update

lib/security/encryption.dart

@@ -0,0 +1,24 @@
+import 'package:lazyxchacha/keypair.dart' as kp;
+import 'package:lazyxchacha/lazyxchacha.dart';
+
+final key = kp.KeyPair.newKeyPair();
+
+Future<String> encrypt(String text) async {
+  final lazyxchacha = LazyXChaCha.instance;
+  final localKey = await key;
+
+  final sharedKey = await localKey.sharedKey(localKey.pk);
+  final ciphertext = await lazyxchacha.encrypt(text, sharedKey);
+
+  return ciphertext;
+}
+
+Future<String> decrypt(String encrypted) async {
+  final lazyXChaCha = LazyXChaCha.instance;
+  final localKey = await key;
+
+  final sharedKey = await localKey.sharedKey(localKey.pk);
+  final plaintext = await lazyXChaCha.decrypt(encrypted, sharedKey);
+
+  return plaintext;
+}