Subject: Re: [bitcoin-dev] Ark: An Alternative Privacy-preserving Second Layer Solution

From: Burak Keceli <[email-masked]>
Date: Wed, 24 May 2023 10:53:50 +0300 (TRT)

> 0-conf transactions are unsafe since it is possible to double-spend the inputs they consume, invalidating the 0-conf transaction.

A future extension of Ark can potentially utilize a hypothetical data manipulation opcode (OP_XOR or OP_CAT) to constrain the ASP's nonce in their signatures to disincentivize double-spending. If a double-spend occurs in a pool transaction, users can forge ASP's signature to claim their previously redeemed vTXOs. This is effectively an inbound liquidity-like tradeoff without compromising on the protocol design.

For the time being, you have to wait for on-chain confirmations to consider a payment 'final'. However, this doesn't prevent you from paying lightning invoices with your zero-conf coins. Ark has immediate availability with delayed finality.

Best,
Burak