cake_wallet/cw_bitcoin/lib/bitcoin_mnemonic.dart

import 'dart:convert';
import 'dart:math';
import 'dart:typed_data';

import 'package:crypto/crypto.dart';
import 'package:cryptography/cryptography.dart' as cryptography;
import 'package:cw_core/sec_random_native.dart';
import 'package:cw_core/utils/text_normalizer.dart';

const segwit = '100';
const mweb = 'eb';
final wordlist = englishWordlist;

double logBase(num x, num base) => log(x) / log(base);

String mnemonicEncode(int i) {
  var _i = i;
  final n = wordlist.length;
  final words = <String>[];

  while (_i > 0) {
    final x = i % n;
    _i = (i / n).floor();
    words.add(wordlist[x]);
  }

  return words.join(' ');
}

int mnemonicDecode(String seed) {
  var i = 0;
  final n = wordlist.length;
  final words = seed.split(' ');

  while (words.length > 0) {
    final word = words.removeLast();
    final k = wordlist.indexOf(word);
    i = i * n + k;
  }

  return i;
}

bool isNewSeed(String seed, {String prefix = segwit}) {
  final hmacSha512 = Hmac(sha512, utf8.encode('Seed version'));
  final digest = hmacSha512.convert(utf8.encode(normalizeText(seed)));
  final hx = digest.toString();
  return hx.startsWith(prefix.toLowerCase());
}

void maskBytes(Uint8List bytes, int bits) {
  final skipCount = (bits / 8).floor();
  var lastByte = (1 << bits % 8) - 1;

  for (var i = bytes.length - 1 - skipCount; i >= 0; i--) {
    bytes[i] &= lastByte;

    if (lastByte > 0) {
      lastByte = 0;
    }
  }
}

String bufferToBin(Uint8List data) => data.map((e) => e.toRadixString(2).padLeft(8, '0')).join('');

String encode(Uint8List data) {
  final dataBitLen = data.length * 8;
  final wordBitLen = logBase(wordlist.length, 2).ceil();
  final wordCount = (dataBitLen / wordBitLen).floor();
  maskBytes(data, wordCount * wordBitLen);
  final bin = bufferToBin(data);
  final binStr = bin.substring(bin.length - (wordCount * wordBitLen));
  final result = <Object>[];

  for (var i = 0; i < wordCount; i++) {
    final wordBin = binStr.substring(i * wordBitLen, (i + 1) * wordBitLen);
    result.add(wordlist[int.parse(wordBin, radix: 2)]);
  }

  return result.join(' ');
}

List<bool> prefixMatches(String source, List<String> prefixes) {
  final hmacSha512 = Hmac(sha512, utf8.encode('Seed version'));
  final digest = hmacSha512.convert(utf8.encode(normalizeText(source)));
  final hx = digest.toString();

  return prefixes.map((prefix) => hx.startsWith(prefix.toLowerCase())).toList();
}

Future<String> generateElectrumMnemonic({int strength = 264, String prefix = segwit}) async {
  final wordBitlen = logBase(wordlist.length, 2).ceil();
  final wordCount = strength / wordBitlen;
  final byteCount = ((wordCount * wordBitlen).ceil() / 8).ceil();
  var result = '';

  do {
    final bytes = await secRandom(byteCount);
    maskBytes(bytes, strength);
    result = encode(bytes);
  } while (!prefixMatches(result, [prefix]).first);

  return result;
}

Future<bool> checkIfMnemonicIsElectrum2(String mnemonic) async {
  return prefixMatches(mnemonic, [segwit]).first;
}

Future<String> getMnemonicHash(String mnemonic) async {
  final hmacSha512 = Hmac(sha512, utf8.encode('Seed version'));
  final digest = hmacSha512.convert(utf8.encode(normalizeText(mnemonic)));
  return digest.toString();
}

