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

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.

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.

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.

Your Recovery Key can be saved in one of two ways.

Assisted Backup:

Your Recovery Key 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.

Manual Backup:

Just create an account with information of your choice, manually store your Recovery Key, and away you go.

KYC (Know Your Customer) or IDV (Identity Verification) is not required to use the Numio

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

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.

No. Numio is free to use.

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.

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.

The Ethereum L1 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 “Ethereum L1 Wallet”. 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.

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.

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.

The only way you are able to deposit your digital assets into your zkSync 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 .

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.

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.

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.

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

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.

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.

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

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

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.

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