Adds dart implementation and test cases

ref/dart/pubspec.yaml

@@ -0,0 +1,10 @@
+name: bech32
+description: bech32 address encoding
+publish_to: 'none'
+
+dependencies:
+  convert: ^2.1.1
+  test: any
+
+environment:
+  sdk: ">=1.19.0 <3.0.0"

ref/dart/segwit_addr.dart

@@ -0,0 +1,181 @@
+// Copyright (c) 2020 J.K. Zhou
+//
+// 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.
+
+
+// This file is just a re-write of bech32 python version
+// Thanks to Pieter Wuille
+
+var CHARSET = [
+  'q','p','z','r','y','9','x','8',
+  'g','f','2','t','v','d','w','0',
+  's','3','j','n','5','4','k','h',
+  'c','e','6','m','u','a','7','l'];
+
+var GENERATOR = [
+  0x3b6a57b2,
+  0x26508e6d,
+  0x1ea119fa,
+  0x3d4233dd,
+  0x2a1462b3
+];
+
+int bech32_polymod(List<int> values) {
+  int chk = 1;
+  values.forEach((v) {
+    var top = chk >> 25;
+    chk = (chk & 0x1ffffff) << 5 ^ v;
+    for(var i = 0; i < 5; i ++) {
+      chk ^= (top >> i) & 0x01 > 0 ? GENERATOR[i] : 0;
+    }
+  });
+  return chk;
+}
+
+List<int> bech32_hrp_expand(String hrp) {
+  var codes = hrp.codeUnits;
+  List<int> ret = [];
+  ret.addAll(codes.map((i) => i >> 5));
+  ret.add(0);
+  ret.addAll(codes.map((i) => i & 31));
+  return ret;
+}
+
+/// Compute checksum values given HRP and data
+List<int> bech32_create_checksum(String hrp, List<int> data) {
+  var values = bech32_hrp_expand(hrp) + data;
+  var polymod = bech32_polymod(values + [0, 0, 0, 0, 0, 0]) ^ 1;
+  return [0, 1, 2, 3, 4, 5].map((i) => (polymod >> 5 * (5 - i)) & 0x1f).toList();
+}
+
+bool bech32_verify_checksum(String hrp, List<int> data) {
+  return bech32_polymod(bech32_hrp_expand(hrp) + data) == 1;
+}
+
+String bech32_encode(String hrp, List<int> data) {
+  var combined = data + bech32_create_checksum(hrp, data);
+  return hrp + '1' + combined.map((i) => CHARSET[i]).join('');
+}
+
+/// Validate a bech32 string, and return a list containing HRP and validated data
+/// 
+/// If validate fails, throw Exception
+List<dynamic> bech32_decode(String bech) {
+  if(bech.length > 90) {
+    throw Exception('invalid address format, length too long');
+  }
+  if(bech.toLowerCase() != bech && bech.toUpperCase() != bech) {
+    throw Exception('mixin use of lower and upper chars');
+  }
+  bech = bech.toLowerCase();
+  var pos = bech.indexOf('1');
+  if(pos < 1 || pos + 7 > bech.length) {
+    throw Exception('invalid split char position');
+  }
+
+  for(var i = 0; i < pos; i++) {
