diff options
| author | Martin Habovštiak <martin.habovstiak@gmail.com> | 2025-04-01 17:35:53 +0200 |
|---|---|---|
| committer | bitcoindev <bitcoindev@googlegroups.com> | 2025-04-01 15:38:38 -0700 |
| commit | 8ac86c6b9b65e009b7442f97368db59b8ac6f20b (patch) | |
| tree | 74b6ae27fe56cd68db6130ba59bc81f92f2e5487 | |
| parent | 9d37e85d1b395e29f152d1ea8056a95799065787 (diff) | |
| download | pi-bitcoindev-master.tar.gz pi-bitcoindev-master.zip | |
| -rw-r--r-- | 91/1e4d9153589d98366e09239cd6bb4744605535 | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/91/1e4d9153589d98366e09239cd6bb4744605535 b/91/1e4d9153589d98366e09239cd6bb4744605535 new file mode 100644 index 000000000..b458f004c --- /dev/null +++ b/91/1e4d9153589d98366e09239cd6bb4744605535 @@ -0,0 +1,339 @@ +Delivery-date: Tue, 01 Apr 2025 15:38:38 -0700 +Received: from mail-oo1-f55.google.com ([209.85.161.55]) + by mail.fairlystable.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 + (Exim 4.94.2) + (envelope-from <bitcoindev+bncBDZPZFXW2IMRBY6VWG7QMGQEQ7HKREI@googlegroups.com>) + id 1tzkFh-0000nH-5D + for bitcoindev@gnusha.org; Tue, 01 Apr 2025 15:38:38 -0700 +Received: by mail-oo1-f55.google.com with SMTP id 006d021491bc7-603fd09171bsf321327eaf.1 + for <bitcoindev@gnusha.org>; Tue, 01 Apr 2025 15:38:37 -0700 (PDT) +ARC-Seal: i=2; a=rsa-sha256; t=1743547111; cv=pass; + d=google.com; s=arc-20240605; + b=ifLSYKyV+ZmQl/VTBFaFhkktYXDcL/VcMTQ8Thm5+MHAxx3tmk1lMZpDY+Tu6/cTgm + TDL3frG7NYzDgM9/tl5kolxwKsA0UArv7QHVR0sVlFC4Rl/u5/VvXc3e5VYNANH8k1s+ + PzoaB+OV9dJ/Tm7l7sNMQzAjl8od10n2A9XqYXChfT+8ALrdKap1fFwFUGDvFgWHwiJM + mEJHp1Jk+/owYbRF71YY0wCFQbqBuEDucHk/Bh6nQ+2W9qXcqG6VqF8L3nLH8fHLedIx + Cuij8TVHQQQskLDE1kDw6PiQyy7j16NC+MGmPQcZOD+XDovc0yasUrK8aneb+8yhMtrf + uQpA== +ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20240605; + h=list-unsubscribe:list-subscribe:list-archive:list-help:list-post + :list-id:mailing-list:precedence:cc:to:subject:message-id:date:from + :in-reply-to:references:mime-version:sender:dkim-signature + :dkim-signature; + bh=PFjfduBnjzsQkzi2DI5PY5AK3iMzVsUFQwg9ojp2GPA=; + fh=WmXfssJedKHy9Vzrl/7g1B6T6W4WapF59YdUBaRh61k=; + b=OH/yCEprhVOCD3SNFTWlYahUWbjJnAwqiTXEyz/QCBLl0xlfyQ4ByQJw83YJooSN7r + oxNOClVaOeFy8bNAnOXd388CS/y945RN7BAnbmw4ppuqGyP4Nmes7kyBW94jl8U+lcyM + +OzWoKIqB/4VmfQ6WJ+IvgA6aRAeC85ziJpC5P/iXUtH8tO3vtUjsUngBiXGaG7vBPoB + nig3EHyvuVwawZLPLG84WA9kf4nePjWMTYAJRorkV9SZTeUbS4FKG/Y5RZnP0jfr+QMd + GBB27ea3LMOJMJpvP/u5RXXOw7DrTcOV2Xx/psZgFsMYL8CRYJO/aUg9zjTULfPeobSu + hNhQ==; + darn=gnusha.org +ARC-Authentication-Results: i=2; gmr-mx.google.com; + dkim=pass header.i=@gmail.com header.s=20230601 header.b="fl5PD/ud"; + spf=pass (google.com: domain of martin.habovstiak@gmail.com designates 2607:f8b0:4864:20::736 as permitted sender) smtp.mailfrom=martin.habovstiak@gmail.com; + dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com; + dara=pass