Quantum computers and security of blockchain

Hello Guys,
I have just come accross article where they write that it’s not very distant future that Quantum computers will be threat to blockchain security as they are uncomparrable faster than todays computers.

What do you think and how is Cardano standing on this comparing to other crytpto currencies?

Here is the article, probably you’ve heard it before, but it looks they are progressing faster than we thought:


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Hello @Jakub_Pavlik

Actually Charles had this question in his latest AMA on YouTube. Here is his answer:

Thanks for the info, that was the thing I was talking about, in my opinion it’s better to be prepared now, we for sure don’t know exactly how far the progress in development of quantum physics is.

Whether be it sophisticated hacker groups or certain goverments they won’t tell for sure how far their research is, they use the moment of surprise to their advantage. So they can be just happy when people think it is far away.

From what I understand from the video, Charles said they won’t do it now not just because it is far away, but mainly because it would cost really big bunch of money, so it is comfortable to think it is far away and this is wrong attitude.

Reminds me little a story of Titanic when people asked why there is so little safe boats on the ship.

On the other side this would be really good marketing move, just imagine to say that Cardano has Quantum proof security, how it would resonate inside people, this investition would have been quickly paid off, plus we have security for the future.


I have not read the article, but as a very brief and simple explanation:

  1. If bitcoin is cracked by quantum computers all the other relevant cryptography in finance erc., will be too.
  2. Hashing algorithms are QC resistant.
  3. ECDSAs are not QC resistant, but bitcoin and Cardano addresses (public keys) are hashed, meaning you have some sort of protection until the public keys are exposed, which usually happens when you spend the fund from an UTxO (relevant to that pubkey address, meaning exposed as witness in the transaction). That is one of the reason to use different HD derived (new) addresses for every new spending transaction outputs (different change and or public addresses).
  4. There are ongoing researches for QC resistant signatures, there are some but very slow and very big, which is, atm, useless for validation. But, by the time we will have these kind, and of course some other type, of protection.

Thank you for this explanation! Was something I was wondering about, since it does not really enhance privacy to use fresh addresses that are linked to the same stake key/wallet.

Thank you as well for taking time and explaining, I really appreciate it.

Somebody who is capable of putting the effort and money into this isn’t interessted in a measly 1 Tri $ BTC. They would go for governments and their military.

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isnt that all blockchains wil switch over their chains to quantum computers or is it not so eazy as i say???:thinking:

No, it’s not that easy. Quantum computers are not just very fast computers, but they work totally differently.

Just because a quantum computer can break some cryptographic scheme, it does not mean that it can also enable a new cryptographic scheme that is resistant.

But even if it were possible, the blockchains would have to upgrade their networks faster than the adversaries can buy quantum computers. That would also sound like a quite dangerous race with lots of lost crypto currency on the way.

On the other hand, there are also some schemes in development that are resistant against quantum computers and can be run on traditional ones. So, we can probably upgrade our cryptography in time.


this is very useful info my friend🤔 so you think in 10years every household has a qtum computer @ home with a qtum wallet on it?? how much faster they are against whats on the market now???

He said, that it is not necessary to have a quantum computer to have quantum proof security.
Here is a video how it works, it looks little scientifically, but explanation is good


Thanks for the topic. It’s very interesting!

Thanks for the explanation.

I hope so.