first commit

.github/CODEOWNERS

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+# This file is used to define a set of default reviewers.
+* @justkawal

.github/FUNDING.yml

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+# These are supported funding model platforms
+
+github: # Replace with up to 4 GitHub Sponsors-enabled usernames e.g., [user1, user2]
+patreon: # Replace with a single Patreon username
+open_collective: # Replace with a single Open Collective username
+ko_fi: kawal
+tidelift: # Replace with a single Tidelift platform-name/package-name e.g., npm/babel
+community_bridge: # Replace with a single Community Bridge project-name e.g., cloud-foundry
+liberapay: # Replace with a single Liberapay username
+issuehunt: # Replace with a single IssueHunt username
+otechie: # Replace with a single Otechie username
+lfx_crowdfunding: # Replace with a single LFX Crowdfunding project-name e.g., cloud-foundry
+custom: https://paypal.me/justkawal

.github/workflows/dart.yml

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+# This workflow uses actions that are not certified by GitHub.
+# They are provided by a third-party and are governed by
+# separate terms of service, privacy policy, and support
+# documentation.
+
+name: Dart
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+
+      # Note: This workflow uses the latest stable version of the Dart SDK.
+      # You can specify other versions if desired, see documentation here:
+      # https://github.com/dart-lang/setup-dart/blob/main/README.md
+      # - uses: dart-lang/setup-dart@v1
+      - uses: dart-lang/setup-dart@9a04e6d73cca37bd455e0608d7e5092f881fd603
+
+      - name: Install dependencies
+        run: dart pub get
+
+      # Uncomment this step to verify the use of 'dart format' on each commit.
+      - name: Verify formatting
+        run: dart format --output=none --set-exit-if-changed .
+
+      # Consider passing '--fatal-infos' for slightly stricter analysis.
+      - name: Analyze project source
+        run: dart analyze --fatal-infos
+
+      # Your project will need to have tests in test/ and a dependency on
+      # package:test for this step to succeed. Note that Flutter projects will
+      # want to change this to 'flutter test'.
+      - name: Run tests
+        run: dart test

.gitignore

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+# https://dart.dev/guides/libraries/private-files
+# Created by `dart pub`
+.dart_tool/
+
+# Avoid committing pubspec.lock for library packages; see
+# https://dart.dev/guides/libraries/private-files#pubspeclock.
+pubspec.lock

CHANGELOG.md

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+## 1.0.0
+- Initial version.
+
+## 1.0.1
+- Publish version.

LICENSE

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+The MIT License (MIT)
+
+Copyright (C) 2023 - Kawaljeet Singh
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

analysis_options.yaml

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+# This file configures the static analysis results for your project (errors,
+# warnings, and lints).
+#
+# This enables the 'recommended' set of lints from `package:lints`.
+# This set helps identify many issues that may lead to problems when running
+# or consuming Dart code, and enforces writing Dart using a single, idiomatic
+# style and format.
+#
+# If you want a smaller set of lints you can change this to specify
+# 'package:lints/core.yaml'. These are just the most critical lints
+# (the recommended set includes the core lints).
+# The core lints are also what is used by pub.dev for scoring packages.
+
+include: package:lints/recommended.yaml
+
+# Uncomment the following section to specify additional rules.
+
+linter:
+ rules:
+    prefer_final_fields
+
+# analyzer:
+#   exclude:
+#     - path/to/excluded/files/**
+
+# For more information about the core and recommended set of lints, see
+# https://dart.dev/go/core-lints
+
+# For additional information about configuring this file, see
+# https://dart.dev/guides/language/analysis-options

