--- /dev/null
+const createKeccakHash = require('keccak')
+const secp256k1 = require('secp256k1')
+const assert = require('assert')
+const rlp = require('rlp')
+const BN = require('bn.js')
+const createHash = require('create-hash')
+const Buffer = require('safe-buffer').Buffer
+Object.assign(exports, require('ethjs-util'))
+
+/**
+ * the max integer that this VM can handle (a ```BN```)
+ * @var {BN} MAX_INTEGER
+ */
+exports.MAX_INTEGER = new BN('ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff', 16)
+
+/**
+ * 2^256 (a ```BN```)
+ * @var {BN} TWO_POW256
+ */
+exports.TWO_POW256 = new BN('10000000000000000000000000000000000000000000000000000000000000000', 16)
+
+/**
+ * Keccak-256 hash of null (a ```String```)
+ * @var {String} KECCAK256_NULL_S
+ */
+exports.KECCAK256_NULL_S = 'c5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470'
+
+/**
+ * Keccak-256 hash of null (a ```Buffer```)
+ * @var {Buffer} KECCAK256_NULL
+ */
+exports.KECCAK256_NULL = Buffer.from(exports.KECCAK256_NULL_S, 'hex')
+
+/**
+ * Keccak-256 of an RLP of an empty array (a ```String```)
+ * @var {String} KECCAK256_RLP_ARRAY_S
+ */
+exports.KECCAK256_RLP_ARRAY_S = '1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347'
+
+/**
+ * Keccak-256 of an RLP of an empty array (a ```Buffer```)
+ * @var {Buffer} KECCAK256_RLP_ARRAY
+ */
+exports.KECCAK256_RLP_ARRAY = Buffer.from(exports.KECCAK256_RLP_ARRAY_S, 'hex')
+
+/**
+ * Keccak-256 hash of the RLP of null (a ```String```)
+ * @var {String} KECCAK256_RLP_S
+ */
+exports.KECCAK256_RLP_S = '56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421'
+
+/**
+ * Keccak-256 hash of the RLP of null (a ```Buffer```)
+ * @var {Buffer} KECCAK256_RLP
+ */
+exports.KECCAK256_RLP = Buffer.from(exports.KECCAK256_RLP_S, 'hex')
+
+/**
+ * [`BN`](https://github.com/indutny/bn.js)
+ * @var {Function}
+ */
+exports.BN = BN
+
+/**
+ * [`rlp`](https://github.com/ethereumjs/rlp)
+ * @var {Function}
+ */
+exports.rlp = rlp
+
+/**
+ * [`secp256k1`](https://github.com/cryptocoinjs/secp256k1-node/)
+ * @var {Object}
+ */
+exports.secp256k1 = secp256k1
+
+/**
+ * Returns a buffer filled with 0s
+ * @method zeros
+ * @param {Number} bytes the number of bytes the buffer should be
+ * @return {Buffer}
+ */
+exports.zeros = function (bytes) {
+ return Buffer.allocUnsafe(bytes).fill(0)
+}
+
+/**
+ * Returns a zero address
+ * @method zeroAddress
+ * @return {String}
+ */
+exports.zeroAddress = function () {
+ const addressLength = 20
+ const zeroAddress = exports.zeros(addressLength)
+ return exports.bufferToHex(zeroAddress)
+}
+
+/**
+ * Left Pads an `Array` or `Buffer` with leading zeros till it has `length` bytes.
+ * Or it truncates the beginning if it exceeds.
+ * @method lsetLength
+ * @param {Buffer|Array} msg the value to pad
+ * @param {Number} length the number of bytes the output should be
+ * @param {Boolean} [right=false] whether to start padding form the left or right
+ * @return {Buffer|Array}
+ */
+exports.setLengthLeft = exports.setLength = function (msg, length, right) {
+ const buf = exports.zeros(length)
+ msg = exports.toBuffer(msg)
+ if (right) {
+ if (msg.length < length) {
+ msg.copy(buf)
+ return buf
+ }
+ return msg.slice(0, length)
+ } else {
+ if (msg.length < length) {
+ msg.copy(buf, length - msg.length)
+ return buf
+ }
+ return msg.slice(-length)
+ }
+}
+
+/**
+ * Right Pads an `Array` or `Buffer` with leading zeros till it has `length` bytes.
