refactor: PR #26

ethicnology · Apr 20, 2023 · e6add66 · e6add66
1 parent cc429de
commit e6add66
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Showing 3 changed files with 76 additions and 126 deletions.
diff --git a/lib/src/event.dart b/lib/src/event.dart
@@ -128,27 +128,26 @@ class Event {
  );
  }
 
- /// Instantiate Event object from the minimum available data
+ /// Instantiate Event object from the minimum needed data
  ///
  /// ```dart
  ///Event event = Event.from(
  /// kind: 1,
- /// tags: [],
  /// content: "",
  /// privkey:
  /// "5ee1c8000ab28edd64d74a7d951ac2dd559814887b1b9e1ac7c5f89e96125c12",
  ///);
  ///```
  factory Event.from({
- int createdAt = 0,
+ int? createdAt,
  required int kind,
- required List<List<String>> tags,
+ List<List<String>> tags = const [],
  required String content,
  required String privkey,
  String? subscriptionId,
  bool verify = false,
  }) {
- if (createdAt == 0) createdAt = currentUnixTimestampSeconds();
+ createdAt ??= currentUnixTimestampSeconds();
  final pubkey = bip340.getPublicKey(privkey).toLowerCase();
 
  final id = _processEventId(
@@ -271,20 +270,6 @@ class Event {
  );
  }
 
- factory Event.quick(
- String content,
- String privkey,
- ) {
- Event event = Event.partial();
- event.kind = 1;
- event.content = content;
- event.createdAt = currentUnixTimestampSeconds();
- event.pubkey = bip340.getPublicKey(privkey).toLowerCase();
- event.id = event.getEventId();
- event.sig = event.getSignature(privkey);
- return event;
- }
-
  /// To obtain the event.id, we sha256 the serialized event.
  /// The serialization is done over the UTF-8 JSON-serialized string (with no white space or line breaks) of the following structure:
  ///

diff --git a/lib/src/nips/nip_004/crypto.dart b/lib/src/nips/nip_004/crypto.dart
@@ -1,105 +1,66 @@
 import 'dart:convert';
 import 'dart:math';
 import 'dart:typed_data';
+import 'package:nostr/src/crypto/kepler.dart';
 import 'package:pointycastle/export.dart';
 
-import '../../crypto/kepler.dart';
-
 class Nip4 {
- static Map<String, List<List<int>>> gMapByteSecret = {};
- // pointy castle source https://github.com/PointyCastle/pointycastle/blob/master/tutorials/aes-cbc.md
- // https://github.com/bcgit/pc-dart/blob/master/tutorials/aes-cbc.md
- // 3 https://github.com/Dhuliang/flutter-bsv/blob/42a2d92ec6bb9ee3231878ffe684e1b7940c7d49/lib/src/aescbc.dart
-
- // Encrypt data using self private key in nostr format ( with trailing ?iv=)
- static String cipher(
- String privkey,
- String pubkey,
- String plaintext,
- ) {
- Uint8List uintInputText = Utf8Encoder().convert(plaintext);
- final secretIV = Kepler.byteSecret(privkey, pubkey);
- final key = Uint8List.fromList(
- secretIV[0],
+ static Uint8List generateNonce() {
+ final random = Random.secure();
+ return Uint8List.fromList(
+ List<int>.generate(16, (i) => random.nextInt(256)),
  );
-
- // generate iv https://stackoverflow.com/questions/63630661/aes-engine-not-initialised-with-pointycastle-securerandom
- FortunaRandom fr = FortunaRandom();
- final sGen = Random.secure();
- fr.seed(KeyParameter(
- Uint8List.fromList(List.generate(32, (_) => sGen.nextInt(255)))));
- final iv = fr.nextBytes(16);
-
- CipherParameters params = PaddedBlockCipherParameters(
- ParametersWithIV(KeyParameter(key), iv), null);
-
- PaddedBlockCipherImpl cipherImpl =
- PaddedBlockCipherImpl(PKCS7Padding(), CBCBlockCipher(AESEngine()));
-
- cipherImpl.init(
- true, // means to encrypt
- params as PaddedBlockCipherParameters<CipherParameters?,
- CipherParameters?>);
-
- // allocate space
- final Uint8List outputEncodedText = Uint8List(uintInputText.length + 16);
-
- var offset = 0;
- while (offset < uintInputText.length - 16) {
- offset += cipherImpl.processBlock(
- uintInputText, offset, outputEncodedText, offset);
- }
-
- //add padding
- offset +=
- cipherImpl.doFinal(uintInputText, offset, outputEncodedText, offset);
- final Uint8List finalEncodedText = outputEncodedText.sublist(0, offset);
-
- String stringIv = base64.encode(iv);
- String outputPlainText = base64.encode(finalEncodedText);
- outputPlainText = "$outputPlainText?iv=$stringIv";
- return outputPlainText;
  }
 
