ethers.js/lib/secret-storage.js
2016-08-01 14:14:53 -04:00

337 lines
10 KiB
JavaScript

'use strict';
var aes = require('aes-js');
var pbkdf2 = require('pbkdf2');
var scrypt = require('scrypt-js');
var uuid = require('uuid');
var Randomish = require('./randomish.js');
var SigningKey = require('./signing-key.js');
var utils = require('./utils.js')
// Search an Object and its children recursively, caselessly.
function searchPath(object, path) {
var currentChild = object;
var comps = path.toLowerCase().split('/');
for (var i = 0; i < comps.length; i++) {
// Search for a child object with a case-insensitive matching key
var matchingChild = null;
for (var key in currentChild) {
if (key.toLowerCase() === comps[i]) {
matchingChild = currentChild[key];
break;
}
}
// Didn't find one. :'(
if (matchingChild === null) {
return null;
}
// Now check this child...
currentChild = matchingChild;
}
return currentChild;
}
/*
function SecretStorage(json, signingKey) {
if (!(this instanceof SecretStorage)) { throw new Error('missing new'); }
utils.defineProperty(this, 'json', json);
Object.defineProperty(this, 'data', {
enumerable: true,
get: function() { return JSON.parse(json); }
});
utils.defineProperty(this, 'address', signingKey.privateKey);
utils.defineProperty(this, 'signingKey', signingKey);
}
*/
var secretStorage = {};
utils.defineProperty(secretStorage, 'isCrowdsaleWallet', function(json) {
try {
var data = JSON.parse(json);
} catch (error) { return false; }
return (data.encseed && data.ethaddr);
});
utils.defineProperty(secretStorage, 'isValidWallet', function(json) {
try {
var data = JSON.parse(json);
} catch (error) { return false; }
if (!data.version || parseInt(data.version) !== data.version || parseInt(data.version) !== 3) {
return false;
}
// @TODO: Put more checks to make sure it has kdf, iv and all that good stuff
return true;
});
// See: https://github.com/ethereum/pyethsaletool
utils.defineProperty(secretStorage, 'decryptCrowdsale', function(json, password) {
var data = JSON.parse(json);
// Ethereum Address
var ethaddr = SigningKey.getAddress(searchPath(data, 'ethaddr'));
// Encrypted Seed
var encseed = new Buffer(searchPath(data, 'encseed'), 'hex');
if (!encseed || (encseed.length % 16) !== 0) {
throw new Error('invalid encseed');
}
var key = pbkdf2.pbkdf2Sync(password, password, 2000, 32, 'sha256').slice(0, 16);
var iv = encseed.slice(0, 16);
var encryptedSeed = encseed.slice(16);
// Decrypt the seed
var seed = new Buffer(0);
var aesCbc = new aes.ModeOfOperation.cbc(key, iv);
for (var i = 0; i < encryptedSeed.length; i += 16) {
seed = Buffer.concat([seed, new Buffer(aesCbc.decrypt(encryptedSeed.slice(i, i + 16)))]);
}
// Check PKCS#7 padding is valid
var pad = seed[seed.length - 1];
if (pad > 16 || pad > seed.length) {
throw new Error('invalid password');
}
for (var i = seed.length - pad; i < seed.length; i++) {
if (seed[i] !== pad) {
throw new Error('invalid password');
}
}
// Strip the padding
seed = seed.slice(0, seed.length - pad);
// This wallet format is weird... Convert the binary encoded hex to a string.
var seedHex = '';
for (var i = 0; i < seed.length; i++) {
seedHex += String.fromCharCode(seed[i]);
}
var signingKey = new SigningKey(utils.sha3(new Buffer(seedHex)));
if (signingKey.address !== ethaddr) {
throw new Error('corrupt crowdsale wallet');
}
return signingKey;
});
utils.defineProperty(secretStorage, 'decrypt', function(json, password, callback) {
if (!Buffer.isBuffer(password)) { throw new Error('password must be a buffer'); }
var data = JSON.parse(json);
var fail = function(reason) {
console.log('fail', reason);
setTimeout(function() { callback(new Error(reason)); }, 0);
}
var decrypt = function(key, ciphertext) {
var cipher = searchPath(data, 'crypto/cipher');
if (cipher === 'aes-128-ctr') {
var iv = new Buffer(searchPath(data, 'crypto/cipherparams/iv'), 'hex')
var counter = new aes.Counter(iv);
var aesCtr = new aes.ModeOfOperation.ctr(key, counter);
return new Buffer(aesCtr.decrypt(ciphertext));
}
return null;
};
var computeMAC = function(derivedHalf, ciphertext) {
return utils.sha3(Buffer.concat([derivedHalf, ciphertext]));
}
var kdf = searchPath(data, 'crypto/kdf');
if (kdf && kdf.toLowerCase() === 'scrypt') {
var salt = new Buffer(searchPath(data, 'crypto/kdfparams/salt'), 'hex');
var N = parseInt(searchPath(data, 'crypto/kdfparams/n'));