Future<Uint8List> mnemonicToSeedBytes(String mnemonic,
    {String prefix = segwit, String passphrase = ''}) async {
  final pbkdf2 =
      cryptography.Pbkdf2(macAlgorithm: cryptography.Hmac.sha512(), iterations: 2048, bits: 512);
  final text = normalizeText(mnemonic);
  final passphraseBytes = utf8.encode(normalizeText(passphrase));
  final key = await pbkdf2.deriveKey(
      secretKey: cryptography.SecretKey(text.codeUnits),
      nonce: [...'electrum'.codeUnits, ...passphraseBytes]);
  final bytes = await key.extractBytes();
  return Uint8List.fromList(bytes);
}

bool matchesAnyPrefix(String mnemonic) => prefixMatches(mnemonic, [segwit, mweb]).any((el) => el);

bool validateMnemonic(String mnemonic, {String prefix = segwit}) {
  try {
    return matchesAnyPrefix(mnemonic);
  } catch (e) {
    return false;
  }
}

final englishWordlist = <String>[
  'abandon',
  'ability',
  'able',
  'about',
  'above',
  'absent',
  'absorb',
  'abstract',
  'absurd',
  'abuse',
  'access',
  'accident',
  'account',
  'accuse',
  'achieve',
  'acid',
  'acoustic',
  'acquire',
  'across',
  'act',
  'action',
  'actor',
  'actress',
  'actual',
  'adapt',
  'add',
  'addict',
  'address',
  'adjust',
  'admit',
  'adult',
  'advance',
  'advice',
  'aerobic',
  'affair',
  'afford',
  'afraid',
  'again',
  'age',
  'agent',
  'agree',
  'ahead',
  'aim',
  'air',
  'airport',
  'aisle',
  'alarm',
  'album',
  'alcohol',
  'alert',
  'alien',
  'all',
  'alley',
  'allow',
  'almost',
  'alone',
  'alpha',
  'already',
  'also',
  'alter',
  'always',
  'amateur',
  'amazing',
  'among',
  'amount',
  'amused',
  'analyst',
  'anchor',
  'ancient',
  'anger',
  'angle',
  'angry',
  'animal',
  'ankle',
  'announce',
  'annual',
  'another',
  'answer',
  'antenna',
  'antique',
  'anxiety',
  'any',
  'apart',
  'apology',
  'appear',
  'apple',
  'approve',
  'april',
  'arch',
  'arctic',
  'area',
  'arena',
  'argue',
  'arm',
  'armed',
  'armor',
  'army',
  'around',
  'arrange',
  'arrest',
  'arrive',
  'arrow',
  'art',
  'artefact',
  'artist',
  'artwork',
  'ask',
  'aspect',
  'assault',
  'asset',
  'assist',
  'assume',
  'asthma',
  'athlete',
  'atom',
  'attack',
  'attend',
  'attitude',
  'attract',
  'auction',
  'audit',
  'august',
  'aunt',
  'author',
  'auto',
  'autumn',
  'average',
  'avocado',
  'avoid',
  'awake',
  'aware',
  'away',
  'awesome',
  'awful',
  'awkward',
  'axis',
  'baby',
  'bachelor',
  'bacon',
  'badge',
  'bag',
  'balance',
  'balcony',
  'ball',
  'bamboo',
  'banana',
  'banner',
  'bar',
  'barely',
  'bargain',
  'barrel',
  'base',
  'basic',
  'basket',
  'battle',
  'beach',
  'bean',
  'beauty',
  'because',
  'become',
  'beef',
  'before',
  'begin',
  'behave',
  'behind',
  'believe',
  'below',
  'belt',
  'bench',
  'benefit',
  'best',
  'betray',
  'better',
  'between',
  'beyond',
  'bicycle',
  'bid',
  'bike',
  'bind',
  'biology',
  'bird',
  'birth',
  'bitter',
  'black',
  'blade',
  'blame',
  'blanket',
  'blast',
  'bleak',
  'bless',
  'blind',
  'blood',
  'blossom',
  'blouse',
  'blue',
