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| author | Mark Friedenbach <mark@friedenbach.org> | 2017-09-20 12:29:17 -0700 |
|---|---|---|
| committer | bitcoindev <bitcoindev@gnusha.org> | 2017-09-20 19:29:22 +0000 |
| commit | 5ce5c96ca3a15634a6c28de3bb27e2389da2c429 (patch) | |
| tree | 5b1c6df4e8fd6a4a85ecf097eaa6cea90894138e | |
| parent | 2ebeb943f940445afb0ad2cb233ec9c7cf21695e (diff) | |
| download | pi-bitcoindev-5ce5c96ca3a15634a6c28de3bb27e2389da2c429.tar.gz pi-bitcoindev-5ce5c96ca3a15634a6c28de3bb27e2389da2c429.zip | |
Re: [bitcoin-dev] cleanstack alt stack & softfork improvements (Was: Merkle branch verification & tail-call semantics for generalized MAST)
| -rw-r--r-- | 4d/aaf979e4edead5b846edcc818bc9ffe88b1fd6 | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/4d/aaf979e4edead5b846edcc818bc9ffe88b1fd6 b/4d/aaf979e4edead5b846edcc818bc9ffe88b1fd6 new file mode 100644 index 000000000..171c5f31e --- /dev/null +++ b/4d/aaf979e4edead5b846edcc818bc9ffe88b1fd6 @@ -0,0 +1,125 @@ +Return-Path: <mark@friedenbach.org> +Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org + [172.17.192.35]) + by mail.linuxfoundation.org (Postfix) with ESMTPS id A6D44C87 + for <bitcoin-dev@lists.linuxfoundation.org>; + Wed, 20 Sep 2017 19:29:22 +0000 (UTC) +X-Greylist: whitelisted by SQLgrey-1.7.6 +Received: from mail-pg0-f42.google.com (mail-pg0-f42.google.com [74.125.83.42]) + by smtp1.linuxfoundation.org (Postfix) with ESMTPS id DF8164C3 + for <bitcoin-dev@lists.linuxfoundation.org>; + Wed, 20 Sep 2017 19:29:20 +0000 (UTC) +Received: by mail-pg0-f42.google.com with SMTP id k193so2222049pgc.8 + for <bitcoin-dev@lists.linuxfoundation.org>; + Wed, 20 Sep 2017 12:29:20 -0700 (PDT) +DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; + d=friedenbach-org.20150623.gappssmtp.com; s=20150623; + h=mime-version:subject:from:in-reply-to:date:cc + :content-transfer-encoding:message-id:references:to; + bh=ZFnKcKeD6kpy1vkKlJ5NdBlDHdgv85Jtl/6guABWqdg=; + b=Mi+5CmmkGimM62m2Xpd/6O+3IYoFeiG8eEnrzHPbsAef+NbD/aJr4FW1TChBAXcGLP + NWofC9itPcUCGdIwlOn101egD5Y5W3G3gdVeip4eXsJn/xBS5/g5OxYvyBW2hkpKfSnI + i5uxsp7MS9xSJxzNLfmcVo+ge9zWQJS1LXNkv4PwRGC8Rk415alrI8JIL5vMIG0NUzf6 + F1YhJs9/Vy9Q/G+z8SZP2lLEyXb90lwImUOCNlkAkdtGJFOcIXThAKumOT80ZCshoq4u + 0gZbMyOZso5y4t8ykqWAC4isUqw5mgTYVL+PqcOzTnpQ8TWzC7FOS+hOqJIx2GJMXBQl + j0Tw== +X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; + d=1e100.net; s=20161025; + h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc + :content-transfer-encoding:message-id:references:to; + bh=ZFnKcKeD6kpy1vkKlJ5NdBlDHdgv85Jtl/6guABWqdg=; + b=uHmRby7HUnBH+GsUuUGK5SNG7jzWrC6u8WUoY907rn4BWRLogpH2yPGO+LMB0K2k+Y + JFmLzdWU4/9FH2W6DRyBcW24wtWW3ZrSVUsAMzSYFqTvM000gVvTYNfnOJECDYkTvulW + /toqcYzt0FoKDRanBKfvJM2/EhwSo9nxctZKTyCcu6446PJZw1u0+uhnnKxrYu9iOdhI + T9RWrYM7FIPpP0srW28qA0ZOKLX0/K0YOVzZchMj8lFCbYGgVW5aroIZXIuul8RKDgR9 + UEGDquCbQlxC0t9wkSmqC/jvMpx07C0t84ExQgEOfV5LgBTeG7TDMSahxsVG4O4MnfJc + iJaw== +X-Gm-Message-State: AHPjjUjNc4R9SONlqoCgICE73yDjbc3n34rgAPIZlo24IhO4awhPBKlm + 9uzoXItGPJDx+/m+n5TPaUnUMF1qSmM= +X-Google-Smtp-Source: AOwi7QBV83bUqcjwXj9IXKJLGLAAWUcLoYZ9z1nJ6anFR2JjH+FWJ16PNd3cTzwOMezEJJLlqUQb7g== +X-Received: by 10.99.115.28 with SMTP id o28mr3258064pgc.374.1505935760327; + Wed, 20 Sep 2017 12:29:20 -0700 (PDT) +Received: from ?IPv6:2601:647:4600:9c66:ad56:e3e4:8af6:2572? + ([2601:647:4600:9c66:ad56:e3e4:8af6:2572]) + by smtp.gmail.com with ESMTPSA id 89sm9292476pfn.75.2017.09.20.12.29.18 + (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); + Wed, 20 Sep 2017 12:29:18 -0700 (PDT) +Content-Type: text/plain; charset=utf-8 +Mime-Version: 1.0 (Mac OS X Mail 10.3 \(3273\)) +From: Mark Friedenbach <mark@friedenbach.org> +In-Reply-To: <B8C5E7EF-9062-4431-9B63-06FF855B1D78@xbt.hk> +Date: Wed, 20 Sep 2017 12:29:17 -0700 +Content-Transfer-Encoding: quoted-printable +Message-Id: <34163C93-5F2C-4DC8-9FB2-7E28805C0184@friedenbach.org> +References: <5B6756D0-6BEF-4A01-BDB8-52C646916E29@friedenbach.org> + <C623794E-F061-4C7A-B05D-378798ED2BF7@friedenbach.org> + <201709190309.08669.luke@dashjr.org> + <B8C5E7EF-9062-4431-9B63-06FF855B1D78@xbt.hk> +To: Johnson Lau <jl2012@xbt.hk> +X-Mailer: Apple Mail (2.3273) +X-Spam-Status: No, score=0.0 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, + RCVD_IN_DNSWL_NONE autolearn=disabled version=3.3.1 +X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on + smtp1.linux-foundation.org +X-Mailman-Approved-At: Wed, 20 Sep 2017 22:54:58 +0000 +Cc: bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> +Subject: Re: [bitcoin-dev] cleanstack alt stack & softfork improvements + (Was: Merkle branch verification & tail-call semantics for generalized + MAST) +X-BeenThere: bitcoin-dev@lists.linuxfoundation.org +X-Mailman-Version: 2.1.12 +Precedence: list +List-Id: Bitcoin Protocol Discussion <bitcoin-dev.lists.linuxfoundation.org> +List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>, + <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe> +List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/> +List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org> +List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help> +List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>, + <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe> +X-List-Received-Date: Wed, 20 Sep 2017 19:29:22 -0000 + + +> On Sep 19, 2017, at 10:13 PM, Johnson Lau <jl2012@xbt.hk> wrote: +>=20 +> If we don=E2=80=99t want this ugliness, we could use a new script = +version for every new op code we add. In the new BIP114 (see link = +above), I suggest to move the script version to the witness, which is = +cheaper. + +To be clear, I don=E2=80=99t think it is so much that the version should = +be moved to the witness, but rather that there are two separate version = +values here =E2=80=94 one in the scriptPubKey which specifies the format = +and structure of the segwit commitment itself, and another in the = +witness which gates functionality in script or whatever else is used by = +that witness type. Segwit just unfortunately didn=E2=80=99t include the = +latter, an oversight that should be corrected on the on the next upgrade = +opportunity. + +The address-visible =E2=80=9Cscript version=E2=80=9D field should = +probably be renamed =E2=80=9Cwitness type=E2=80=9D as it will only be = +used in the future to encode how to check the witness commitment in the = +scriptPubKey against the data provided in the witness. Upgrades and = +improvements to the features supported by those witness types won=E2=80=99= +t require new top-level witness types to be defined. Defining a new = +opcode, even one with modifies the stack, doesn=E2=80=99t change the = +hashing scheme used by the witness type. + +v0,32-bytes is presently defined to calculate the double-SHA256 hash of = +the top-most serialized item on the stack, and compare that against the = +32-byte commitment value. Arguably it probably should have hashed the = +top two values, one of which would have been the real script version. = +This could be fixed however, even without introducing a new witness = +type. Do a soft-fork upgrade that checks if the witness redeem script is = +push-only, and if so then pop the last push off as the script version = +(>=3D 1), and concatenate the rest to form the actual redeem script. We = +inherit a little technical debt from having to deal with push limits, = +but we avoid burning v0 in an upgrade to v1 that does little more than = +add a script version. + +v1,32-bytes would then be used for a template version of MAST, or = +whatever other idea comes along that fundamentally changes the way the = +witness commitment is calculated. + +Mark= + |