WIP: basic electrum mnemonic utils

diff --git a/lib/utilities/electrum_seed_utils.dart b/lib/utilities/electrum_seed_utils.dart
new file mode 100644
index 0000000..337987a
--- /dev/null
+++ b/lib/utilities/electrum_seed_utils.dart
@@ -0,0 +1,1098 @@
+import 'dart:typed_data';
+
+import 'package:pointycastle/export.dart';
+import 'package:unorm_dart/unorm_dart.dart';
+
+import 'extensions/extensions.dart';
+
+abstract class ElectrumSeedUtils {
+  static const kSeedPrefix = "01"; // standard
+  static const kSeedPrefixSegwit = "100"; // segwit
+  static const kSeedPrefix2fa = "101"; // 2FA standard
+  static const kSeedPrefix2faSegwit = "102"; // 2FA segwit
+
+  static Uint8List electrumMnemonicToSeedBytes(
+    final String mnemonic, {
+    final String passphrase = "",
+  }) {
+    final salt = Uint8List.fromList([
+      ..."electrum".toUint8ListFromUtf8,
+      ...normalize(passphrase).toUint8ListFromUtf8,
+    ]);
+
+    final kdf = PBKDF2KeyDerivator(HMac.withDigest(SHA512Digest()))
+      ..init(Pbkdf2Parameters(salt, 2048, 64));
+
+    return kdf.process(normalize(mnemonic).toUint8ListFromUtf8);
+  }
+
+  // based on https://electrum.readthedocs.io/en/latest/seedphrase.html#version-number
+  static String electrumMnemonicVersion(
+    final String mnemonic, {
+    final String passphrase = "",
+  }) {
+    final normalized = normalize(mnemonic).toUint8ListFromUtf8;
+
+    final hash = _hmacHex(normalized);
+
+    final length = int.parse(hash[0], radix: 16) + 2;
+
+    return hash.substring(0, length);
+  }
+
+  static bool isNewSeed(final String mnemonic, {String prefix = kSeedPrefix}) {
+    final normalized = normalize(mnemonic).toUint8ListFromUtf8;
+    final hash = _hmacHex(normalized);
+    return hash.startsWith(prefix);
+  }
+
+  static String normalize(final String mnemonic) {
+    final characters = String.fromCharCodes(
+      nfkd(
+        mnemonic,
+      ).toLowerCase().runes.where((e) => !_kNonZeroCCCCodeUnits.contains(e)),
+    ).split(RegExp(r"\s+")).join(" ").trim().split("");
+
+    final buffer = StringBuffer();
+
+    for (int i = 0; i < characters.length; i++) {
+      final char = characters[i];
+      final isSpace = RegExp(r"\s").hasMatch(char);
+      assert(char.runes.length == 1);
+
+      if (isSpace && i > 0 && i < characters.length - 1) {
+        final prev = characters[i - 1];
+        final next = characters[i + 1];
+        if (_isCJK(prev.runes.first) && _isCJK(next.runes.first)) {
+          continue;
+        }
+      }
+
+      buffer.write(char);
+    }
+
+    return buffer.toString();
+  }
+
+  static String _hmacHex(Uint8List message) =>
+      (HMac.withDigest(SHA512Digest())
+            ..init(KeyParameter("Seed version".toUint8ListFromUtf8)))
+          .process(message)
+          .toHex;
+
+  static bool _isCJK(int code) {
+    for (final (min, max, _) in _kCjkIntervals) {
+      if (min <= code && code <= max) {
+        return true;
+      }
+    }
+    return false;
+  }
+}
+
+// https://www.unicode.org/reports/tr44/tr44-34.html#Canonical_Combining_Class_Values
+// generated from https://www.unicode.org/Public/UCD/latest/ucd/UnicodeData.txt
+const _kNonZeroCCCCodeUnits = {
+  768,
+  769,
+  770,
+  771,
+  772,
+  773,
+  774,
+  775,
+  776,
+  777,
+  778,
+  779,
+  780,
+  781,
+  782,
+  783,
+  784,
+  785,
+  786,
+  787,
