Feedback on a simple 2-path vault design (2-of-2 + CLTV recovery) and use of pruned nodes for UTXO retrieval

The system architecture includes a normal spending path, necessitating a 2-of-2 multisig (requiring both key A and key B) for immediate transactions, and a recovery path which allows key B alone to execute transactions after a certain block height, utilizing a CheckLockTimeVerify (CLTV) operation for time-delayed access. This setup is primarily tested on regtest environments, confirming the functionality of both spending paths and the CLTV enforcement without any custodial interference. PSBTs (Partially Signed Bitcoin Transactions) are signed using two Ledger devices, ensuring a secure transaction process.

The main concern revolves around the feasibility of integrating this system with a pruned Bitcoin Core node due to storage and deployment conveniences. Victor questions the reliability of such nodes in accurately returning UTXOs associated with the vault address, providing necessary fields for PSBT inputs, validating timelocked script spends, and broadcasting final transactions. There's an inquiry into whether pruned nodes can support this workflow adequately, especially when dealing with scripts that incorporate multiple spending paths.

Antoine responds by urging a reconsideration of the terminology used to describe these mechanisms, noting the diluted specificity of the term "vault" within the Bitcoin community. He references Victor's design as similar to Liana, a system that also aims for enhanced security through multisig and timelock features but opts for relative timelocks (CSV) over absolute (CLTV) to avoid descriptor expiration issues and user confusion. Antoine points out that Liana integrates with a pruned Bitcoin Core node using its watchonly wallet function to monitor coins and suggests configuring an Electrum server for remote node operations, indicating Bitcoin Core's RPC interface might not be ideally suited for Victor's needs. This dialogue underscores the importance of clear terminology and highlights considerations for developing secure, user-friendly Bitcoin storage solutions. For further details on Bitcoin vaults, Antoine provides a link to Bitcoin Ops and shares the GitHub repository for Liana at https://github.com/wizardsardine/liana.