From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id C29F0C016F for ; Mon, 8 Jun 2020 09:28:43 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id A579A2052B for ; Mon, 8 Jun 2020 09:28:43 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id og0oV4exTog9 for ; Mon, 8 Jun 2020 09:28:42 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-lj1-f194.google.com (mail-lj1-f194.google.com [209.85.208.194]) by silver.osuosl.org (Postfix) with ESMTPS id C771D2051A for ; Mon, 8 Jun 2020 09:28:41 +0000 (UTC) Received: by mail-lj1-f194.google.com with SMTP id y11so17911730ljm.9 for ; Mon, 08 Jun 2020 02:28:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=88WSRCxVkAX9LtoIW14+VJJwdS0Qzo2bK/UdgMEeq+o=; b=LK18xC5DPMrECNBnSCFENcv7uCqgZvTmqOEWr6A+0K5R1nvj4jK6A2dB73P7jdD4bI ETMFkKGnsJkqnIbdmsuMXsO4rIaRGcXSudH2LRTjkEKuOP+9ZeVRJ/FldpLiL8HNCEAI ausw+7+ETzNubW9Ph3nPG5Ja8TL504eFc1fH6ZPKMOgKSnjiFewiI/uV+agr1brKqnn/ YlyZF/3heMlSQfNNxhugHpCJcuzcwJi9p3fTBmLt1xwUxNsXleBBRh312KUt9ETY/czb DA5QQ3z6vg4h4whReotqJbAt4Q6JOygkH/m2QDGXC0Kesu/jZRg/chMuz+LGV39CXyv9 Zg6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=88WSRCxVkAX9LtoIW14+VJJwdS0Qzo2bK/UdgMEeq+o=; b=g54YN2Ojtd/w8rXKTVAx/IkrSdPKBRwU1ZAeKTGosdudB8mr0GBiSsKAr17kk7w9pZ 9g+HlKfcOerwbBzmxOsjmv9A3jp4erpBllYEUFgBJ49rD5/5ee2ff+e/RMEwSyPr528H DJPeJhTxYb60FuIxisnZDdkfUQp6JyvZop1A8/kTm+YY7ze5bItW+ruz4RMfq2iWUNFh M9mswpkaHL5LHlTc09yBMIcsJiNaaDREp3VyKEJul2ggjO3+mS/sK6KiBOiGq1OzWBdf pbO/Hrkhipa+R+tIIluy6ee3+rQz2Xo3b7bM1qiFLG4NU2fXfeXPtzdbsqK6LtaNRm+I +Dcg== X-Gm-Message-State: AOAM531Uxj5oLfwlwq3V030u66UNXgU/QqYN9XWPJ/9Hk+NsiEVGfD6q uM1zQE595hdGotaRbH/psZSqWQaMqAQyrC9pOCGkE7Q/9xo7vw== X-Google-Smtp-Source: ABdhPJy6AyYwMHolWhqQQwe+GxiNX3J9jcIxabnzrvajQp8JV2ecV2FRzh7K/E/TAIEKbuwr758y6d/+CoXoWjs3HL8= X-Received: by 2002:a2e:81d4:: with SMTP id s20mr10422968ljg.248.1591608519522; Mon, 08 Jun 2020 02:28:39 -0700 (PDT) MIME-Version: 1.0 From: Salvatore Ingala Date: Mon, 8 Jun 2020 11:28:28 +0200 Message-ID: To: bitcoin-dev@lists.linuxfoundation.org Content-Type: multipart/alternative; boundary="0000000000006d7f0d05a78f3c1a" X-Mailman-Approved-At: Mon, 08 Jun 2020 09:33:42 +0000 Subject: [bitcoin-dev] Hash-based accumulators with quick insertion 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, 08 Jun 2020 09:28:43 -0000 --0000000000006d7f0d05a78f3c1a Content-Type: text/plain; charset="UTF-8" Dear all, I have been working on some constructions for cryptographic accumulators that optimise for quick insertion. As a brief background, an accumulator is a data structure that maintains compact commitments to a potentially very large (and dynamic) set, while keeping proofs of membership short. Unsurprisingly, they are getting more popular, and one notable application in Bitcoin is to create light-weight full nodes that do not need to store the UTXO set (Utreexo accumulator[1]). In this work, I focus on additive accumulators that supports adding new elements, but not removing them. My motivation is to support extending Script with access to an arbitrarily large portion of the blockchain history and state (e.g., past blocks, txids, or any more complex state obtained from them - with all due care). The additional storage and computation cost for nodes is small, and the cost (in additional bytesize) for any transaction that wishes to access state committed in the accumulator should be just slightly bigger than typical Merkle proofs. I have focused on: - An accumulator with insertion time O(1) and proof size O(log^2 n) - A construction with insertion time O(log log n) and proof size O(log n log log n) All the performance metrics above are in "number of hashes". You can find: - draft writeup: https://github.com/bigspider/accumulator/blob/master/docs/paper-draft.pdf - sample python code (only for the first construction at this time): https://github.com/bigspider/accumulator While this is still an unfinished work, the ideas in the draft are hopefully clear enough and easy to understand. I wanted to share it at this stage as it can benefit from comments to improve the constructions, to cover any related work or to find potential applications in Bitcoin (e.g. Script, layer2, side chains, etc). Best, Salvatore Ingala [1] - Thaddeus Dryja, Utreexo: A dynamic hash-based accumulator optimized for the Bitcoin UTXO set - https://eprint.iacr.org/2019/611.pdf --0000000000006d7f0d05a78f3c1a Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Dear all,

I have been working on some constructions= for cryptographic accumulators that optimise for quick insertion.

= As a brief background, an accumulator is a data structure that maintains co= mpact commitments to a potentially very large (and dynamic) set, while keep= ing proofs of membership short. Unsurprisingly, they are getting more popul= ar, and one notable application in Bitcoin is to create light-weight full n= odes that do not need to store the UTXO set (Utreexo accumulator[1]).
In this work, I focus on additive accumulators that supports adding new e= lements, but not removing them. My motivation is to support extending Scrip= t with access to an arbitrarily large portion of the blockchain history and= state (e.g., past blocks, txids, or any more complex state obtained from t= hem - with all due care). The additional storage and computation cost for n= odes is small, and the cost (in additional bytesize) for any transaction th= at wishes to access state committed in the accumulator should be just sligh= tly bigger than typical Merkle proofs.

I have focused on:
- An a= ccumulator with insertion time O(1) and proof size O(log^2 n)
- A constr= uction with insertion time O(log log n) and proof size O(log n log log n)
All the performance metrics above are in "number of = hashes".

You can find:
- draft writeup: https://g= ithub.com/bigspider/accumulator/blob/master/docs/paper-draft.pdf
- s= ample python code (only for the first construction at this time): https://github.com/bigspider/= accumulator

While this is still an unfinished work, the ideas in= the draft are hopefully clear enough and easy to understand. I wanted to s= hare it at this stage as it can benefit from comments to improve the constr= uctions, to cover any related work or to find potential applications in Bit= coin (e.g. Script, layer2, side chains, etc).

Best,
Salvatore Ing= ala

[1] - Thaddeus Dryja, Utreexo: A dynamic hash-based accumulator = optimized for the Bitcoin UTXO set - https://eprint.iacr.org/2019/611.pdf
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