diff --git a/spec/unit/crypto.spec.js b/spec/unit/crypto.spec.js
index 18cc930b0..9039d77d9 100644
--- a/spec/unit/crypto.spec.js
+++ b/spec/unit/crypto.spec.js
@@ -10,6 +10,7 @@ import * as olmlib from "../../src/crypto/olmlib";
 import {sleep} from "../../src/utils";
 import {EventEmitter} from "events";
 import {CRYPTO_ENABLED} from "../../src/client";
+import {DeviceInfo} from "../../src/crypto/deviceinfo";
 
 const Olm = global.Olm;
 
@@ -26,6 +27,62 @@ describe("Crypto", function() {
         expect(Crypto.getOlmVersion()[0]).toEqual(3);
     });
 
+    describe("encrypted events", function() {
+        it("provides encryption information", async function() {
+            const client = (new TestClient(
+                "@alice:example.com", "deviceid",
+            )).client;
+            await client.initCrypto();
+
+            // unencrypted event
+            const event = {
+                getId: () => "$event_id",
+                getSenderKey: () => null,
+                getWireContent: () => {return {};},
+            };
+
+            let encryptionInfo = client.getEventEncryptionInfo(event);
+            expect(encryptionInfo.encrypted).toBeFalsy();
+
+            // unknown sender (e.g. deleted device), forwarded megolm key (untrusted)
+            event.getSenderKey = () => 'YmJiYmJiYmJiYmJiYmJiYmJiYmJiYmJiYmJiYmJiYmI';
+            event.getWireContent = () => {return {algorithm: olmlib.MEGOLM_ALGORITHM};};
+            event.getForwardingCurve25519KeyChain = () => ["not empty"];
+            event.isKeySourceUntrusted = () => false;
+            event.getClaimedEd25519Key = () => 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA';
+
+            encryptionInfo = client.getEventEncryptionInfo(event);
+            expect(encryptionInfo.encrypted).toBeTruthy();
+            expect(encryptionInfo.authenticated).toBeFalsy();
+            expect(encryptionInfo.sender).toBeFalsy();
+
+            // known sender, megolm key from backup
+            event.getForwardingCurve25519KeyChain = () => [];
+            event.isKeySourceUntrusted = () => true;
+            const device = new DeviceInfo("FLIBBLE");
+            device.keys["curve25519:FLIBBLE"] = 'YmJiYmJiYmJiYmJiYmJiYmJiYmJiYmJiYmJiYmJiYmI';
+            device.keys["ed25519:FLIBBLE"] = 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA';
+            client._crypto._deviceList.getDeviceByIdentityKey = () => device;
+
+            encryptionInfo = client.getEventEncryptionInfo(event);
+            expect(encryptionInfo.encrypted).toBeTruthy();
+            expect(encryptionInfo.authenticated).toBeFalsy();
+            expect(encryptionInfo.sender).toBeTruthy();
+            expect(encryptionInfo.mismatchedSender).toBeFalsy();
+
+            // known sender, trusted megolm key, but bad ed25519key
+            event.isKeySourceUntrusted = () => false;
+            device.keys["ed25519:FLIBBLE"] = 'BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB';
+
+            encryptionInfo = client.getEventEncryptionInfo(event);
+            expect(encryptionInfo.encrypted).toBeTruthy();
+            expect(encryptionInfo.authenticated).toBeTruthy();
+            expect(encryptionInfo.sender).toBeTruthy();
+            expect(encryptionInfo.mismatchedSender).toBeTruthy();
+
+            client.stopClient();
+        });
+    });
 
     describe('Session management', function() {
         const otkResponse = {
diff --git a/src/client.js b/src/client.js
index 65c15c79d..fc89de3c5 100644
--- a/src/client.js
+++ b/src/client.js
@@ -1193,13 +1193,15 @@ MatrixClient.prototype.checkEventSenderTrust = async function(event) {
  * @param {module:models/event.MatrixEvent} event event to be checked
  *
  * @return {object} An object with the fields:
- *    - encrypted: whether the event is encrypted
+ *    - encrypted: whether the event is encrypted (if not encrypted, some of the
+ *      other properties may not be set)
  *    - senderKey: the sender's key
  *    - algorithm: the algorithm used to encrypt the event
  *    - authenticated: whether we can be sure that the owner of the senderKey
  *      sent the event
- *    - sender: the sender's device information
+ *    - sender: the sender's device information, if available
  *    - mismatchedSender: if the event's ed25519 and curve25519 keys don't match
+ *      (only meaningful if `sender` is set)
  */
 
 /**
diff --git a/src/crypto/index.js b/src/crypto/index.js
index 272f7c79b..0d3f4153c 100644
--- a/src/crypto/index.js
+++ b/src/crypto/index.js
@@ -2292,13 +2292,15 @@ Crypto.prototype.getEventSenderDeviceInfo = function(event) {
  * @param {module:models/event.MatrixEvent} event event to be checked
  *
  * @return {object} An object with the fields:
- *    - encrypted: whether the event is encrypted
+ *    - encrypted: whether the event is encrypted (if not encrypted, some of the
+ *      other properties may not be set)
  *    - senderKey: the sender's key
  *    - algorithm: the algorithm used to encrypt the event
  *    - authenticated: whether we can be sure that the owner of the senderKey
  *      sent the event
- *    - sender: the sender's device information
+ *    - sender: the sender's device information, if available
  *    - mismatchedSender: if the event's ed25519 and curve25519 keys don't match
+ *      (only meaningful if `sender` is set)
  */
 Crypto.prototype.getEventEncryptionInfo = function(event) {
     const ret = {};
@@ -2345,7 +2347,7 @@ Crypto.prototype.getEventEncryptionInfo = function(event) {
         ret.mismatchedSender = true;
     }
 
-    if (claimedKey !== ret.sender.getFingerprint()) {
+    if (ret.sender && claimedKey !== ret.sender.getFingerprint()) {
         logger.warn(
             "Event " + event.getId() + " claims ed25519 key " + claimedKey +
                 "but sender device has key " + ret.sender.getFingerprint());