diff --git a/.gitignore b/.gitignore
index 4d9b87d1..40dcabc2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,7 +2,7 @@
 *.class
 *.log
 *.pyc
-*.swp
+*.sw*
 .DS_Store
 .atom/
 .buildlog/
diff --git a/lib/src/model/matrix_keys.dart b/lib/src/model/matrix_keys.dart
index 432dccfc..ca25a197 100644
--- a/lib/src/model/matrix_keys.dart
+++ b/lib/src/model/matrix_keys.dart
@@ -42,8 +42,25 @@ abstract class MatrixSignableKey {
         userId = json['user_id'] as String,
         keys = Map<String, String>.from(json['keys'] as Map<String, dynamic>),
         // we need to manually copy to ensure that our map is Map<String, Map<String, String>>
-        signatures = json.tryGetMap<String, Map<String, String>>('signatures'),
-        unsigned = json.tryGetMap<String, dynamic>('unsigned');
+        signatures = (() {
+          final orig = json.tryGetMap<String, dynamic>('signatures');
+          final res = <String, Map<String, String>>{};
+          for (final entry
+              in (orig?.entries ?? <MapEntry<String, dynamic>>[])) {
+            final deviceSigs = entry.value;
+            if (deviceSigs is Map<String, dynamic>) {
+              for (final nestedEntry in deviceSigs.entries) {
+                final nestedValue = nestedEntry.value;
+                if (nestedValue is String) {
+                  (res[entry.key] ??= <String, String>{})[nestedEntry.key] =
+                      nestedValue;
+                }
+              }
+            }
+          }
+          return res;
+        }()),
+        unsigned = json.tryGetMap<String, dynamic>('unsigned')?.copy();
 
   Map<String, dynamic> toJson() {
     final data = _json ?? <String, dynamic>{};
diff --git a/test/matrix_api_test.dart b/test/matrix_api_test.dart
index 98331e3c..57454e72 100644
--- a/test/matrix_api_test.dart
+++ b/test/matrix_api_test.dart
@@ -1197,7 +1197,7 @@ void main() {
           'ed25519:82mAXjsmbTbrE6zyShpR869jnrANO75H8nYY0nDLoJ8':
               '82mAXjsmbTbrE6zyShpR869jnrANO75H8nYY0nDLoJ8',
         },
-        'signatures': <String, dynamic>{},
+        'signatures': <String, Map<String, String>>{},
       });
       final selfSigningKey = MatrixCrossSigningKey.fromJson({
         'user_id': '@test:fakeServer.notExisting',
@@ -1206,7 +1206,7 @@ void main() {
           'ed25519:F9ypFzgbISXCzxQhhSnXMkc1vq12Luna3Nw5rqViOJY':
               'F9ypFzgbISXCzxQhhSnXMkc1vq12Luna3Nw5rqViOJY',
         },
-        'signatures': <String, dynamic>{},
+        'signatures': <String, Map<String, String>>{},
       });
       final userSigningKey = MatrixCrossSigningKey.fromJson({
         'user_id': '@test:fakeServer.notExisting',
@@ -1215,7 +1215,7 @@ void main() {
           'ed25519:0PiwulzJ/RU86LlzSSZ8St80HUMN3dqjKa/orIJoA0g':
               '0PiwulzJ/RU86LlzSSZ8St80HUMN3dqjKa/orIJoA0g',
         },
-        'signatures': <String, dynamic>{},
+        'signatures': <String, Map<String, String>>{},
       });
       await matrixApi.uploadCrossSigningKeys(
           masterKey: masterKey,
@@ -1638,7 +1638,7 @@ void main() {
       final algorithm = BackupAlgorithm.mMegolmBackupV1Curve25519AesSha2;
       final authData = <String, dynamic>{
         'public_key': 'GXYaxqhNhUK28zUdxOmEsFRguz+PzBsDlTLlF0O0RkM',
-        'signatures': <String, dynamic>{},
+        'signatures': <String, Map<String, String>>{},
       };
       final ret = await matrixApi.postRoomKeysVersion(algorithm, authData);
       expect(
@@ -1663,7 +1663,7 @@ void main() {
       final algorithm = BackupAlgorithm.mMegolmBackupV1Curve25519AesSha2;
       final authData = <String, dynamic>{
         'public_key': 'GXYaxqhNhUK28zUdxOmEsFRguz+PzBsDlTLlF0O0RkM',
-        'signatures': <String, dynamic>{},
+        'signatures': <String, Map<String, String>>{},
       };
       await matrixApi.putRoomKeysVersion('5', algorithm, authData);
     });