header.i=@googlegroups.com +DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; + d=googlegroups.com; s=20230601; t=1743547111; x=1744151911; darn=gnusha.org; + h=list-unsubscribe:list-subscribe:list-archive:list-help:list-post + :list-id:mailing-list:precedence:x-original-authentication-results + :x-original-sender:cc:to:subject:message-id:date:from:in-reply-to + :references:mime-version:sender:from:to:cc:subject:date:message-id + :reply-to; + bh=PFjfduBnjzsQkzi2DI5PY5AK3iMzVsUFQwg9ojp2GPA=; + b=f74r+UbNfw/kaXInHHKkM70b7mIEsBNbf0iIXRqM/RzrLgivstGCgbEIsgvIL33M2d + 9m3Hb0jiKwTDCQzAHzRloKtdxMvLBgKN8TRERq0NcMmX7abOxxmvTL6komNiXgkFCoGN + 6vVDU92MQNbiX81niYaj9I+AIl1U2XF2VXpNyPmxjAurxHH4qqa4GpYOC1hqVeMUCjzd + td9p2I1I1R8rTz77dFdFmqU222SMEcsdaVExFexre8JS8EO4FBjZ1UpxOlvwUtB1kf7K + CekZo0CxrYJawB8AulOv/OD4wOJaNsXuC3mvee8DCZWxqXDGXjYx+eaJ9zFolaSYTEmg + KIGg== +DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; + d=gmail.com; s=20230601; t=1743547111; x=1744151911; darn=gnusha.org; + h=list-unsubscribe:list-subscribe:list-archive:list-help:list-post + :list-id:mailing-list:precedence:x-original-authentication-results + :x-original-sender:cc:to:subject:message-id:date:from:in-reply-to + :references:mime-version:from:to:cc:subject:date:message-id:reply-to; + bh=PFjfduBnjzsQkzi2DI5PY5AK3iMzVsUFQwg9ojp2GPA=; + b=h69kNIBP914h3Q/a4rs3KzbNiHGDCG4ryS5FOWVXRijBEjuAtug0H/ic1z+Jy72h2n + 4nMZsiAIlq6DFVqa4ABQU3tIjkxrvjEquapbvRWZYT08rnzrcxeQx0SBwCDhdXqBIxhE + 4qkYcz5Ji/GqpECfTk+8oBv22OdeeKTb17Vo1IGWAYkgcUPaEdq3ZTcjQKoGPqGVdnp7 + qlTpfy50UEJ3TgaoRfOFjgbs9ZrN//ORTDIgYulOMiHP0HQ9QfJ9V3yJIJI33NS/PVRF + hnx2Me6iZBBTNYSDGDkPZ9Vp1UPQPuyfI165Dypug3/msoe3WKQPG7aQRFNBZTzmm/iP + c3dA== +X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; + d=1e100.net; s=20230601; t=1743547111; x=1744151911; + h=list-unsubscribe:list-subscribe:list-archive:list-help:list-post + :list-id:mailing-list:precedence:x-original-authentication-results + :x-original-sender:cc:to:subject:message-id:date:from:in-reply-to + :references:mime-version:x-beenthere:x-gm-message-state:sender:from + :to:cc:subject:date:message-id:reply-to; + bh=PFjfduBnjzsQkzi2DI5PY5AK3iMzVsUFQwg9ojp2GPA=; + b=oErK5kz6rCA26hRaYdH9/bSnEqPPlTDNAjd8X8b2pnOt3uYkvYjh7r/jT+aAr0pwjP + CYPk6O1DSdRL1ecz5/JqFqQWo7Giyj91Yu0UVNPXJtcGTVBMk6XtoBtZYmwAd6nr49dM + dXxvcUqJQp8W4iqVi4JlsimiyerJuAlLnoYTs8yJE5kA6Zh7BsKxRdAFY07N9oFpHrku + 5nZTSpnT9rIOv8X25wkE4fSWCvjHuLHrdU2GXOIOhQWcK6ZchlZtT9APqhWX4iz8PiQA + VqjqvmuFZzqq3dobS1mwrhzg2FfRYCUJQYdFgkib2XnTiA2lXAWWcZIaJ/pC78nA+IFA + lFvw== +Sender: bitcoindev@googlegroups.com +X-Forwarded-Encrypted: i=2; AJvYcCWqrTP+XKcBgWnuAJH5Zw2azyLXk/QZOZOF1XrBhUjAHnMq0UmgkpolSnqT+lt4rkCXfytJNyoJxEJL@gnusha.org +X-Gm-Message-State: AOJu0YyZekHJirUbadFCHYMHHacNgDtybI9hsNunsWZUQvyvTXqeQ2F2 + 9dU4kOuWFi4haOBVIK+VDMo7nM6YDA9IHxajSdWOJ0CUJuq7VrS6 +X-Google-Smtp-Source: AGHT+IHYNI0EWh0lIAoM8JXTvRLg30APZrwgr8eDQT2Umej4wgik6dAGeUkssN39h8tk1451iORgyA== +X-Received: by 2002:a05:6820:2107:b0:603:f777:9801 with SMTP id 006d021491bc7-603f7779c95mr2088125eaf.3.1743547111003; + Tue, 01 Apr 2025 15:38:31 -0700 (PDT) +X-BeenThere: bitcoindev@googlegroups.com; h=ARLLPALZ66IIHkeinGsjmtfFzN9sYIB1V1+5ulGR8BYyeJrZ9A== +Received: by 2002:a4a:a641:0:b0:603:be8f:a31e with SMTP id 006d021491bc7-603be8fa5c8ls667467eaf.1.