+  788,
+  789,
+  790,
+  791,
+  792,
+  793,
+  794,
+  795,
+  796,
+  797,
+  798,
+  799,
+  800,
+  801,
+  802,
+  803,
+  804,
+  805,
+  806,
+  807,
+  808,
+  809,
+  810,
+  811,
+  812,
+  813,
+  814,
+  815,
+  816,
+  817,
+  818,
+  819,
+  820,
+  821,
+  822,
+  823,
+  824,
+  825,
+  826,
+  827,
+  828,
+  829,
+  830,
+  831,
+  832,
+  833,
+  834,
+  835,
+  836,
+  837,
+  838,
+  839,
+  840,
+  841,
+  842,
+  843,
+  844,
+  845,
+  846,
+  848,
+  849,
+  850,
+  851,
+  852,
+  853,
+  854,
+  855,
+  856,
+  857,
+  858,
+  859,
+  860,
+  861,
+  862,
+  863,
+  864,
+  865,
+  866,
+  867,
+  868,
+  869,
+  870,
+  871,
+  872,
+  873,
+  874,
+  875,
+  876,
+  877,
+  878,
+  879,
+  1155,
+  1156,
+  1157,
+  1158,
+  1159,
+  1425,
+  1426,
+  1427,
+  1428,
+  1429,
+  1430,
+  1431,
+  1432,
+  1433,
+  1434,
+  1435,
+  1436,
+  1437,
+  1438,
+  1439,
+  1440,
+  1441,
+  1442,
+  1443,
+  1444,
+  1445,
+  1446,
+  1447,
+  1448,
+  1449,
+  1450,
+  1451,
+  1452,
+  1453,
+  1454,
+  1455,
+  1456,
+  1457,
+  1458,
+  1459,
+  1460,
+  1461,
+  1462,
+  1463,
+  1464,
+  1465,
+  1466,
+  1467,
+  1468,
+  1469,
+  1471,
+  1473,
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+  1476,
+  1477,
+  1479,
+  1552,
+  1553,
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+  1555,
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+  1558,
+  1559,
+  1560,
+  1561,
+  1562,
+  1611,
+  1612,
+  1613,
+  1614,
+  1615,
+  1616,
+  1617,
+  1618,
+  1619,
+  1620,
+  1621,
+  1622,
+  1623,
+  1624,
+  1625,
+  1626,
+  1627,
+  1628,
+  1629,
+  1630,
+  1631,
+  1648,
+  1750,
+  1751,
+  1752,
+  1753,
+  1754,
+  1755,
+  1756,
+  1759,
+  1760,
+  1761,
+  1762,
+  1763,
+  1764,
+  1767,
+  1768,
+  1770,
+  1771,
+  1772,
+  1773,
+  1809,
+  1840,
+  1841,
+  1842,
+  1843,
+  1844,
+  1845,
+  1846,
+  1847,
+  1848,
+  1849,
+  1850,
+  1851,
+  1852,
+  1853,
+  1854,
+  1855,
+  1856,
+  1857,
+  1858,
+  1859,
+  1860,
+  1861,
+  1862,
+  1863,
+  1864,
+  1865,
+  1866,
+  2027,
+  2028,
+  2029,
+  2030,
+  2031,
+  2032,
+  2033,
+  2034,
+  2035,
+  2045,
+  2070,
+  2071,
+  2072,
+  2073,
+  2075,
+  2076,
+  2077,
+  2078,
+  2079,
+  2080,
+  2081,
+  2082,
+  2083,
+  2085,
+  2086,
+  2087,
+  2089,
+  2090,
+  2091,
+  2092,
+  2093,
+  2137,
+  2138,
+  2139,
+  2199,
+  2200,
+  2201,
+  2202,
+  2203,
+  2204,
+  2205,
+  2206,
+  2207,
+  2250,
+  2251,
+  2252,
+  2253,
+  2254,
+  2255,
+  2256,
+  2257,
+  2258,
+  2259,
+  2260,
+  2261,
+  2262,
+  2263,
+  2264,
+  2265,
+  2266,
+  2267,
+  2268,
+  2269,
+  2270,
+  2271,
+  2272,
+  2273,
+  2275,
+  2276,
+  2277,
+  2278,
+  2279,
+  2280,
+  2281,
+  2282,
+  2283,
+  2284,
+  2285,
+  2286,
+  2287,
+  2288,
+  2289,
+  2290,
+  2291,
+  2292,
+  2293,
+  2294,
+  2295,
+  2296,
+  2297,
+  2298,
+  2299,
+  2300,
+  2301,
+  2302,
+  2303,
+  2364,
+  2381,
+  2385,
+  2386,
+  2387,
+  2388,
+  2492,
+  2509,
+  2558,
+  2620,
+  2637,
+  2748,
+  2765,
+  2876,
+  2893,
+  3021,
+  3132,
+  3149,
+  3157,
+  3158,
+  3260,
+  3277,
+  3387,
+  3388,
+  3405,
+  3530,
+  3640,
+  3641,
+  3642,
+  3656,
+  3657,
+  3658,
+  3659,
+  3768,
+  3769,
+  3770,
+  3784,
+  3785,
+  3786,
+  3787,
+  3864,
+  3865,
+  3893,
+  3895,
+  3897,
