diff --git a/lib/src/algorithm.dart b/lib/src/algorithm.dart
index f40e1e0..4119216 100644
--- a/lib/src/algorithm.dart
+++ b/lib/src/algorithm.dart
@@ -18,7 +18,7 @@ abstract class Algorithm {
   static Algorithm decode(String hash) {
     final parts = hash.split('\$');
     final algoFactory = _algorithms[parts[1]];
-    final algorithm = algoFactory(parts[2].split(','), parts[3]);
+    final algorithm = algoFactory!(parts[2].split(','), parts[3]);
 
     return algorithm;
   }
diff --git a/lib/src/algorithms/pbkdf2.dart b/lib/src/algorithms/pbkdf2.dart
index baa7378..eb16b91 100644
--- a/lib/src/algorithms/pbkdf2.dart
+++ b/lib/src/algorithms/pbkdf2.dart
@@ -18,14 +18,14 @@ class PBKDF2 extends Algorithm {
   final int iterationCount;
   final int desiredKeyLength;
 
-  PBKDF2KeyDerivator _derivator;
-  Uint8List _salt;
+  late PBKDF2KeyDerivator _derivator;
+  late Uint8List _salt;
 
   PBKDF2(
       {this.blockLength = 64,
       this.iterationCount = 10000,
       this.desiredKeyLength = 64,
-      String salt = null}) {
+      String? salt = null}) {
     final rnd = new FortunaRandom()..seed(new KeyParameter(new Uint8List(32)));
 
     _salt =
diff --git a/pubspec.yaml b/pubspec.yaml
index 5c3392c..3dc6bb3 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,13 +1,14 @@
 name: password
-version: 1.0.0
+version: 2.0.0
 description: A set of high-level APIs over PointyCastle to hash and verify passwords securely.
 author: leocavalcante <lc@leocavalcante.com>
 homepage: https://github.com/leocavalcante/password-dart
 environment:
-  sdk: ">=2.0.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
-  pointycastle: ^1.0.0
+  pointycastle: ^3.0.1
+
 
 dev_dependencies:
   test: ^1.5.1+1