diff --git a/lib/encryption/encryption.dart b/lib/encryption/encryption.dart
index 9fe95ff2..d078d32c 100644
--- a/lib/encryption/encryption.dart
+++ b/lib/encryption/encryption.dart
@@ -314,7 +314,7 @@ class Encryption {
     }
     // we clone the payload as we do not want to remove 'm.relates_to' from the
     // original payload passed into this function
-    payload = Map<String, dynamic>.from(payload);
+    payload = payload.copy();
     final Map<String, dynamic> mRelatesTo = payload.remove('m.relates_to');
     final payloadContent = {
       'content': payload,
diff --git a/lib/encryption/ssss.dart b/lib/encryption/ssss.dart
index 9c4a3eef..4c4191f9 100644
--- a/lib/encryption/ssss.dart
+++ b/lib/encryption/ssss.dart
@@ -49,10 +49,6 @@ const SSSS_KEY_LENGTH = 32;
 const PBKDF2_DEFAULT_ITERATIONS = 500000;
 const PBKDF2_SALT_LENGTH = 64;
 
-Map<String, dynamic> _deepcopy(Map<String, dynamic> data) {
-  return json.decode(json.encode(data));
-}
-
 /// SSSS: **S**ecure **S**ecret **S**torage and **S**haring
 /// Read more about SSSS at:
 /// https://matrix.org/docs/guides/implementing-more-advanced-e-2-ee-features-such-as-cross-signing#3-implementing-ssss
@@ -310,7 +306,7 @@ class SSSS {
     final encrypted = encryptAes(secret, key, type);
     Map<String, dynamic> content;
     if (add && client.accountData[type] != null) {
-      content = _deepcopy(client.accountData[type].content);
+      content = client.accountData[type].content.copy();
       if (!(content['encrypted'] is Map)) {
         content['encrypted'] = <String, dynamic>{};
       }
@@ -341,7 +337,7 @@ class SSSS {
       throw Exception('Secrets do not match up!');
     }
     // now remove all other keys
-    final content = _deepcopy(client.accountData[type].content);
+    final content = client.accountData[type].content.copy();
     final otherKeys =
         Set<String>.from(content['encrypted'].keys.where((k) => k != keyId));
     content['encrypted'].removeWhere((k, v) => otherKeys.contains(k));
diff --git a/lib/encryption/utils/session_key.dart b/lib/encryption/utils/session_key.dart
index f2f18e1b..3d8e4cda 100644
--- a/lib/encryption/utils/session_key.dart
+++ b/lib/encryption/utils/session_key.dart
@@ -84,8 +84,7 @@ class SessionKey {
         Event.getMapFromPayload(dbEntry.allowedAtIndex);
     final parsedSenderClaimedKeys =
         Event.getMapFromPayload(dbEntry.senderClaimedKeys);
-    content =
-        parsedContent != null ? Map<String, dynamic>.from(parsedContent) : null;
+    content = parsedContent;
     // we need to try...catch as the map used to be <String, int> and that will throw an error.
     try {
       indexes = parsedIndexes != null
diff --git a/lib/matrix_api.dart b/lib/matrix_api.dart
index 56ee7d16..2e13945f 100644
--- a/lib/matrix_api.dart
+++ b/lib/matrix_api.dart
@@ -20,6 +20,7 @@ library matrix_api;
 
 export 'matrix_api/matrix_api.dart';
 export 'matrix_api/utils/logs.dart';
+export 'matrix_api/utils/map_copy_extension.dart';
 export 'matrix_api/utils/try_get_map_extension.dart';
 export 'matrix_api/model/algorithm_types.dart';
 export 'matrix_api/model/basic_event.dart';
diff --git a/lib/matrix_api/model/basic_event.dart b/lib/matrix_api/model/basic_event.dart
index 095b2b21..7a91f559 100644
--- a/lib/matrix_api/model/basic_event.dart
+++ b/lib/matrix_api/model/basic_event.dart
@@ -16,6 +16,8 @@
  *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+import '../utils/map_copy_extension.dart';
+
 class BasicEvent {
   String type;
   Map<String, dynamic> content;
@@ -27,7 +29,7 @@ class BasicEvent {
 
   BasicEvent.fromJson(Map<String, dynamic> json) {
     type = json['type'];
-    content = Map<String, dynamic>.from(json['content']);
+    content = (json['content'] as Map<String, dynamic>).copy();
   }
   Map<String, dynamic> toJson() {
     final data = <String, dynamic>{};
diff --git a/lib/matrix_api/model/keys_query_response.dart b/lib/matrix_api/model/keys_query_response.dart
index b368b4f1..ed02e87d 100644
--- a/lib/matrix_api/model/keys_query_response.dart
+++ b/lib/matrix_api/model/keys_query_response.dart
@@ -17,6 +17,7 @@
  */
 
 import 'matrix_keys.dart';
+import '../utils/map_copy_extension.dart';
 
 class KeysQueryResponse {
   Map<String, dynamic> failures;
@@ -26,9 +27,7 @@ class KeysQueryResponse {
   Map<String, MatrixCrossSigningKey> userSigningKeys;
 