+  3953,
+  3954,
+  3956,
+  3962,
+  3963,
+  3964,
+  3965,
+  3968,
+  3970,
+  3971,
+  3972,
+  3974,
+  3975,
+  4038,
+  4151,
+  4153,
+  4154,
+  4237,
+  4957,
+  4958,
+  4959,
+  5908,
+  5909,
+  5940,
+  6098,
+  6109,
+  6313,
+  6457,
+  6458,
+  6459,
+  6679,
+  6680,
+  6752,
+  6773,
+  6774,
+  6775,
+  6776,
+  6777,
+  6778,
+  6779,
+  6780,
+  6783,
+  6832,
+  6833,
+  6834,
+  6835,
+  6836,
+  6837,
+  6838,
+  6839,
+  6840,
+  6841,
+  6842,
+  6843,
+  6844,
+  6845,
+  6847,
+  6848,
+  6849,
+  6850,
+  6851,
+  6852,
+  6853,
+  6854,
+  6855,
+  6856,
+  6857,
+  6858,
+  6859,
+  6860,
+  6861,
+  6862,
+  6863,
+  6864,
+  6865,
+  6866,
+  6867,
+  6868,
+  6869,
+  6870,
+  6871,
+  6872,
+  6873,
+  6874,
+  6875,
+  6876,
+  6877,
+  6880,
+  6881,
+  6882,
+  6883,
+  6884,
+  6885,
+  6886,
+  6887,
+  6888,
+  6889,
+  6890,
+  6891,
+  6964,
+  6980,
+  7019,
+  7020,
+  7021,
+  7022,
+  7023,
+  7024,
+  7025,
+  7026,
+  7027,
+  7082,
+  7083,
+  7142,
+  7154,
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+  7223,
+  7376,
+  7377,
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+  7380,
+  7381,
+  7382,
+  7383,
+  7384,
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+  7386,
+  7387,
+  7388,
+  7389,
+  7390,
+  7391,
+  7392,
+  7394,
+  7395,
+  7396,
+  7397,
+  7398,
+  7399,
+  7400,
+  7405,
+  7412,
+  7416,
+  7417,
+  7616,
+  7617,
+  7618,
+  7619,
+  7620,
+  7621,
+  7622,
+  7623,
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+  7625,
+  7626,
+  7627,
+  7628,
+  7629,
+  7630,
+  7631,
+  7632,
+  7633,
+  7634,
+  7635,
+  7636,
+  7637,
+  7638,
+  7639,
+  7640,
+  7641,
+  7642,
+  7643,
+  7644,
+  7645,
+  7646,
+  7647,
+  7648,
+  7649,
+  7650,
+  7651,
+  7652,
+  7653,
+  7654,
+  7655,
+  7656,
+  7657,
+  7658,
+  7659,
+  7660,
+  7661,
+  7662,
+  7663,
+  7664,
+  7665,
+  7666,
+  7667,
+  7668,
+  7669,
+  7670,
+  7671,
+  7672,
+  7673,
+  7674,
+  7675,
+  7676,
+  7677,
+  7678,
+  7679,
+  8400,
+  8401,
+  8402,
+  8403,
+  8404,
+  8405,
+  8406,
+  8407,
+  8408,
+  8409,
+  8410,
+  8411,
+  8412,
+  8417,
+  8421,
+  8422,
+  8423,
+  8424,
+  8425,
+  8426,
+  8427,
+  8428,
+  8429,
+  8430,
+  8431,
+  8432,
+  11503,
+  11504,
+  11505,
+  11647,
+  11744,
+  11745,
+  11746,
+  11747,
+  11748,
+  11749,
+  11750,
+  11751,
+  11752,
+  11753,
+  11754,
+  11755,
+  11756,
+  11757,
+  11758,
+  11759,
+  11760,
+  11761,
+  11762,
+  11763,
+  11764,
+  11765,
+  11766,
+  11767,
+  11768,
+  11769,
+  11770,
+  11771,
+  11772,
+  11773,
+  11774,
+  11775,
+  12330,
+  12331,
+  12332,
+  12333,
+  12334,
+  12335,
+  12441,
+  12442,
+  42607,
+  42612,
+  42613,
+  42614,
+  42615,
+  42616,
+  42617,
+  42618,
+  42619,
+  42620,
+  42621,
+  42654,
+  42655,
+  42736,
+  42737,
+  43014,
+  43052,
+  43204,
+  43232,
+  43233,
+  43234,
+  43235,
+  43236,
+  43237,
+  43238,
+  43239,
+  43240,
+  43241,
+  43242,
+  43243,
+  43244,
+  43245,
+  43246,
+  43247,
+  43248,
+  43249,
+  43307,
+  43308,
+  43309,
+  43347,
+  43443,
+  43456,
+  43696,
+  43698,
+  43699,
+  43700,
+  43703,
+  43704,
+  43710,
+  43711,
+  43713,
+  43766,
+  44013,
+  64286,
+  65056,
+  65057,
+  65058,
+  65059,
+  65060,
+  65061,
+  65062,
+  65063,
+  65064,
