diff --git a/lib/encryption/ssss.dart b/lib/encryption/ssss.dart
index 6c3342c4..22247dac 100644
--- a/lib/encryption/ssss.dart
+++ b/lib/encryption/ssss.dart
@@ -24,7 +24,10 @@ import 'dart:async';
 import 'package:base58check/base58.dart';
 import 'package:crypto/crypto.dart';
 import 'package:encrypt/encrypt.dart';
-import 'package:password_hash/password_hash.dart';
+import 'package:pointycastle/digests/sha512.dart';
+import 'package:pointycastle/key_derivators/api.dart';
+import 'package:pointycastle/key_derivators/pbkdf2.dart';
+import 'package:pointycastle/macs/hmac.dart';
 
 import '../famedlysdk.dart';
 import '../src/database/database.dart';
@@ -155,9 +158,12 @@ class SSSS {
     if (info.algorithm != AlgorithmTypes.pbkdf2) {
       throw Exception('Unknown algorithm');
     }
-    final generator = PBKDF2(hashAlgorithm: sha512);
-    return Uint8List.fromList(generator.generateKey(passphrase, info.salt,
-        info.iterations, info.bits != null ? (info.bits / 8).ceil() : 32));
+    final out = Uint8List(info.bits != null ? (info.bits / 8).ceil() : 32);
+    final generator = PBKDF2KeyDerivator(HMac(SHA512Digest(), 128));
+    generator.init(
+        Pbkdf2Parameters(utf8.encode(info.salt), info.iterations, out.length));
+    generator.deriveKey(utf8.encode(passphrase), 0, out, 0);
+    return out;
   }
 
   void setValidator(String type, FutureOr<bool> Function(String) validator) {
diff --git a/pubspec.yaml b/pubspec.yaml
index e0f32195..17edca7c 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -15,15 +15,18 @@ dependencies:
   html_unescape: ^1.0.2
   moor: ^4.0.0
   random_string: ^2.1.0
-  encrypt: ^4.1.0
-  crypto: ^2.1.5
-  base58check: ^1.0.1
-  password_hash: ^2.0.0
+  encrypt: ^5.0.0-beta.1
+  crypto: ^3.0.0
+  base58check: ^2.0.0
   olm: ^2.0.0
-  matrix_file_e2ee: ^1.1.0
+  matrix_file_e2ee:
+    git:
+      url: https://gitlab.com/famedly/libraries/matrix_file_e2ee.git
+      ref: nullsafety
   isolate: ^2.0.3
   logger: ^1.0.0
   matrix_api_lite: ^0.2.4
+  pointycastle: ^3.0.0-nullsafety.2
 
 dev_dependencies:
   test: ^1.15.7
@@ -35,5 +38,4 @@ dev_dependencies:
   #flutter_test: {sdk: flutter}
 
 dependency_overrides:
-  # needed until crypto packages upgrade
-  convert: ^3.0.0
+  args: ^2.0.0