Return-Path: Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 948DFC002D for ; Fri, 20 May 2022 23:48:03 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 83488426A3 for ; Fri, 20 May 2022 23:48:03 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org X-Spam-Flag: NO X-Spam-Score: -1.602 X-Spam-Level: X-Spam-Status: No, score=-1.602 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, FROM_LOCAL_NOVOWEL=0.5, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no Authentication-Results: smtp4.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=protonmail.com Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id xpMpRDrvJKmb for ; Fri, 20 May 2022 23:48:02 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mail-4318.protonmail.ch (mail-4318.protonmail.ch [185.70.43.18]) by smtp4.osuosl.org (Postfix) with ESMTPS id 876F04263C for ; Fri, 20 May 2022 23:48:02 +0000 (UTC) Date: Fri, 20 May 2022 23:47:54 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=protonmail.com; s=protonmail3; t=1653090479; x=1653349679; bh=cYu7GVc4cAPHx03LXbnDCUoUZS9NP3UE4VzCkPoJHsg=; h=Date:To:From:Cc:Reply-To:Subject:Message-ID:In-Reply-To: References:Feedback-ID:From:To:Cc:Date:Subject:Reply-To: Feedback-ID:Message-ID; b=yHPCEo/T0ew0Q8VcjGQztXhJjnyBRe59F+mSVq5p0jTYdxFu/jMOwNJ6+Vg7rEZHF GAPdVOt7xQCAWz3vRJNX8Z3/lEdGd+s6+2gElER5CtZHufR0pdu8N1Wj/Wn3bvBuaB N+OGx4KdnWtAerjrmRPzRki+lvvdNnShZCe/OKPGTMGIzhCqFA7padnDECEwJbO4pM 31/XY7Ue0U/vJgmRFo90bM+DSl8y7dBT5z+46JwLQI1MNGIqNq9LAfrrmjNyVDsZ9j YX8z+SNuuqurPoJAZMri2scR6telXjpsbj3TF90Imb2vytUmaULDA1cf4m0FLQr4nK eOk7ja5RlE4VQ== To: alicexbt From: ZmnSCPxj Reply-To: ZmnSCPxj Message-ID: In-Reply-To: <15z3VVTB7kcfg_qPey-bpkPtF551URlIDOq_qIvO9SdYWBW6duAfZjCOXT0o5hkQIdDznLsGSP9WqVw3ChXalEDyvttuUMyXT9x9SAqNfiE=@protonmail.com> References: <4FE6Gygz1J6ehzVcTMyfSGbhSPvvkg06LjxqKy-lhPgGlYOGAbxgjYEkGBys8iE09FCOOU1rzq2GLqnMNjMhbstTTdtYNqzHWaLro1CA5FM=@protonmail.com> <15z3VVTB7kcfg_qPey-bpkPtF551URlIDOq_qIvO9SdYWBW6duAfZjCOXT0o5hkQIdDznLsGSP9WqVw3ChXalEDyvttuUMyXT9x9SAqNfiE=@protonmail.com> Feedback-ID: 2872618:user:proton MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Cc: Bitcoin Protocol Discussion Subject: Re: [bitcoin-dev] CTV BIP Meeting #9 Notes X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 May 2022 23:48:03 -0000 Good morning fd0, > > In addition, covenant mechanisms that require large witness data are pr= obably more vulnerable to MEV. > > > Which covenant mechanisms require large witness data? `OP_CSFS` + `OP_CAT`, which requires that you copy parts of the transaction= into the witness data if you want to use it for covenants. And the script itself is in the witness data, and AFAIK `OP_CSFS` needs lar= ge scripts if used for covenants. Arguably though `OP_CSFS` is not designed for covenants, it just *happens t= o enable* covenants when you throw enough data at it. If we are going to tolerate recursive covenants, we might want an opcode th= at explicitly supports recursion, instead of one that happens to enable rec= ursive covenants, because the latter is likely to require more data to be p= ushed on the witness stack. E.g. instead of the user having to quine the script (i.e. the script is rea= lly written twice, so it ends up doubling the witness size of the SCRIPT pa= rt), make an explicitly quining opcode. Basically, Do not Repeat Yourself. Regards, ZmnSCPxj