+  65065,
+  65066,
+  65067,
+  65068,
+  65069,
+  65070,
+  65071,
+  66045,
+  66272,
+  66422,
+  66423,
+  66424,
+  66425,
+  66426,
+  68109,
+  68111,
+  68152,
+  68153,
+  68154,
+  68159,
+  68325,
+  68326,
+  68900,
+  68901,
+  68902,
+  68903,
+  68969,
+  68970,
+  68971,
+  68972,
+  68973,
+  69291,
+  69292,
+  69370,
+  69371,
+  69373,
+  69374,
+  69375,
+  69446,
+  69447,
+  69448,
+  69449,
+  69450,
+  69451,
+  69452,
+  69453,
+  69454,
+  69455,
+  69456,
+  69506,
+  69507,
+  69508,
+  69509,
+  69702,
+  69744,
+  69759,
+  69817,
+  69818,
+  69888,
+  69889,
+  69890,
+  69939,
+  69940,
+  70003,
+  70080,
+  70090,
+  70197,
+  70198,
+  70377,
+  70378,
+  70459,
+  70460,
+  70477,
+  70502,
+  70503,
+  70504,
+  70505,
+  70506,
+  70507,
+  70508,
+  70512,
+  70513,
+  70514,
+  70515,
+  70516,
+  70606,
+  70607,
+  70608,
+  70722,
+  70726,
+  70750,
+  70850,
+  70851,
+  71103,
+  71104,
+  71231,
+  71350,
+  71351,
+  71467,
+  71737,
+  71738,
+  71997,
+  71998,
+  72003,
+  72160,
+  72244,
+  72263,
+  72345,
+  72767,
+  73026,
+  73028,
+  73029,
+  73111,
+  73537,
+  73538,
+  90415,
+  92912,
+  92913,
+  92914,
+  92915,
+  92916,
+  92976,
+  92977,
+  92978,
+  92979,
+  92980,
+  92981,
+  92982,
+  94192,
+  94193,
+  113822,
+  119141,
+  119142,
+  119143,
+  119144,
+  119145,
+  119149,
+  119150,
+  119151,
+  119152,
+  119153,
+  119154,
+  119163,
+  119164,
+  119165,
+  119166,
+  119167,
+  119168,
+  119169,
+  119170,
+  119173,
+  119174,
+  119175,
+  119176,
+  119177,
+  119178,
+  119179,
+  119210,
+  119211,
+  119212,
+  119213,
+  119362,
+  119363,
+  119364,
+  122880,
+  122881,
+  122882,
+  122883,
+  122884,
+  122885,
+  122886,
+  122888,
+  122889,
+  122890,
+  122891,
+  122892,
+  122893,
+  122894,
+  122895,
+  122896,
+  122897,
+  122898,
+  122899,
+  122900,
+  122901,
+  122902,
+  122903,
+  122904,
+  122907,
+  122908,
+  122909,
+  122910,
+  122911,
+  122912,
+  122913,
+  122915,
+  122916,
+  122918,
+  122919,
+  122920,
+  122921,
+  122922,
+  123023,
+  123184,
+  123185,
+  123186,
+  123187,
+  123188,
+  123189,
+  123190,
+  123566,
+  123628,
+  123629,
+  123630,
+  123631,
+  124140,
+  124141,
+  124142,
+  124143,
+  124398,
+  124399,
+  124643,
+  124646,
+  124654,
+  124655,
+  124661,
+  125136,
+  125137,
+  125138,
+  125139,
+  125140,
+  125141,
+  125142,
+  125252,
+  125253,
+  125254,
+  125255,
+  125256,
+  125257,
+  125258,
+};
+
+// see https://github.com/spesmilo/electrum/blob/master/electrum/mnemonic.py#L39-L70
+// which references http://www.asahi-net.or.jp/~ax2s-kmtn/ref/unicode/e_asia.html
+const _kCjkIntervals = [
+  (0x4E00, 0x9FFF, "CJK Unified Ideographs"),
+  (0x3400, 0x4DBF, "CJK Unified Ideographs Extension A"),
+  (0x20000, 0x2A6DF, "CJK Unified Ideographs Extension B"),
+  (0x2A700, 0x2B73F, "CJK Unified Ideographs Extension C"),
+  (0x2B740, 0x2B81F, "CJK Unified Ideographs Extension D"),
+  (0xF900, 0xFAFF, "CJK Compatibility Ideographs"),
+  (0x2F800, 0x2FA1D, "CJK Compatibility Ideographs Supplement"),
+  (0x3190, 0x319F, "Kanbun"),
+  (0x2E80, 0x2EFF, "CJK Radicals Supplement"),
+  (0x2F00, 0x2FDF, "CJK Radicals"),
+  (0x31C0, 0x31EF, "CJK Strokes"),
+  (0x2FF0, 0x2FFF, "Ideographic Description Characters"),