   KeysQueryResponse.fromJson(Map<String, dynamic> json) {
-    failures = json['failures'] != null
-        ? Map<String, dynamic>.from(json['failures'])
-        : null;
+    failures = (json['failures'] as Map<String, dynamic>)?.copy();
     deviceKeys = json['device_keys'] != null
         ? (json['device_keys'] as Map).map(
             (k, v) => MapEntry(
diff --git a/lib/matrix_api/model/matrix_event.dart b/lib/matrix_api/model/matrix_event.dart
index 2f5f35f0..83fe7596 100644
--- a/lib/matrix_api/model/matrix_event.dart
+++ b/lib/matrix_api/model/matrix_event.dart
@@ -17,6 +17,7 @@
  */
 
 import 'stripped_state_event.dart';
+import '../utils/map_copy_extension.dart';
 
 class MatrixEvent extends StrippedStateEvent {
   String eventId;
@@ -38,12 +39,8 @@ class MatrixEvent extends StrippedStateEvent {
     roomId = json['room_id'];
     originServerTs =
         DateTime.fromMillisecondsSinceEpoch(json['origin_server_ts']);
-    unsigned = json['unsigned'] != null
-        ? Map<String, dynamic>.from(json['unsigned'])
-        : null;
-    prevContent = json['prev_content'] != null
-        ? Map<String, dynamic>.from(json['prev_content'])
-        : null;
+    unsigned = (json['unsigned'] as Map<String, dynamic>)?.copy();
+    prevContent = (json['prev_content'] as Map<String, dynamic>)?.copy();
     redacts = json['redacts'];
   }
 
diff --git a/lib/matrix_api/model/matrix_keys.dart b/lib/matrix_api/model/matrix_keys.dart
index c0f00386..317ef390 100644
--- a/lib/matrix_api/model/matrix_keys.dart
+++ b/lib/matrix_api/model/matrix_keys.dart
@@ -16,6 +16,8 @@
  *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+import '../utils/map_copy_extension.dart';
+
 class MatrixSignableKey {
   String userId;
   String identifier;
@@ -33,13 +35,12 @@ class MatrixSignableKey {
     _json = json;
     userId = json['user_id'];
     keys = Map<String, String>.from(json['keys']);
+    // we need to manually copy to ensure that our map is Map<String, Map<String, String>>
     signatures = json['signatures'] is Map
         ? Map<String, Map<String, String>>.from((json['signatures'] as Map)
             .map((k, v) => MapEntry(k, Map<String, String>.from(v))))
         : null;
-    unsigned = json['unsigned'] is Map
-        ? Map<String, dynamic>.from(json['unsigned'])
-        : null;
+    unsigned = (json['unsigned'] as Map<String, dynamic>)?.copy();
   }
 
   Map<String, dynamic> toJson() {
diff --git a/lib/matrix_api/model/one_time_keys_claim_response.dart b/lib/matrix_api/model/one_time_keys_claim_response.dart
index 7834211c..7607892b 100644
--- a/lib/matrix_api/model/one_time_keys_claim_response.dart
+++ b/lib/matrix_api/model/one_time_keys_claim_response.dart
@@ -16,13 +16,17 @@
  *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+import '../utils/map_copy_extension.dart';
+
 class OneTimeKeysClaimResponse {
   Map<String, dynamic> failures;
   Map<String, Map<String, dynamic>> oneTimeKeys;
 
   OneTimeKeysClaimResponse.fromJson(Map<String, dynamic> json) {
-    failures = Map<String, dynamic>.from(json['failures'] ?? {});
-    oneTimeKeys = Map<String, Map<String, dynamic>>.from(json['one_time_keys']);
+    failures = (json['failures'] as Map<String, dynamic>)?.copy() ?? {};
+    // We still need a Map<...>.from(...) to ensure all second-level entries are also maps
+    oneTimeKeys = Map<String, Map<String, dynamic>>.from(
+        (json['one_time_keys'] as Map<String, dynamic>).copy());
   }
 
