From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id E0580C000E for ; Mon, 5 Jul 2021 02:10:31 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id B0133403F7 for ; Mon, 5 Jul 2021 02:10:31 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org X-Spam-Flag: NO X-Spam-Score: -1.9 X-Spam-Level: X-Spam-Status: No, score=-1.9 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no Authentication-Results: smtp4.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=blockstream-com.20150623.gappssmtp.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 TuMlg1QaJMTT for ; Mon, 5 Jul 2021 02:10:30 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.8.0 Received: from mail-qv1-xf32.google.com (mail-qv1-xf32.google.com [IPv6:2607:f8b0:4864:20::f32]) by smtp4.osuosl.org (Postfix) with ESMTPS id 422E240371 for ; Mon, 5 Jul 2021 02:10:30 +0000 (UTC) Received: by mail-qv1-xf32.google.com with SMTP id j14so7641662qvu.6 for ; Sun, 04 Jul 2021 19:10:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=blockstream-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=CbQgUasHtmW3a5ddC8Wg/WaLSewb8sMsityccABrdQU=; b=lOIt2J8GcMrUQVIrRAWD75WfzH1zw7ldQO5BdQRqhvprydEdqkt6miOQIsSXA6QHm1 8AzPJMGy+gFS5iu1taFkO+cRW6wZT8p9TGR0kQXtOzdjdsVI2Yy43QwgypuNB3iZogde j25XyGuCwGBjbbKTie4vuuT258s2/Mhq2kTmpqia+HB0Z4WByY+rH+UHbwP6UfQVrrJO 3wTmUOOaiFG0vQ2+FdmqS+o+BU2z41aw7o93ASGslHkpoTyKWXDO8CixtrUNQ+zcJ0D7 EtWCxLZfdjrRI/3qRDuvdefLgOxwfXhOGug5f7z10kWXBuFOt1dMtQ1ugwEWqRvsrLcZ b4HQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=CbQgUasHtmW3a5ddC8Wg/WaLSewb8sMsityccABrdQU=; b=DMvaWBtYnGFPpZd5WRKC7b0uGzqPgV7v19N3ipap6nSRl+8lLuCagBSdcTD4ij16vh MYMn6lXtTUYVEX0OzL2TcwkYHRtzqCqImmVnwAtxAGV6JzUT6w2vq0HQZF90oFkAb5ui mjSulg+07v5mhuJmslQcCLsM6KyPqOhkqmvGR45jkYzYMIRkCcJeZShSIj5x7MnB09uJ nbeLsQ6JlVNkRbAECXoBzmPCWr/RrrzZnj+z13YLoJJaHf02WS3sCTsOWMu9+MLaQ0WR Sr4JUAFTPRtGJGPu6lNX7fvaajl/0bHJ74RNP+skvRq8rWFibQIE+gM+7tcv8owBnKGn zhRw== X-Gm-Message-State: AOAM531YpEfIOo9r9IOlPqHTrazHvOBGkidCk9QiDv9j8iA9JYEOHiUK VT4quFZ5zu82mfxMbxrviP6CcFJTH7DON4l0E4xWpQ== X-Google-Smtp-Source: ABdhPJwSDq3LhWmHkNXKCqaAKXpDbeTrRgNJPcdV/uqxyBUNj/fV8YFM3dyNaH91uZOvEcGgtqOm5/mDSNmIbU+uefU= X-Received: by 2002:a0c:eb51:: with SMTP id c17mr4548635qvq.13.1625451029027; Sun, 04 Jul 2021 19:10:29 -0700 (PDT) MIME-Version: 1.0 References: <20210704011341.ddbiruuomqovrjn6@ganymede> <20210704203230.37hlpdyzr4aijiet@ganymede> <5keA_aPvmCO5yBh_mBQ6Z5SwnnvEW0T-3vahesaDh57f-qv4FbG1SFAzDvT3rFhre6kFl282VsxV_pynwn_CdvF7fzH2q9NW1ZQHPH1pmdo=@protonmail.com> In-Reply-To: From: "Russell O'Connor" Date: Sun, 4 Jul 2021 22:10:17 -0400 Message-ID: To: ZmnSCPxj , Bitcoin Protocol Discussion Content-Type: multipart/alternative; boundary="0000000000002f71fd05c656cfb4" Subject: Re: [bitcoin-dev] Unlimited covenants, was Re: CHECKSIGFROMSTACK/{Verify} BIP for Bitcoin 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: Mon, 05 Jul 2021 02:10:32 -0000 --0000000000002f71fd05c656cfb4 Content-Type: text/plain; charset="UTF-8" On Sun, Jul 4, 2021 at 9:02 PM Russell O'Connor wrote: > Bear in mind that when people are talking about enabling covenants, we are > talking about whether OP_CAT should be allowed or not. > > That said, recursive covenants, the type that are most worrying, seems to > require some kind of OP_TWEAK operation, and I haven't yet seen any > evidence that this can be simulated with CHECKSIG(FROMSTACK). So maybe we > should leave such worries for the OP_TWEAK operation. > Upon further thought, you can probably make recursive covenants even with a fixed scritpubkey by sneaking the state into a few bits of the UTXO's amount. Or if you try really hard, you may be able to stash your state into a sibling output that is accessed via the txid embedded in the prevoutpoint. --0000000000002f71fd05c656cfb4 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Sun, Jul 4, 2021 at 9:02 PM Russell O'Connor <roconnor@blockstream.com> wrote:
=
Bear in mind that when people are talking about enabling covenants, we a= re talking about whether OP_CAT should be allowed or not.

That said, recursive covenants, the type that are most worrying, se= ems to require some kind of OP_TWEAK operation, and I haven't yet seen = any evidence that this can be simulated with CHECKSIG(FROMSTACK).=C2=A0 So = maybe we should leave such worries for the OP_TWEAK operation.

Upon further thought, you can probably = make recursive covenants even with a fixed scritpubkey by sneaking the stat= e into a few bits of the UTXO's amount.=C2=A0 Or if you try really hard= , you may be able to stash your state into a sibling output that is accesse= d via the txid embedded in the prevoutpoint.
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