coinstring

coinstring

coinstring is a JavaScript component that is fully compatible with Node.js and the browser. It's used to generate relevant addresses and wallet import formats used by various crypto currencies.

Note: It's an experimental functional replacement for https://github.com/cryptocoinjs/btc-address

Installation

npm install coinstring --save

Usage

There are three functions in this module.

API

coinstring(version, bytes)

Used to convert either a hash160 or private key into an address or wallet import format string respectively.

• version: Is an integer representing the version. See below for more information.
• bytes: A Buffer of bytes, either the hash160 or private key.

decode(version, str)

It is the inverse of the coinstring() function i.e. it converts the address or wallet import format into a Buffer of bytes. It throws if the address or wallet import format is not valid. Not valid means that the version doesn't match, or the checksum is incorrect.

• version: Is an integer representing the version. See below for more information.
• str: A string that is either the wallet import format or public address.

validate(version, str)

Validates whether the address string or wallet import format string is valid. Returns a true or false.

• version: Is an integer representing the version. See below for more information.
• str: A string that is either the wallet import format or public address.

Common Examples

Convert Private Key to Bitcoin Wallet Import Format

var conv = require('binstring');
var coinstring = require('coinstring');

var privateKeyHex = "1184cd2cdd640ca42cfc3a091c51d549b2f016d454b2774019c2b2d2e08529fd";
var privateKeyHexBuf = conv(privateKeyHex, {in: 'hex', out: 'buffer'});
var version = 0x080; //Bitcoin private key

console.log(coinstring(version, privateKeyHexBuf)); // => 5Hx15HFGyep2CfPxsJKe2fXJsCVn5DEiyoeGGF6JZjGbTRnqfiD

Convert hash160 (aka pubkeyhash) to Bitcoin Address

var conv = require('binstring');
var coinstring = require('coinstring');

var hash160 = "3c176e659bea0f29a3e9bf7880c112b1b31b4dc8"; //hash representing uncompressed
var hash160Buf = conv(hash160, {in: 'hex', out: 'buffer'});
var version = 0x00; //Bitcoin public address

console.log(coinstring(version, hash160Buf)); // => 16UjcYNBG9GTK4uq2f7yYEbuifqCzoLMGS

Convert Private Key to Compressed Bitcoin Wallet Import Format

var conv = require('binstring');
var coinstring = require('coinstring');

var privateKeyHex = "1184cd2cdd640ca42cfc3a091c51d549b2f016d454b2774019c2b2d2e08529fd";

//for compressed, append "01"
privateKeyHex += '01';

var privateKeyHexBuf = conv(privateKeyHex, {in: 'hex', out: 'buffer'});
var version = 0x080; //Bitcoin private key

console.log(coinstring(version, privateKeyHexBuf)); // => KwomKti1X3tYJUUMb1TGSM2mrZk1wb1aHisUNHCQXTZq5auC2qc3

Convert hash160 (aka pubkeyhash) to Dogecoin Address

var conv = require('binstring');
var coinstring = require('coinstring');

var hash160 = "3c176e659bea0f29a3e9bf7880c112b1b31b4dc8"; //hash representing uncompressed
var hash160Buf = conv(hash160, {in: 'hex', out: 'buffer'});
var version = 0x1E; //Dogecoin public address

console.log(coinstring(version, hash160Buf)); // => DAcq9oJpZZAjr56RmF7Y5zmWboZWQ4HAsW

Functional Goodness

coinstring also has some functional goodies. All functions can be partially applied.

Function to Generate Bitcoin Wallet Import Format

var conv = require('binstring');
var coinstring = require('coinstring');

var privateKeyHex = "1184cd2cdd640ca42cfc3a091c51d549b2f016d454b2774019c2b2d2e08529fd";
var privateKeyHexBuf = conv(privateKeyHex, {in: 'hex', out: 'buffer'});
var version = 0x080; //Bitcoin private key

var toBtcWif = coinstring(version)

//later in your program
console.log(toBtcWif(privateKeyHexBuf)); // => 5Hx15HFGyep2CfPxsJKe2fXJsCVn5DEiyoeGGF6JZjGbTRnqfiD

Function to Parse Bitcoin Wallet Import Format

var conv = require('binstring');
var coinstring = require('coinstring');

var wif = "5Hx15HFGyep2CfPxsJKe2fXJsCVn5DEiyoeGGF6JZjGbTRnqfiD";
var version = 0x080; //Bitcoin private key

var fromBtcWif = coinstring.decode(version)

//later in your program
console.log(fromBtcWif(wif).toString('hex')); // => 51184cd2cdd640ca42cfc3a091c51d549b2f016d454b2774019c2b2d2e08529fd

Function to Validate Bitcoin Testnet Addresses

var conv = require('binstring');
var coinstring = require('coinstring');

var hash160 = "3c176e659bea0f29a3e9bf7880c112b1b31b4dc8"; //hash representing uncompressed
var hash160Buf = conv(hash160, {in: 'hex', out: 'buffer'});
var version = 0x6F; //Bitcoin Testnet Address

var testnetAddressValidator = coinstring.validate(version);

console.log(testnetAddressValidator("mkzgubTA5Ahi6BPSkE6MN9pEafRutznkMe")) // => true

List of Common Crypto Currency Versions

The following is a table of common crypto currency versions. It may seem a bit user unfriendly to have to input the number instead of something like "BTC"; we agree. Another module will be created to address this. In the meantime, use the table below.

Crypto Coin	Public Address	Private Wallet Import Format
Bitcoin	0x00	0x80
Bitcoin Script Hash	0x05	N/A
Bitcoin Testnet	0x6E	0xEF
Bitcoin Testnet Script Hash	0xC4	N/A
Dogecoin	0x1E	0x9E
Litecoin	0x30	0xB0
Namecoin	0x34	0xB4

Use in the Browser

Clone the repo:

git clone https://github.com/cryptocoinjs/coinstring

Install Browserify

npm install -g browserify

Nav to repo:

cd coinstring

Install dependencies:

npm install

Run browserify:

browserify --standalone coinstring < lib/coinstring.js > lib/coinstring.bundle.js

You can now drop coinstring.bundle.js in a <script> tag.

References

• http://procbits.com/2013/08/27/generating-a-bitcoin-address-with-javascript
• http://brainwallet.org/

License

(MIT License)