Numio FAQ

What is Numio?

Numio is a mobile application built on Ethereum, which is the first product supporting zkRollups (an Ethereum scaling solution) on Google Play. Numio gives people the the power to have more control over their money and digital identity.

What are public and private keys?

Cryptocurrency transactions are carried out using public-key cryptography. When you initiate your first cryptocurrency transaction, a unique pair of a public key and private key is created to ensure the security of your cryptocurrency. Here are the roles they play:

  1. The public key is a long string of random letters and numbers that allows you to accept cryptocurrencies into your account. This can be thought of as your crypto address. You can make the public key openly available so others can pay you in crypto. 
  2. The private key is also a long string of random letters and numbers that acts as your digital signature for crypto transactions. It belongs to you and only you, and gives you the authorization to send, withdraw, spend, or execute other transactions from your account. Your private key must remain private at all times to ensure the security of your cryptocurrency.

What is the difference between custodial and non-custodial wallets?

A custodial wallet is a cryptocurrency software wallet where your private keys are stored by a third party. 

Advantages of a custodial wallet are the same as software wallets:

  • Convenient to use, especially for frequent trading and payments.
  • Ability to access your account in case you lose your password.

Disadvantages include:

  • You don’t have full control over your funds; the custodian (company who developed the wallet) does.
  • Your wallet can get hacked and you can lose your crypto.

Examples of custodial wallets include those that are provided by cryptocurrency exchanges such as Coinbase, Binance, Kraken, and others. Your private keys are in their possession and custody. If these exchanges get hacked, you can lose your cryptocurrency that you store with them.

A non-custodial wallet is one where you hold your private keys. Hardware wallets are all non-custodial. There are some software wallets that are non-custodial, including Trust Wallet, Blockchain, Jaxx Liberty, and others. These wallets typically store your private keys on the device where the software resides.

Numio is a non-custodial wallet.

Remember, if you don’t have your private keys, your stored assets are not fully under your control.

Can I obtain my private keys from Numio?

After creating your wallet on Numio, tap on the settings icon within the app. There is a button you can tap on to “Copy your Private Key”. Make sure to store this in a secure place and treat it as sensitive data.

The Numio team will never ask for your private keys. Do not share this with anyone. 

What is a Recovery Key?

The Recovery Key is different from your Private Key (which is described above). The Recovery Key allows you to recover your account from the Numio mobile app, and that is it. This is encrypted and stored in your personal Google Drive account as a .txt file. You can then make a copy of this file and store it elsewhere if you choose as an extended level of security. This file should be treated as sensitive data, similar to your private key. 

In the case that someone gains access to your recovery key, they will still be unable to recover your personal account on Numio. When you choose to recover your account, that data gets decrypted by your unique FaceMap biometrics, and in the case it wasn’t you, the recovery would fail.

Do you have to conduct KYC to use Numio?

KYC (Know Your Customer) or IDV (Identity Verification) is not required to use the Numio app. The only requirement is a Google email.

If I become Numio Verified, does the Numio team or company have access to my PII (Personal Identifiable Information) on their servers?

No. The Numio team does not have any backdoor access to this data on our servers. It is encrypted and stored in your personal NumioCloud, and is only able to be decrypted by your unique biometrics.

At a future point in time, this data will be able to be deleted by end users and removed from their NumioCloud through their Numio app

What is NumioCloud?

NumioCloud is software that the Numio team has developed which utilizes zero-knowledge proofs (zkProofs) to secure any type of information. Numio has no backdoor access to this information and the only way to decrypt it is through an end user’s biometrics. 

Any information in the NumioCloud is already encrypted upon entering it, and then further encrypted a second time to ensure maximum security. 

Is there a fee to use Numio?

No. Numio is free to use.

What digital assets does the Numio Wallet support?

Currently Numio supports the following digital assets:

  • ETH
  • wBTC
  • PHNX
  • USDC

We will be adding more support for tokens and this list will evolve over time.

Is Numio open source?

No, Numio is not open source. 

Numio leverages many open source technologies, such as blockchain, smart contracts, databases, and programming languages, but the intellectual property of Numio is owned by Numio, Inc. 

