<p>I will use Ark, a new layer 2 solution for Bitcoin as a reference.</p>
<p>You can know more about Ark at <a href="https://arkdev.info/" rel="nofollow noreferrer">https://arkdev.info/</a></p>
<blockquote>
<p>It sounds great in theory... but who is coordinating this shared UTXO?</p>
</blockquote>
<p>A central party, we call it the Ark Service Provider, or ASP.</p>
<blockquote>
<p>Aren't we also falling back to a trusted solution to coordinate, in all honesty? It appears more trustless than Fedimint after the UTXO is coordinated and mined.... but the coordination still requires trust, does it not?</p>
</blockquote>
<p>No trust is required with the usage of <a href="https://joaobordalo.com/labs/ark/#onboarding" rel="nofollow noreferrer">Anchored transactions</a>.</p>
<p>Also, all on-chain transactions are funded 100% by the ASP.</p>
<blockquote>
<p>Does anybody actually have a trust minimized solution for this coordination of sharing UTXOs?</p>
</blockquote>
<p>Ark is completely trustless.</p>
<blockquote>
<p>Also... I'm curious if anyone has an estimate on how many vBytes would be required for a Tx with 1,000 users sharing 1 UTXO. Any rough ideas or a possible range?</p>
</blockquote>
<p>Ark on-chain transactions are regular transactions, with 2 or 3 outputs at most.</p>

CC BY-SA 4.0
2024-02-22T19:25:47.307Z
2024-02-22T19:25:47.307Z
bordalix
<p>CTV can not be used to completely trustlessly coordinate, it relies on central parties hosting servers and off-chain data.</p>

CC BY-SA 4.0
2024-07-21T23:40:30.140Z
2024-07-21T23:40:30.140Z
Poseidon
<p>Lots of CTV talk lately.  I believe I understand the basic concept, which is that, say, 1,000 users could share 1 UTXO, while any 1 of those users can withdraw funds to the main chain at any time.  So the partial UTXO ownership means you still have sovereign, trustless ownership.</p>
<p>It sounds great in theory... <strong>but who is coordinating this shared UTXO?</strong>  Aren't we also falling back to a trusted solution to coordinate, in all honesty?  It appears more trustless than Fedimint <em>after</em> the UTXO is coordinated and mined.... but the coordination still requires trust, does it not?</p>
<p>Does anybody actually have a trust minimized solution for this coordination of sharing UTXOs?</p>
<p>Also... I'm curious if anyone has an estimate on how many vBytes would be required for a Tx with 1,000 users sharing 1 UTXO.  Any rough ideas or a possible range?</p>

CC BY-SA 4.0
2024-02-22T17:26:09.710Z
You might be mixing up a couple things. It seems to me when you say CVT, you are referring to [OP_CHECKTEMPLATEVERIFY (CTV)](https://bitcoinops.org/en/topics/op_checktemplateverify/), a proposed opcode, but your question seems to relate to  [JoinPools](https://bitcoinops.org/en/topics/joinpools/), could you perhaps clarify what you are interested in?
Murch
CC BY-SA 4.0
2024-02-22T17:35:30.617Z
Correct... referring to CTV.  Thanks for the correction!
DoctorBuzz1
<scalability><trust><transaction-weight><covenants><bip119-checktemplateverify>
CTV real world usage -- How to trustlessly coordinate 1,000 people sharing 1 UTXO? And how many vBytes would be required for such an onboarding Tx?
DoctorBuzz1
# CTV real world usage -- How to trustlessly coordinate 1,000 people sharing 1 UTXO? And how many vBytes would be required for such an onboarding Tx?

(Asked by: username_0 on 2024-02-22)

Lots of CTV talk lately. I believe I understand the basic concept, which is that, say, 1,000 users could share 1 UTXO, while any 1 of those users can withdraw funds to the main chain at any time. So the partial UTXO ownership means you still have sovereign, trustless ownership.

It sounds great in theory... **but who is coordinating this shared UTXO?** Aren't we also falling back to a trusted solution to coordinate, in all honesty? It appears more trustless than Fedimint *after* the UTXO is coordinated and mined.... but the coordination still requires trust, does it not?

Does anybody actually have a trust minimized solution for this coordination of sharing UTXOs?

Also... I'm curious if anyone has an estimate on how many vBytes would be required for a Tx with 1,000 users sharing 1 UTXO. Any rough ideas or a possible range?

**Tags:** scalability, trust, transaction-weight, covenants, bip119-checktemplateverify

> **Comments:**
> **username_1**: You might be mixing up a couple things. It seems to me when you say CVT, you are referring to [OP_CHECKTEMPLATEVERIFY (CTV)](https://bitcoinops.org/en/topics/op_checktemplateverify/), a proposed opcode, but your question seems to relate to  [JoinPools](https://bitcoinops.org/en/topics/joinpools/), could you perhaps clarify what you are interested in?  
> **username_0**: Correct... referring to CTV.  Thanks for the correction!  

---

## 2 answers

### Answer by username_2 on 2024-02-22. Score: 0

I will use Ark, a new layer 2 solution for Bitcoin as a reference.

You can know more about Ark at <https://arkdev.info/>

> It sounds great in theory... but who is coordinating this shared UTXO?

A central party, we call it the Ark Service Provider, or ASP.

> Aren't we also falling back to a trusted solution to coordinate, in all honesty? It appears more trustless than Fedimint after the UTXO is coordinated and mined.... but the coordination still requires trust, does it not?

No trust is required with the usage of [Anchored transactions](https://joaobordalo.com/labs/ark/#onboarding).

Also, all on-chain transactions are funded 100% by the ASP.

> Does anybody actually have a trust minimized solution for this coordination of sharing UTXOs?

Ark is completely trustless.

> Also... I'm curious if anyone has an estimate on how many vBytes would be required for a Tx with 1,000 users sharing 1 UTXO. Any rough ideas or a possible range?

Ark on-chain transactions are regular transactions, with 2 or 3 outputs at most.


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### Answer by username_3 on 2024-07-21. Score: 0

CTV can not be used to completely trustlessly coordinate, it relies on central parties hosting servers and off-chain data.


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