id: &UserId, auth_events: &StateMap<A
         }
     } else {
         // if no power level event found the creator gets 100 everyone else gets 0
-        let key = (EventType::RoomCreate, Some("".into()));
+        let key = (EventType::RoomCreate, "".into());
         if let Some(create) = auth_events.get(&key) {
             if let Ok(c) =
                 serde_json::from_value::<room::create::CreateEventContent>(create.content())
@@ -758,7 +756,8 @@ pub fn get_send_level<E: Event>(
                             content.events_default
                         }
                     })
-                }).ok()
+                })
+                .ok()
         })
         .map(|int| i64::from(int))
         .unwrap_or_else(|| if state_key.is_some() { 50 } else { 0 })
@@ -767,7 +766,7 @@ pub fn get_send_level<E: Event>(
 /// Check user can send invite.
 pub fn can_send_invite<E: Event>(event: &Arc<E>, auth_events: &StateMap<Arc<E>>) -> Result<bool> {
     let user_level = get_user_power_level(&event.sender(), auth_events);
-    let key = (EventType::RoomPowerLevels, Some("".into()));
+    let key = (EventType::RoomPowerLevels, "".into());
     let invite_level = auth_events
         .get(&key)
         .map_or_else(
diff --git a/src/lib.rs b/src/lib.rs
index 99080d75..f41a0de7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -28,7 +28,7 @@ pub use state_store::StateStore;
 const _YIELD_AFTER_ITERATIONS: usize = 100;
 
 /// A mapping of event type and state_key to some value `T`, usually an `EventId`.
-pub type StateMap<T> = BTreeMap<(EventType, Option<String>), T>;
+pub type StateMap<T> = BTreeMap<(EventType, String), T>;
 
 /// A mapping of `EventId` to `T`, usually a `ServerPdu`.
 pub type EventMap<T> = BTreeMap<EventId, T>;
@@ -48,6 +48,8 @@ impl StateResolution {
         current_state: &StateMap<EventId>,
         event_map: &EventMap<Arc<E>>,
     ) -> Result<bool> {
+        let state_key = incoming_event.state_key().ok_or_else(|| Error::InvalidPdu("State event had no state key".to_owned()))?;
+
         log::info!("Applying a single event, state resolution starting");
         let ev = incoming_event;
 
@@ -59,7 +61,7 @@ impl StateResolution {
 
         let mut auth_events = StateMap::new();
         for key in
-            event_auth::auth_types_for_event(&ev.kind(), &ev.sender(), ev.state_key(), ev.content())
+            event_auth::auth_types_for_event(&ev.kind(), &ev.sender(), Some(state_key), ev.content())
         {
             if let Some(ev_id) = current_state.get(&key) {
                 if let Ok(event) = StateResolution::get_or_load_event(room_id, ev_id, event_map) {
@@ -183,7 +185,7 @@ impl StateResolution {
         );
 
         // This "epochs" power level event
-        let power_event = resolved_control.get(&(EventType::RoomPowerLevels, Some("".into())));
+        let power_event = resolved_control.get(&(EventType::RoomPowerLevels, "".into()));
 
         log::debug!("PL {:?}", power_event);
 
@@ -498,12 +500,13 @@ impl StateResolution {
 
         for (idx, event_id) in events_to_check.iter().enumerate() {
             let event = StateResolution::get_or_load_event(room_id, event_id, event_map)?;
+            let state_key = event.state_key().ok_or_else(|| Error::InvalidPdu("State event had no state key".to_owned()))?;
 
