solutaut/src/stellar_validator.js

Multicoin address validator for Bitcoin and other Altcoins.

var baseX = require('base-x');
var crc = require('crc');
var cryptoUtils = require('./crypto/utils');

var ALPHABET = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';

var base32 = baseX(ALPHABET);
var regexp = new RegExp('^[' + ALPHABET + ']{56}$');
var ed25519PublicKeyVersionByte = (6 << 3);

function swap16(number) {
    var lower = number & 0xFF;
    var upper = (number >> 8) & 0xFF;
    return (lower << 8) | upper;
}

module.exports = {
    isValidAddress: function (address) {
        if (regexp.test(address)) {
            return this.verifyChecksum(address);
        }

        return false;
    },

    verifyChecksum: function (address) {
        // based on https://github.com/stellar/js-stellar-base/blob/master/src/strkey.js#L126
        var bytes = base32.decode(address);
        if (bytes[0] !== ed25519PublicKeyVersionByte) {
            return false;
        }

        var computedChecksum = cryptoUtils.numberToHex(swap16(crc.crc16xmodem(bytes.slice(0, -2))), 4);
        var checksum = cryptoUtils.toHex(bytes.slice(-2));

        return computedChecksum === checksum
    }
};