-pod-prod-08-us; + Tue, 01 Apr 2025 15:38:27 -0700 (PDT) +X-Forwarded-Encrypted: i=2; AJvYcCUKl9pHxZZYLZmu8hCKaayyYPITelChzTXj/IT4vUpA86/P2ARJXO6a+Az4BFnmUXxvmPWQRRS0J0ar@googlegroups.com +X-Received: by 2002:a05:6808:2019:b0:3fe:ab15:5e93 with SMTP id 5614622812f47-3ff0f524c93mr9182358b6e.11.1743547107585; + Tue, 01 Apr 2025 15:38:27 -0700 (PDT) +Received: by 2002:a05:6808:985:b0:3fa:6f09:b173 with SMTP id 5614622812f47-3feefbac77emsb6e; + Tue, 1 Apr 2025 08:36:05 -0700 (PDT) +X-Forwarded-Encrypted: i=2; AJvYcCXjxoCibe7zW6VnL+ja4KgqTpbKCw7G82en5Ygdx8E5kwIoBoLaRiIxza+sidqGt52GML5u8AowSfh9@googlegroups.com +X-Received: by 2002:a17:90b:2e07:b0:2ee:53b3:3f1c with SMTP id 98e67ed59e1d1-30531f7c07cmr19794566a91.5.1743521764783; + Tue, 01 Apr 2025 08:36:04 -0700 (PDT) +ARC-Seal: i=1; a=rsa-sha256; t=1743521764; cv=none; + d=google.com; s=arc-20240605; + b=NITLkxzZva/ZZNMPhpL7chQEXMhHFxc5gZJB2yS2KAFrq+5ALcsyO0CZs+5W3p+nb1 + EnT0p8zV/Wwg6C8BEhcQa/9aQ3uZjQ4EM3xY10LnKqkd/ZcHVKyh3m46xL77Ty5fzrFy + qMn6j/aQhK07E2nRfyxnsb9vyOC4akia/x/On4SPssEodjeN04uJ3g0d/6GRfbxUNS4A + nJ6JnIQLz3M6ticGF/zlWqrP9MJrtLF4HHQypD9AQccK33snIZaje0daSW52JowFuHyS + rcQsF9vb0jxWiONr95V5Wt2YD3v4npiQJimEoCGN83maoGb0CMm+3lQEk76H5QEY/sXo + Z60w== +ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20240605; + h=cc:to:subject:message-id:date:from:in-reply-to:references + :mime-version:dkim-signature; + bh=r2K2TgMkVJjTLkR4tG9GmvR/WYaTX9V++QzBCL7n0PM=; + fh=UslS9DHPkWd0noc2pTWy5Ft6VFWJ5hH0DY6AiDFuLK8=; + b=gQAflzQw50Gv1svmOUE3AAt6oWuXRwbcsmGYXQb/BEhKFHsZ+nkN8CdutqOvY7rwzg + Qkr3QUR7ec59oPkV65WCXXleNWIbhec1RGvzYDAgTVYy5k44qWg3cKP7oYbsynJoZbHT + eDLCzZydry0koPOc9tHSBt2Vh6/pB2Oe6YMXiiwfHoIw0jOHoVbfATHtv+H9OoLONUPC + 1YprVF/dJzEIz7RSFUi05UsGlrrBQfojD6k0rQPWDfouE4AKFN0QlNGWO9r72YjAakBo + k3nuXznLRe4rg9OBz3Y3gOa1YdHN9ZMUf7P0/s8XjI1LJJK5pJZlRY9jvFuaqMKu8IUV + bF9Q==; + dara=google.com +ARC-Authentication-Results: i=1; gmr-mx.google.com; + dkim=pass header.i=@gmail.com header.s=20230601 header.b="fl5PD/ud"; + spf=pass (google.com: domain of martin.habovstiak@gmail.com designates 2607:f8b0:4864:20::736 as permitted sender) smtp.mailfrom=martin.habovstiak@gmail.com; + dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com; + dara=pass header.i=@googlegroups.com +Received: from mail-qk1-x736.google.com (mail-qk1-x736.google.com. [2607:f8b0:4864:20::736]) + by gmr-mx.google.com with ESMTPS id d9443c01a7336-2291eed881fsi5283895ad.1.2025.04.01.08.36.04 + for <bitcoindev@googlegroups.com> + (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); + Tue, 01 Apr 2025 08:36:04 -0700 (PDT) +Received-SPF: pass (google.com: domain of martin.habovstiak@gmail.com designates 2607:f8b0:4864:20::736 as permitted sender) client-ip=2607:f8b0:4864:20::736; +Received: by mail-qk1-x736.google.com with SMTP id af79cd13be357-7c559b3eb0bso328406785a.1 + for <bitcoindev@googlegroups.com>; Tue, 01 Apr 2025 08:36:04 -0700 (PDT) +X-Forwarded-Encrypted: i=1; AJvYcCX+QOTXsEHXmJerV8H+y4MBW28nlYkf1GjsBKNx3+ld0sRQX5g/vNnGWELurtxNY+6XIwHqOnykQZ7+@googlegroups.com +X-Gm-Gg: ASbGncsWq/6CPiIRIdS0+BrKDal09fQIiShz+NaHw0YUSZ+d+Nz+MQlwxUYaD3HWz2B + pPIeeeuA9qlbUWOBih0smV4K+jGlwRQMJB6FwyxOVovh8IovT/wY0ghrWcKsxAteQB2Xs1QNMjA + Tao1vyR0SWUY1zd+vddJ3t9PMhiQ== +X-Received: by 2002:a05:620a:4544:b0:7c0:9f12:2b7e with SMTP id + af79cd13be357-7c6862ebcdemr1758761285a.11.1743521764058; Tue, 01 Apr 2025 + 08:36:04 -0700 (PDT) +MIME-Version: 1.0 +References: <f844a85e-8be8-4429-8687-bc19dd4b96ffn@googlegroups.com> + <Z9hTu2TjMlLr5-Eg@petertodd.org> <678d40e3-3e22-4d55-82c0-b25ccafb87ecn@googlegroups.com> + <CAD2YOAp=ft+pApAwh6CQvwMpujfZ0ysSK+=7zKA64nBeB5w3nA@mail.gmail.com> + <8c823e50-197e-479c-8651-9e0407a4168en@googlegroups.com> <b4594133-e6e5-438b-aa56-98d6171296fan@googlegroups.com> + <e8c30db7-b509-4fbd-93ef-0bca0313003cn@googlegroups.com> <frERrHlzWhpskJw74fBQorSrXEaBP1d4XBUgM-Nkww_2ulhc7i2Lqmu2kcAlvh5fd7LzYiBmX5HNBtg7Ownbsa0KZ26ihfJjri6R01kuozA=@wuille.net> +In-Reply-To: <frERrHlzWhpskJw74fBQorSrXEaBP1d4XBUgM-Nkww_2ulhc7i2Lqmu2kcAlvh5fd7LzYiBmX5HNBtg7Ownbsa0KZ26ihfJjri6R01kuozA=@wuille.net> +From: =?UTF-8?Q?Martin_Habov=C5=A1tiak?= <martin.habovstiak@gmail.com> +Date: Tue, 1 Apr 2025 17:35:53 +0200 +X-Gm-Features: AQ5f1Jonb64K8xwBCp_kuJq8yZNRre_fWTfTsBymB-tWsSBmqhpWzVEB--Uz7xU +Message-ID: <CALkkCJb1RdC646q1QrOP+yQut7EG4NLJNm3cyxW4S1=Ex1NBmQ@mail.gmail.com> +Subject: =?UTF-8?Q?Re=3A_=5Bbitcoindev=5D_New_Proposal=EF=BC=9AString_Substring_Sea?= + =?UTF-8?Q?rch_in_Bitcoin_Script_=2D_OP=5FISSUBSTR?= +To: Pieter Wuille <bitcoin-dev@wuille.net> +Cc: Javier Mateos <javierpmateos@gmail.com>, + Bitcoin Development Mailing List <bitcoindev@googlegroups.com> +Content-Type: multipart/alternative; boundary="00000000000067ab4a0631b94b28" +X-Original-Sender: martin.habovstiak@gmail.com +X-Original-Authentication-Results: gmr-mx.google.com; dkim=pass + header.i=@gmail.com header.s=20230601 header.b="fl5PD/ud"; spf=pass + (google.com: domain of martin.habovstiak@gmail.com designates + 2607:f8b0:4864:20::736 as permitted sender) smtp.mailfrom=martin.habovstiak@gmail.com; + dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com; + dara=pass header.i=@googlegroups.com +Precedence: list +Mailing-list: list bitcoindev@googlegroups.com; contact bitcoindev+owners@googlegroups.com +List-ID: <bitcoindev.googlegroups.com> +X-Google-Group-Id: 786775582512 +List-Post: <https://groups.google.com/group/bitcoindev/post>, <mailto:bitcoindev@googlegroups.com> +List-Help: <https://groups.google.com/support/>, <mailto:bitcoindev+help@googlegroups.com> +List-Archive: <https://groups.google.com/group/bitcoindev +List-Subscribe: <https://groups.google.com/group/bitcoindev/subscribe>, <mailto:bitcoindev+subscribe@googlegroups.com> +List-Unsubscribe: <mailto:googlegroups-manage+786775582512+unsubscribe@googlegroups.com>, + <https://groups.google.com/group/bitcoindev/subscribe> +X-Spam-Score: -0.5 (/) + +--00000000000067ab4a0631b94b28 +Content-Type: text/plain; charset="UTF-8" +Content-Transfer-Encoding: quoted-printable + +Hi, + +I was dismissing the proposal for the same reason you do but it just +occurred to me that substrings might be better than OP_CAT because it's +possible to make them unabusable without any arbitrary limit on item size. + +The idea is to store stack elements on the heap inside struct { ref_count, +length, data[] } and put struct { pointer_to_item, position, length } on +the stack. (Rust developers may be familiar with the `bytes` crate that +does this.) +Substring operations would only duplicate the pointers with adjusted +position and length so there's no way to blow up the stack using them. + +Of course there's an exception if OP_SHA256 is used on a shorter slice but +the same is true today - you can already write OP_ZERO OP_SHA256 OP_DUP +OP_DUP... + +Funnily, this can be used to optimize OP_DUP as well which would now add +constant amount of memory, so the "exploit" above would need to use two +bytes per every large object. + +Anyway, while I would personally prefer not having arbitrary limits on item +sizes, since the limit is already there, it might not matter. I guess +something worth considering if any other future soft fork somehow enables +larger items. + +Have a nice day! + +Martin + + +D=C5=88a ut 1. 4. 2025, 16:49 Pieter Wuille <bitcoin-dev@wuille.net> nap=C3= +=ADsal(a): + +> On Monday, March 31st, 2025 at 4:41 PM, Javier Mateos < +> javierpmateos@gmail.com> wrote: +> +> The solution of splitting the string and using OP_CAT only works if the +> exact position of the substring is known. How would a case be handled whe= +re +> the substring could be in any position +> +> +> Whoever produces the signature/witness for spending the coin always knows +> the position already, so the script can always be modified to instead tak= +e +> that position as an additional input. +> +> This is a general principle: the point of scripts is verifying provided +> information, not computing it. As another example, this means that there = +is +> no need for a division or square root opcode if one has a multiplication +> opcode. +> +> -- +> Pieter +> +> -- +> You received this message because you are subscribed to the Google Groups +> "Bitcoin Development Mailing List" group. +> To unsubscribe from this group and