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From: =?UTF-8?B?44Ki44Or44Og44CA44Kr44O844Or44Oo44OP44Oz?= <karl@dglab.com>
Date: Wed, 28 Feb 2018 04:34:18 +0000
Message-ID: <CALJw2w7BQcMEHDa=mx6Gf_JQP603D_hpPq1YN5Em1cfsr4BDAw@mail.gmail.com>
To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
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Subject: Re: [bitcoin-dev] Simple lock/unlock mechanism
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A few p.s.'es:

1. Graftroot probably breaks this (someone could just sign the
time-locked output with a script that has no time-lock).

2. Address reuse of discarded privkeys would be a problem. A way to
alleviate might be that freezing includes a send to a new address and
the privkeys for that new one are discarded instead. One extra
transaction, but reduces the risk of accidentally throwing away
`donations4mybook` vanity keys.

-Kalle.

On Wed, Feb 28, 2018 at 3:47 AM, =E3=82=A2=E3=83=AB=E3=83=A0=E3=80=80=E3=82=
=AB=E3=83=BC=E3=83=AB=E3=83=A8=E3=83=8F=E3=83=B3 <karl@dglab.com> wrote:
> With the recent trend of physically robbing people for bitcoin (or
> other cryptocurrencies), I thought it would be beneficial to introduce
> a standard for locking up a portion of your bitcoin in a simple
> 'gotta-wait-awhile' system.
>
> The idea is to simply create a transaction spending a set of UTXOs to
> a P2SH address with an OP_CSV attached to it, and then throw away the
> private keys.
>
> To spend the bitcoin, you would have to broadcast the transaction and
> wait the given amount of time, then use the new txout.
>
> There are several ways to shoot yourself in the foot trying to do this
> manually, but e.g. Bitcoin Core could handle this in a fairly
> straightforward manner by introducing two new commands, which I call
> freeze and unfreeze:
>
> bitcoin-cli freeze [amount OR array of txid+vout objects] [days, default =
1]
>
> E.g. bitcoin-cli freeze 10 5
> E.g. bitcoin-cli freeze ["abc123:1", "def346:0"] 3
>
> The unfreeze command would by default list all freezes:
>
> bitcoin-cli unfreeze
> txid         days     status
> bcd123   5           frozen
> dca999   3           frozen
>
> including the txid would broadcast the unfreeze and status would
> become 'thawing' until the amount becomes available:
>
> bitcoin-cli unfreeze bcd123
>
> bitcoin-cli unfreeze
> txid         days     status
> bcd123   5           thawing
> dca999   3           frozen
>
> The benefit of this is that it becomes physically impossible for you
> to spend the coins until you thaw them, and if this becomes standard
> enough, it should disincentivize potential robbers as it would be
> expected that you keep most of your assets locked up. They could of
> course hold you hostage until the period is over, which may be worse,
> but I think that kind of operation would be substantially more
> difficult than a simply rob-and-run.
>
> The drawback is that you have to broadcast a transaction in order to
> spend the content, and you cannot bump the fee so the transaction
> could get stuck in a high-fee situation.
>
> -Kalle.