From: ZmnSCPxj <ZmnSCPxj@protonmail•com>
To: Zac Greenwood <zachgrw@gmail•com>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] User Resisted Soft Fork for CTV
Date: Mon, 25 Apr 2022 10:01:28 +0000 [thread overview]
Message-ID: <ID4VQ7kbkdRwf38kiXtxuhanlkFy7ggmL26NlK_t4h9KdAzrIMFXGdgwsGxIixQXhkdyeaSupmVEVDp14aQPwShHm1AryWFiYAkZO5Thb4k=@protonmail.com> (raw)
In-Reply-To: <CAJ4-pEB1zWxWapt3qit=X1p3WuSSn2_K=rygDp8JzpS7GimgMg@mail.gmail.com>
Good morning Zac,
> On Mon, 25 Apr 2022 at 07:36, ZmnSCPxj <zmnscpxj@protonmail•com> wrote
>
> > CTV *can* benefit layer 2 users, which is why I switched from vaguely apathetic to CTV, to vaguely supportive of it.
>
>
> Other proposals exist that also benefit L2 solutions. What makes you support CTV specifically?
It is simple to implement, and a pure `OP_CTV` SCRIPT on a P2WSH / P2SH is only 32 bytes + change on the output and 32 bytes + change on the input/witness, compared to signature-based schemes which require at least 32 bytes + change on the output and 64 bytes + change on the witness ***IF*** they use the Taproot format (and since we currently gate the Taproot format behind actual Taproot usages, any special SCRIPT that uses Taproot-format signatures would need at least the 33-byte internal pubkey revelation; if we settle with the old signature format, then that is 73 bytes for the signature).
To my knowledge as well, hashes (like `OP_CTV` uses) are CPU-cheaper (and memory-cheaper?) than even highly-optimized `libsecp256k1` signature validation, and (to my knowledge) you cannot use batch validation for SCRIPT-based signature checks.
It definitely does not enable recursive covenants, which I think deserve more general research and thinking before we enable recursive covenants.
Conceptually, I see `OP_CTV` as the "AND" to the "OR" of MAST.
In both cases, you have a hash-based tree, but in `OP_CTV` you want *all* these pre-agreed cases, while in MAST you want *one* of these pre-agreed cases.
Which is not to say that other proposals do not benefit L2 solutions *more* (`SIGHASH_ANYPREVOUT` when please?), but other proposals are signature-based and would be larger in this niche.
Regards,
ZmnSCPxj
next prev parent reply other threads:[~2022-04-25 10:01 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-21 16:45 Michael Folkson
2022-04-21 23:36 ` Keagan McClelland
2022-04-22 9:03 ` Zac Greenwood
2022-04-22 15:40 ` Corey Haddad
2022-04-23 5:07 ` Billy Tetrud
2022-04-23 14:48 ` Erik Aronesty
2022-04-24 14:47 ` Peter Todd
2022-04-25 5:36 ` ZmnSCPxj
2022-04-25 9:06 ` Zac Greenwood
2022-04-25 10:01 ` ZmnSCPxj [this message]
2022-04-22 9:53 ` Michael Folkson
2022-04-23 20:40 ` Jorge Timón
2022-04-24 12:17 ` Michael Folkson
2022-04-24 12:57 ` Jorge Timón
2022-04-24 12:55 ` Ryan Grant
2022-04-24 13:11 ` Jorge Timón
2022-04-24 13:15 ` Ryan Grant
2022-04-25 16:11 alicexbt
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