             let mut auth_events = BTreeMap::new();
             for aid in &event.auth_events() {
                 if let Ok(ev) = StateResolution::get_or_load_event(room_id, &aid, event_map) {
                     // TODO synapse check "rejected_reason", I'm guessing this is redacted_because in ruma ??
-                    auth_events.insert((ev.kind(), ev.state_key()), ev);
+                    auth_events.insert((ev.kind(), state_key.clone()), ev);
                 } else {
                     log::warn!("auth event id for {} is missing {}", aid, event_id);
                 }
@@ -512,7 +515,7 @@ impl StateResolution {
             for key in event_auth::auth_types_for_event(
                 &event.kind(),
                 &event.sender(),
-                event.state_key(),
+                Some(state_key.clone()),
                 event.content(),
             ) {
                 if let Some(ev_id) = resolved_state.get(&key) {
@@ -550,7 +553,7 @@ impl StateResolution {
                 current_third_party,
             )? {
                 // add event to resolved state map
-                resolved_state.insert((event.kind(), event.state_key()), event_id.clone());
+                resolved_state.insert((event.kind(), state_key), event_id.clone());
             } else {
                 // synapse passes here on AuthError. We do not add this event to resolved_state.
                 log::warn!(
diff --git a/tests/event_auth.rs b/tests/event_auth.rs
index 4d9c6fe7..46e14758 100644
--- a/tests/event_auth.rs
+++ b/tests/event_auth.rs
@@ -37,7 +37,7 @@ fn test_ban_pass() {
     );
 
     assert!(valid_membership_change(
-        requester.state_key().as_deref(),
+        &requester.state_key(),
         requester.sender(),
         requester.content(),
         prev,
@@ -72,7 +72,7 @@ fn test_ban_fail() {
     );
 
     assert!(!valid_membership_change(
-        requester.state_key().as_deref(),
+        &requester.state_key(),
         requester.sender(),
         requester.content(),
         prev,
diff --git a/tests/event_sorting.rs b/tests/event_sorting.rs
index 78688322..a1a56904 100644
--- a/tests/event_sorting.rs
+++ b/tests/event_sorting.rs
@@ -61,7 +61,7 @@ fn test_event_sort() {
 
     shuffle(&mut events_to_sort);
 
-    let power_level = resolved_power.get(&(EventType::RoomPowerLevels, Some("".to_string())));
+    let power_level = resolved_power.get(&(EventType::RoomPowerLevels, "".to_string()));
 
     let sorted_event_ids = state_res::StateResolution::mainline_sort(
         &room_id(),
diff --git a/tests/utils.rs b/tests/utils.rs
index 7423eb0e..3d365092 100644
--- a/tests/utils.rs
+++ b/tests/utils.rs
@@ -132,16 +132,14 @@ pub fn do_check(
 
         let mut state_after = state_before.clone();
 
-        if fake_event.state_key().is_some() {
-            let ty = fake_event.kind();
-            let key = fake_event.state_key();
-            state_after.insert((ty, key), event_id.clone());
-        }
+        let ty = fake_event.kind();
+        let key = fake_event.state_key();
+        state_after.insert((ty, key), event_id.clone());
 
         let auth_types = state_res::auth_types_for_event(
             &fake_event.kind(),
             fake_event.sender(),
-            fake_event.state_key(),
+            Some(fake_event.state_key()),
             fake_event.content(),
         );
 
@@ -160,7 +158,7 @@ pub fn do_check(
             e.event_id().as_str(),
             e.sender().clone(),
             e.kind().clone(),
-            e.state_key().as_deref(),
+            Some(&e.state_key()),
             e.content(),
             &auth_events,
             prev_events,
@@ -555,7 +553,7 @@ pub mod event {
         }
 
         fn state_key(&self) -> Option<String> {
-            self.state_key()
+            Some(self.state_key())
         }
         fn prev_events(&self) -> Vec<EventId> {
             self.prev_event_ids()
@@ -796,11 +794,11 @@ pub mod event {
                 },
             }
         }
-        pub fn state_key(&self) -> Option<String> {
+        pub fn state_key(&self) -> String {
             match self {
                 Self::Full(_, ev) => match ev {
-                    Pdu::RoomV1Pdu(ev) => ev.state_key.clone(),
-                    Pdu::RoomV3Pdu(ev) => ev.state_key.clone(),
+                    Pdu::RoomV1Pdu(ev) => ev.state_key.clone().unwrap(),
+                    Pdu::RoomV3Pdu(ev) => ev.state_key.clone().unwrap(),
                 },
             }
         }