What is the difference between a “Standard Wallet 🐢” and “Numio Wallet ⚡️”?

The Standard Wallet 🐢 is your traditional Ethereum mainnet wallet. This is subject to high gas fees, and long confirmation times. 

When you import a new wallet, it will appear as “Standard Wallet 2 🐢”. As you import other wallets, they will increase in number (e.g. Standard Wallet 3, 4, 5, and so on).

The “Numio Wallet ⚡️” is your zkRollup wallet, which uses the rollup developed by Matter Labs. This is referred to some as a “Layer-2/L2” account, as noted below in the following question. 

Wallet names will be customizable in the future. 

What are zkRollups?

zkRollups are regarded as a respected Ethereum scaling solution, which takes some of the computation work off of the main Ethereum blockchain, but keeps all data availability on Ethereum. Transactions are batched together and sent back onto the Ethereum network. 

A great analogy to understand how a zkRollup operates is similar to a train. It is able to pick up a bunch of passengers (transactions) who are all going to the same location (where this data is pushed onto the Ethereum mainnet). The train stops at different locations and picks up new passengers (new transactions into the rollup), and once the train is entirely full, it reaches its location, and all of the passengers leave (transaction gets pushed onto the Ethereum mainnet). 

This means that the operators of the rollup are able to give breadcrumbs from the zkRollup about what is occurring within the smart contract directly to the L1 (layer-1, or Ethereum mainnet) allowing for people to easily access their money, in the case that the zkRollup network operators shut off. 

Data availability is stored on-chain, and zkRollups use zkSNARKs for computation. Previously, one of the main disadvantages for zkRollups is that you were not able to port the bytecode of the EVM for solidity smart contracts, which is no longer the case. 

What are the easiest ways to move funds into your Numio Wallet ⚡️ (your zkRollup/ L2 account)?

If you are using a brand new wallet on Numio, the easiest way to get funds into your Layer-2 wallet, also known as “Numio Wallet ⚡️”, is either purchasing crypto through the widget in the app, or by importing a wallet. 

When purchasing funds, you can buy them through the widget, and then follow this process to move them to your Numio Wallet ⚡️. 

If you are looking to move all of your assets to Layer-2, make sure to move your assets other than ETH to your Numio Wallet ⚡️first (e.g. PHNX assuming this token is already in your wallet), followed by ETH. 

Steps to move ETH with an imported wallet:

  1. Tap the three dots in your balance card and select “Import Wallet”.
  2. Enter your private key (this can be from any other wallet, like Metamask, Trust Wallet, imToken, Rainbow, Coinbase Wallet, Dharma, Argent, Enjin, etc.) and tap “Import”.
  3. Make sure the token you have selected is ETH. If not tap on the token change button, and choose ETH.
  4. Tap the three dots in your balance card and “select “Internal Transfer”.
  5. “Source Wallet” will be “Standard Wallet 2 🐢”. This is your imported wallet.
  6. Select how much ETH you would like to transfer- please make sure you have enough leftover in your balance to cover gas fees
  7. Choose your source wallet as “Numio Wallet ⚡️”, which is your Layer-2 wallet and tap “Confirm”.

Steps to move both an ERC20 token (e.g. PHNX) along with ETH which have been deposited into “Standard Wallet 🐢”:

  1. Select token Balance & choose PHNX.
  2. Click on three dots and tap “Internal Transfer”.
  3. Choose wallet holding both ETH & PHNX in the wallet, “Standard Wallet 🐢”.
  4. Select the number of PHNX you wish to send and make sure the destination wallet is Numio Wallet ⚡️.
  5. Tap “Confirm” (if you need more ETH to confirm the transaction, you may need to purchase more).
  6. Tap the “Token” change button and Choose ETH.
  7. Tap the three dots on your balance card and select “Internal Transfer”.
  8. Select wallet with ETH & PHNX in the wallet, “Standard Wallet 🐢”.
  9. Select the number of PHNX you wish to send and Make sure the destination wallet is Numio Wallet ⚡️.
  10.  Tap “Confirm” (if you need more ETH to confirm the transaction, you may need to purchase more).