   Map<String, dynamic> toJson() {
diff --git a/lib/matrix_api/model/server_capabilities.dart b/lib/matrix_api/model/server_capabilities.dart
index 0e449e9d..0ae7c1ee 100644
--- a/lib/matrix_api/model/server_capabilities.dart
+++ b/lib/matrix_api/model/server_capabilities.dart
@@ -16,6 +16,8 @@
  *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+import '../utils/map_copy_extension.dart';
+
 enum RoomVersionStability { stable, unstable }
 
 class ServerCapabilities {
@@ -30,7 +32,7 @@ class ServerCapabilities {
     mRoomVersions = json['m.room_versions'] != null
         ? MRoomVersions.fromJson(json['m.room_versions'])
         : null;
-    customCapabilities = Map<String, dynamic>.from(json);
+    customCapabilities = json.copy();
     customCapabilities.remove('m.change_password');
     customCapabilities.remove('m.room_versions');
   }
diff --git a/lib/matrix_api/model/third_party_location.dart b/lib/matrix_api/model/third_party_location.dart
index 68083805..39546099 100644
--- a/lib/matrix_api/model/third_party_location.dart
+++ b/lib/matrix_api/model/third_party_location.dart
@@ -16,6 +16,8 @@
  *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+import '../utils/map_copy_extension.dart';
+
 class ThirdPartyLocation {
   String alias;
   String protocol;
@@ -24,7 +26,7 @@ class ThirdPartyLocation {
   ThirdPartyLocation.fromJson(Map<String, dynamic> json) {
     alias = json['alias'];
     protocol = json['protocol'];
-    fields = Map<String, dynamic>.from(json['fields']);
+    fields = (json['fields'] as Map<String, dynamic>).copy();
   }
 
   Map<String, dynamic> toJson() {
diff --git a/lib/matrix_api/model/third_party_user.dart b/lib/matrix_api/model/third_party_user.dart
index fd84f907..e19818e8 100644
--- a/lib/matrix_api/model/third_party_user.dart
+++ b/lib/matrix_api/model/third_party_user.dart
@@ -16,6 +16,8 @@
  *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+import '../utils/map_copy_extension.dart';
+
 class ThirdPartyUser {
   String userId;
   String protocol;
@@ -24,7 +26,7 @@ class ThirdPartyUser {
   ThirdPartyUser.fromJson(Map<String, dynamic> json) {
     userId = json['userid'];
     protocol = json['protocol'];
-    fields = Map<String, dynamic>.from(json['fields']);
+    fields = (json['fields'] as Map<String, dynamic>).copy();
   }
 
   Map<String, dynamic> toJson() {
diff --git a/lib/matrix_api/utils/map_copy_extension.dart b/lib/matrix_api/utils/map_copy_extension.dart
new file mode 100644
index 00000000..84ddc272
--- /dev/null
+++ b/lib/matrix_api/utils/map_copy_extension.dart
@@ -0,0 +1,33 @@
+/*
+ *   Famedly Matrix SDK
+ *   Copyright (C) 2020 Famedly GmbH
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as
+ *   published by the Free Software Foundation, either version 3 of the
+ *   License, or (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+extension MapCopyExtension on Map<String, dynamic> {
+  /// Deep-copies a given json map
+  Map<String, dynamic> copy() {
+    final copy = Map<String, dynamic>.from(this);
+    for (final entry in copy.entries) {
+      if (entry.value is Map<String, dynamic>) {
+        copy[entry.key] = (entry.value as Map<String, dynamic>).copy();
+      }
+      if (entry.value is List) {
+        copy[entry.key] = List.from(entry.value);
+      }
+    }
+    return copy;
+  }
+}
diff --git a/lib/src/room.dart b/lib/src/room.dart
index a5f0eee7..751f83d6 100644
--- a/lib/src/room.dart
+++ b/lib/src/room.dart
@@ -750,7 +750,7 @@ class Room {
       };
     }
     if (editEventId != null) {
-      final newContent = Map<String, dynamic>.from(content);
+      final newContent = content.copy();
       content['m.new_content'] = newContent;
       content['m.relates_to'] = {
         'event_id': editEventId,
diff --git a/lib/src/utils/device_keys_list.dart b/lib/src/utils/device_keys_list.dart
index f4cd4bfc..96402b5b 100644
--- a/lib/src/utils/device_keys_list.dart
+++ b/lib/src/utils/device_keys_list.dart
@@ -145,8 +145,7 @@ abstract class SignableKey extends MatrixSignableKey {
   }
 
   MatrixSignableKey cloneForSigning() {
-    final newKey =
-        MatrixSignableKey.fromJson(Map<String, dynamic>.from(toJson()));
+    final newKey = MatrixSignableKey.fromJson(toJson().copy());
     newKey.identifier = identifier;
     newKey.signatures ??= <String, Map<String, String>>{};
     newKey.signatures.clear();
@@ -154,7 +153,7 @@ abstract class SignableKey extends MatrixSignableKey {
   }
 
   String get signingContent {
-    final data = Map<String, dynamic>.from(super.toJson());
+    final data = super.toJson().copy();
     // some old data might have the custom verified and blocked keys
     data.remove('verified');
     data.remove('blocked');
@@ -303,7 +302,7 @@ abstract class SignableKey extends MatrixSignableKey {
 
