From: Greg Sanders <gsanders87@gmail.com>
To: Bitcoin Development Mailing List <bitcoindev@googlegroups.com>
Subject: Re: [bitcoindev] Prohibit Merkle Internal Node Preimages That Encode Minimal 64-Byte Transactions
Date: Tue, 2 Jun 2026 05:36:55 -0700 (PDT) [thread overview]
Message-ID: <923b3d65-3472-4d7d-9b13-da44753fe5f8n@googlegroups.com> (raw)
In-Reply-To: <45558bbd-762c-45a4-a4a1-6105d7462a8en@googlegroups.com>
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Hi Jeremy,
Why does the SPV verifier need to do additional checks? SPV implies it's
simply trusting the heaviest chain. Clearly they could validate it, but I'm
not seeing necessity in the security model.
Greg
On Monday, June 1, 2026 at 4:22:28 PM UTC-4 jeremy wrote:
> Antoine,
>
> Rejecting nodes with any valid tx in path, without this rule, is
> problematic, because it _can_ be possible for an attacking miner to
> engineer that scenario by grinding one TXID leaf to mask a subtree, which
> could have major consequences. Third party malleability vulnerability to
> deposit / withdrawal masking is a serious bug. Worth thinking that through
> very carefully before recommending these mitigations. Do you have an
> end-to-end working example of such a mitigation that doesn't have these
> issues?
>
> > This is incorrect for any bridge, wallet, or deposit system that does
> not receive funds to a script that either burns the funds or that anyone
> can spend.
>
> The problem is that from the perspective of a wide variety of layer 2
> protocols, you actually do want to be able to simply close out a UTXO and
> prove a UTXO is spent.
>
> In the current L2 protocol design space, value doesn't always flow
> directly along the output, the UTXO may be being used as a connector
> input, and the spend of that output may be making a different output
> available after a timeout and excluding an alternative spend.
>
> Best,
>
> Jeremy
>
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next prev parent reply other threads:[~2026-06-02 12:40 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-01 17:46 [bitcoindev] Prohibit Merkle Internal Node Preimages That Encode Minimal 64-Byte Transactions jeremy
2026-06-01 18:49 ` 'Antoine Poinsot' via Bitcoin Development Mailing List
2026-06-01 20:17 ` jeremy
2026-06-02 12:36 ` Greg Sanders [this message]
2026-06-02 18:15 ` jeremy
2026-06-03 1:05 ` Antoine Riard
2026-06-03 15:07 ` jeremy
2026-06-05 21:34 ` 'Antoine Poinsot' via Bitcoin Development Mailing List
2026-06-09 16:28 ` jeremy
2026-06-09 16:37 ` jeremy
2026-06-09 18:30 ` Matt Corallo
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