BIP21 allows more parameters to be added to QR codes for BTC payments.
The BOLT12 protocol is much more practical than BOLT11, but is still under development.
QR codes are a tool that has revolutionized the world of smartphone payments, ranging from fiat banking applications to Bitcoin wallets, and even Lightning Network (LN).
The growth that the adoption of payments in BTC via Lightning has been experiencing is a hopeful fact. According to a report recently published by CriptoNoticias, Bitcoin’s Lightning network has already exceeded 88,000 payment channels enabled and 40,000 BTC of sending capacity.
Despite the increase in the number of LN users, many bitcoiners and sites, web or physical, that accept payments in BTC, do not have a Lightning network wallet for this purpose. In the best case, those that do accept bitcoin and LN payments need to show both addresses and corresponding QR codes. In addition, it is important to indicate which code corresponds to which type of wallet, to avoid confusion in the clientele that can cause irreversible losses of BTC balance.
No more separate QR codes for Bitcoin and LN
Handling multiple QR codes can be confusing for users making a payment. Nevertheless, there is a solution that can simplify BTC payments regardless of whether they are on the main chain or via Lightning: the unified QR codes.
The current level of development of Bitcoin and Lightning is advanced enough to adopt the use of unified QR codes, which would be the ideal solution for BTC and LN users. The seller or whoever would receive the payment would not need to publish two QR codes or confirm with the buyer which of the two payment methods he prefers.
In the case of the buyer, he would not have to worry about choosing the QR code to use, but you could confidently scan the one QR code presented to you and choose whether to pay with BTC on the main chain or in LN. That is if the wallet works with both chains, well, otherwise, the payment would be made automatically with the only one available for the wallet or application.
BIP21 and the unified QR codes for Bitcoin and Lightning
The idea of unified QR codes for Bitcoin and Lightning part of Bitcoin Improvement Proposal 21 (BIP21). This proposal has been perfected for several years and has had the participation of important developers in the Bitcoin ecosystem, such as: Luke Dashjr, William Swanson and Peter Todd, among others.
The BIP21 It consists of applying a URI scheme (Uniform Resource Identifier, for its acronym in English) to carry out transactions in a simple way with BTC. Payments are made by clicking links or scanning QR codes. Added to this is the possibility of adding an additional form of payment through the query or search component.
How are the Bitcoin Mainnet and the Lightning Network combined into a single QR Code?
A valuable feature of BIP21 is that it opens up the possibility of being extended, that is, you can include other parameters that enrich its functionality. Therefore, the door would be open to include payments in Lightning using the BOLT11 or BOLT12 protocols.
It is important to mention that BOLT11 is a protocol used to send receipts or bills for collection on the Lightning Network, in order to make a payment in favor of the person who sends said invoice. BOLT12, on the other hand, is a more modern protocol that allows the sending of both invoices and payment offers in LN.
BOLT12 would be the ideal one to be added to BIP21 for several reasons. Firstly, being able to ask or offer a payment makes it more versatile than BOLT11. It is also a simpler and shorter format, so the size of the QR code can be reduced much more. However, BOLT12 has one crucial factor working against it: it is still in development. If BOLT12 becomes fully implemented and adopted by LN users, it would be a plus that would optimize many aspects of this network.
Which wallets are currently enabled to use unified QR?
There are several categories into which wallets can be classified based on their interaction with the unified QR codes for Bitcoin payments on the main chain and on LN. There are those that can scan QR codes with BIP21, those that can recognize the LN parameter in the code, and those that can generate their own QR code with BIP21.
Wallets limited to reading QR codes with BIP21
Among the wallets that can scan QR codes with BIP21, but do not recognize LN parameters are: Samourai, BitPay, Green, Casa, Coinbase, Hexa, Nunchuk, Chaincase, Edge Wallet and River.
There are particular cases such as the BitcoinBeach, Chivo, Strike and Zeus wallets. These wallets, although they are compatible with sending BTC, both on the main chain and via Lightning, do not recognize the LN parameter present in the QR code. In these cases, it is necessary for the developers of these applications to work on their compatibility with QR codes generated with BIP21.
Lightning parameter-aware wallets
Wallets that can currently scan QR codes with BIP21 and recognize LN parameters include Alby, The Bitcoin Company, Blixt, BlueWallet, Breez, Muun, Phoenix, Simple Bitcoin Wallet, Wallet of Satoshi, and Zap.
Website users bitcoinqr.dev that tested the compatibility of these wallets with the unified QR codes published comments on some of them. BlueWallet, for example, asks the user to select whether they want to pay with their main chain wallet or with the LN wallet (which should be the standard). Zap, for its part, automatically ignores the LN parameter if the invoice is overdue. However, if the invoice has not expired, the wallet will also recognize the Lightning network parameter.
Wallets that generate QR codes with BIP21
Finally, there are only three wallets capable of generating their own QR code with BIP21 at the moment: BTCPay, Kraken and OpenNode. Curiously, none of these wallets make payments on the Lightning network, so they don’t recognize that parameter. As for BTCPay, to generate invoices with BOLT11 it is necessary for the user to enable this option.
If you promote and facilitate the adoption of Bitcoin and Lightning, you are welcome.
There is still a long way to go before Bitcoin and Lightning, its second layer solution, can be truly massively adopted globally. Therefore, any invention that can accelerate the advancement towards the adoption of these tools is welcome.
It is worth noting that there are also ethical principles of Bitcoin that must be respected for each improvement that tries to be implemented to its protocol. The right to privacy, liberty and security are essential and they cannot be sacrificed in order to obtain the support and promotion of traditional financial entities or governments.
Likewise, it is also important that each improvement made to Bitcoin and the Lightning network is carried out as thoroughly as possible, without rushing, but without pauses. Quoting Eric Lombrozo, developer of Bitcoin Core, in a recent discussion about implementing a pending improvement proposal for Bitcoin: “It only takes a well exploited systemic vulnerability to destroy the network. And there is no second chance.”