solutaut/src/dot_validator.js

Multicoin address validator for Bitcoin and other Altcoins.

const cryptoUtils = require('./crypto/utils');

// from https://github.com/paritytech/substrate/wiki/External-Address-Format-(SS58)
const addressFormats = [
    { addressLength: 3, accountIndexLength: 1, checkSumLength: 1 },
    { addressLength: 4, accountIndexLength: 2, checkSumLength: 1 },
    { addressLength: 5, accountIndexLength: 2, checkSumLength: 2 },
    { addressLength: 6, accountIndexLength: 4, checkSumLength: 1 },
    { addressLength: 7, accountIndexLength: 4, checkSumLength: 2 },
    { addressLength: 8, accountIndexLength: 4, checkSumLength: 3 },
    { addressLength: 9, accountIndexLength: 4, checkSumLength: 4 },
    { addressLength: 10, accountIndexLength: 8, checkSumLength: 1 },
    { addressLength: 11, accountIndexLength: 8, checkSumLength: 2 },
    { addressLength: 12, accountIndexLength: 8, checkSumLength: 3 },
    { addressLength: 13, accountIndexLength: 8, checkSumLength: 4 },
    { addressLength: 14, accountIndexLength: 8, checkSumLength: 5 },
    { addressLength: 15, accountIndexLength: 8, checkSumLength: 6 },
    { addressLength: 16, accountIndexLength: 8, checkSumLength: 7 },
    { addressLength: 17, accountIndexLength: 8, checkSumLength: 8 },
    { addressLength: 34, accountIndexLength: 32, checkSumLength: 2 },
];

module.exports = {
    isValidAddress: function (address, currency, opts = {}) {
        const { networkType = 'prod' } = opts;

        return this.verifyChecksum(address)
    },

    verifyChecksum: function (address) {

        try {
            const preImage = '53533538505245'

            const decoded = cryptoUtils.base58(address);
            const addressType = cryptoUtils.byteArray2hexStr(decoded.slice(0, 1));
            const addressAndChecksum = decoded.slice(1)

            // get the address format
            const addressFormat = addressFormats.find(af => af.addressLength === addressAndChecksum.length);

            if (!addressFormat) {
                throw new Error('Invalid address length');
            }

            const decodedAddress = cryptoUtils.byteArray2hexStr(addressAndChecksum.slice(0, addressFormat.accountIndexLength));
            const checksum = cryptoUtils.byteArray2hexStr(addressAndChecksum.slice(-addressFormat.checkSumLength));

            const calculatedHash = cryptoUtils
                .blake2b(preImage + addressType + decodedAddress, 64)
                .substr(0, addressFormat.checkSumLength * 2)
                .toUpperCase();

            return calculatedHash == checksum;
        } catch(err) {
            return false;
        }
    }
}