diff --git a/app_crypto/analysis_options.yaml b/app_crypto/analysis_options.yaml
index e684295..12e20d7 100644
--- a/app_crypto/analysis_options.yaml
+++ b/app_crypto/analysis_options.yaml
@@ -1,2 +1,6 @@
 # tekartik strict extension
-include: package:tekartik_lints/strict.yaml
\ No newline at end of file
+include: package:tekartik_lints/strict.yaml
+
+linter:
+  rules:
+    # avoid_print: true
\ No newline at end of file
diff --git a/app_crypto/bin/generate_password.dart b/app_crypto/bin/generate_password.dart
index b8bb77f..4e583c8 100644
--- a/app_crypto/bin/generate_password.dart
+++ b/app_crypto/bin/generate_password.dart
@@ -1,5 +1,7 @@
+import 'dart:io';
+
 import 'package:tekartik_app_crypto/src/generate_password.dart';
 
 Future<void> main() async {
-  print(generatePassword());
+  stdout.writeln(generatePassword());
 }
diff --git a/app_crypto/pubspec.yaml b/app_crypto/pubspec.yaml
index 65af546..770ef97 100644
--- a/app_crypto/pubspec.yaml
+++ b/app_crypto/pubspec.yaml
@@ -31,7 +31,7 @@ dev_dependencies:
   build_test: any
   build_web_compilers: any
   process_run: '>=0.12.0+1'
-
+  cryptography: '>=1.0.0'
 _dependency_overrides:
   encrypt:
     git:
diff --git a/app_crypto/test/aes_test.dart b/app_crypto/test/aes_test.dart
index 3798c8a..ae96c6d 100644
--- a/app_crypto/test/aes_test.dart
+++ b/app_crypto/test/aes_test.dart
@@ -9,7 +9,7 @@ void main() {
   void aesRoundTrip(String decoded, String password) {
     var encrypter = aesEncrypterFromPassword(password);
     var encrypted = encrypter.encrypt(decoded);
-    print('${decoded.length}:${encrypted.length}');
+    // print('${decoded.length}:${encrypted.length}');
     encrypter = aesEncrypterFromPassword(password);
     expect(encrypter.decrypt(encrypted), decoded);
   }
@@ -75,7 +75,7 @@ void main() {
     for (var i = 0; i < count; i++) {
       aes.decrypt(aes.encrypt(textWithLength(count * 10)));
     }
-    print('aes round trip: ${sw.elapsedMilliseconds} ms');
+    // print('aes round trip: ${sw.elapsedMilliseconds} ms');
     sw = Stopwatch()..start();
 
     for (var i = 0; i < count; i++) {
diff --git a/app_crypto/test/manual_perf_test_.dart b/app_crypto/test/manual_perf_test_.dart
new file mode 100644
index 0000000..7f532da
--- /dev/null
+++ b/app_crypto/test/manual_perf_test_.dart
@@ -0,0 +1,93 @@
+import 'package:tekartik_app_crypto/encrypt.dart';
+import 'package:tekartik_common_utils/num_utils.dart';
+import 'package:test/test.dart';
+
+class _TestEncrypter {
+  final String name;
+  final StringEncrypter encrypter;
+  _TestEncrypter(this.name, this.encrypter);
+}
+
+class _TestAction {
+  final String name;
+  final void Function() action;
+  _TestAction(this.name, this.action);
+}
+
+String textWithLength(int length) {
+  return List.generate(length, (i) => i.toString().substring(0, 1)).join();
+}
+
+void main() {
+  var password = encryptTextPassword16FromText('password');
+  var testEncrypters = [
+    _TestEncrypter('aes', aesEncrypterFromPassword(password)),
+    _TestEncrypter('salsa20', salsa20EncrypterFromPassword(password)),
+  ];
+
+  group('perf', () {
+    for (var testEncrypter in testEncrypters) {
+      var name = testEncrypter.name;
+      test(name, () {
+        var encrypter = testEncrypter.encrypter;
+        for (var data in [
+          textWithLength(10),
+          textWithLength(1000),
+          textWithLength(10000)
+        ]) {
+          var encryptedData = encrypter.encrypt(data);
+          expect(encrypter.decrypt(encryptedData), data);
+
+          var initialEstimationSize = 10;
+
+          int actionsDurationMs(int count, void Function() action) {
+            var sw = Stopwatch()..start();
+            for (var i = 0; i < count; i++) {
+              action();
+            }
+            sw.stop();
+            return sw.elapsedMilliseconds;
+          }
+
+          void execute(_TestAction testAction) {
+            void action() {
+              testAction.action();
+            }
+
+            var count = initialEstimationSize;
+            int ms;
+            while (true) {
+              ms = actionsDurationMs(count, action);
+              // print('count: $count ms: $ms');
+              if (ms < 50) {
+                count = (count * 1.2).toInt();
+              } else {
+                break;
+              }
+            }
+            var countPerMs = count / ms;
+            var durationTestMs = 500;
+            var countTest = (countPerMs * durationTestMs).toInt();
+
+            // print('countTest: $countTest (${(countPerMs * 1000).toInt()} per/s)');
+            for (var i = 0; i < 1; i++) {
+              encryptedData = encrypter.encrypt(data);
+
+              var msTest = actionsDurationMs(countTest, action).boundedMin(1);
+              countPerMs = countTest / msTest;
+              print(
+                  '$name ${data.length} ${testAction.name}: (${(countPerMs * 1000).toInt()} per/s)');
+            }
+          }
+
+          execute(_TestAction('encrypt', () {
+            encrypter.encrypt(data);
+          }));
+          execute(_TestAction('decrypt', () {
+            encrypter.decrypt(encryptedData);
+          }));
+        }
+      });
+    }
+  });
+}