Quantum computers do carry a certain threat to decentralized systems, blockchains and cryptocurrencies, but solutions are already being developed for this challenge, tells Russian mathematician Vladimir Gisin.

Vladimir Gisin, the head of the master program “The blockchain technology and cryptocurrency” and associate professor at the Financial University under the Russian government, believes that the bitcoin network will face the high risk of being hacked when 100-qubit quantum computers appear in the world.

“For a successful attack on the bitcoin network, a quantum computer must have several hundred qubits. When such a computer appears, the end will come for bitcoin in its current form,” Gisin said in an interview posted on the website of the Financial University.

But at the same time, Gisin added that post-quantum computing can help blockchains to resist such attacks.

“In response to such risks, post-quantum computing and algorithms based on the principles of post-quantum cryptography are being developed. They will be stable in the era of quantum computers.”

Gisin even suggested that there may already be successful hacking mechanisms for the bitcoin blockchain, but nothing is known about them because their authors do not want to reveal their knowledge.

Earlier, top managers of IBM warned about risks faced by blockchains and cryptocurrencies in the upcoming era of quantum computing.

According to Jesse Lund, vice president of blockchain and digital currencies at IBM, private keys can be revealed by quantum computing through reverse engineering. Lund predicts that more than half of all existing blockchain systems will be susceptible to this threat.

“Bitcoin is a public ledger. So you can go out and see which public keys are holding the largest balances and you could go out and target those (the hundred or thousands of bitcoin in there) and say I’m gonna spend effort (computing resource) to reverse engineer the private key from the public key, which is exposed. I think that’s even a near term threat,” said Lund.

Nev Zunic, chief technology officer for IBM data security services added that the risks associated with quantum computers need to be thought of today.

“Companies need to be aware of quantum and the potential risk that it will bring so they can take actions today so that they are not hackable at some point in the life cycle of their products.”

In November 2017, IBM revealed its 50-qubit quantum computer.