+  (0xE0100, 0xE01EF, "Variation Selectors Supplement"),
+  (0x3100, 0x312F, "Bopomofo"),
+  (0x31A0, 0x31BF, "Bopomofo Extended"),
+  (0xFF00, 0xFFEF, "Halfwidth and Fullwidth Forms"),
+  (0x3040, 0x309F, "Hiragana"),
+  (0x30A0, 0x30FF, "Katakana"),
+  (0x31F0, 0x31FF, "Katakana Phonetic Extensions"),
+  (0x1B000, 0x1B0FF, "Kana Supplement"),
+  (0xAC00, 0xD7AF, "Hangul Syllables"),
+  (0x1100, 0x11FF, "Hangul Jamo"),
+  (0xA960, 0xA97F, "Hangul Jamo Extended A"),
+  (0xD7B0, 0xD7FF, "Hangul Jamo Extended B"),
+  (0x3130, 0x318F, "Hangul Compatibility Jamo"),
+  (0xA4D0, 0xA4FF, "Lisu"),
+  (0x16F00, 0x16F9F, "Miao"),
+  (0xA000, 0xA48F, "Yi Syllables"),
+  (0xA490, 0xA4CF, "Yi Radicals"),
+];
diff --git a/pubspec.lock b/pubspec.lock
index bcd7d7b..3a81a8c 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -2254,7 +2254,7 @@ packages:
     source: hosted
     version: "2.2.2"
   unorm_dart:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: unorm_dart
       sha256: "5b35bff83fce4d76467641438f9e867dc9bcfdb8c1694854f230579d68cd8f4b"
diff --git a/scripts/app_config/templates/pubspec.template.yaml b/scripts/app_config/templates/pubspec.template.yaml
index d29dea1..742f44e 100644
--- a/scripts/app_config/templates/pubspec.template.yaml
+++ b/scripts/app_config/templates/pubspec.template.yaml
@@ -245,6 +245,7 @@ dependencies:
   fixnum: ^1.1.1
   saf_util: ^0.11.0
   saf_stream: ^0.12.3
+  unorm_dart: ^0.2.0
 
 dev_dependencies:
   flutter_test:
diff --git a/test/utilities/electrum_seed_utils_test.dart b/test/utilities/electrum_seed_utils_test.dart
new file mode 100644
index 0000000..a726cbb
--- /dev/null
+++ b/test/utilities/electrum_seed_utils_test.dart
@@ -0,0 +1,302 @@
+import 'package:coinlib_flutter/coinlib_flutter.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:stackwallet/utilities/electrum_seed_utils.dart';
+import 'package:stackwallet/utilities/extensions/extensions.dart';
+
+class _TestCase {
+  final String words, bip32Seed, seedVersion;
+  final String? lang, wordsHex, passphrase, passphraseHex;
+
+  const _TestCase({
+    required this.words,
+    required this.bip32Seed,
+    this.seedVersion = ElectrumSeedUtils.kSeedPrefix,
+    this.lang,
+    this.wordsHex,
+    this.passphrase,
+    this.passphraseHex,
+  });
+}
+
+// horror data sourced from https://github.com/spesmilo/electrum/blob/master/tests/test_wallet_vertical.py#L31-L33
+const kUnicodeHorror =
+    "₿ 😀 😈     う けたま わる w͢͢͝h͡o͢͡ ̸͢k̵͟n̴͘ǫw̸̛s͘ ̀́w͘͢ḩ̵a҉̡͢t ̧̕h́o̵r͏̵rors̡ ̶͡͠lį̶e͟͟ ̶͝in͢ ͏t̕h̷̡͟e ͟͟d̛a͜r̕͡k̢̨ ͡h̴e͏a̷̢̡rt́͏ ̴̷͠ò̵̶f̸ u̧͘ní̛͜c͢͏o̷͏d̸͢e̡͝?͞";
+const kUnicodeHorrorHex =
+    "e282bf20f09f988020f09f98882020202020e3818620e38191e3819fe381be20e3828fe382"
+    "8b2077cda2cda2cd9d68cda16fcda2cda120ccb8cda26bccb5cd9f6eccb4cd98c7ab77ccb8"
+    "cc9b73cd9820cc80cc8177cd98cda2e1b8a9ccb561d289cca1cda27420cca7cc9568cc816f"
+    "ccb572cd8fccb5726f7273cca120ccb6cda1cda06cc4afccb665cd9fcd9f20ccb6cd9d696e"
+    "cda220cd8f74cc9568ccb7cca1cd9f6520cd9fcd9f64cc9b61cd9c72cc95cda16bcca2cca8"
+    "20cda168ccb465cd8f61ccb7cca2cca17274cc81cd8f20ccb4ccb7cda0c3b2ccb5ccb666cc"
+    "b82075cca7cd986ec3adcc9bcd9c63cda2cd8f6fccb7cd8f64ccb8cda265cca1cd9d3fcd9e";
+
+// test cases sourced from https://github.com/spesmilo/electrum/blob/master/tests/test_mnemonic.py
+const kTestCases = {
+  "english": _TestCase(
+    words:
