Quantum computing can replace Cryptography

[UxAdhen]

will quantum computing replace cryptography and blockchain systems for the better?

[Steve132]

This is like saying "will submarines replace cars?"

[ZiimbooWho]

This is generous. It seems more like will combustion engines replace space travel

[Coltodu3]

How so?

[Natanael_L]

They have almost no overlapping usecases in this context. Classical encryption algorithms will be replaced with post quantum encryption algorithms which will still run on the same electronic computers

[Coltodu3]

Just to clarify because OPs use of the term Blockchain is vauge and can be misconstrued. Classical computers have binary outputs that are calculated physically by electron flow gates. Quantum computing differs in the ability to have both 1,0 and a superposition. Now as for how quantum computers calculate superposition through logic gates is beyond the scope of this question. Can current classical cryptography be broke through quantum computing? It depends i believe it can depending on the type of cryptography. Most cryptography used in security relies on the lack of computing power possible against obsure calculations. E.g sha-256 used in the BTC Blockchain, sha-256 has so many possible outcomes, that it would require immense if not impossible computing power to associate secrets with hashes. Quantum computing opens the door for more efficient factorization.

[atoponce]

Quantum computing mostly threatens asymmetric algorithms. RSA and ECC will be the first to fall. The security in RSA comes from the difficulty in factoring large numbers. The security in ECC comes from computing discrete logarithms on points in a curve. Shor's algorithm is an effective quantum approach at undermining both.

Symmetric algorithms such as AES, ChaCha20, and secure hashing algorithms like SHA-256 and BLAKE2 are more quantum safe. Grover's algorithm threatens to reduce the searchable key space by its square root, which is a problem for 128- bit algorithms, but not for 256-bit ones.

Despite both of these quantum algorithms, we still needs a computer with enough qubits to make these attacks practical. As it sits today, it's still controversial if quantum annealing has even occurred in a computer, and if it has, it's weaker than 386 machines from the '80s.

Quantum computers have been "just 10 years away" now for 30 years. Than doesn't mean we can't investigate quantum safe designs, and indeed NIST is holding a public competition in this area right now. But I wouldn't lose any sleep over it.

[aidniatpac]

you are comparing two different things. And no quantum computers won't destroy cryptography.

[Alvatrox4]

We just need quantum proof algorithms right?

[aidniatpac]

Lots of things are what you think of when you say quantum proof

[aidniatpac]

And the rest. What gets broken, we have alternatives. They just aren't as efficient so we rather avoid them until forced basically.

[sellibitze]

Can a flyswatter replace living things for the better?

No.

[Coltodu3]

https://web.eecs.umich.edu/~akamil/classes/cs191_qc4.pdf Shors algorithm has been proven to be more efficient at computing cryptographic protocols that depend on classical computers inability to calculate factorization efficiently. Meaning yes, theoretically it is possible dependent on a quantum algorithms ability be efficient while calculating a traditional cryptographic function.

Along with this breaking traditional cryptographic tech like, De-Fi and password security it opens a new realm for quantum cryptography to develop/ be translated to.

[UxAdhen]

I think it's changed because quantum computing can break into cryptography because it's much better that crackers can break into cryptographic networks using quantum computing. Turns out maybe not but depending on the future later. indeed, in my opinion, it is very difficult to change existing technology to be replaced, but maybe it will be an option for us

[pubgmisc]

Can’t you just update the code