Phase B
- A deadline will be announced after which it won't be possible to spend and sign using legacy ECDSA/Schnorr signatures.
- This requires a consensus rule change, where nodes will reject the old signature formats.
- Quantum-vulnerable UTXOs become unspendable.
- The recommended deadline is around 5 years after the activation of Phase A.
This is not a good thing at all. This will destroy all really long term cold storage setups, cause a lot of congestion and security risk. The rest of the proposal is fine with me.
Phase A: Disallows sending of any funds to quantum-vulnerable addresses
I think sending to old output types should be made non-standard, but not invalid. Because even now, you can send coins to "OP_TRUE", or to "OP_2 OP_2 OP_ADD OP_4 OP_EQUAL". If every existing output type will be disabled, then it would simply mean, that we will no longer have any Script.
What is the benefit of keeping useless and vulnerable features? We should clean up everything that poses a risk and not create technical debt when there are no clear benefits for it.