73 lines
1.8 KiB
JavaScript
73 lines
1.8 KiB
JavaScript
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/**
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* Working with Bitmessage addresses.
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* @module bitmessage/address
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*/
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"use strict";
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var bufferEqual = require("buffer-equal");
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var bs58 = require("bs58");
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var varint = require("./varint");
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var bmcrypto = require("./crypto");
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var assert = require("./utils").assert;
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/**
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* Parse Bitmessage Base58 encoded address (with or without `BM-`
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* prefix) into address object.
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*/
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exports.decode = function(str) {
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str = str.trim();
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if (str.slice(0, 3) === "BM-") {
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str = str.slice(3);
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}
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var bytes;
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try {
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bytes = bs58.decode(str);
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} catch(e) {
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return Promise.reject(e);
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}
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// Checksum validating.
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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 bmcrypto.sha512(data).then(bmcrypto.sha512).then(function(dhash) {
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assert(bufferEqual(dhash.slice(0, 4), checksum), "Bad checkum");
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var decoded = varint.decode(data);
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var version = decoded.value;
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assert(version <= 4, "Version too high");
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assert(version >= 1, "Version too low");
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data = decoded.rest;
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decoded = varint.decode(data);
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var stream = decoded.value;
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var ripe = decoded.rest;
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var ripelen = ripe.length;
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switch (version) {
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case 1:
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assert(ripelen === 20);
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break;
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case 2:
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case 3:
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assert(ripelen >= 18, "Ripe too short");
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assert(ripelen <= 20, "Ripe too long");
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break;
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case 4:
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assert(ripelen >= 4, "Ripe too short");
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assert(ripelen <= 20, "Ripe too long");
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assert(ripe[0] !== 0, "Ripe encode error");
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break;
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}
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// Prevent extra allocation. God, kill me please for premature
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// optimizations.
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if (ripelen < 20) {
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var zeroes = new Buffer(Array(20 - ripelen));
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ripe = Buffer.concat([zeroes, ripe]);
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}
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return {version: version, stream: stream, ripe: ripe};
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});
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};
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