+ * Or it truncates the beginning if it exceeds.
+ * @param {Buffer|Array} msg the value to pad
+ * @param {Number} length the number of bytes the output should be
+ * @return {Buffer|Array}
+ */
+exports.setLengthRight = function (msg, length) {
+ return exports.setLength(msg, length, true)
+}
+
+/**
+ * Trims leading zeros from a `Buffer` or an `Array`
+ * @param {Buffer|Array|String} a
+ * @return {Buffer|Array|String}
+ */
+exports.unpad = exports.stripZeros = function (a) {
+ a = exports.stripHexPrefix(a)
+ let first = a[0]
+ while (a.length > 0 && first.toString() === '0') {
+ a = a.slice(1)
+ first = a[0]
+ }
+ return a
+}
+/**
+ * Attempts to turn a value into a `Buffer`. As input it supports `Buffer`, `String`, `Number`, null/undefined, `BN` and other objects with a `toArray()` method.
+ * @param {*} v the value
+ */
+exports.toBuffer = function (v) {
+ if (!Buffer.isBuffer(v)) {
+ if (Array.isArray(v)) {
+ v = Buffer.from(v)
+ } else if (typeof v === 'string') {
+ if (exports.isHexString(v)) {
+ v = Buffer.from(exports.padToEven(exports.stripHexPrefix(v)), 'hex')
+ } else {
+ v = Buffer.from(v)
+ }
+ } else if (typeof v === 'number') {
+ v = exports.intToBuffer(v)
+ } else if (v === null || v === undefined) {
+ v = Buffer.allocUnsafe(0)
+ } else if (BN.isBN(v)) {
+ v = v.toArrayLike(Buffer)
+ } else if (v.toArray) {
+ // converts a BN to a Buffer
+ v = Buffer.from(v.toArray())
+ } else {
+ throw new Error('invalid type')
+ }
+ }
+ return v
+}
+
+/**
+ * Converts a `Buffer` to a `Number`
+ * @param {Buffer} buf
+ * @return {Number}
+ * @throws If the input number exceeds 53 bits.
+ */
+exports.bufferToInt = function (buf) {
+ return new BN(exports.toBuffer(buf)).toNumber()
+}
+
+/**
+ * Converts a `Buffer` into a hex `String`
+ * @param {Buffer} buf
+ * @return {String}
+ */
+exports.bufferToHex = function (buf) {
+ buf = exports.toBuffer(buf)
+ return '0x' + buf.toString('hex')
+}
+
+/**
+ * Interprets a `Buffer` as a signed integer and returns a `BN`. Assumes 256-bit numbers.
+ * @param {Buffer} num
+ * @return {BN}
+ */
+exports.fromSigned = function (num) {
+ return new BN(num).fromTwos(256)
+}
+
+/**
+ * Converts a `BN` to an unsigned integer and returns it as a `Buffer`. Assumes 256-bit numbers.
