Quantum computing an end to Bitcoin?


New Member
May 23, 2016
Let me fists state that I am by no means a expert in cyphers or quantum computing.

I recently read that IBM is once again in the thick of this nascent computing revolution. Its scientists have built a quantum processor that can be accessed through the cloud by literally anyone with Internet access. Called IBM Quantum Experience and accessible via www.research.ibm.com/quantum, it allows users to run algorithms and experiments by working with the individual quantum bits (qubits).

According to the article:
quantum computers could potentially threaten the very existence of bitcoin. The article predates that IBM quantum cloud announcement, stating that the threat if far in the future, due to cost and complexity.

However has the time come already? Any thoughts?


Staff member
Dec 16, 2015
I believe QC at scale may become available to nation states sooner than we imagine (if indeed it isn't already). Barring unforeseen breakthroughs in the private sector, I don't believe it will become available to the general public any time soon, and even then there would surely be crackdowns by governments wanting to gatekeep such technology.

That said, there ought to be a defensive research track to bring major crypto updates, including post-QC security, into Bitcoin - at least to have confidence in emergency solutions ready to go at short notice.

I found this an interesting read:



Active Member
Dec 31, 2015
Alarmism is alarmist.

QC will not suddenly crack bitcoin. Advances in cryptography -- including QC -- will continue to weaken cryptography. However, while ECC is potentially very weak in the face of QC advances, hashing is universally viewed as to not be stepwise vulnerable to QC.

As bitcoin addresses are hashes (of hashes) of public keys, we are safe for the foreseeable future. Reused addresses might be someday vulnerable to advances in QC (due to the exposure of the public key). But contemporary wallets do not reuse addresses anyway.

As advances in computing and cryptography happen in a farily gradual fashion, we will have ample time to switch the underlying cryptography to something QC-safe.

Net: our grandkids may face a problem, but it will be a manageable one.


Oct 2, 2015
If cryptography is broken by QC, it will affect a lot more than Bitcoin. What about the military, banking, e-commerce and anything else dependent on strong encryption?

It seems to me that if QC breaks electronic encryption, some form of quantum encryption will replace it.

If not we're doomed to going back to the dark ages of an unsecured internet.

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Active Member
Mar 29, 2016
I think the present risks are overstated, what are the odds that the public's early encounters with the concept are right when it's about to be immediately implementable in a useful way to break bitcoin. It's not a computer problem, it's a materials problem. I think it's still quite far away, but I could look into the more recent research.