var r = parseInt(searchPath(data, 'crypto/kdfparams/r'));
var p = parseInt(searchPath(data, 'crypto/kdfparams/p'));
if (!N || !r || !p) {
return fail('unsupported key-derivation function parameters');
}
// Make sure N is a power of 2
if ((N & (N - 1)) !== 0) {
return fail('unsupported key-derivation function parameter value for N')
}
var dkLen = searchPath(data, 'crypto/kdfparams/dklen');
if (dkLen !== 32) {
return fail('unsupported key-derivation derived-key length');
}
scrypt(password, salt, N, r, p, dkLen, function(error, progress, key) {
if (error) {
callback(error, null, progress);
} else if (key) {
key = new Buffer(key);
var ciphertext = new Buffer(searchPath(data, 'crypto/ciphertext'), 'hex');
var computedMAC = computeMAC(key.slice(16, 32), ciphertext).toString('hex').toLowerCase();
if (computedMAC !== searchPath(data, 'crypto/mac').toLowerCase()) {
return fail('invalid password');
}
var privateKey = decrypt(key.slice(0, 16), ciphertext);
if (!privateKey) {
return fail('unsupported cipher');
}
var signingKey = new SigningKey(privateKey);
if (signingKey.address !== SigningKey.getAddress(data.address)) {
return fail('address mismatch');
}
callback(null, signingKey, 1.0);
} else {
return callback(null, null, progress);
}
});
} else {
// @TOOD: Support pbkdf2 kdf
return fail('unsupported key-derivation function');
}
});
utils.defineProperty(secretStorage, 'encrypt', function(privateKey, password, options, callback) {
// the options are optional, so adjust the call as needed
if (typeof(options) === 'function' && !callback) {
callback = options;
options = {};
}
if (!options) { options = {}; }
// Check the private key
if (privateKey instanceof SigningKey) {
privateKey = privateKey.privateKey;
}
privateKey = utils.hexOrBuffer(privateKey, 'private key');
if (privateKey.length !== 32) { throw new Erro('invalid private key'); }
// Check the password
if (!Buffer.isBuffer(password)) { throw new Error('password must be a buffer'); }
// Check/generate the salt
var salt = options.salt;
if (salt) {
salt = utils.hexOrBuffer(salt, 'salt');
} else {
salt = (new Randomish()).randomBytes(32);;
}
// Override initialization vector
var iv = null;
if (options.iv) {
iv = utils.hexOrBuffer(options.iv, 'iv');
if (iv.length !== 16) { throw new Error('invalid iv'); }
}
// Override the uuid
var uuidRandom = options.uuid;
if (uuidRandom) {
uuidRandom = utils.hexOrBuffer(uuidRandom, 'uuid');
if (uuidRandom.length !== 16) { throw new Error('invalid uuid'); }
}
// Override the scrypt password-based key derivation function parameters
var N = (1 << 17), r = 8, p = 1;
if (options.scrypt) {
if (options.scrypt.N) { N = options.scrypt.N; }
if (options.scrypt.r) { r = options.scrypt.r; }
if (options.scrypt.p) { p = options.scrypt.p; }
}
// We take 64 bytes:
// - 32 bytes As normal for the Web3 secret storage (derivedKey, macPrefix)
// - 16 bytes The initialization vector
// - 16 bytes The UUID random bytes
scrypt(password, salt, N, r, p, 64, function(error, progress, key) {
if (error) {
return callback(error, null, progress);
} else if (key) {
// Convert the array-like to a Buffer
key = new Buffer(key);
// These will be used to encrypt the wallet (as per Web3 secret storage)
var derivedKey = key.slice(0, 16);
var macPrefix = key.slice(16, 32);
// Get the initialization vector
if (!iv) { iv = key.slice(32, 48); }
// Get the UUID random data
if (!uuidRandom) { uuidRandom = key.slice(48, 64); }
// Get the address for this private key
var address = (new SigningKey(privateKey)).address;
// Encrypt the private key
var counter = new aes.Counter(iv);
var aesCtr = new aes.ModeOfOperation.ctr(derivedKey, counter);
var ciphertext = new Buffer(aesCtr.encrypt(privateKey));
// Compute the message authentication code, used to check the password
var mac = utils.sha3(Buffer.concat([macPrefix, ciphertext]))
// See: https://github.com/ethereum/wiki/wiki/Web3-Secret-Storage-Definition
var data = {
address: address,
id: uuid.v4({random: uuidRandom}),
version: 3,
Crypto: {
cipher: 'aes-128-ctr',
cipherparams: {
iv: iv.toString('hex')
},
ciphertext: ciphertext.toString('hex'),
kdf: 'scrypt',
kdfparams: {
salt: salt.toString('hex'),
n: N,
dklen: 32,
p: p,
r: r
},
mac: mac.toString('hex')
}
};
return callback(null, JSON.stringify(data), 1);
} else {
return callback(null, null, progress);
}
});
});
module.exports = secretStorage;