Re: [bitcoin-dev] Replay attacks make BIP148 and BIP149 untennable

[Tao Effect <contact@taoeffect.com>]

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> Please read my email more carefully; the replay threat would be moot because there would be no alternative chain to replay the TX on,

In order to *get to that point*, you need >51%.

Not only that, but, if you started out with <51%, then you need >>51% in order to *catch up* and replace the large number of blocks added to the legacy chain in the mean time.

So, since >51% is _required_ for BIP148 to succeed (and likely >>51%)... you might as well do as SegWit did originally, or lower the threshold to 80% or something (as BIP91 does).

Without replay protection at the outset, BIP148, as far as I can tell, isn't a threat to miners.

--
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> On Jun 6, 2017, at 5:29 PM, Kekcoin <kekcoin@protonmail.com <mailto:kekcoin@protonmail.com>> wrote:
> 
> Please read my email more carefully; the replay threat would be moot because there would be no alternative chain to replay the TX on, as the non-148 chain would have been reorganized into oblivion.
> 
> 
> Sent with ProtonMail <https://protonmail.com/> Secure Email.
> 
>> -------- Original Message --------
>> Subject: Re: [bitcoin-dev] Replay attacks make BIP148 and BIP149 untennable
>> Local Time: June 7, 2017 3:26 AM
>> UTC Time: June 7, 2017 12:26 AM
>> From: contact@taoeffect.com <mailto:contact@taoeffect.com>
>> To: Kekcoin <kekcoin@protonmail.com <mailto:kekcoin@protonmail.com>>
>> Anthony Towns <aj@erisian.com.au <mailto:aj@erisian.com.au>>, bitcoin-dev@lists.linuxfoundation.org <mailto:bitcoin-dev@lists.linuxfoundation.org> <bitcoin-dev@lists.linuxfoundation.org <mailto:bitcoin-dev@lists.linuxfoundation.org>>
>> 
>> I don't know what you mean by "render the replay threat moot."
>> 
>> If you don't have replay protection, replay is always a threat. A very serious one.
>> 
>> --
>> Please do not email me anything that you are not comfortable also sharing with the NSA.
>> 
>>> On Jun 6, 2017, at 5:19 PM, Kekcoin <kekcoin@protonmail.com <mailto:kekcoin@protonmail.com>> wrote:
>>> 
>>> Hmm, that's not the difference I was talking about. I was referring to the fact that using "post-chainsplit coinbases from the non-148 chain" to unilaterally (ie. can be done without action on the 148-chain) taint coins is more secure in extreme-adverserial cases such as secret-mining reorg attacks (as unfeasibly expensive they may be); the only large-scale (>100 block) reorganization the non-148 chain faces should be a resolution of the chainsplit and therefore render the replay threat moot.
>>> 
> 


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