- static String decipher(
+ static String cipher(
  String privkey,
  String pubkey,
- String ciphertext, [
- String nonce = "",
- ]) {
- Uint8List cipherText = base64.decode(ciphertext);
- List<List<int>> byteSecret = gMapByteSecret[pubkey] ?? [];
- if (byteSecret.isEmpty) {
- byteSecret = Kepler.byteSecret(privkey, pubkey);
- gMapByteSecret[pubkey] = byteSecret;
+ String payload,
+ bool cipher, {
+ String? nonce,
+ }) {
+ // if cipher=false –> decipher –> nonce needed
+ if (!cipher && nonce == null) throw Exception("missing nonce");
+
+ // init variables
+ Uint8List input, output, iv;
+ if (!cipher && nonce != null) {
+ input = base64.decode(payload);
+ output = Uint8List(input.length);
+ iv = base64.decode(nonce);
+ } else {
+ input = Utf8Encoder().convert(payload);
+ output = Uint8List(input.length + 16);
+ iv = generateNonce();
  }
- final secretIV = byteSecret;
- final key = Uint8List.fromList(secretIV[0]);
- final iv = nonce.length > 6
- ? base64.decode(nonce)
- : Uint8List.fromList(secretIV[1]);
 
- CipherParameters params = PaddedBlockCipherParameters(
- ParametersWithIV(KeyParameter(key), iv), null);
-
- PaddedBlockCipherImpl cipherImpl =
- PaddedBlockCipherImpl(PKCS7Padding(), CBCBlockCipher(AESEngine()));
-
- cipherImpl.init(
- false,
- params as PaddedBlockCipherParameters<CipherParameters?,
- CipherParameters?>);
- final Uint8List finalPlainText =
- Uint8List(cipherText.length); // allocate space
+ // params
+ List<List<int>> keplerSecret = Kepler.byteSecret(privkey, pubkey);
+ var key = Uint8List.fromList(keplerSecret[0]);
+ var params = PaddedBlockCipherParameters(
+ ParametersWithIV(KeyParameter(key), iv),
+ null,
+ );
+ var algo = PaddedBlockCipherImpl(
+ PKCS7Padding(),
+ CBCBlockCipher(AESEngine()),
+ );
 
+ // processing
+ algo.init(cipher, params);
  var offset = 0;
- while (offset < cipherText.length - 16) {
- offset +=
- cipherImpl.processBlock(cipherText, offset, finalPlainText, offset);
+ while (offset < input.length - 16) {
+ offset += algo.processBlock(input, offset, output, offset);
+ }
+ offset += algo.doFinal(input, offset, output, offset);
+ Uint8List result = output.sublist(0, offset);
+
+ if (cipher) {
+ String stringIv = base64.encode(iv);
+ String plaintext = base64.encode(result);
+ return "$plaintext?iv=$stringIv";
+ } else {
+ return Utf8Decoder().convert(result);
  }
- //remove padding
- offset += cipherImpl.doFinal(cipherText, offset, finalPlainText, offset);
- Uint8List result = finalPlainText.sublist(0, offset);
- return Utf8Decoder().convert(result);
  }
 }
diff --git a/lib/src/nips/nip_004/event.dart b/lib/src/nips/nip_004/event.dart
@@ -4,8 +4,6 @@ import 'package:nostr/src/nips/nip_004/crypto.dart';
 import 'package:nostr/src/utils.dart';
 
 class EncryptedDirectMessage extends Event {
- static Map<String, List<List<int>>> gMapByteSecret = {};
-
  EncryptedDirectMessage(Event event)
  : super(
  event.id,
@@ -31,36 +29,42 @@ class EncryptedDirectMessage extends Event {
  event.tags = [
  ['p', receiverPubkey]
  ];
- event.content = Nip4.cipher(senderPrivkey, '02$receiverPubkey', message);
+ event.content = Nip4.cipher(
+ senderPrivkey,
+ '02$receiverPubkey',
+ message,
+ true,
+ );
  event.id = event.getEventId();
  event.sig = event.getSignature(senderPrivkey);
  return EncryptedDirectMessage(event);
  }
 
  String? get receiverPubkey => findPubkey();
 
+ String get nonce {
+ List<String> split = content.split("?iv=");
+ if (split.length != 2) throw Exception("invalid nip4 content");
+ return split[1];
+ }
+
  String getCiphertext(String senderPrivkey, String receiverPubkey) {
- String ciphertext =
- Nip4.cipher(senderPrivkey, '02$receiverPubkey', content);
- return ciphertext;
+ return Nip4.cipher(senderPrivkey, '02$receiverPubkey', content, true);
  }
 
- String getPlaintext(String receiverPrivkey, [String senderPubkey=""]) {
- if (senderPubkey.length == 0) {
- senderPubkey = pubkey;
- }
+ String getPlaintext(String receiverPrivkey) {
+ String ciphertext = content.split("?iv=")[0];
  String plaintext = "";
- int ivIndex = content.indexOf("?iv=");
- if( ivIndex <= 0) {
- print("Invalid content for dm, could not get ivIndex: $content");
- return plaintext;
- }
- String iv = content.substring(ivIndex + "?iv=".length, content.length);
- String ciphertext = content.substring(0, ivIndex);
  try {
- plaintext = Nip4.decipher(receiverPrivkey, "02$senderPubkey", ciphertext, iv);
- } catch(e) {
- print("Fail to decrypt: ${e}");
+ plaintext = Nip4.cipher(
+ receiverPrivkey,
+ "02$pubkey",
+ ciphertext,
+ false,
+ nonce: nonce,
+ );
+ } catch (e) {
+ throw Exception("Fail to decipher: $e");
  }
  return plaintext;
  }