   @override
   Map<String, dynamic> toJson() {
-    final data = Map<String, dynamic>.from(super.toJson());
+    final data = super.toJson().copy();
     // some old data may have the verified and blocked keys which are unneeded now
     data.remove('verified');
     data.remove('blocked');
@@ -336,7 +335,7 @@ class CrossSigningKey extends SignableKey {
   }
 
   CrossSigningKey.fromMatrixCrossSigningKey(MatrixCrossSigningKey k, Client cl)
-      : super.fromJson(Map<String, dynamic>.from(k.toJson()), cl) {
+      : super.fromJson(k.toJson().copy(), cl) {
     final json = toJson();
     identifier = k.publicKey;
     usage = json['usage'].cast<String>();
@@ -352,7 +351,7 @@ class CrossSigningKey extends SignableKey {
   }
 
   CrossSigningKey.fromJson(Map<String, dynamic> json, Client cl)
-      : super.fromJson(Map<String, dynamic>.from(json), cl) {
+      : super.fromJson(json.copy(), cl) {
     final json = toJson();
     usage = json['usage'].cast<String>();
     if (keys != null && keys.isNotEmpty) {
@@ -409,7 +408,7 @@ class DeviceKeys extends SignableKey {
   }
 
   DeviceKeys.fromMatrixDeviceKeys(MatrixDeviceKeys k, Client cl)
-      : super.fromJson(Map<String, dynamic>.from(k.toJson()), cl) {
+      : super.fromJson(k.toJson().copy(), cl) {
     final json = toJson();
     identifier = k.deviceId;
     algorithms = json['algorithms'].cast<String>();
@@ -425,7 +424,7 @@ class DeviceKeys extends SignableKey {
   }
 
   DeviceKeys.fromJson(Map<String, dynamic> json, Client cl)
-      : super.fromJson(Map<String, dynamic>.from(json), cl) {
+      : super.fromJson(json.copy(), cl) {
     final json = toJson();
     identifier = json['device_id'];
     algorithms = json['algorithms'].cast<String>();
diff --git a/test/matrix_api/map_copy_extension_test.dart b/test/matrix_api/map_copy_extension_test.dart
new file mode 100644
index 00000000..3e21cf40
--- /dev/null
+++ b/test/matrix_api/map_copy_extension_test.dart
@@ -0,0 +1,39 @@
+/*
+ *   Famedly Matrix SDK
+ *   Copyright (C) 2020 Famedly GmbH
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as
+ *   published by the Free Software Foundation, either version 3 of the
+ *   License, or (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import 'package:famedlysdk/matrix_api/utils/map_copy_extension.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('Map-copy-extension', () {
+    test('it should work', () {
+      final original = <String, dynamic>{
+        'attr': 'fox',
+        'child': <String, dynamic>{
+          'attr': 'bunny',
+          'list': [1, 2],
+        },
+      };
+      final copy = original.copy();
+      original['child']['attr'] = 'raccoon';
+      expect(copy['child']['attr'], 'bunny');
+      original['child']['list'].add(3);
+      expect(copy['child']['list'], [1, 2]);
+    });
+  });
+}
diff --git a/test/matrix_api/try_get_map_extension_test.dart b/test/matrix_api/try_get_map_extension_test.dart
new file mode 100644
index 00000000..646d7348
--- /dev/null
+++ b/test/matrix_api/try_get_map_extension_test.dart
@@ -0,0 +1,45 @@
+/*
+ *   Famedly Matrix SDK
+ *   Copyright (C) 2020 Famedly GmbH
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as
+ *   published by the Free Software Foundation, either version 3 of the
+ *   License, or (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import 'package:famedlysdk/matrix_api/utils/try_get_map_extension.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('Try-get-map-extension', () {
+    test('it should work', () {
+      final data = <String, dynamic>{
+        'str': 'foxies',
+        'int': 42,
+        'list': [2, 3, 4],
+        'map': <String, dynamic>{
+          'beep': 'boop',
+        },
+      };
+      expect(data.tryGet<String>('str'), 'foxies');
+      expect(data.tryGet<int>('str'), null);
+      expect(data.tryGet<int>('int'), 42);
+      expect(data.tryGet<List>('list'), [2, 3, 4]);
+      expect(data.tryGet<Map<String, dynamic>>('map')?.tryGet<String>('beep'),
+          'boop');
+      expect(data.tryGet<Map<String, dynamic>>('map')?.tryGet<String>('meep'),
+          null);
+      expect(data.tryGet<Map<String, dynamic>>('pam')?.tryGet<String>('beep'),
+          null);
+    });
+  });
+}