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QR Code

What Is A QR Code?

What Is A QR Code?

A QR Code, short for quick response code, is a type of two-dimensional barcode that can be read by QR scanners, smartphones, tablets, and other mobile devices. They are often used to provide quick and easy access to information or websites and have become the de facto means for bitcoiners to share bitcoin addresses, on-chain payment requests, LN invoices, xPub keys, seed phrases, BIP 47 payment codes, partially signed bitcoin transactions, and more.

On-Chain Payments

QR codes can be used to display bitcoin addresses in a variety of ways. For example, you can use them in person to send bitcoin from one mobile wallet to another.

To receive a payment, simply provide your bitcoin address in QR format so others can scan the code with their wallet. Funds will then be sent directly to your bitcoin address.

You can also use QR codes to display bitcoin addresses on websites. Simply embed the code into a website, and visitors will be able to see your bitcoin address when they scan the code.

This is a great way to accept payments from customers or donations from supporters.

Finally, you can use QR codes to send bitcoin payments across devices. For example, you can scan a QR code on a desktop wallet with a mobile wallet to send funds from one device to another. This is a convenient way to send bitcoin payments without having to enter long addresses manually or share any other information between sender and receiver such as sharing an address (or other info) via email or a messaging app.

LNURL

LNURL, short for lightning network URL, is a protocol that allows users to securely authenticate themselves on third-party sites and log in to LN-enabled sites and applications without revealing their personal information.

Using LNURL-Auth, users can register and log in to services simply by scanning a QR code with their lightning wallet rather than providing an email address and password. LNURL-auth can also be used as a form of 2-factor authentication instead of using an app like Google Authenticator or Authy.

BIP 47 Payment Codes

If you’re looking for a more private way to receive payments and donations online, you can use a BIP 47 payment code instead of a static bitcoin address. BIP 47 payment codes generate a new address for each transaction that you receive, so your bitcoin balance is not publicly visible simply by attempting to look up your payment code on a block explorer. Only the sender and receiver know about each transaction sent to a payment code. Payment codes allow you to publicly share a donation QR code but make it much more difficult for someone to know your balance.

Seed Phrases & xPub Keys

The SeedSigner project offers a great solution for those looking for a way to generate seed phrases with an open-source air-gapped device. Once the seed phrase has been generated offline, a QR code can be used to relay the xPub key to a desktop wallet so that addresses can be generated and transactions can be built. You can write your seed phrase in a QR code format for quick and easy use with SeedSigner and other wallets that adopt the compact code format commonly used.

QR codes have become the standard for sharing information between completely offline devices and desktop or mobile wallets that have a direct internet connection.

When you need to recover your bitcoin wallet and load the seed phrase back onto the device, all you need to do is scan the QR code of the seed phrase rather than manually entering each word.

Partially Signed Bitcoin Transactions

Partially signed bitcoin transactions (PSBT) have become the standard for sending bitcoin from a hardware wallet that is completely offline and air-gapped. Rather than connecting your hardware wallet to your internet-connected computer to sign transactions, you can create the transaction on your computer and then relay the details of that transaction to your air-gapped hardware wallet via a series of QR codes called a fountain QR code.

This process helps to ensure the security of your bitcoin by keeping your private key offline and away from potential hackers.

Once the transaction is signed on your hardware device, QR codes can then be used to relay the signed transaction details back to the internet-connected device and then broadcast to nodes to be added to the blockchain.

Fountain QR codes are an easy and secure way to send bitcoin from your hardware wallet, and they provide an extra layer of safety by keeping your private keys completely offline.