Whit Jackson designed one that appears to get built utilizing HTML/Javascript (GitHub url). He also experienced a web site where you could generate the addresses consumer aspect, but it really appears to become down now. BTC addresses use Base58 (like Base64 but without related character: IOl0+/) and must begin with https://vanity-address-generator85295.jts-blog.com/29091939/a-simple-key-for-ethaddress-unveiled