Topic: What does Quantum Computing mean for Bitcoin? - page 5. (Read 23216 times)

If I can break ECDSA with a quantum computer I can steal all the money on bitcoin and make all the bitcoins disappear from day to night.
However if i can break RSA, banks and people only have to stop relying on SSL meanwhile they implement a new algorithm. ( Probably they would have to stop using credit cards for a while but they won't loose all their money at all )

So, the first problem is that a quantum computer able to break crypto is a death threat to Bitcoin, meanwhile for a bank that relies on RSA is only a major threat.

The second problem is that the first company who will own a quantum computer able to break crypto will be sure the "US Government". And in the future, when Bitcoin will be much popular than now, I am sure that the US Goverment will have strong incentives to make bitcoin disappear because the bitcoin thing is a major threat to the debt-based economic system of the dollar.

So far.. how much you think will take to the US Gov own such quantum computer and break the ECDSA system of bitcoin? 5 years perhaps?

Still, not too soon to examine plans for switching bitcoin from ECDSA to something post-quantum.

Remember, when "true" quantum computers become a reality, far more than bitcoin is defeated.  HTTPS (which uses RSA) is defeated.  So basically all internet traffic (passwords, credit card numbers, etc) will be readable by anyone on the same wifi, by an employee at your ISP, or someone at your ISP's ISP, etc.

D-Wave is smoke and mirrors.  It is more like 128 1-bit analog computers, as the qubits are not entangled.  Without entanglement, there is no quantum speedup over classical computation.  Even the 8-bit system they published in Nature is not entangled.

The highest number of qubits which have demonstrated entanglement is 3.

Still, not too soon to examine plans for switching bitcoin from ECDSA to something post-quantum.

Remember, when "true" quantum computers become a reality, far more than bitcoin is defeated.  HTTPS (which uses RSA) is defeated.  So basically all internet traffic (passwords, credit card numbers, etc) will be readable by anyone on the same wifi, by an employee at your ISP, or someone at your ISP's ISP, etc.

Then I think that we should do this ASAP.

quantum computers are a reality, you can buy a 128qubit one for "only" 10$ million (that's small change for a large company)

http://venturebeat.com/2011/05/27/first-quantum-computer-sold/
http://www.dwavesys.com/en/products-services.html


How difficult would be change the algorithm of the public-key encryption for Bitcoin to one not vulnerable to quantum attacks?
Would we have to start from scratch or we could change the algorithm "on the fly" without losing our coins?

Is cryptography dead?

Imagine that it’s fifteen years from now and someone announces the successful construction of a large quantum computer. The New York Times runs a frontpage article reporting that all of the public-key algorithms used to protect the Internet have been broken. Users panic. What exactly will happen to cryptography?

Perhaps, after seeing quantum computers destroy RSA and DSA and ECDSA, Internet users will leap to the conclusion that cryptography is dead; that there is no hope of scrambling information to make it incomprehensible to, and unforgeable by, attackers; that securely storing and communicating information means using expensive physical shields to prevent attackers from seeing the information—for example, hiding USB sticks inside a locked brief-case chained to a trusted courier’s wrist.

A closer look reveals, however, that there is no justification for the leap from “quantum computers destroy RSA and DSA and ECDSA” to “quantum computers destroy cryptography.” There are many important classes of cryptographic systems beyond RSA and DSA and ECDSA

• Hash-based cryptography. The classic example is Merkle’s hash-tree public-key signature system (1979), building upon a one-message-signature idea of Lamport and Diffie.
• Code-based cryptography. The classic example is McEliece’s hidden-Goppa-code public-key encryption system (1978).
• Lattice-based cryptography. The example that has perhaps attracted the most interest, not the first example historically, is the Hoffstein–Pipher–Silverman “NTRU” public-key-encryption system (1998).
• Multivariate-quadratic-equations cryptography. One of many interesting examples is Patarin’s “HFEv− ” public-key-signature system (1996), generalizing a proposal by Matsumoto and Imai.
• Secret-key cryptography. The leading example is the Daemen–Rijmen “Rijndael” cipher (1998), subsequently renamed “AES,” the Advanced Encryption Standard.

All of these systems are believed to resist classical computers and quantum computers. Nobody has figured out a way to apply “Shor’s algorithm”—the quantum-computer discrete-logarithm algorithm that breaks RSA and DSA and ECDSA—to any of these systems. Another quantum algorithm, “Grover’s algorithm,” does have some applications to these systems; but Grover’s algorithm is not as shockingly fast as Shor’s algorithm, and cryptographers can easily compensate for it by choosing somewhat larger key sizes.

The ECDSA public key crypto could be changed to one not vulnerable to quantum attacks, like Unbalanced Oil and Vinegar.

http://en.wikipedia.org/wiki/Post-quantum_cryptography

"Please explain, How?

As I see it, you would need to crack the Key Pair almost instantaneously before it got added to the chain, if another Key pair is then generated before the next transaction..."

"But if Quantum Computing becomes prevalent so would Quantum Pairing. No one would be able to see the transaction or intercept it between parties."

I thought about this also. A true Quantum computer could end the current bitcoin system. Even though it is only theoretical now. The speed of development is impressive. A system for sending messages using wave collapse already exists!

Nothing, at least until Quantum Computing transcends from realm of myth to reality.

Somebody needs to write an article series on cryptography.