timestamp – Can Taproot be used to commit arbitrary information to chain with none extra footprint?
Sure, you possibly can decide to information this fashion, however there may be nothing particular about Taproot right here.
The Pay-to-Contract building used to tweak the foundation key in Taproot is usually usable, and has in reality been used for precisely this goal. The truth is, it is likely one of the mechanisms utilized in OpenTimestamps to decide to timestamped information (together with a variant sign-to-contract which makes a signature decide to information quite than a public key). It’s also utilized in Blockstream’s Liquid pegin mechanism, the place transfers from Bitcoin to Liquid pay to an handle derived utilizing a tweaked key of the federation, which commits to the switch data.
The truth is, utilizing a further leaf in Taproot for that is overkill, and would inevitably enhance the depth within the Merkle tree for at the very least one different leaf – leading to elevated spending price. Simply utilizing pay-to-contract or sign-to-contract instantly on one of many public keys concerned could be executed with zero price to on-chain spending insurance policies.
Would this not considerably cut back the price of providers like coloured cash, timestamping providers, and so forth, which commit their information instantly onto the chain?
Respectable timestamping providers already use higher methods.
For coloured cash it relies upon whether or not they simply want timestamping or precise publication of knowledge. My understanding is that it is usually the latter (as in any other case, they want one other censorship-resistant channel to switch the precise information, which may then most likely be used instantly).