+    var c = bech.codeUnitAt(i);
+    if(c < 33 || c > 126)
+      throw Exception('invalid hrp character at index ${i}');
+  }
+  List<int> data = [];
+  for(var i = pos + 1; i < bech.length; i++) {
+    var c = String.fromCharCode(bech.codeUnitAt(i));
+    var idx = CHARSET.indexOf(c);
+    if(idx == -1) {
+      throw Exception('invalid data character at index ${i}');
+    }
+    data.add(idx);
+  }
+  var hrp = bech.substring(0, pos);
+  if(!bech32_verify_checksum(hrp, data)) {
+    throw Exception('invalid bech32 checksum');
+  }
+
+  return [hrp, data.sublist(0, data.length - 6)];
+}
+
+/// General Power-of-2 base conversion
+List<int> convertBits(List<int> data, int fromBits, int toBits, {bool pad = true}) {
+  List<int> ret = [];
+  var acc = 0;
+  var bits = 0;
+  var maxV = (1 << toBits) - 1;
+  var maxAcc = (1 << (fromBits + toBits - 1)) - 1;
+  data.forEach((v) {
+    if(v < 0 || (v >> fromBits) > 0) {
+      return null;
+    }
+    acc = ((acc << fromBits) | v) & maxAcc;
+    bits += fromBits;
+    while(bits >= toBits) {
+      bits -= toBits;
+      ret.add((acc >> bits) & maxV);
+    }
+  });
+
+  if(pad) {
+    if(bits > 0) {
+      ret.add((acc << (toBits - bits)) & maxV);
+    }
+  } else {
+    if(bits >= fromBits || ((acc << (toBits - bits)) & maxV > 0)) {
+      return null;
+    }
+  }
+  return ret;
+}
+
+/// decode a bech32 address with given hrp
+/// 
+/// return a list containing two items:
+/// [witVer, witProg]
+/// 
+/// where witVer is an integer and witProg is List<int>
+/// 
+/// throws exception if bech32 validation fails
+List<dynamic> decode(String hrp, String addr) {
+  var ret = bech32_decode(addr);
+  var hrpFromAddr = ret[0] as String;
+  var data = ret[1] as List<int>;
+  if(hrpFromAddr != hrp) {
+    throw Exception("incompatible hrp");
+  }
+
+  if(data.length == 0) {
+    throw Exception("invalid address");
+  }
+  var decoded = convertBits(data.sublist(1), 5, 8, pad: false);
+  if(decoded == null || decoded.length < 2 || decoded.length > 40) {
+    throw Exception("invalid address");
+  }
+  if(data[0] > 16) {
+    throw Exception("invalid address");
+  }
+
+  if(data[0] == 0 && decoded.length != 20 && decoded.length != 32) {
+    throw Exception("invalid address length");
+  }
+  return [data[0], decoded];
+}
+
+String encode(String hrp, int witVer, List<int> witProg) {
+  var ret = bech32_encode(hrp, [witVer] + convertBits(witProg, 8, 5));
+  return ret;
+}