+ * @param {BN} num
+ * @return {Buffer}
+ */
+exports.toUnsigned = function (num) {
+ return Buffer.from(num.toTwos(256).toArray())
+}
+
+/**
+ * Creates Keccak hash of the input
+ * @param {Buffer|Array|String|Number} a the input data
+ * @param {Number} [bits=256] the Keccak width
+ * @return {Buffer}
+ */
+exports.keccak = function (a, bits) {
+ a = exports.toBuffer(a)
+ if (!bits) bits = 256
+
+ return createKeccakHash('keccak' + bits).update(a).digest()
+}
+
+/**
+ * Creates Keccak-256 hash of the input, alias for keccak(a, 256)
+ * @param {Buffer|Array|String|Number} a the input data
+ * @return {Buffer}
+ */
+exports.keccak256 = function (a) {
+ return exports.keccak(a)
+}
+
+/**
+ * Creates SHA256 hash of the input
+ * @param {Buffer|Array|String|Number} a the input data
+ * @return {Buffer}
+ */
+exports.sha256 = function (a) {
+ a = exports.toBuffer(a)
+ return createHash('sha256').update(a).digest()
+}
+
+/**
+ * Creates RIPEMD160 hash of the input
+ * @param {Buffer|Array|String|Number} a the input data
+ * @param {Boolean} padded whether it should be padded to 256 bits or not
+ * @return {Buffer}
+ */
+exports.ripemd160 = function (a, padded) {
+ a = exports.toBuffer(a)
+ const hash = createHash('rmd160').update(a).digest()
+ if (padded === true) {
+ return exports.setLength(hash, 32)
+ } else {
+ return hash
+ }
+}
+
+/**
+ * Creates SHA-3 hash of the RLP encoded version of the input
+ * @param {Buffer|Array|String|Number} a the input data
+ * @return {Buffer}
+ */
+exports.rlphash = function (a) {
+ return exports.keccak(rlp.encode(a))
+}
+
+/**
+ * Checks if the private key satisfies the rules of the curve secp256k1.
+ * @param {Buffer} privateKey
+ * @return {Boolean}
+ */
+exports.isValidPrivate = function (privateKey) {
+ return secp256k1.privateKeyVerify(privateKey)
+}
+
+/**
+ * Checks if the public key satisfies the rules of the curve secp256k1
+ * and the requirements of Ethereum.
+ * @param {Buffer} publicKey The two points of an uncompressed key, unless sanitize is enabled
+ * @param {Boolean} [sanitize=false] Accept public keys in other formats
+ * @return {Boolean}
+ */
+exports.isValidPublic = function (publicKey, sanitize) {
+ if (publicKey.length === 64) {
+ // Convert to SEC1 for secp256k1
+ return secp256k1.publicKeyVerify(Buffer.concat([ Buffer.from([4]), publicKey ]))
+ }
+
+ if (!sanitize) {
+ return false
+ }
+
+ return secp256k1.publicKeyVerify(publicKey)
+}
+
+/**
+ * Returns the ethereum address of a given public key.
+ * Accepts "Ethereum public keys" and SEC1 encoded keys.
+ * @param {Buffer} pubKey The two points of an uncompressed key, unless sanitize is enabled
+ * @param {Boolean} [sanitize=false] Accept public keys in other formats
+ * @return {Buffer}
+ */
+exports.pubToAddress = exports.publicToAddress = function (pubKey, sanitize) {
+ pubKey = exports.toBuffer(pubKey)
+ if (sanitize && (pubKey.length !== 64)) {
+ pubKey = secp256k1.publicKeyConvert(pubKey, false).slice(1)
+ }
+ assert(pubKey.length === 64)
+ // Only take the lower 160bits of the hash
+ return exports.keccak(pubKey).slice(-20)
+}
+
+/**
+ * Returns the ethereum public key of a given private key
+ * @param {Buffer} privateKey A private key must be 256 bits wide
+ * @return {Buffer}
+ */
+const privateToPublic = exports.privateToPublic = function (privateKey) {
+ privateKey = exports.toBuffer(privateKey)
+ // skip the type flag and use the X, Y points
+ return secp256k1.publicKeyCreate(privateKey, false).slice(1)
+}
+
+/**
+ * Converts a public key to the Ethereum format.
+ * @param {Buffer} publicKey
+ * @return {Buffer}
+ */
+exports.importPublic = function (publicKey) {
+ publicKey = exports.toBuffer(publicKey)
+ if (publicKey.length !== 64) {
+ publicKey = secp256k1.publicKeyConvert(publicKey, false).slice(1)
+ }
+ return publicKey
+}
+
+/**
+ * ECDSA sign
+ * @param {Buffer} msgHash
+ * @param {Buffer} privateKey
+ * @param {Number} [chainId]
+ * @return {Object}
+ */
+exports.ecsign = function (msgHash, privateKey, chainId) {
+ const sig = secp256k1.sign(msgHash, privateKey)
+
+ const ret = {}
+ ret.r = sig.signature.slice(0, 32)
+ ret.s = sig.signature.slice(32, 64)
+ ret.v = chainId ? sig.recovery + (chainId * 2 + 35) : sig.recovery + 27
+ return ret
+}
+
+/**
+ * Returns the keccak-256 hash of `message`, prefixed with the header used by the `eth_sign` RPC call.