+        "wild father tree among universe such"
+        " mobile favorite target dynamic credit identify",
+    seedVersion: ElectrumSeedUtils.kSeedPrefixSegwit,
+    bip32Seed:
+        "aac2a6302e48577ab4b46f23dbae0774e2e62c796f797d0a1b5faeb528301e3064342d"
+        "afb79069e7c4c6b8c38ae11d7a973bec0d4f70626f8cc5184a8d0b0756",
+  ),
+  "english_with_passphrase": _TestCase(
+    words:
+        "wild father tree among universe such"
+        " mobile favorite target dynamic credit identify",
+    seedVersion: ElectrumSeedUtils.kSeedPrefixSegwit,
+    passphrase: "Did you ever hear the tragedy of Darth Plagueis the Wise?",
+    bip32Seed:
+        "4aa29f2aeb0127efb55138ab9e7be83b36750358751906f86c662b21a1ea1370f949e6"
+        "d1a12fa56d3d93cadda93038c76ac8118597364e46f5156fde6183c82f",
+  ),
+  "japanese": _TestCase(
+    lang: "ja",
+    words: "なのか ひろい しなん まなぶ つぶす さがす おしゃれ かわく おいかける けさき かいとう さたん",
+    wordsHex:
+        "e381aae381aee3818b20e381b2e3828de3818420e38197e381aae3829320e381bee381"
+        "aae381b5e3829920e381a4e381b5e38299e3819920e38195e3818be38299e38199"
+        "20e3818ae38197e38283e3828c20e3818be3828fe3818f20e3818ae38184e3818b"
+        "e38191e3828b20e38191e38195e3818d20e3818be38184e381a8e3818620e38195"
+        "e3819fe38293",
+    bip32Seed:
+        "d3eaf0e44ddae3a5769cb08a26918e8b308258bcb057bb704c6f69713245c0b35cb92c"
+        "03df9c9ece5eff826091b4e74041e010b701d44d610976ce8bfb66a8ad",
+  ),
+  "japanese_with_passphrase": _TestCase(
+    lang: "ja",
+    words: "なのか ひろい しなん まなぶ つぶす さがす おしゃれ かわく おいかける けさき かいとう さたん",
+    wordsHex:
+        "e381aae381aee3818b20e381b2e3828de3818420e38197e381aae3829320e381bee381"
+        "aae381b5e3829920e381a4e381b5e38299e3819920e38195e3818be38299e38199"
+        "20e3818ae38197e38283e3828c20e3818be3828fe3818f20e3818ae38184e3818b"
+        "e38191e3828b20e38191e38195e3818d20e3818be38184e381a8e3818620e38195"
+        "e3819fe38293",
+    passphrase: kUnicodeHorror,
+    passphraseHex: kUnicodeHorrorHex,
+    bip32Seed:
+        "251ee6b45b38ba0849e8f40794540f7e2c6d9d604c31d68d3ac50c034f8b64e4bc037c"
+        "5e1e985a2fed8aad23560e690b03b120daf2e84dceb1d7857dda042457",
+  ),
+  "chinese": _TestCase(
+    lang: "zh",
+    words: "眼 悲 叛 改 节 跃 衡 响 疆 股 遂 冬",
+    wordsHex:
+        "e79cbc20e682b220e58f9b20e694b920e88a8220e8b78320e8a1a120e5938d20e79686"
+        "20e882a120e9818220e586ac",
+    seedVersion: ElectrumSeedUtils.kSeedPrefixSegwit,
+    bip32Seed:
+        "0b9077db7b5a50dbb6f61821e2d35e255068a5847e221138048a20e12d80b673ce306b"
+        "6fe7ac174ebc6751e11b7037be6ee9f17db8040bb44f8466d519ce2abf",
+  ),
+  "chinese_with_passphrase": _TestCase(
+    lang: "zh",
+    words: "眼 悲 叛 改 节 跃 衡 响 疆 股 遂 冬",
+    wordsHex:
+        "e79cbc20e682b220e58f9b20e694b920e88a8220e8b78320e8a1a120e5938d20e79686"
+        "20e882a120e9818220e586ac",
+    seedVersion: ElectrumSeedUtils.kSeedPrefixSegwit,
+    passphrase: "给我一些测试向量谷歌",
+    passphraseHex:
+        "e7bb99e68891e4b880e4ba9be6b58be8af95e59091e9878fe8b0b7e6ad8c",
+    bip32Seed:
+        "6c03dd0615cf59963620c0af6840b52e867468cc64f20a1f4c8155705738e87b8edb0f"
+        "c8a6cee4085776cb3a629ff88bb1a38f37085efdbf11ce9ec5a7fa5f71",
+  ),
+  "spanish": _TestCase(
+    lang: "es",
+    words:
+        "almíbar tibio superar vencer hacha peatón"
+        " príncipe matar consejo polen vehículo odisea",
