From 437e21b0fef0eb87b70530a77a19f19df9154706 Mon Sep 17 00:00:00 2001
From: Christien Rioux <chris@veilid.org>
Date: Sun, 24 Sep 2023 22:36:15 -0400
Subject: [PATCH] encryption tools

---
 veilid-flutter/lib/veilid_crypto.dart | 46 +++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/veilid-flutter/lib/veilid_crypto.dart b/veilid-flutter/lib/veilid_crypto.dart
index a6b3bead..85d22397 100644
--- a/veilid-flutter/lib/veilid_crypto.dart
+++ b/veilid-flutter/lib/veilid_crypto.dart
@@ -186,6 +186,52 @@ abstract class VeilidCryptoSystem {
   Future<Uint8List> cryptNoAuth(
       Uint8List body, Nonce nonce, SharedSecret sharedSecret);
 
+  Future<Uint8List> encryptAeadWithNonce(
+      Uint8List body, SharedSecret secret) async {
+    // generate nonce
+    final nonce = await randomNonce();
+    // crypt and append nonce
+    final b = BytesBuilder()
+      ..add(await encryptAead(body, nonce, secret, null))
+      ..add(nonce.decode());
+    return b.toBytes();
+  }
+
+  Future<Uint8List> decryptAeadWithNonce(
+      Uint8List body, SharedSecret secret) async {
+    if (body.length < Nonce.decodedLength()) {
+      throw const FormatException('not enough data to decrypt');
+    }
+    final nonce =
+        Nonce.fromBytes(body.sublist(body.length - Nonce.decodedLength()));
+    final encryptedData = body.sublist(0, body.length - Nonce.decodedLength());
+    // decrypt
+    return decryptAead(encryptedData, nonce, secret, null);
+  }
+
+  Future<Uint8List> encryptAeadWithPassword(
+      Uint8List body, String password) async {
+    final ekbytes = Uint8List.fromList(utf8.encode(password));
+    final nonce = await randomNonce();
+    final saltBytes = nonce.decode();
+    final sharedSecret = await deriveSharedSecret(ekbytes, saltBytes);
+    return Uint8List.fromList(
+        (await encryptAead(body, nonce, sharedSecret, null)) + saltBytes);
+  }
+
+  Future<Uint8List> decryptAeadWithPassword(
+      Uint8List body, String password) async {
+    if (body.length < Nonce.decodedLength()) {
+      throw const FormatException('not enough data to decrypt');
+    }
+    final ekbytes = Uint8List.fromList(utf8.encode(password));
+    final bodyBytes = body.sublist(0, body.length - Nonce.decodedLength());
+    final saltBytes = body.sublist(body.length - Nonce.decodedLength());
+    final nonce = Nonce.fromBytes(saltBytes);
+    final sharedSecret = await deriveSharedSecret(ekbytes, saltBytes);
+    return decryptAead(bodyBytes, nonce, sharedSecret, null);
+  }
+
   Future<Uint8List> encryptNoAuthWithNonce(
       Uint8List body, SharedSecret secret) async {
     // generate nonce