+ * The output of this function can be fed into `ecsign` to produce the same signature as the `eth_sign`
+ * call for a given `message`, or fed to `ecrecover` along with a signature to recover the public key
+ * used to produce the signature.
+ * @param message
+ * @returns {Buffer} hash
+ */
+exports.hashPersonalMessage = function (message) {
+ const prefix = exports.toBuffer('\u0019Ethereum Signed Message:\n' + message.length.toString())
+ return exports.keccak(Buffer.concat([prefix, message]))
+}
+
+/**
+ * ECDSA public key recovery from signature
+ * @param {Buffer} msgHash
+ * @param {Number} v
+ * @param {Buffer} r
+ * @param {Buffer} s
+ * @param {Number} [chainId]
+ * @return {Buffer} publicKey
+ */
+exports.ecrecover = function (msgHash, v, r, s, chainId) {
+ const signature = Buffer.concat([exports.setLength(r, 32), exports.setLength(s, 32)], 64)
+ const recovery = calculateSigRecovery(v, chainId)
+ if (!isValidSigRecovery(recovery)) {
+ throw new Error('Invalid signature v value')
+ }
+ const senderPubKey = secp256k1.recover(msgHash, signature, recovery)
+ return secp256k1.publicKeyConvert(senderPubKey, false).slice(1)
+}
+
+/**
+ * Convert signature parameters into the format of `eth_sign` RPC method
+ * @param {Number} v
+ * @param {Buffer} r
+ * @param {Buffer} s
+ * @param {Number} [chainId]
+ * @return {String} sig
+ */
+exports.toRpcSig = function (v, r, s, chainId) {
+ let recovery = calculateSigRecovery(v, chainId)
+ if (!isValidSigRecovery(recovery)) {
+ throw new Error('Invalid signature v value')
+ }
+
+ // geth (and the RPC eth_sign method) uses the 65 byte format used by Bitcoin
+ return exports.bufferToHex(Buffer.concat([
+ exports.setLengthLeft(r, 32),
+ exports.setLengthLeft(s, 32),
+ exports.toBuffer(v)
+ ]))
+}
+
+/**
+ * Convert signature format of the `eth_sign` RPC method to signature parameters
+ * NOTE: all because of a bug in geth: https://github.com/ethereum/go-ethereum/issues/2053
+ * @param {String} sig
+ * @return {Object}
+ */
+exports.fromRpcSig = function (sig) {
+ sig = exports.toBuffer(sig)
+
+ // NOTE: with potential introduction of chainId this might need to be updated
+ if (sig.length !== 65) {
+ throw new Error('Invalid signature length')
+ }
+
+ let v = sig[64]
+ // support both versions of `eth_sign` responses
+ if (v < 27) {
+ v += 27
+ }
+
+ return {
+ v: v,
+ r: sig.slice(0, 32),
+ s: sig.slice(32, 64)
+ }
+}
+
+/**
+ * Returns the ethereum address of a given private key
+ * @param {Buffer} privateKey A private key must be 256 bits wide
+ * @return {Buffer}
+ */
+exports.privateToAddress = function (privateKey) {
+ return exports.publicToAddress(privateToPublic(privateKey))
+}
+
+/**
+ * Checks if the address is a valid. Accepts checksummed addresses too
+ * @param {String} address
+ * @return {Boolean}
+ */
+exports.isValidAddress = function (address) {
+ return /^0x[0-9a-fA-F]{40}$/.test(address)
+}
+
+/**
+ * Checks if a given address is a zero address
+ * @method isZeroAddress
+ * @param {String} address
+ * @return {Boolean}
+ */
+exports.isZeroAddress = function (address) {
+ const zeroAddress = exports.zeroAddress()
+ return zeroAddress === exports.addHexPrefix(address)
+}
+
+/**
+ * Returns a checksummed address
+ * @param {String} address
+ * @return {String}
+ */
+exports.toChecksumAddress = function (address) {
+ address = exports.stripHexPrefix(address).toLowerCase()
+ const hash = exports.keccak(address).toString('hex')
+ let ret = '0x'
+
+ for (let i = 0; i < address.length; i++) {
+ if (parseInt(hash[i], 16) >= 8) {
+ ret += address[i].toUpperCase()