example/example.dart

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+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'package:convert/convert.dart';
+import 'package:merlin/merlin.dart';
+
+void main() {
+  {
+    //Simple Transcript
+    final mt = Transcript('test protocol');
+
+    mt.appendMessage(Uint8List.fromList(utf8.encode('some label')),
+        Uint8List.fromList(utf8.encode('some data')));
+
+    final cBytes =
+        mt.extractBytes(Uint8List.fromList(utf8.encode('challenge')), 32);
+
+    // d5a21972d0d5fe320c0d263fac7fffb8145aa640af6e9bca177c03c7efcf0615
+    final cHex = hex.encode(cBytes);
+    print(cHex);
+  }
+
+  {
+    // Complex Transcript
+    final tr = Transcript('test protocol');
+    tr.appendMessage(utf8.encode('step1'), utf8.encode('some data'));
+
+    final data = Uint8List(1024)..fillRange(0, 1024, 99);
+
+    late List<int> chlBytes;
+    for (var i = 0; i < 32; i++) {
+      chlBytes = tr.extractBytes(utf8.encode('challenge'), 32);
+      tr
+        ..appendMessage(utf8.encode('bigdata'), data)
+        ..appendMessage(utf8.encode('challengedata'), chlBytes);
+    }
+
+    // a8c933f54fae76e3f9bea93648c1308e7dfa2152dd51674ff3ca438351cf003c
+    final chlHex = hex.encode(chlBytes);
+    print(chlHex);
+  }
+}

lib/merlin.dart

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+import 'dart:convert';
+import 'dart:typed_data';
+import 'package:strobe/strobe.dart';
+
+const merlinProtocolLabel = 'Merlin v1.0';
+const domainSeparatorLabel = 'dom-sep';
+
+class Transcript {
+  late Strobe s;
+  Transcript(String appLabel) {
+    s = Strobe.initStrobe(merlinProtocolLabel, Security.bit128);
+    appendMessage(utf8.encode(domainSeparatorLabel), utf8.encode(appLabel));
+  }
+
+  // Append adds the message to the transcript with the supplied label.
+  void appendMessage(List<int> label, List<int> message) {
+    final sizeBuffer = Uint8List(4);
+    ByteData.view(sizeBuffer.buffer)
+        .setUint32(0, message.length, Endian.little);
+
+    final labelSize = Uint8List.fromList([...label, ...sizeBuffer]);
+    s
+      ..aD(true, labelSize)
+      ..aD(false, message);
+  }
+
+  // ExtractBytes returns a buffer filled with the verifier's challenge bytes.
+  // The label parameter is metadata about the challenge, and is also appended to
+  // the transcript. See the Transcript Protocols section of the Merlin website
+  // for details on labels.
+  List<int> extractBytes(List<int> label, int outLen) {
+    final sizeBuffer = Uint8List(4);
+    ByteData.view(sizeBuffer.buffer).setUint32(0, outLen, Endian.little);
+
+    final labelSize = Uint8List.fromList([...label, ...sizeBuffer]);
+    s.aD(true, labelSize);
+
+    return s.prf(outLen);
+  }
+}

pubspec.yaml

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+name: merlin
+description: A starting point for Dart libraries or applications.
+version: 1.0.1
+repository: https://github.com/justkawal/merlin
+
+environment:
+  sdk: ^3.1.5
+
+dependencies:
+  strobe: ^1.0.1
+
+dev_dependencies:
+  convert: ^3.1.1
+  lints: ^3.0.0
+  test: ^1.21.0

test/merlin_test.dart

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+import 'dart:convert';
+import 'dart:typed_data';
+import 'package:convert/convert.dart';
+import 'package:merlin/merlin.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test('Test Simple Transcript', () {
+    final mt = Transcript('test protocol');
+    mt.appendMessage(Uint8List.fromList(utf8.encode('some label')),
+        Uint8List.fromList(utf8.encode('some data')));
+
+    final cBytes =
+        mt.extractBytes(Uint8List.fromList(utf8.encode('challenge')), 32);
+    final cHex = hex.encode(cBytes);
+
+    expect(cHex,
+        'd5a21972d0d5fe320c0d263fac7fffb8145aa640af6e9bca177c03c7efcf0615');
+  });
+
+  test('Test Complex Transcript', () {
+    final tr = Transcript('test protocol');
+    tr.appendMessage(utf8.encode('step1'), utf8.encode('some data'));
+
+    final data = Uint8List(1024)..fillRange(0, 1024, 99);
+
+    late List<int> chlBytes;
+    for (var i = 0; i < 32; i++) {
+      chlBytes = tr.extractBytes(utf8.encode('challenge'), 32);
+      tr
+        ..appendMessage(utf8.encode('bigdata'), data)
+        ..appendMessage(utf8.encode('challengedata'), chlBytes);
+    }
+    final chlHex = hex.encode(chlBytes);
+
+    expect(chlHex,
+        'a8c933f54fae76e3f9bea93648c1308e7dfa2152dd51674ff3ca438351cf003c');
+  });
+}