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 To: Kekcoin Anthony Towns , 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 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.