  'blur',
  'blush',
  'board',
  'boat',
  'body',
  'boil',
  'bomb',
  'bone',
  'bonus',
  'book',
  'boost',
  'border',
  'boring',
  'borrow',
  'boss',
  'bottom',
  'bounce',
  'box',
  'boy',
  'bracket',
  'brain',
  'brand',
  'brass',
  'brave',
  'bread',
  'breeze',
  'brick',
  'bridge',
  'brief',
  'bright',
  'bring',
  'brisk',
  'broccoli',
  'broken',
  'bronze',
  'broom',
  'brother',
  'brown',
  'brush',
  'bubble',
  'buddy',
  'budget',
  'buffalo',
  'build',
  'bulb',
  'bulk',
  'bullet',
  'bundle',
  'bunker',
  'burden',
  'burger',
  'burst',
  'bus',
  'business',
  'busy',
  'butter',
  'buyer',
  'buzz',
  'cabbage',
  'cabin',
  'cable',
  'cactus',
  'cage',
  'cake',
  'call',
  'calm',
  'camera',
  'camp',
  'can',
  'canal',
  'cancel',
  'candy',
  'cannon',
  'canoe',
  'canvas',
  'canyon',
  'capable',
  'capital',
  'captain',
  'car',
  'carbon',
  'card',
  'cargo',
  'carpet',
  'carry',
  'cart',
  'case',
  'cash',
  'casino',
  'castle',
  'casual',
  'cat',
  'catalog',
  'catch',
  'category',
  'cattle',
  'caught',
  'cause',
  'caution',
  'cave',
  'ceiling',
  'celery',
  'cement',
  'census',
  'century',
  'cereal',
  'certain',
  'chair',
  'chalk',
  'champion',
  'change',
  'chaos',
  'chapter',
  'charge',
  'chase',
  'chat',
  'cheap',
  'check',
  'cheese',
  'chef',
  'cherry',
  'chest',
  'chicken',
  'chief',
  'child',
  'chimney',
  'choice',
  'choose',
  'chronic',
  'chuckle',
  'chunk',
  'churn',
  'cigar',
  'cinnamon',
  'circle',
  'citizen',
  'city',
  'civil',
  'claim',
  'clap',
  'clarify',
  'claw',
  'clay',
  'clean',
  'clerk',
  'clever',
  'click',
  'client',
  'cliff',
  'climb',
  'clinic',
  'clip',
  'clock',
  'clog',
  'close',
  'cloth',
  'cloud',
  'clown',
  'club',
  'clump',
  'cluster',
  'clutch',
  'coach',
  'coast',
  'coconut',
  'code',
  'coffee',
  'coil',
  'coin',
  'collect',
  'color',
  'column',
  'combine',
  'come',
  'comfort',
  'comic',
  'common',
  'company',
  'concert',
  'conduct',
  'confirm',
  'congress',
  'connect',
  'consider',
  'control',
  'convince',
  'cook',
  'cool',
  'copper',
  'copy',
  'coral',
  'core',
  'corn',
  'correct',
  'cost',
  'cotton',
  'couch',
  'country',
  'couple',
  'course',
  'cousin',
  'cover',
  'coyote',
  'crack',
  'cradle',
  'craft',
  'cram',
  'crane',
  'crash',
  'crater',
  'crawl',
  'crazy',
  'cream',
  'credit',
  'creek',
  'crew',
  'cricket',
  'crime',
  'crisp',
  'critic',
  'crop',
  'cross',
  'crouch',
  'crowd',
  'crucial',
  'cruel',
  'cruise',
  'crumble',
  'crunch',
  'crush',
  'cry',
  'crystal',
  'cube',
  'culture',
  'cup',
  'cupboard',
  'curious',
  'current',
  'curtain',
  'curve',
  'cushion',
  'custom',
  'cute',
  'cycle',
  'dad',
  'damage',
  'damp',
  'dance',
  'danger',
  'daring',
  'dash',
  'daughter',
  'dawn',
  'day',
  'deal',
  'debate',
  'debris',
  'decade',
  'december',
  'decide',
  'decline',
  'decorate',
  'decrease',
  'deer',
  'defense',
  'define',
  'defy',
  'degree',
  'delay',
  'deliver',
  'demand',
  'demise',
  'denial',
  'dentist',
  'deny',
  'depart',
  'depend',
  'deposit',
  'depth',
  'deputy',
  'derive',
  'describe',
  'desert',
  'design',
  'desk',
  'despair',
  'destroy',
  'detail',
  'detect',
  'develop',
  'device',
  'devote',
  'diagram',
  'dial',
  'diamond',
  'diary',
  'dice',
  'diesel',
  'diet',
  'differ',
  'digital',
  'dignity',
  'dilemma',
  'dinner',
  'dinosaur',
  'direct',
  'dirt',
  'disagree',
  'discover',
  'disease',
  'dish',
  'dismiss',
  'disorder',
  'display',
  'distance',
  'divert',
  'divide',
  'divorce',
  'dizzy',
  'doctor',
  'document',
  'dog',
  'doll',
  'dolphin',
  'domain',
  'donate',
  'donkey',
  'donor',
  'door',
  'dose',
  'double',
  'dove',
  'draft',
  'dragon',
  'drama',
  'drastic',
  'draw',
  'dream',
  'dress',
  'drift',
  'drill',
  'drink',
  'drip',
  'drive',
  'drop',
  'drum',
  'dry',
  'duck',
  'dumb',
  'dune',
  'during',
  'dust',
  'dutch',
  'duty',
  'dwarf',
  'dynamic',
  'eager',
  'eagle',
  'early',
  'earn',
  'earth',
  'easily',
  'east',
  'easy',
  'echo',
  'ecology',
  'economy',
  'edge',
  'edit',
  'educate',
  'effort',
  'egg',
  'eight',
  'either',
  'elbow',
  'elder',
  'electric',
  'elegant',
  'element',
  'elephant',
  'elevator',
  'elite',
  'else',
  'embark',
  'embody',
  'embrace',
  'emerge',
  'emotion',
  'employ',
  'empower',
  'empty',
  'enable',
  'enact',
  'end',
  'endless',
  'endorse',
  'enemy',
  'energy',
  'enforce',
  'engage',
  'engine',
  'enhance',
  'enjoy',
  'enlist',
  'enough',
  'enrich',
  'enroll',
  'ensure',
  'enter',
  'entire',
  'entry',
  'envelope',
  'episode',
  'equal',
  'equip',
  'era',
  'erase',
  'erode',
  'erosion',
  'error',
  'erupt',
  'escape',
  'essay',
  'essence',
  'estate',
  'eternal',
  'ethics',
  'evidence',
  'evil',
  'evoke',
  'evolve',
  'exact',
  'example',
  'excess',
  'exchange',
  'excite',
  'exclude',
  'excuse',
  'execute',
  'exercise',
  'exhaust',
  'exhibit',
  'exile',
  'exist',
  'exit',
  'exotic',
  'expand',
  'expect',
  'expire',
  'explain',
  'expose',
  'express',
  'extend',
  'extra',
  'eye',
  'eyebrow',
  'fabric',
  'face',
  'faculty',
  'fade',
  'faint',
  'faith',
  'fall',
  'false',
  'fame',
  'family',
  'famous',
  'fan',
  'fancy',
  'fantasy',
  'farm',
  'fashion',
  'fat',
  'fatal',
  'father',
  'fatigue',
  'fault',
  'favorite',
  'feature',
  'february',
  'federal',
  'fee',
  'feed',
  'feel',
  'female',
  'fence',
  'festival',
  'fetch',
  'fever',
  'few',
  'fiber',
  'fiction',
  'field',
  'figure',
  'file',
  'film',
  'filter',
  'final',
  'find',
  'fine',
  'finger',
  'finish',
  'fire',
  'firm',
  'first',
  'fiscal',
  'fish',
  'fit',
  'fitness',
  'fix',
  'flag',
  'flame',
  'flash',
  'flat',
  'flavor',
  'flee',
  'flight',
  'flip',
  'float',
  'flock',
  'floor',
  'flower',
  'fluid',
  'flush',
  'fly',
  'foam',
  'focus',
  'fog',
  'foil',
  'fold',
  'follow',
  'food',
  'foot',
  'force',
  'forest',
  'forget',
  'fork',
  'fortune',
  'forum',
  'forward',
  'fossil',
  'foster',
  'found',
  'fox',