Why is it expensive to do an “Internal Transfer” to the Numio Wallet ⚡️?

Interacting with certain smart contracts and functions can charge higher computation costs. Depositing assets into the zkSync smart contract, which is the zkRollup, requires significantly higher computation costs than making a regular transaction on Ethereum. 

This transaction fee goes to the Ethereum miners supporting and securing the network, and does not go to Numio.

Can I deposit to my Numio Wallet ⚡️from an external wallet?

The only way you are able to deposit your digital assets into your Numio Wallet ⚡️ from an external wallet is by importing your wallet to Numio. 

To import your wallet, tap on the three dots and select “Import Wallet”. From there, enter your private key or mnemonic phrase, and you will have your wallet imported. 

After importing this wallet, you can complete an internal transfer to send your funds directly to your Numio Wallet ⚡. 

What currencies are available to purchase from MoonPay?

The list of assets supported by MoonPay can be found here: 

What are Gas/Network Fees?

Gas, also known as network fees, are the fees used to help power decentralized networks. Using the Standard Wallet 🐢, you are required to use ETH to help complete transactions, as ETH helps to power the network.

Using the Numio Wallet ⚡ for certain assets that are supported, you are able to pay the network in the same asset you are transacting with (not only ETH). These assets currently are:

  • wBTC
  • ETH
  • USDC

As more assets become available on zKSync, and are integrated into Numio we will update our list. 

What is the L2 Initiation Fee?

When using the Numio Wallet ⚡️, there is a cost that you have to pay to the network, which allows you to store your account ID (data, balances and information) on the network forever. 

This process creates an account on the zkSync network. It is a one time fee, which you will never have to pay again. 

Numio is not being paid for this transaction.

What happens if I send to the wrong Numio-ID or address when sending a transaction?

If you accidentally type the wrong Numio-ID and it does not exist, you will get an error message. 

Before any transaction gets sent, a confirmation screen is presented to confirm the Numio-ID of the person you are sending it to is correct. 

If you confirm a transaction going to the wrong Numio-ID, we are unable to retrieve your funds as we can’t access the user’s assets, or revert any transactions. 

What do I do if I purchased a new phone?

If you have purchased a new phone, you are able to recover your account by tapping “Recover” on the main app screen.

I have PHNX tokens in my Numio Wallet ⚡️, and I am trying to withdraw them, but it is saying I need to add ETH to my wallet. I have sent ETH to my wallet, but I cannot withdraw them. What am I doing wrong?

If you have PHNX tokens in your Numio Wallet ⚡️, and are attempting to make a transaction, whether to pay someone, conduct an internal transfer, or withdrawal, you will need to have ETH in your Numio Wallet ⚡️.

Depositing ETH into your Standard Wallet 🐢 will not be able to cover these fees. ETH will need to be sent to your Numio Wallet ⚡️ by doing an internal transfer.

What does “Backup Wallet” mean when I first click a button in the app?

When you first register with the app then pressing any button will present you with a ‘Backup Wallet’ screen. This is to create and store an encrypted recovery key.

The backup process currently takes place by adding an encrypted recovery key (.txt file) to your Google Drive. Future versions of the app will support a manual backup and alternative email options.

Doing the backup is essential to securing your wallet and if you don’t do it then you will not be able to recover your account.

Will there be an iOS version of the app?

Yes! The iOS version is currently in development and is on TestFlight. Stay tuned for its release 👀.

When using the wallet, am I able to send multiple tokens at the same time? Or do I need to pay for a transaction each time?

Because of how Ethereum works, you have to send one transaction at a time in order for it to process.

My transaction on my Standard Wallet 🐢has been pending for a while, what do I do?

Ethereum mainnet can be quite congested sometimes, and leads to spikes in gwei, causing transactions to take a while to confirm. 

We will introduce features which will allow you to speed up the transactions to improve their confirmation times. 

Why does my Government ID not work for “Identity”?

Our AI software for authenticating documents is not able to support government ID’s yet. Currently, we only support drivers licenses and passports. We will support additional documents in the future, including Government ID’s.