+    wordsHex:
+        "616c6d69cc8162617220746962696f20737570657261722076656e6365722068616368"
+        "6120706561746fcc816e20707269cc816e63697065206d6174617220636f6e7365"
+        "6a6f20706f6c656e2076656869cc8163756c6f206f6469736561",
+    bip32Seed:
+        "18bffd573a960cc775bbd80ed60b7dc00bc8796a186edebe7fc7cf1f316da0fe937852"
+        "a969c5c79ded8255cdf54409537a16339fbe33fb9161af793ea47faa7a",
+  ),
+  "spanish_with_passphrase": _TestCase(
+    lang: "es",
+    words:
+        "almíbar tibio superar vencer hacha peatón "
+        "príncipe matar consejo polen vehículo odisea",
+    wordsHex:
+        "616c6d69cc8162617220746962696f20737570657261722076656e6365722068616368"
+        "6120706561746fcc816e20707269cc816e63697065206d6174617220636f6e73656a6f"
+        "20706f6c656e2076656869cc8163756c6f206f6469736561",
+    passphrase: "araña difícil solución término cárcel",
+    passphraseHex:
+        "6172616ecc83612064696669cc8163696c20736f6c7563696fcc816e207465cc81726d"
+        "696e6f206361cc817263656c",
+    bip32Seed:
+        "363dec0e575b887cfccebee4c84fca5a3a6bed9d0e099c061fa6b85020b031f8fe3636"
+        "d9af187bf432d451273c625e20f24f651ada41aae2c4ea62d87e9fa44c",
+  ),
+  "spanish2": _TestCase(
+    lang: "es",
+    words:
+        "equipo fiar auge langosta hacha calor "
+        "trance cubrir carro pulmón oro áspero",
+    wordsHex:
+        "65717569706f20666961722061756765206c616e676f7374612068616368612063616c"
+        "6f72207472616e63652063756272697220636172726f2070756c6d6fcc816e206f"
+        "726f2061cc81737065726f",
+    seedVersion: ElectrumSeedUtils.kSeedPrefixSegwit,
+    bip32Seed:
+        "001ebce6bfde5851f28a0d44aae5ae0c762b600daf3b33fc8fc630aee0d207646b6f98"
+        "b18e17dfe3be0a5efe2753c7cdad95860adbbb62cecad4dedb88e02a64",
+  ),
+  "spanish3": _TestCase(
+    lang: "es",
+    words:
+        "vidrio jabón muestra pájaro capucha"
+        " eludir feliz rotar fogata pez rezar oír",
+    wordsHex:
+        "76696472696f206a61626fcc816e206d756573747261207061cc816a61726f20636170"
+        "7563686120656c756469722066656c697a20726f74617220666f67617461207065"
+        "7a2072657a6172206f69cc8172",
+    seedVersion: ElectrumSeedUtils.kSeedPrefixSegwit,
+    passphrase:
+        "¡Viva España! repiten veinte pueblos y al hablar dan fe "
+        "del ánimo español... ¡Marquen arado martillo y clarín",
+    passphraseHex:
+        "c2a1566976612045737061c3b16121207265706974656e207665696e74652070756562"
+        "6c6f73207920616c206861626c61722064616e2066652064656c20c3a16e696d6f"
+        "2065737061c3b16f6c2e2e2e20c2a14d61727175656e20617261646f206d617274"
+        "696c6c6f207920636c6172c3ad6e",
+    bip32Seed:
+        "c274665e5453c72f82b8444e293e048d700c59bf000cacfba597629d202dcf3aab1cf9"
+        "c00ba8d3456b7943428541fed714d01d8a0a4028fc3a9bb33d981cb49f",
+  ),
+};
+
+void main() {
+  const kElectrumMnemonic =
+      "party reward jealous build maze tunnel eternal candy recipe february kid animal";
+
+  test(
+    "standard seed prefix",
+    () => expect(ElectrumSeedUtils.kSeedPrefix, "01"),
+  );
+  test(
+    "segwit seed prefix",
+    () => expect(ElectrumSeedUtils.kSeedPrefixSegwit, "100"),
+  );
+  test(
+    "2fa standard seed prefix",
+    () => expect(ElectrumSeedUtils.kSeedPrefix2fa, "101"),
+  );
+  test(
+    "2fa segwit seed prefix",
