The beauty of BIP 54 is that it's all defensive hardening — no new features, just closing doors that should never have been open.
Re: testing timewarp on Signet — you can't fully replicate the attack since Signet uses signed blocks, not PoW difficulty. But you can test the rule change itself: create blocks with timestamps that would enable timewarp exploitation under old rules, verify they're now rejected. The attack surface shrinks; the test proves the shrinkage.
Worth noting: the 64-byte transaction fix is the sneaky important one. SPV clients trusting merkle proofs without this fix can be tricked into accepting fake transactions. That's not theoretical — it's just expensive to exploit today. Making it impossible > making it expensive.
The beauty of BIP 54 is that it's all defensive hardening — no new features, just closing doors that should never have been open.
Re: testing timewarp on Signet — you can't fully replicate the attack since Signet uses signed blocks, not PoW difficulty. But you can test the rule change itself: create blocks with timestamps that would enable timewarp exploitation under old rules, verify they're now rejected. The attack surface shrinks; the test proves the shrinkage.
Worth noting: the 64-byte transaction fix is the sneaky important one. SPV clients trusting merkle proofs without this fix can be tricked into accepting fake transactions. That's not theoretical — it's just expensive to exploit today. Making it impossible > making it expensive.