refactor: PR #25

ethicnology · Apr 17, 2023 · 385f211 · ntheden · Apr 17, 2023 · ethicnology
1 parent 37f5645
commit 385f211
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Showing 6 changed files with 132 additions and 229 deletions.
diff --git a/lib/src/event.dart b/lib/src/event.dart
@@ -1,12 +1,9 @@
 import 'dart:convert';
 import 'dart:typed_data';
-import 'package:bip340/bip340.dart' as bip340;
 import 'package:convert/convert.dart';
 import 'package:pointycastle/export.dart';
-
-import 'nips/nip_004/crypto.dart';
-import 'utils.dart';
-import 'settings.dart';
+import 'package:bip340/bip340.dart' as bip340;
+import 'package:nostr/src/utils.dart';
 
 /// The only object type that exists is the event, which has the following format on the wire:
 ///
@@ -49,11 +46,6 @@ class Event {
   /// subscription_id is a random string that should be used to represent a subscription.
   String? subscriptionId;
 
-  /// Nip04: If event is of kind 4, then `decrypted` flag indicates whether `content` was
-  /// successfully decrypted. Unsuccessful decryption on a valid event is typically caused
-  /// by missing or mismatched private key.
-  bool decrypted = false;
-
   /// Default constructor
   ///
   /// verify: ensure your event isValid() –> id, signature, timestamp…
@@ -262,14 +254,11 @@ class Event {
       throw Exception('invalid input');
     }
 
-    if (json['tags'] is String) {
-      json['tags'] = jsonDecode(json['tags']);
-    }
-    List<List<String>> tags = (json['tags'] as List<dynamic>)
+    var tags = (json['tags'] as List<dynamic>)
         .map((e) => (e as List<dynamic>).map((e) => e as String).toList())
         .toList();
 
-    Event event = Event(
+    return Event(
       json['id'],
       json['pubkey'],
       json['created_at'],
@@ -280,24 +269,6 @@ class Event {
       subscriptionId: subscriptionId,
       verify: verify,
     );
-    if (event.kind == 4) {
-      event.nip04Decrypt();
-    }
-    return event;
-  }
-
-  factory Event.newEvent(
-    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.
@@ -331,7 +302,7 @@ class Event {
     String content,
   ) {
     List data = [0, pubkey.toLowerCase(), createdAt, kind, tags, content];
-    String serializedEvent = jsonEncode(data);
+    String serializedEvent = json.encode(data);
     Uint8List hash = SHA256Digest()
         .process(Uint8List.fromList(utf8.encode(serializedEvent)));
     return hex.encode(hash);
@@ -357,14 +328,6 @@ class Event {
   /// Verify if event checks such as id, signature, non-futuristic are valid
   /// Performances could be a reason to disable event checks
   bool isValid() {
-    if (decrypted) {
-      // isValid() check was already performed when the Event was created at
-      // deserialization off of the input stream. Post-decryption, id check will
-      // fail as the content has changed.
-      // Alternatively, getEventId() could compute id from a `plaintext` field
-      // when `decrypted` is true.
-      return true;
-    }
     String verifyId = getEventId();
     if (createdAt.toString().length == 10 &&
         id == verifyId &&
@@ -374,21 +337,4 @@ class Event {
       return false;
     }
   }
-
-  bool nip04Decrypt() {
-    int ivIndex = content.indexOf("?iv=");
-    if (ivIndex <= 0) {
-      print("Invalid content for dm, could not get ivIndex: $content");
-      return false;
-    }
-    String iv = content.substring(ivIndex + "?iv=".length, content.length);
-    String encString = content.substring(0, ivIndex);
-    try {
-      content = Nip04.decrypt(userPrivateKey, "02$pubkey", encString, iv);
-      decrypted = true;
-    } catch (e) {
-      //print("Fail to decrypt: ${e}");
-    }
-    return decrypted;
-  }
 }
diff --git a/lib/src/message.dart b/lib/src/message.dart
@@ -17,6 +17,7 @@ class Message {
     switch (type) {
       case "EVENT":
         message = Event.deserialize(data);
+        if (message.kind == 4) message = EncryptedDirectMessage(message);
         break;
       case "REQ":
         message = Request.deserialize(data);

diff --git a/lib/src/nips/nip_004/crypto.dart b/lib/src/nips/nip_004/crypto.dart
@@ -5,22 +5,23 @@ import 'package:pointycastle/export.dart';
 
 import '../../crypto/kepler.dart';
 
-class Nip04 {
+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 encryptMessage(
-      String privateString, String publicString, String plainText) {
-    Uint8List uintInputText = Utf8Encoder().convert(plainText);
-    final encryptedString =
-        encryptMessageRaw(privateString, publicString, uintInputText);
-    return encryptedString;
-  }
-
-  static String encryptMessageRaw(
-      String privateString, String publicString, Uint8List uintInputText) {
-    final secretIV = Kepler.byteSecret(privateString, publicString);
-    final key = Uint8List.fromList(secretIV[0]);
+  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],
+    );
 
     // generate iv  https://stackoverflow.com/questions/63630661/aes-engine-not-initialised-with-pointycastle-securerandom
     FortunaRandom fr = FortunaRandom();
@@ -60,31 +61,23 @@ class Nip04 {
     return outputPlainText;
   }
 
-  // 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
-
-  /// Decrypt data using self private key
-  static String decrypt(
-      String privateString, String publicString, String b64encoded,
-      [String b64IV = ""]) {
-    Uint8List encdData = base64.decode(b64encoded);
-    final rawData = decryptRaw(privateString, publicString, encdData, b64IV);
-    return Utf8Decoder().convert(rawData.toList());
-  }
-
-  static Uint8List decryptRaw(
-      String privateString, String publicString, Uint8List cipherText,
-      [String b64IV = ""]) {
-    List<List<int>> byteSecret = gMapByteSecret[publicString] ?? [];
+  // Decrypt data using self private key
+  static String decipher(
+    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(privateString, publicString);
-      gMapByteSecret[publicString] = byteSecret;
+      byteSecret = Kepler.byteSecret(privkey, pubkey);
+      gMapByteSecret[pubkey] = byteSecret;
     }
     final secretIV = byteSecret;
     final key = Uint8List.fromList(secretIV[0]);
-    final iv = b64IV.length > 6
-        ? base64.decode(b64IV)
+    final iv = nonce.length > 6
+        ? base64.decode(nonce)
         : Uint8List.fromList(secretIV[1]);
 
     CipherParameters params = PaddedBlockCipherParameters(
@@ -107,6 +100,7 @@ class Nip04 {
     }
     //remove padding
     offset += cipherImpl.doFinal(cipherText, offset, finalPlainText, offset);
-    return finalPlainText.sublist(0, offset);
+    Uint8List result = finalPlainText.sublist(0, offset);
+    return Utf8Decoder().convert(result.toList());
   }
 }
diff --git a/lib/src/nips/nip_004/event.dart b/lib/src/nips/nip_004/event.dart
@@ -1,93 +1,59 @@
 import 'package:bip340/bip340.dart' as bip340;
-
-import '../../event.dart';
-import '../../utils.dart';
-import 'crypto.dart';
+import 'package:nostr/src/event.dart';
+import 'package:nostr/src/nips/nip_004/crypto.dart';
+import 'package:nostr/src/utils.dart';
 
 class EncryptedDirectMessage extends Event {
-  late String peerPubkey;
-  late String? plaintext;
-  late String? referenceEventId;
-
-  EncryptedDirectMessage(
-    this.peerPubkey,
-    id,
-    pubkey,
-    createdAt,
-    kind,
-    tags,
-    content,
-    sig, {
-    subscriptionId,
-    bool verify = false,
-    this.plaintext,
-    this.referenceEventId,
-  }) : super(
-          id,
-          pubkey,
-          createdAt,
-          kind,
-          tags,
-          content,
-          sig,
-          subscriptionId: subscriptionId,
-          verify: verify,
-        ) {
-    kind = 4;
-    plaintext = content;
-  }
+  static Map<String, List<List<int>>> gMapByteSecret = {};
 
-  factory EncryptedDirectMessage.partial({
-    peerPubkey = "",
-    id = "",
-    pubkey = "",
-    createdAt = 0,
-    kind = 4,
-    tags = const <List<String>>[],
-    content = "",
-    sig = "",
-    plaintext,
-    referenceEventId,
-    subscriptionId,
-    bool verify = false,
-  }) {
-    return EncryptedDirectMessage(
-      peerPubkey,
-      id,
-      pubkey,
-      createdAt,
-      kind,
-      tags,
-      content,
-      sig,
-      plaintext: plaintext,
-      referenceEventId: referenceEventId,
-      subscriptionId: subscriptionId,
-      verify: verify,
-    );
-  }
+  EncryptedDirectMessage(Event event)
+      : super(
+          event.id,
+          event.pubkey,
+          event.createdAt,
+          4,
+          event.tags,
+          event.content,
+          event.sig,
+          subscriptionId: event.subscriptionId,
+          verify: true,
+        );
 
-  factory EncryptedDirectMessage.newEvent(
-    String peerPubkey,
-    String plaintext,
-    String privkey, {
-    String? referenceEventId,
-  }) {
-    EncryptedDirectMessage event = EncryptedDirectMessage.partial();
-    event.content = Nip04.encryptMessage(privkey, '02$peerPubkey', plaintext);
-    event.kind = 4;
+  factory EncryptedDirectMessage.quick(
+    String senderPrivkey,
+    String receiverPubkey,
+    String message,
+  ) {
+    var event = Event.partial();
+    event.pubkey = bip340.getPublicKey(senderPrivkey).toLowerCase();
     event.createdAt = currentUnixTimestampSeconds();
-    event.pubkey = bip340.getPublicKey(privkey).toLowerCase();
+    event.kind = 4;
     event.tags = [
-      ['p', peerPubkey],
+      ['p', receiverPubkey]
     ];
-    event.peerPubkey = peerPubkey;
-    event.plaintext = plaintext;
-    if (referenceEventId != null) {
-      event.tags.add(['e', referenceEventId]);
-    }
+    event.content = Nip4.cipher(senderPrivkey, '02$receiverPubkey', message);
     event.id = event.getEventId();
-    event.sig = event.getSignature(privkey);
-    return event;
+    event.sig = event.getSignature(senderPrivkey);
+    return EncryptedDirectMessage(event);
+  }
+
+  String? get receiverPubkey => findPubkey();
+
+  String getCiphertext(String senderPrivkey, String receiverPubkey) {
+    String ciphertext =
+        Nip4.cipher(senderPrivkey, '02$receiverPubkey', content);
+    return ciphertext;
+  }
+
+  String getPlaintext(String receiverPrivkey, String senderPubkey) {
+    return Nip4.decipher(receiverPrivkey, senderPubkey, content);
+  }
+
+  String? findPubkey() {
+    String prefix = "p";
+    for (List<String> tag in tags) {
+      if (tag.isNotEmpty && tag[0] == prefix && tag.length > 1) return tag[1];
+    }
+    return null;
   }
 }
diff --git a/lib/src/settings.dart b/lib/src/settings.dart