stop receiving emails from it, send an +> email to bitcoindev+unsubscribe@googlegroups.com. +> To view this discussion visit +> https://groups.google.com/d/msgid/bitcoindev/frERrHlzWhpskJw74fBQorSrXEaB= +P1d4XBUgM-Nkww_2ulhc7i2Lqmu2kcAlvh5fd7LzYiBmX5HNBtg7Ownbsa0KZ26ihfJjri6R01k= +uozA%3D%40wuille.net +> <https://groups.google.com/d/msgid/bitcoindev/frERrHlzWhpskJw74fBQorSrXEa= +BP1d4XBUgM-Nkww_2ulhc7i2Lqmu2kcAlvh5fd7LzYiBmX5HNBtg7Ownbsa0KZ26ihfJjri6R01= +kuozA%3D%40wuille.net?utm_medium=3Demail&utm_source=3Dfooter> +> . +> +> + +--=20 +You received this message because you are subscribed to the Google Groups "= +Bitcoin Development Mailing List" group. +To unsubscribe from this group and stop receiving emails from it, send an e= +mail to bitcoindev+unsubscribe@googlegroups.com. +To view this discussion visit https://groups.google.com/d/msgid/bitcoindev/= +CALkkCJb1RdC646q1QrOP%2ByQut7EG4NLJNm3cyxW4S1%3DEx1NBmQ%40mail.gmail.com. + +--00000000000067ab4a0631b94b28 +Content-Type: text/html; charset="UTF-8" +Content-Transfer-Encoding: quoted-printable + +<div dir=3D"auto">Hi,<div dir=3D"auto"><br></div><div dir=3D"auto">I was di= +smissing the proposal for the same reason you do but it just occurred to me= + that substrings might be better than OP_CAT because it's possible to m= +ake them unabusable without any arbitrary limit on item size.</div><div dir= +=3D"auto"><br></div><div dir=3D"auto">The idea is to store stack elements o= +n the heap inside struct { ref_count, length, data[] } and put struct { poi= +nter_to_item, position, length } on the stack. (Rust developers may be fami= +liar with the `bytes` crate that does this.)</div><div dir=3D"auto">Substri= +ng operations would only duplicate the pointers with adjusted position and = +length so there's no way to blow up the stack using them.</div><div dir= +=3D"auto"><br></div><div dir=3D"auto">Of course there's an exception if= + OP_SHA256 is used on a shorter slice but the same is true today - you can = +already write OP_ZERO OP_SHA256 OP_DUP OP_DUP...</div><div dir=3D"auto"><br= +></div><div dir=3D"auto">Funnily, this can be used to optimize OP_DUP as we= +ll which would now add constant amount of memory, so the "exploit"= +; above would need to use two bytes per every large object.</div><div dir= +=3D"auto"><br></div><div dir=3D"auto">Anyway, while I would personally pref= +er not having arbitrary limits on item sizes, since the limit is already th= +ere, it might not matter. I guess something worth considering if any other = +future soft fork somehow enables larger items.</div><div dir=3D"auto"><br><= +/div><div dir=3D"auto">Have a nice day!</div><div dir=3D"auto"><br></div><d= +iv dir=3D"auto">Martin</div><br><br><div class=3D"gmail_quote gmail_quote_c= +ontainer" dir=3D"auto"><div dir=3D"ltr" class=3D"gmail_attr">D=C5=88a ut 1.= + 4. 