  'fragile',
  'frame',
  'frequent',
  'fresh',
  'friend',
  'fringe',
  'frog',
  'front',
  'frost',
  'frown',
  'frozen',
  'fruit',
  'fuel',
  'fun',
  'funny',
  'furnace',
  'fury',
  'future',
  'gadget',
  'gain',
  'galaxy',
  'gallery',
  'game',
  'gap',
  'garage',
  'garbage',
  'garden',
  'garlic',
  'garment',
  'gas',
  'gasp',
  'gate',
  'gather',
  'gauge',
  'gaze',
  'general',
  'genius',
  'genre',
  'gentle',
  'genuine',
  'gesture',
  'ghost',
  'giant',
  'gift',
  'giggle',
  'ginger',
  'giraffe',
  'girl',
  'give',
  'glad',
  'glance',
  'glare',
  'glass',
  'glide',
  'glimpse',
  'globe',
  'gloom',
  'glory',
  'glove',
  'glow',
  'glue',
  'goat',
  'goddess',
  'gold',
  'good',
  'goose',
  'gorilla',
  'gospel',
  'gossip',
  'govern',
  'gown',
  'grab',
  'grace',
  'grain',
  'grant',
  'grape',
  'grass',
  'gravity',
  'great',
  'green',
  'grid',
  'grief',
  'grit',
  'grocery',
  'group',
  'grow',
  'grunt',
  'guard',
  'guess',
  'guide',
  'guilt',
  'guitar',
  'gun',
  'gym',
  'habit',
  'hair',
  'half',
  'hammer',
  'hamster',
  'hand',
  'happy',
  'harbor',
  'hard',
  'harsh',
  'harvest',
  'hat',
  'have',
  'hawk',
  'hazard',
  'head',
  'health',
  'heart',
  'heavy',
  'hedgehog',
  'height',
  'hello',
  'helmet',
  'help',
  'hen',
  'hero',
  'hidden',
  'high',
  'hill',
  'hint',
  'hip',
  'hire',
  'history',
  'hobby',
  'hockey',
  'hold',
  'hole',
  'holiday',
  'hollow',
  'home',
  'honey',
  'hood',
  'hope',
  'horn',
  'horror',
  'horse',
  'hospital',
  'host',
  'hotel',
  'hour',
  'hover',
  'hub',
  'huge',
  'human',
  'humble',
  'humor',
  'hundred',
  'hungry',
  'hunt',
  'hurdle',
  'hurry',
  'hurt',
  'husband',
  'hybrid',
  'ice',
  'icon',
  'idea',
  'identify',
  'idle',
  'ignore',
  'ill',
  'illegal',
  'illness',
  'image',
  'imitate',
  'immense',
  'immune',
  'impact',
  'impose',
  'improve',
  'impulse',
  'inch',
  'include',
  'income',
  'increase',
  'index',
  'indicate',
  'indoor',
  'industry',
  'infant',
  'inflict',
  'inform',
  'inhale',
  'inherit',
  'initial',
  'inject',
  'injury',
  'inmate',
  'inner',
  'innocent',
  'input',
  'inquiry',
  'insane',
  'insect',
  'inside',
  'inspire',
  'install',
  'intact',
  'interest',
  'into',
  'invest',
  'invite',
  'involve',
  'iron',
  'island',
  'isolate',
  'issue',
  'item',
  'ivory',
  'jacket',
  'jaguar',
  'jar',
  'jazz',
  'jealous',
  'jeans',
  'jelly',
  'jewel',
  'job',
  'join',
  'joke',
  'journey',
  'joy',
  'judge',
  'juice',
  'jump',
  'jungle',
  'junior',
  'junk',
  'just',
  'kangaroo',
  'keen',
  'keep',
  'ketchup',
  'key',
  'kick',
  'kid',
  'kidney',
  'kind',
  'kingdom',
  'kiss',
  'kit',
  'kitchen',
  'kite',
  'kitten',
  'kiwi',
  'knee',
  'knife',
  'knock',
  'know',
  'lab',
  'label',
  'labor',
  'ladder',
  'lady',
  'lake',
  'lamp',
  'language',
  'laptop',
  'large',
  'later',
  'latin',
  'laugh',
  'laundry',
  'lava',
  'law',
  'lawn',
  'lawsuit',
  'layer',
  'lazy',
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];