+    () => expect(ElectrumSeedUtils.kSeedPrefix2faSegwit, "102"),
+  );
+
+  group("electrum mnemonic to seed tests", () {
+    for (final entry in kTestCases.entries) {
+      final name = entry.key;
+      final testCase = entry.value;
+
+      if (testCase.wordsHex != null) {
+        test("$name: mnemonic to bytes to hex", () {
+          expect(testCase.wordsHex, testCase.words.toUint8ListFromUtf8.toHex);
+        });
+      }
+
+      if (testCase.passphraseHex != null && testCase.passphrase != null) {
+        test("$name: passphrase to bytes to hex", () {
+          expect(
+            testCase.passphraseHex,
+            testCase.passphrase!.toUint8ListFromUtf8.toHex,
+          );
+        });
+      }
+
+      test("$name: isNewSeed", () {
+        expect(
+          ElectrumSeedUtils.isNewSeed(
+            testCase.words,
+            prefix: testCase.seedVersion,
+          ),
+          true,
+        );
+      });
+      test("$name: electrumMnemonicToSeedBytes", () {
+        expect(
+          ElectrumSeedUtils.electrumMnemonicToSeedBytes(
+            testCase.words,
+            passphrase: testCase.passphrase ?? "",
+          ).toHex,
+          testCase.bip32Seed,
+        );
+      });
+    }
+  });
+
+  test("test segwit version", () async {
+    expect(
+      ElectrumSeedUtils.electrumMnemonicVersion(kElectrumMnemonic),
+      ElectrumSeedUtils.kSeedPrefixSegwit,
+    );
+  });
+
+  group("test group requires coinlib", () {
+    setUpAll(() => loadCoinlib());
+
+    test("test master electrum fingerprint", () async {
+      final bytes = ElectrumSeedUtils.electrumMnemonicToSeedBytes(
+        kElectrumMnemonic,
+      );
+      final hd = HDPrivateKey.fromSeed(bytes);
+      expect(BigInt.from(hd.fingerprint).toHex, "ec8d82aa");
+    });
+
+    test("test root zpub", () async {
+      final bytes = ElectrumSeedUtils.electrumMnemonicToSeedBytes(
+        kElectrumMnemonic,
+      );
+      final hd = HDPrivateKey.fromSeed(bytes);
+      final master = hd.derivePath("m/0'");
+
+      const zpubHDVersion =
+          0x04b24746; // https://github.com/satoshilabs/slips/blob/master/slip-0132.md
+      expect(
+        master.hdPublicKey.encode(zpubHDVersion),
+        "zpub6oHsSqJH7vSzDJTFB8NR4YpzFU13XRmkJaVW9jQTePrnf5BPHHAQXxBMiBot12Z7DqfuTykmyPxGowrQfNa7M8xiAdEvQG47V5jhx5Tk158",
+      );
+    });
+
+    test("test first receiving address", () async {
+      final bytes = ElectrumSeedUtils.electrumMnemonicToSeedBytes(
+        kElectrumMnemonic,
+      );
+      final hd = HDPrivateKey.fromSeed(bytes);
+      final master = hd.derivePath("m/0'");
+
+      expect(
+        P2WPKHAddress.fromHash(
+          hash160(master.derivePath("0/0").publicKey.data),
+          hrp: "bc",
+        ).toString(),
+        "bc1qgfjuzurxzhl9vdalmjgw68s680lj5q933k37h5",
+      );
+    });
+
+    test("test 9th change address", () async {
+      final bytes = ElectrumSeedUtils.electrumMnemonicToSeedBytes(
+        kElectrumMnemonic,
+      );
+      final hd = HDPrivateKey.fromSeed(bytes);
+      final master = hd.derivePath("m/0'");
+
+      expect(
+        P2WPKHAddress.fromHash(
+          hash160(master.derivePath("1/8").publicKey.data),
+          hrp: "bc",
+        ).toString(),
+        "bc1qzz0mvhza5sdd2fy77klh3w8h5z238avztvqjdx",
+      );
+    });
+  });
+}