2025, 16:49 Pieter Wuille <<a href=3D"mailto:bitcoin-dev@wuille.net"= +>bitcoin-dev@wuille.net</a>> nap=C3=ADsal(a):<br></div><blockquote class= +=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padd= +ing-left:1ex"><div style=3D"font-family:Arial,sans-serif;font-size:14px"><d= +iv><div> + On Monday, March 31st, 2025 at 4:41 PM, Javier Mateos <<a href= +=3D"mailto:javierpmateos@gmail.com" target=3D"_blank" rel=3D"noreferrer">ja= +vierpmateos@gmail.com</a>> wrote:<br> + <blockquote type=3D"cite"><div> + The solution of splitting the string and using OP_CAT only + works if the exact position of the substring is known. How would a case + be handled where the substring could be in any position</div></blockquote>= +<div><br></div><div>Whoever + produces the signature/witness for spending the coin always knows the=20 +position already, so the script can always be modified to instead take=20 +that position as an additional input.</div><div><br></div><div>This is a + general principle: the point of scripts is verifying provided=20 +information, not computing it. As another example, this means that there + is no need for a division or square root opcode if one has a=20 +multiplication opcode.</div><div><br></div><div>-- <br></div><div>Pieter</d= +iv><br></div></div></div> + +<p></p> + +-- <br> +You received this message because you are subscribed to the Google Groups &= +quot;Bitcoin Development Mailing List" group.<br> +To unsubscribe from this group and stop receiving emails from it, send an e= +mail to <a href=3D"mailto:bitcoindev+unsubscribe@googlegroups.com" target= +=3D"_blank" rel=3D"noreferrer">bitcoindev+unsubscribe@googlegroups.com</a>.= +<br> +To view this discussion visit <a href=3D"https://groups.google.com/d/msgid/= +bitcoindev/frERrHlzWhpskJw74fBQorSrXEaBP1d4XBUgM-Nkww_2ulhc7i2Lqmu2kcAlvh5f= +d7LzYiBmX5HNBtg7Ownbsa0KZ26ihfJjri6R01kuozA%3D%40wuille.net?utm_medium=3Dem= +ail&utm_source=3Dfooter" target=3D"_blank" rel=3D"noreferrer">https://g= +roups.google.com/d/msgid/bitcoindev/frERrHlzWhpskJw74fBQorSrXEaBP1d4XBUgM-N= +kww_2ulhc7i2Lqmu2kcAlvh5fd7LzYiBmX5HNBtg7Ownbsa0KZ26ihfJjri6R01kuozA%3D%40w= +uille.net</a>.<br><br> +</blockquote></div></div> + +<p></p> + +-- <br /> +You received this message because you are subscribed to the Google Groups &= +quot;Bitcoin Development Mailing List" group.<br /> +To unsubscribe from this group and stop receiving emails from it, send an e= +mail to <a href=3D"mailto:bitcoindev+unsubscribe@googlegroups.com">bitcoind= +ev+unsubscribe@googlegroups.com</a>.<br /> +To view this discussion visit <a href=3D"https://groups.google.com/d/msgid/= +bitcoindev/CALkkCJb1RdC646q1QrOP%2ByQut7EG4NLJNm3cyxW4S1%3DEx1NBmQ%40mail.g= +mail.com?utm_medium=3Demail&utm_source=3Dfooter">https://groups.google.com/= +d/msgid/bitcoindev/CALkkCJb1RdC646q1QrOP%2ByQut7EG4NLJNm3cyxW4S1%3DEx1NBmQ%= +40mail.gmail.com</a>.<br /> + +--00000000000067ab4a0631b94b28-- + |