ref/dart/tests.dart

@@ -0,0 +1,100 @@
+// Copyright (c) 2020 J.K. Zhou
+//
+// 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.
+
+import 'package:convert/convert.dart';
+import 'package:test/test.dart';
+import 'segwit_addr.dart';
+
+String test_encode(String hrp, int witVer, String hexWitProg) {
+  return encode(hrp, witVer, hex.decode(hexWitProg));
+}
+
+List<dynamic> test_decode(String hrp, String addr) {
+  var ret = decode(hrp, addr);
+  var witVer = ret[0] as int;
+  var witData = ret[1] as List<int>;
+  return [witVer, hex.encode(witData)];
+}
+
+void main() {
+  test('test encode valid', () {
+      expect(
+        test_encode('bc', 0, '751e76e8199196d454941c45d1b3a323f1433bd6'),
+        'bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4');
+      expect(
+        test_encode('tb', 0, '1863143c14c5166804bd19203356da136c985678cd4d27a1b8c6329604903262'), 
+        'tb1qrp33g0q5c5txsp9arysrx4k6zdkfs4nce4xj0gdcccefvpysxf3q0sl5k7');
+      expect(
+        test_encode('bc', 1, '751e76e8199196d454941c45d1b3a323f1433bd6751e76e8199196d454941c45d1b3a323f1433bd6'), 
+        'bc1pw508d6qejxtdg4y5r3zarvary0c5xw7kw508d6qejxtdg4y5r3zarvary0c5xw7k7grplx');
+      expect(
+        test_encode('bc', 0x10, '751e'),
+        'bc1sw50qa3jx3s');
+      expect(
+        test_encode('bc', 0x02, '751e76e8199196d454941c45d1b3a323'),
+        'bc1zw508d6qejxtdg4y5r3zarvaryvg6kdaj');
+      expect(
+        test_encode('tb', 0, '000000c4a5cad46221b2a187905e5266362b99d5e91c6ce24d165dab93e86433'),
+        'tb1qqqqqp399et2xygdj5xreqhjjvcmzhxw4aywxecjdzew6hylgvsesrxh6hy');
+  });
+
+  test('test decode valid', () {
+    expect(
+      test_decode('bc', 'bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t4'), 
+      [0, '751e76e8199196d454941c45d1b3a323f1433bd6']);
+    expect(
+      test_decode('tb', 'tb1qrp33g0q5c5txsp9arysrx4k6zdkfs4nce4xj0gdcccefvpysxf3q0sl5k7'),
+      [0, '1863143c14c5166804bd19203356da136c985678cd4d27a1b8c6329604903262']);
+    expect(
+      test_decode('bc', 'bc1pw508d6qejxtdg4y5r3zarvary0c5xw7kw508d6qejxtdg4y5r3zarvary0c5xw7k7grplx'),
+      [1, '751e76e8199196d454941c45d1b3a323f1433bd6751e76e8199196d454941c45d1b3a323f1433bd6']);
+    expect(
+      test_decode('bc', 'bc1sw50qa3jx3s'),
+      [0x10, '751e']);
+    expect(
+      test_decode('bc', 'bc1zw508d6qejxtdg4y5r3zarvaryvg6kdaj'),
+      [0x02, '751e76e8199196d454941c45d1b3a323']);
+    expect(
+      test_decode('tb', 'tb1qqqqqp399et2xygdj5xreqhjjvcmzhxw4aywxecjdzew6hylgvsesrxh6hy'),
+      [0, '000000c4a5cad46221b2a187905e5266362b99d5e91c6ce24d165dab93e86433']);
+  });
+
+  test('test invalid checksum', () {
+    expect(() => test_decode('bc', 'bc1nwldj5'), throwsException);
+    expect(() => test_decode('bc', 'bc1nwldj5'), throwsException);
+    expect(() => test_decode('bc', 'bc1an84characterslonghumanreadablepartthatcontainsthenumber1andtheexcludedcharactersbio1569pvx'), throwsException);
+    expect(() => test_decode('bc', 'bc1pzry9x0s0muk'), throwsException);
+    expect(() => test_decode('x', 'x1b4n0q5v'), throwsException);
+    expect(() => test_decode('li', 'li1dgmt3'), throwsException);
+  });
+
+  test('test invalid address', () {
+    expect(() => test_decode('bc', 'tc1qw508d6qejxtdg4y5r3zarvary0c5xw7kg3g4ty'), throwsException);
+    expect(() => test_decode('bc', 'bc1qw508d6qejxtdg4y5r3zarvary0c5xw7kv8f3t5'), throwsException);
+    expect(() => test_decode('bc', 'BC13W508D6QEJXTDG4Y5R3ZARVARY0C5XW7KN40WF2'), throwsException);
+    expect(() => test_decode('bc', 'bc1rw5uspcuh'), throwsException);
+    expect(() => test_decode('bc', 'bc10w508d6qejxtdg4y5r3zarvary0c5xw7kw508d6qejxtdg4y5r3zarvary0c5xw7kw5rljs90'), throwsException);
+    expect(() => test_decode('bc', 'BC1QR508D6QEJXTDG4Y5R3ZARVARYV98GJ9P'), throwsException);
+    expect(() => test_decode('tb', 'tb1qrp33g0q5c5txsp9arysrx4k6zdkfs4nce4xj0gdcccefvpysxf3q0sL5k7'), throwsException);
+    expect(() => test_decode('bc', 'bc1zw508d6qejxtdg4y5r3zarvaryvqyzf3du'), throwsException);
+    expect(() => test_decode('tb', 'tb1qrp33g0q5c5txsp9arysrx4k6zdkfs4nce4xj0gdcccefvpysxf3pjxtptv'), throwsException);
+    expect(() => test_decode('bc', 'bc1gmk9yu'), throwsException);
+  });
+}