Design proposal: Deposits through single bitcoin output

[netrome]

Proposal

From this Discord discussion: https://discord.com/channels/621759717756370964/730814571517968436/1135960606919368734

Briefly the idea is to allow a deposit flow with two steps:

1. The user submits a deposit commit transaction. The only deviation from the current spec, is that this transaction cannot be immediately reclaimable by the user. It can be reclaimable through a time lock, as long as it can be proven that only the Stackers can spend this UTXO for the next few reward cycles.
2. The Stackers accept the deposit through a smart contract call on Stacks and mint the sBTC to the user. This call would reveal the witness script committed to in 1. so that anyone can verify that the minted amount is correct.

Motivation:

With this change, users would only have to subsidize a single BTC transaction to deposit - as opposed to the current commit-reveal scheme where they would have to subsidize two transactions.

Definition of done

We have explored the possibility of supporting the deposit flow described above and any related variants, and decided on whether or not to include it in the design.

[netrome]

Following the discussion for withdrawals, and in the interest of keeping the scope for 1.0 manageable let's aim for this to be a sBTC 1.1 feature earliest.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.