1 | 'use strict';
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2 |
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3 | var _ = require('lodash');
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4 | var Base58 = require('./base58');
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5 | var buffer = require('buffer');
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6 | var sha256sha256 = require('../crypto/hash').sha256sha256;
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7 |
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8 | var Base58Check = function Base58Check(obj) {
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9 | if (!(this instanceof Base58Check))
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10 | return new Base58Check(obj);
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11 | if (Buffer.isBuffer(obj)) {
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12 | var buf = obj;
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13 | this.fromBuffer(buf);
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14 | } else if (typeof obj === 'string') {
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15 | var str = obj;
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16 | this.fromString(str);
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17 | } else if (obj) {
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18 | this.set(obj);
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19 | }
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20 | };
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21 |
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22 | Base58Check.prototype.set = function(obj) {
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23 | this.buf = obj.buf || this.buf || undefined;
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24 | return this;
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25 | };
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26 |
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27 | Base58Check.validChecksum = function validChecksum(data, checksum) {
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28 | if (_.isString(data)) {
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29 | data = Buffer.from(Base58.decode(data));
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30 | }
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31 | if (_.isString(checksum)) {
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32 | checksum = Buffer.from(Base58.decode(checksum));
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33 | }
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34 | if (!checksum) {
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35 | checksum = data.slice(-4);
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36 | data = data.slice(0, -4);
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37 | }
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38 | return Base58Check.checksum(data).toString('hex') === checksum.toString('hex');
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39 | };
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40 |
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41 | Base58Check.decode = function(s) {
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42 | if (typeof s !== 'string')
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43 | throw new Error('Input must be a string');
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44 |
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45 | var buf = Buffer.from(Base58.decode(s));
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46 |
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47 | if (buf.length < 4)
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48 | throw new Error("Input string too short");
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49 |
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50 | var data = buf.slice(0, -4);
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51 | var csum = buf.slice(-4);
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52 |
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53 | var hash = sha256sha256(data);
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54 | var hash4 = hash.slice(0, 4);
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55 |
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56 | if (csum.toString('hex') !== hash4.toString('hex'))
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57 | throw new Error("Checksum mismatch");
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58 |
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59 | return data;
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60 | };
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61 |
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62 | Base58Check.checksum = function(buffer) {
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63 | return sha256sha256(buffer).slice(0, 4);
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64 | };
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65 |
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66 | Base58Check.encode = function(buf) {
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67 | if (!Buffer.isBuffer(buf))
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68 | throw new Error('Input must be a buffer');
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69 | var checkedBuf = Buffer.alloc(buf.length + 4);
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70 | var hash = Base58Check.checksum(buf);
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71 | buf.copy(checkedBuf);
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72 | hash.copy(checkedBuf, buf.length);
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73 | return Base58.encode(checkedBuf);
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74 | };
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75 |
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76 | Base58Check.prototype.fromBuffer = function(buf) {
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77 | this.buf = buf;
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78 | return this;
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79 | };
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80 |
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81 | Base58Check.prototype.fromString = function(str) {
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82 | var buf = Base58Check.decode(str);
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83 | this.buf = buf;
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84 | return this;
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85 | };
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86 |
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87 | Base58Check.prototype.toBuffer = function() {
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88 | return this.buf;
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89 | };
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90 |
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91 | Base58Check.prototype.toString = function() {
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92 | return Base58Check.encode(this.buf);
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93 | };
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94 |
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95 | module.exports = Base58Check;
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