From: Jacob Eliosoff <jacob.eliosoff@gmail•com>
To: Mats Jerratsch <mats@blockchain•com>
Cc: Bitcoin Dev <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Generalised Replay Protection for Future Hard Forks
Date: Sat, 11 Nov 2017 00:18:11 -0500 [thread overview]
Message-ID: <CAAUaCyg70uUnUp1Q0a6kEoQ1Js68VFLgthyfwyMQaaEqO8R-UQ@mail.gmail.com> (raw)
In-Reply-To: <3FBEE883-A15E-425C-8BF1-F7792FA63961@blockchain.com>
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OK, so nForkId 0 is exactly the "valid on all chains" specifier I was
asking about, cool. And your LN example (and nLockTime txs in general)
illustrate why it's preferable to implement a generic replay protection
scheme like yours *in advance*, rather than before each fork: all ad hoc RP
schemes I know of break old txs on one of the chains, even when that's not
desirable - ie, they offer no wildcard like nForkId 0.
One comment on your LN example: users would have to take note that nForkId
0 txs would be valid not only on future forks, but on *past* forks too.
Eg, if BCH had been deployed with nForkId 2, then a user setting up BTC LN
txs now with nForkId 0 would have to be aware that those txs would be valid
for BCH too. Of course the user could avoid this by funding from a
BTC-only address, but it is a potential minor pitfall of nForkId 0. (Which
I don't see any clean way around.)
On Fri, Nov 10, 2017 at 6:28 AM, Mats Jerratsch <mats@blockchain•com> wrote:
> I guess I wasn't clear on the wildcard, `nForkId=0`
>
> This proposal puts Bitcoin at `nForkId=1`, with the purpose of having
> `nForkId=0` valid on *all* future forks. This means you can create a
> `nLockTime` transaction, delete the private key and still be assured to not
> lose potential future tokens.
>
> In theory `nForkId=0` could be used for an address too, the sending wallet
> should display a warning message about unknown side effects though. This
> address would be future-safe, and you can put it into a safe-deposit box
> (even though I see little reason to back up an _address_. You would always
> back up a _private key_, which translates into funds on any fork.)
>
> Furthermore, `nForkId=0` can be used for L2 applications. Let's say Alice
> and Bob open a payment channel. One week later, project X decides to fork
> the network into a new token, implementing a custom way of providing strong
> two-way replay protection. The protocol Alice and Bob use for the payment
> channel has not implemented this new form of replay protection. Alice and
> Bob now have to make a choice:
>
> (1) Ignore this new token. This comes with an evaluation of how much this
> new token could be worth in the future. They will continue normal channel
> operation, knowing that their funds on the other branch will be locked up
> until eternity. When they close their payment channel, the closing
> transaction will get rejected from the other network, because it's not
> following the format for replay protected transactions.
>
> (2) Close the payment channel before the fork. The transaction, which
> closes the payment channel has to be mined before the fork, potentially
> paying a higher-than-normal fee.
>
> With this proposal implemented, there are two additional choices
>
> (3) Create the commitment transactions with `nForkId=0`. This ensures that
> when the channel gets closed, funds on other chains are released
> accordingly. This also means that after the fork, payments on the channel
> move both, the original token and the new token. Potentially, Alice and Bob
> want to wait before further transacting on the channel, to see if the token
> has substantial value. If it has, they can *then* close the channel and
> open a new channel again. (Note: The funding transaction can use a specific
> `nForkId`, preventing you from locking up multiple coins when funding the
> channel, but you can choose to settle with `nForkId=0` to not lock up
> future coins)
>
> (4) Make the protocol aware of different `nForkId`. After the fork, the
> participants can chose to *only* close the payment channel on the new
> token, making the payment channel Bitcoin-only again. This is the preferred
> option, as it means no disruption to the original network.
>
> > I like the idea of specifying the fork in bech32 [0]. On the other hand,
> the standard already has a human readable part. Perhaps the human readable
> part can be used as the fork id?
>
> I was considering this too. On the other hand, it's only _human readable_
> because thy bytes used currently encode 'bc'. For future forks, this would
> just be two random letters than, but potentially acceptable.
>
>
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next prev parent reply other threads:[~2017-11-11 5:18 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-05 23:48 Mats Jerratsch
[not found] ` <CAAUaCyii2U5VBLS+Va+F3h4Hka0OWDnFFmjtsvyaaD4TKVzV3Q@mail.gmail.com>
2017-11-06 19:21 ` Jacob Eliosoff
2017-11-08 16:45 ` Mats Jerratsch
2017-11-09 20:45 ` Jacob Eliosoff
2017-11-09 21:01 ` Sjors Provoost
[not found] ` <CAAUaCygeOxAK=EpzfWndx6uVvVO9B+=YTs1m-jHa3BFp82jA4w@mail.gmail.com>
[not found] ` <95ECB451-56AE-45E5-AAE6-10058C4B7FD7@sprovoost.nl>
[not found] ` <CAAUaCyg_PGT0F=RHfX89T54j-vuyz5wcbXaYoikJv95WKgsNPg@mail.gmail.com>
[not found] ` <55467A01-A8B2-4E73-8331-38C0A7CD90EF@sprovoost.nl>
[not found] ` <CAAUaCyhncyCt_ao9i0=33LswDOkCf6o-+36zrGxKWD+WranmZw@mail.gmail.com>
[not found] ` <46E317DF-C97C-4797-B989-594298BC6030@sprovoost.nl>
[not found] ` <CAAUaCyibOEHqw1J5O8yEp8v=j8t9sovn2vn=S8bZPZCzCY-gRw@mail.gmail.com>
2017-11-10 11:28 ` Mats Jerratsch
2017-11-11 5:18 ` Jacob Eliosoff [this message]
2017-11-13 10:03 ` Mats Jerratsch
2017-11-13 15:31 ` Jacob Eliosoff
2017-11-13 17:02 ` Spartacus Rex
2017-11-14 13:49 ` Mats Jerratsch
2017-11-15 5:02 ` Jacob Eliosoff
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