Re: [bitcoin-dev] Relative txout amounts with a Merkleized Sum Tree and explicit miner fee.

2022-11-25 Thread Rijndael via bitcoin-dev
Hello Andrew,

As ZmnSCPxj mentioned, covenant schemes are probably something that you
should be looking at and thinking about. In addition to CTV, I'd also
recommend you take a look (if you haven't already) at
`TAPLEAF_UPDATE_VERIFY`
(https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2021-September/019419.html).
 From your description, it sounds like you may be barking up a similar tree.

Rijndael


On 11/21/22 6:52 PM, ZmnSCPxj via bitcoin-dev wrote:
> Good morning Andrew,
>
>>
>> Can output amounts be mapped to a tap branch? For the goal of secure partial 
>> spends of a single UTXO? Looking for feedback on this idea. I got it from 
>> Taro.
>
> Not at all.
>
> The issue you are facing here is that only one tap branch will ever consume 
> the entire input amount.
> That is: while Taproot has multiple leaves, only exactly one leaf will ever 
> be published onchain and that gets the whole amount.
>
> What you want is multiple tree leaves where ALL of them will EVENTUALLY be 
> published, just not right now.
>
> In that case, look at the tree structures for `OP_CHECKTEMPLATEVERIFY`, which 
> are exactly what you are looking for, and help make `OP_CTV` a reality.
>
> Without `OP_CHECKTEMPLATEVERIFY` it is possible to use presigned transactions 
> in a tree structure to do this same construction.
> Presigned transactions are known to be larger than `OP_CHECKTEMPLATEVERIFY` 
> --- signatures on taproot are 64 bytes of witness, but an 
> `OP_CHECKTEMPLATEVERIFY` in a P2WSH reveals just 32 bytes of witness plus the 
> `OP_CHECKTEMPLATEVERIFY` opcode.
>
> Regards,
> ZmnSCPxj
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Re: [bitcoin-dev] Relative txout amounts with a Merkleized Sum Tree and explicit miner fee.

2022-11-21 Thread ZmnSCPxj via bitcoin-dev


Good morning Andrew,

> 
> 
> Can output amounts be mapped to a tap branch? For the goal of secure partial 
> spends of a single UTXO? Looking for feedback on this idea. I got it from 
> Taro.


Not at all.

The issue you are facing here is that only one tap branch will ever consume the 
entire input amount.
That is: while Taproot has multiple leaves, only exactly one leaf will ever be 
published onchain and that gets the whole amount.

What you want is multiple tree leaves where ALL of them will EVENTUALLY be 
published, just not right now.

In that case, look at the tree structures for `OP_CHECKTEMPLATEVERIFY`, which 
are exactly what you are looking for, and help make `OP_CTV` a reality.

Without `OP_CHECKTEMPLATEVERIFY` it is possible to use presigned transactions 
in a tree structure to do this same construction.
Presigned transactions are known to be larger than `OP_CHECKTEMPLATEVERIFY` --- 
signatures on taproot are 64 bytes of witness, but an `OP_CHECKTEMPLATEVERIFY` 
in a P2WSH reveals just 32 bytes of witness plus the `OP_CHECKTEMPLATEVERIFY` 
opcode.

Regards,
ZmnSCPxj
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