Microsoft is saying they will have a viable quantum chip out my 2029. Pretty much all cryptography will be vulnerable. I don't know that the blockchain will survive it. I think a lot of money is going to exit until it is proved safe.
literally a 100% non-issue. My field is very cryptography-adjacent and its something i need to understand for my job role... quantum compute doesnt break any modern cryptography, all it does is require that either 1) key space grows to counteract the increased effectiveness of quantum algorithms like Shor's (easy) or 2) you use a different crypto primitive (still easy). AES-256 is already considered quantum resistant, and thats one of the reasons modern cipher algos have already migrated from AES128 to AES256. If need be, AES512 will be standardized which will be 2^256 times as resistant to factorization than AES256... if quantum compute becomes becomes able to factor AES256 in 1 second, then migrating to AES512 will require 10^67 centuries to crack, longer than the lifetime of the universe. Numbers just work like that.
There also exist entire cipher suites where no known quantum-native algorithms currently exist that will can reduce computational complexity, such as lattice fields
This is a very well researched and well understood topic in the field of number theory and nothing becomes "broken" it just becomes a game where we need to use bigger numbers or swap to different primitives. Modern cryptography is still cryptographically secure against quantum algorithms when key size is scaled larger or when we dont rely on prime factorization or discrete logarithms for complexity.
In crypto currency specifically, algos have become "broken" before and this isnt new territory whatsoever.
When this sort of thing happens and the hashing algo is in danger or has become "broken" the community performs a "fork". they adjust the parameters or the primitives to something which is safe. in the case of post-quantum cryptography this generally just means scaling key size larger, you normally dont actually need to change any of the primitives, just use some larger primes
Maybe quantum becomes a real threat they just migrate away from elliptic curve and start using lattice, or something else that doesnt require factorization or discrete logarithms, idk, its a design decision for the developers.
BTC has been through 3 forks already, one was due to algorithm changes. Monero has been though several to prevent ASIC attacks on the algorithm. litecoin had 2, etherum has had like 10 or more.
this is pretty standard and when crypto communities feel the need to address post-quantum cryptography they will do so, just like they have done in the past with ASIC mining breaking their algos