+ } else {
+ ret += address[i]
+ }
+ }
+
+ return ret
+}
+
+/**
+ * Checks if the address is a valid checksummed address
+ * @param {Buffer} address
+ * @return {Boolean}
+ */
+exports.isValidChecksumAddress = function (address) {
+ return exports.isValidAddress(address) && (exports.toChecksumAddress(address) === address)
+}
+
+/**
+ * Generates an address of a newly created contract
+ * @param {Buffer} from the address which is creating this new address
+ * @param {Buffer} nonce the nonce of the from account
+ * @return {Buffer}
+ */
+exports.generateAddress = function (from, nonce) {
+ from = exports.toBuffer(from)
+ nonce = new BN(nonce)
+
+ if (nonce.isZero()) {
+ // in RLP we want to encode null in the case of zero nonce
+ // read the RLP documentation for an answer if you dare
+ nonce = null
+ } else {
+ nonce = Buffer.from(nonce.toArray())
+ }
+
+ // Only take the lower 160bits of the hash
+ return exports.rlphash([from, nonce]).slice(-20)
+}
+
+/**
+ * Generates an address for a contract created using CREATE2
+ * @param {Buffer} from the address which is creating this new address
+ * @param {Buffer} salt a salt
+ * @param {Buffer} initCode the init code of the contract being created
+ * @return {Buffer}
+ */
+exports.generateAddress2 = function (from, salt, initCode) {
+ from = exports.toBuffer(from)
+ salt = exports.toBuffer(salt)
+ initCode = exports.toBuffer(initCode)
+
+ assert(from.length === 20)
+ assert(salt.length === 32)
+
+ let address = exports.keccak256(Buffer.concat([
+ Buffer.from('ff', 'hex'),
+ from,
+ salt,
+ exports.keccak256(initCode)
+ ]))
+
+ return address.slice(-20)
+}
+
+/**
+ * Returns true if the supplied address belongs to a precompiled account (Byzantium)
+ * @param {Buffer|String} address
+ * @return {Boolean}
+ */
+exports.isPrecompiled = function (address) {
+ const a = exports.unpad(address)
+ return a.length === 1 && a[0] >= 1 && a[0] <= 8
+}
+
+/**
+ * Adds "0x" to a given `String` if it does not already start with "0x"
+ * @param {String} str
+ * @return {String}
+ */
+exports.addHexPrefix = function (str) {
+ if (typeof str !== 'string') {
+ return str
+ }
+
+ return exports.isHexPrefixed(str) ? str : '0x' + str
+}
+
+/**
+ * Validate ECDSA signature
+ * @method isValidSignature
+ * @param {Buffer} v
+ * @param {Buffer} r
+ * @param {Buffer} s
+ * @param {Boolean} [homestead=true]
+ * @param {Number} [chainId]
+ * @return {Boolean}
+ */
+
+exports.isValidSignature = function (v, r, s, homestead, chainId) {
+ const SECP256K1_N_DIV_2 = new BN('7fffffffffffffffffffffffffffffff5d576e7357a4501ddfe92f46681b20a0', 16)
+ const SECP256K1_N = new BN('fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141', 16)
+
+ if (r.length !== 32 || s.length !== 32) {
+ return false
+ }
+
+ if (!isValidSigRecovery(calculateSigRecovery(v, chainId))) {
+ return false
+ }
+
+ r = new BN(r)
+ s = new BN(s)
+
+ if (r.isZero() || r.gt(SECP256K1_N) || s.isZero() || s.gt(SECP256K1_N)) {
+ return false
+ }
+
+ if ((homestead === false) && (new BN(s).cmp(SECP256K1_N_DIV_2) === 1)) {
+ return false
+ }
+
+ return true
+}
+
+/**
+ * Converts a `Buffer` or `Array` to JSON
+ * @param {Buffer|Array} ba
+ * @return {Array|String|null}
+ */
+exports.baToJSON = function (ba) {
+ if (Buffer.isBuffer(ba)) {
+ return '0x' + ba.toString('hex')
+ } else if (ba instanceof Array) {
+ const array = []
+ for (let i = 0; i < ba.length; i++) {
+ array.push(exports.baToJSON(ba[i]))
+ }
+ return array
+ }
+}
+
+/**
+ * Defines properties on a `Object`. It make the assumption that underlying data is binary.
