Bitcoin Forum

Bitcoin => Important Announcements => Topic started by: theymos on July 12, 2017, 08:31:04 PM

Title: August 1 / BIP148 preparedness
Post by: theymos on July 12, 2017, 08:31:04 PM
There is some chance that BIP148 will result in an economic split of the Bitcoin currency at midnight UTC on Aug 1. If this split is non-negligible, then action may be required by all Bitcoin users. Personally, I consider it most likely that the split will be negligible and that you won't have to do anything, but it's still a good idea to prepare just in case.

A very short summary of what you need to do:

1. Ensure that you have no BTC deposited with a Bitcoin bank or other trusted third-party before Aug 1. If there's no technical way for you to export the private keys for your BTC, then that BTC is at risk. Some Bitcoin banks may assure you that they'll definitely keep your BTC safe, but I absolutely wouldn't trust them.
2. Do not send transactions or trust received transactions starting 12 hours before Aug 1 at midnight UTC, and continue this until you hear the "all clear" from several trustworthy sources. For example, I will post a forum news item if everything is OK, or if everything is not OK and action is required.

See my guide here for more a lot more detail:

Title: Re: August 1 / BIP148 preparedness
Post by: theymos on July 24, 2017, 05:49:27 PM

Due to BIP91, an economically-significant split seems quite a bit less likely. However, a large split is still possible if miners renege on BIP91, which wouldn't be very difficult for them to do.

Also, it seems that the Bitcoin Cash (BCC) fork will happen regardless on Aug 1, but everything I've seen leads me to believe that BCC will have very low value. Research and decide for yourself.

As a side-effect of BIP91, the risk of long reorganizations will be somewhat increased for the next month or so. This could cause confirmations on transactions to disappear more easily than otherwise, which could allow for double-spending. If you want to be about as safe as possible, you should wait for 30 confirmations before trusting incoming transactions.

Title: Re: August 1 / BIP148 preparedness
Post by: theymos on July 30, 2017, 08:38:03 AM
Aug 1 schedule

Here's what's expected to happen:

00:00 UTC: possible split 1

This is the BIP148 possible split point, which is what motivated all of the Aug 1 hubub. But due to BIP91's successful activation about a week ago, it is most likely that nothing of note will actually happen. It is however possible that the unexpected could occur.

12:20 UTC: split 2

BCash (BCH/BCC) is expected to split some time after 12:20 UTC. If you have a confirmed BTC balance as of approximately 12:20 UTC, and if you control your private keys, then it should be possible for you to claim an equal amount of BCH. Note that BCH is incompatible with Bitcoin (ie. it can fairly be described as an altcoin), so this split is not expected to affect Bitcoin in any technical way except perhaps some reduction in hashrate.

13:00-23:59 UTC: split instructions and all-clear

If nothing goes unexpectedly in the above two events, I will be aiming to post BCH split instructions and a final summary / "all-clear" before the end of the day, UTC. If something does go unexpectedly, then I will post an update about that ASAP.

Title: Re: August 1 / BIP148 preparedness
Post by: theymos on July 31, 2017, 07:06:27 PM
Note that the 12:20 UTC split time for Bcash is approximate, and the split time could happen some time after that.

Title: Re: August 1 / BIP148 preparedness
Post by: theymos on August 01, 2017, 02:55:37 PM

Bcash split at roughly 14:00 UTC. If you had BTC at (roughly) that point, then it should now be theoretically possible to split your coins. However, Bcash hasn't actually produced any blocks yet, maybe due to the way their difficulty adjusts, or maybe due to bugs (eg. I've heard that Bcash peers are sometimes banning each other).

Bitcoin is fine, and as expected, there was no BIP148/BIP91 split. I'm going to wait a few more hours before putting a green "all clear" thing in the news, but I'd feel pretty safe using Bitcoin normally now. Note that due to Bcash's pseudo-replay-protection, it is likely (but maybe not guaranteed) that Bitcoin transactions will not affect your Bcash balance.

Title: Re: August 1 / BIP148 preparedness
Post by: theymos on August 01, 2017, 07:10:58 PM
Bcash has now mined a few blocks without any unexpected issues, and a lot of time has passed since BIP148 activated, so I am at this point comfortable calling the all clear. See my summary topic here for more info: