From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id F338A7AA for ; Wed, 5 Oct 2016 02:15:58 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-wm0-f54.google.com (mail-wm0-f54.google.com [74.125.82.54]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 78971134 for ; Wed, 5 Oct 2016 02:15:58 +0000 (UTC) Received: by mail-wm0-f54.google.com with SMTP id p138so245706924wmb.1 for ; Tue, 04 Oct 2016 19:15:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=/wc+9Ij4vMJmEzDUhmag6T3TjydkD/OZhGM1Xnkw96g=; b=tlHeRXoT8HHw/e0luYxde/yQeR8MNR3lA1L7QWVN5DM5oq/nB1tYjs5vP//bU3WOLa 39GEZ9KI7Ao+wEn0ou3nln6CcAqFlM25l9kjnmuya0tOHE5eKKIAleuBYKj3nQ9iuaXg okCcTA+HoAOKzddW6RX4xgpjA06zQYmWOiFBtaqN/hWdIimNdt4qKpqi8IImiqsqFYZQ NdSS8vonq6W3A3KfukknleYTM3P7yQrdipEg/voaAg4EErzrYvILwdCB/8N0PytkGXto VDPEONy9xWw2H4kSC+nsYw5kj3XZ+/6wGfrj5fVm9XNY8DrqsDoClVxhISLxgOpf9PXR Vy0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=/wc+9Ij4vMJmEzDUhmag6T3TjydkD/OZhGM1Xnkw96g=; b=D2YgPvgSf09qph9I2LgeqTKG1JMA1RNkSGTLkA6q/DmeKEc4peZdLOfDOt4CvIQ8sT Hnzp1DPu2C9VU30CFtSajaP7UlFJ2vRN1DxghjaefNFWMSBojliYl+2f7BD/AmgRVooM oNtp/5ubNFOetqLb6MAzvYZP3cXmDM8lgExuhozfqp03ffO0N7yO1oArxJUJft/5U9+C yrT3J6MV801mrlB6iZYHmSGMbVSiW6W7r1LMpW16l/u/WHdP3p2O9EZLcv/rlJ4SdMiS ED3Yc8uIc1IEOAPRCwQucm0j0Pd0EguWyJEThrCRenMc3XYeJazwt1w8/KznjZVKVrXF ldew== X-Gm-Message-State: AA6/9RkkNDlOQmMYZSAVh6QR1f0vKc80LqHWKyF7NXObqNa4iS/9RXrWrjDFbb5zvnyD5QaWVrcWsE5sZFjbwg== X-Received: by 10.28.65.10 with SMTP id o10mr5065503wma.99.1475633757144; Tue, 04 Oct 2016 19:15:57 -0700 (PDT) MIME-Version: 1.0 Received: by 10.194.236.2 with HTTP; Tue, 4 Oct 2016 19:15:36 -0700 (PDT) In-Reply-To: <201610010502.09524.luke@dashjr.org> References: <201609230957.03138.luke@dashjr.org> <87oa34d8fz.fsf@rustcorp.com.au> <201610010502.09524.luke@dashjr.org> From: Nathan Cook Date: Wed, 5 Oct 2016 05:15:36 +0300 Message-ID: To: Luke Dashjr , Bitcoin Protocol Discussion Content-Type: multipart/alternative; boundary=001a1148e8cae9d1eb053e14c152 X-Spam-Status: No, score=-1.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, HTML_MESSAGE, RCVD_IN_DNSWL_NONE, RCVD_IN_SORBS_SPAM autolearn=no 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, 05 Oct 2016 02:17:36 +0000 Subject: Re: [bitcoin-dev] BIP draft: OP_CHECKBLOCKATHEIGHT X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 05 Oct 2016 02:15:59 -0000 --001a1148e8cae9d1eb053e14c152 Content-Type: text/plain; charset=UTF-8 On 1 October 2016 at 08:02, Luke Dashjr via bitcoin-dev < bitcoin-dev@lists.linuxfoundation.org> wrote: > On Saturday, October 01, 2016 4:01:04 AM Rusty Russell wrote: > > > - Otherwise of hash is compared to lower of blockhash. > > Lower in what endian? Why only that endian? Why only lower? I can see a > possible use case where one wants to look at only the high bits to ensure > their transaction is only valid in a block with at least a certain > difficulty... Why not use segwit versioning for all this stuff? That lets you re-enable the bitwise operations like OP_AND, permitting arbitrary bit-masks. Further, the "at least a certain difficulty" problem suggests a solution by extending the validity of opcodes like OP_LESSTHAN etc. to 256-bit inputs. --001a1148e8cae9d1eb053e14c152 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

= On 1 October 2016 at 08:02, Luke Dashjr via bitcoin-dev &= lt;bitcoin-dev@lists.linuxfoundation.org> wrote:
On Saturday= , October 01, 2016 4:01:04 AM Rusty Russell wrote:

> - Otherwise <bits> of hash is compared to lower <bits> of = blockhash.

Lower in what endian? Why only that endian? Why only lower? I can se= e a
possible use case where one wants to look at only the high bits to ensure their transaction is only valid in a block with at least a certain
difficulty...

Why not use segwit versioning= for all this stuff? That lets you re-enable the bitwise operations like OP= _AND, permitting arbitrary bit-masks. Further, the "at least a certain= difficulty" problem suggests a solution by extending the validity of = opcodes like OP_LESSTHAN etc. to 256-bit inputs.
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