+ * @param {Object} self the `Object` to define properties on
+ * @param {Array} fields an array fields to define. Fields can contain:
+ * * `name` - the name of the properties
+ * * `length` - the number of bytes the field can have
+ * * `allowLess` - if the field can be less than the length
+ * * `allowEmpty`
+ * @param {*} data data to be validated against the definitions
+ */
+exports.defineProperties = function (self, fields, data) {
+ self.raw = []
+ self._fields = []
+
+ // attach the `toJSON`
+ self.toJSON = function (label) {
+ if (label) {
+ const obj = {}
+ self._fields.forEach((field) => {
+ obj[field] = '0x' + self[field].toString('hex')
+ })
+ return obj
+ }
+ return exports.baToJSON(this.raw)
+ }
+
+ self.serialize = function serialize () {
+ return rlp.encode(self.raw)
+ }
+
+ fields.forEach((field, i) => {
+ self._fields.push(field.name)
+ function getter () {
+ return self.raw[i]
+ }
+ function setter (v) {
+ v = exports.toBuffer(v)
+
+ if (v.toString('hex') === '00' && !field.allowZero) {
+ v = Buffer.allocUnsafe(0)
+ }
+
+ if (field.allowLess && field.length) {
+ v = exports.stripZeros(v)
+ assert(field.length >= v.length, 'The field ' + field.name + ' must not have more ' + field.length + ' bytes')
+ } else if (!(field.allowZero && v.length === 0) && field.length) {
+ assert(field.length === v.length, 'The field ' + field.name + ' must have byte length of ' + field.length)
+ }
+
+ self.raw[i] = v
+ }
+
+ Object.defineProperty(self, field.name, {
+ enumerable: true,
+ configurable: true,
+ get: getter,
+ set: setter
+ })
+
+ if (field.default) {
+ self[field.name] = field.default
+ }
+
+ // attach alias
+ if (field.alias) {
+ Object.defineProperty(self, field.alias, {
+ enumerable: false,
+ configurable: true,
+ set: setter,
+ get: getter
+ })
+ }
+ })
+
+ // if the constuctor is passed data
+ if (data) {
+ if (typeof data === 'string') {
+ data = Buffer.from(exports.stripHexPrefix(data), 'hex')
+ }
+
+ if (Buffer.isBuffer(data)) {
+ data = rlp.decode(data)
+ }
+
+ if (Array.isArray(data)) {
+ if (data.length > self._fields.length) {
+ throw (new Error('wrong number of fields in data'))
+ }
+
+ // make sure all the items are buffers
+ data.forEach((d, i) => {
+ self[self._fields[i]] = exports.toBuffer(d)
+ })
+ } else if (typeof data === 'object') {
+ const keys = Object.keys(data)
+ fields.forEach((field) => {
+ if (keys.indexOf(field.name) !== -1) self[field.name] = data[field.name]
+ if (keys.indexOf(field.alias) !== -1) self[field.alias] = data[field.alias]
+ })
+ } else {
+ throw new Error('invalid data')
+ }
+ }
+}
+
+function calculateSigRecovery (v, chainId) {
+ return chainId ? v - (2 * chainId + 35) : v - 27
+}
+
+function isValidSigRecovery (recovery) {
+ return recovery === 0 || recovery === 1
+}