Bitcoin Core developers have been discussing the possibility of standardizing a method of storing arbitrary data in Bitcoin through a feature called Taproot Append.
According to the Suggestion by Joost Jager, an engineer and developer of Bitcoin and the Lightning network, who is currently “fixing a precise format.” [para el anexo] can take a lot of time.”
The Taproot attachment is a format for adding data in an extension of the field called Witness. where the validating signatures of common bitcoin transactions are contained. This is relevant today as the Taproot Transaction Witness is where the Ordinals NFTs are stored, a protocol that has sparked all sorts of debates since its inception late last year due to its impact on the network and in the markets.
This free format “allows the extension of the usual transaction fields with new records,” explains Antoine Riard, developer of Bitcoin, in one Suggestion submitted in July 2022, which served as the basis for Jager’s proposal. In addition, it is envisaged that this data may be subject to new validation rules.
In other words, the attachment is an optional part of Taproot transactions whose purpose is not yet defined, although ideally it is reserved for future soft forks. It is noteworthy that in the appendices Transaction signatures and attached data are compromised or linked. This makes it impossible for you to change anything in the registry.
A free format for Taproot attachments
Jager acknowledges that there is one important factor that could slow down the progress of the Taproot addendum, whose potential seems to be widely accepted among developers. “Talks about standardization seem to tend to introduce a flexible format Type Length Value (TLV)”, Explain. In short, if the attachment uses this format to record data in transactions, there would be many benefits; but the price would be the time that has to be paid for.
By now the advantages of providing the attachment in an unstructured form are obvious and immediately apparent. By allowing developers to use the Taproot plugin without delay, we can start using its features today without having to wait for a lengthy standardization process to complete.
Joost Jager, Bitcoin and Lightning developer and engineer.
What a hunter suggests Is a free format, “without additional restrictions”, for all attachments starting with “0”. That is, they have no instructions.
The developer concludes that there are at least three benefits to adopting a format like the one he’s proposing.
The former “opens the door to developers Use the Taproot addendum for a variety of applications right out of the boxThis eliminates the need to wait for TLV or any other structured format to be implemented.
The second is to keep options open for future developments while promoting standardization of the appendix.
The third aspect concerns the efficient use of storage space on the blockchain, as “unstructured data may require fewer bytes compared to a likely TLV format, which would require length encoding even if there was only one field.”
Although Riard’s proposal was not widely accepted, Jager’s idea could arouse the interest of other developers. With that in mind, Greg Sanders, another Bitcoin Core and Lightning developer said: brought an idea on the discussion table that Riard himself proposed in October last year.
It’s about the possibility of using attachments to test the LN-Symetry or Eltoo protocol, a tool that replaces the current transaction penalty system in the Lightning Network, which runs when a user makes an old and already invalid string transaction of blocks issues a mechanism that automatically updates the payment channels. That way nobody can use an old channel update that shows a fake balance (something that could be exploited to steal BTC).
Eltoo must use a specific transaction type that can leverage the properties of attachments: soft fork SIGHASH_ANYPREVOUT, “a signature hash (sighash) in which the identifier of the issued UTXO is unsigned, allowing the signature to be used with any UTXO protected by a similar script (i.e. using the same public key)”. UTXO stands for unspent transaction outputor “unspent spending transaction” in Spanish.
Jäger, in turn, responded Vaults could be created to store time-locked bitcoins using pre-signed transactions with ephemeral keys. the developer He suggested that there may be previous research in Bitcoin Core that fixes the attachment retransmission issue in some multi-party protocols.
In any case, the developers talked about how the attachments could increase the efficiency of testimonies by allowing them to include any data without making a financial commitment beyond the cost incurred by that specific transaction. Sort of like the ordinals protocol does. “I think the real benefit is that the commit transaction no longer needs to be posted and paid for. All outputs of a higher-level UTXO can be supplemented with any data in a single transactionJagger added.
When talking about arbitrary data in Bitcoin, the first thing that probably comes to mind is NFTs and BRC-20 tokens, which are having a major impact on the ecosystem today. And with that in mind, it’s impossible to predict what the ultimate fate of a standard that offers a similar utility will be. Only time will tell what has the most value for people using Bitcoin.