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 06A03D24 for ; Sat, 12 Dec 2015 23:01:16 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from nm13-vm0.bullet.mail.bf1.yahoo.com (nm13-vm0.bullet.mail.bf1.yahoo.com [98.139.213.79]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 39A03181 for ; Sat, 12 Dec 2015 23:01:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1449961274; bh=bn1+hWWH8QpxvPIS6rvU4/ZwHaGzS+3GqpQurd+UsgA=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From:Subject; b=TH59QPDBw4giKsS52A1SmCLufNYFbxYl9TGbb72T54/vBf7rrT7SbqAH4ngZFB4SpcJb1/UyrjD1gkaKEs1nm2n+NsyJyJ+vJaLSlRc9kIyFhsWlzuCK6VyCIIOu121/FD3ZqSY2QLw0PFctQSsOLWDmcjQW9y72sJFNu3QoF1fHmTYKlWmKQ2hdsbUB+GQd1pmWcW3QkceX2e5axl8kuqB0UaVGyqJ92weNUHShWop7NiFebfaF4R5jNexKRE7ps/+iN3vq6k7jxmHe4RwrJMtVD/sULSmDbitnce9XmMKHyhFF331kuo1PeFgFhZc5saaRQdFVwkA9fGmbp0c39A== Received: from [98.139.215.141] by nm13.bullet.mail.bf1.yahoo.com with NNFMP; 12 Dec 2015 23:01:14 -0000 Received: from [98.139.211.204] by tm12.bullet.mail.bf1.yahoo.com with NNFMP; 12 Dec 2015 23:01:14 -0000 Received: from [127.0.0.1] by smtp213.mail.bf1.yahoo.com with NNFMP; 12 Dec 2015 23:01:14 -0000 X-Yahoo-Newman-Id: 369121.57927.bm@smtp213.mail.bf1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: kTXHQDUVM1m7Dp8HVHICEv3oMU_OCaYeoQdJXUlcqh9MQ1a ocasP6yga.x7CXSUf2KgHEAyqiAnunqOqg4m4..yeFEEByMyGdFosl9NV12J kG6yUgtIKSGoK3fqxGqGbXSs2KMdjJLAQSUq_sTAa8zJM54pNtZ7oVIcwSM. wjPEzR12U9VqjHptTxFFeUfQpy3fgMvRsCZgPgq6O3lxI9815UELVhvdQiHq md4b8FI4ljR5AiMh6N51lRyHPnFqM_muE6DZkyQG5HXaoq1vGukKODJMYa2A NiBqUjuYzdRVLlYAVs1OnUkgNN2WwAeeLktQk5Gqpnj.ih0S8GPPICxIZMg8 fubPdJBqebyEIBOTtca2yXAkGT.Hj8J5d331m9hKu6OIeRA2ut51EhTISDwV CndfEqSmGDzvi.bieIHyupqChQT9hx6sgzOkhIlL9j2Zpn34UJFa2axA4rDi tP7O2SQfhogbmyCElhjPmgs8l.bAGmr.sekl57846vpLeFjsDglZsnBqibRM qeApj60xKYNKcd5FQ.4NgyzJsWDxd0xgCRuxtD4BaUQ-- X-Yahoo-SMTP: kMAkG6uswBCBwEfDAoIbXivsMA-- Message-ID: <1449961269.2210.5.camel@yahoo.com> From: gb To: jl2012@xbt.hk Date: Sun, 13 Dec 2015 12:01:09 +1300 In-Reply-To: <50e629572d8de852eb789d50b34da308@xbt.hk> References: <50e629572d8de852eb789d50b34da308@xbt.hk> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.11 (3.12.11-1.fc21) Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-2.7 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, RCVD_IN_DNSWL_LOW, T_RP_MATCHES_RCVD autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Sat, 12 Dec 2015 23:29:31 +0000 Cc: bitcoin-dev@lists.linuxfoundation.org Subject: Re: [bitcoin-dev] Forget dormant UTXOs without confiscating bitcoin X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Development Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 12 Dec 2015 23:01:16 -0000 The general concept has merit and the basic outline here seems sound enough. I have harboured a notion for having "archived UTXO" for some time, this is essentially it. The retrieval from archive cost is on the UTXO holder not the entire storage network, which is then only bearing full 'instant' retrieval costs for N blocks. On Sat, 2015-12-12 at 15:09 -0500, jl2012--- via bitcoin-dev wrote: > It is a common practice in commercial banks that a dormant account might= =20 > be confiscated. Confiscating or deleting dormant UTXOs might be too=20 > controversial, but allowing the UTXOs set growing without any limit=20 > might not be a sustainable option. People lose their private keys.=20 > People do stupid things like sending bitcoin to 1BitcoinEater. We=20 > shouldn=E2=80=99t be obliged to store everything permanently. This is my= =20 > proposal: >=20 > Dormant UTXOs are those UTXOs with 420000 confirmations. In every block= =20 > X after 420000, it will commit to a hash for all UTXOs generated in=20 > block X-420000. The UTXOs are first serialized into the form:=20 > txid|index|value|scriptPubKey, then a sorted Merkle hash is calculated.= =20 > After some confirmations, nodes may safely delete the UTXO records of=20 > block X permanently. >=20 > If a user is trying to redeem a dormant UTXO, in addition the signature,= =20 > they have to provide the scriptPubKey, height (X), and UTXO value as=20 > part of the witness. They also need to provide the Merkle path to the=20 > dormant UTXO commitment. >=20 > To confirm this tx, the miner will calculate a new Merkle hash for the= =20 > block X, with the hash of the spent UTXO replaced by 1, and commit the= =20 > hash to the current block. All full nodes will keep an index of latest= =20 > dormant UTXO commitments so double spending is not possible. (a=20 > "meta-UTXO set") >=20 > If all dormant UTXOs under a Merkle branch are spent, hash of the branch= =20 > will become 1. If all dormant UTXOs in a block are spent, the record for= =20 > this block could be forgotten. Full nodes do not need to remember which= =20 > particular UTXO is spent or not, since any person trying to redeem a=20 > dormant UTXO has to provide such information. >=20 > It becomes the responsibility of dormant coin holders to scan the=20 > blockchain for the current status of the UTXO commitment for their coin.= =20 > They may also need to pay extra fee for the increased tx size. >=20 > This is a softfork if there is no hash collision but this is a=20 > fundamental assumption in Bitcoin anyway. The proposal also works=20 > without segregated witness, just by replacing "witness" with "scriptSig" >=20 > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev