Validating a FIO Public Key

Integrators will need to validate the FIO Public Keys used for sending and receiving FIO and interacting with the FIO blockchain.


A FIO Address consists of a username and a domain delimited by an @ symbol, there are not specific requirements around a FIO Address username, but there are format restrictions around the FIO Address as a whole, and then separate requirements for a FIO Domain in particular.

  FIO Address ([email protected]) FIO Domain
Min. Chars 3 1
Max Chars 64 (including FIO Domain) 62
Characters allowed ASCII a-z 0-9 - (dash) with single @ (at sign) ASCII a-z 0-9 - (dash)

Validation using regex

Regex validation may be used. For example, the following regex may be used to validate a FIO Address:


Using the Typescript SDK

This is an example, of how to instantiate the FIOSDK and validate a FIO public key. Use the FIO Testnet Monitor to register your Testnet private/public keys and fund your Testnet account.

const { Ecc } = require('@fioprotocol/fiojs');
const ecurve = require('ecurve');
const secp256k1 = ecurve.getCurveByName('secp256k1');

const validPublicKey = 'FIO5ReMUvFM9X12eSuAR4QKjHsGJ6qponQP36xtV7WZLPBG35dJTr'
const invalidPublicKey = 'FIO5ReMUvFM9X12eSufe4QKjHsGJ6qponQP36xtV7WZLPBG35dJTr'
const invalidPublicKey2 = 'FIO5ReMUvFM9X12eSufe4QKjHsGJ6qponQP36xtWZLPBG35dJTr'

async function main () {

	console.log("\n1. Check if valid:", validPublicKey)

	let isValid = await isPubKeyValid(validPublicKey)

	console.log ("Validation result:", isValid)

	console.log("\n2. Check if valid:", validPublicKey)

	isValid = await isPubKeyValid(invalidPublicKey)

	console.log ("Validation result:", isValid)

	console.log("\n3. Check if valid:", invalidPublicKey2)

	isValid = await isPubKeyValid(invalidPublicKey2)

	console.log ("Validation result:", isValid)

async function isPubKeyValid(publicKey) {

	if (publicKey.length !== 53) return false

	// return Ecc.isValidPublic(publicKey)

	if (publicKey.substr(0, 3) !== PUB_KEY_PREFIX) return false

	const base58Substr = publicKey.substr(PUB_KEY_PREFIX.length);
	try {
		const buffer = Ecc.key_utils.checkDecode(base58Substr)
		ecurve.Point.decodeFrom(secp256k1, buffer)
	} catch (e) {
		return false

	return true