57 lines
1.5 KiB
JavaScript
57 lines
1.5 KiB
JavaScript
/**
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* Implement WIF encoding/decoding.
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* Reference: <https://en.bitcoin.it/wiki/Wallet_import_format>
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* @module bitmessage/wif
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*/
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"use strict";
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require("es6-promise").polyfill();
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var assert = require("assert");
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var bufferEqual = require("buffer-equal");
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var bs58 = require("bs58");
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var bmcrypto = require("./crypto");
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// Compute the WIF checksum for the given data.
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function getchecksum(data) {
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return bmcrypto.sha256(data).then(bmcrypto.sha256).then(function(dhash) {
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return dhash.slice(0, 4);
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});
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}
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/**
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* Decode WIF encoded private key.
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* @param {string} input - Input data
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* @param {Promise.<Buffer,undefined>} A promise than contain private
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* key when fulfilled
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*/
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exports.decode = function(input) {
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var bytes;
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try {
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bytes = bs58.decode(input);
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assert(bytes[0] === 0x80, "Bad WIF");
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} catch(e) {
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return Promise.reject(e);
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}
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var data = new Buffer(bytes.slice(0, -4));
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var checksum = new Buffer(bytes.slice(-4));
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return getchecksum(data).then(function(realchecksum) {
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assert(bufferEqual(checksum, realchecksum), "Bad checkum");
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return data.slice(1);
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});
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};
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/**
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* Convert private key to a WIF.
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* @param {Buffer} privateKey - A private key to encode
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* @return {Promise.<string,undefined>} A promise that contains the
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* encoded key when fulfilled
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*/
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exports.encode = function(privateKey) {
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var data = Buffer.concat([new Buffer([0x80]), privateKey]);
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return getchecksum(data).then(function(checksum) {
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var bytes = Buffer.concat([data, checksum]);
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return bs58.encode(bytes);
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});
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};
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