How to hack bitcoin? BTC blockchain security in front of quantum computer

Want to steal a couple of bitcoins ? All you have to do is calculate the private key to your victim's 16-digit public key by solving the so-called “discrete logarithm of the elliptic curve” problem. Using a regular computer, it will take about 0.65 billion billion years .

But if somewhere there is a quantum computer capable of processing information at a speed that exponentially exceeds the speed of modern supercomputers? Suddenly, what seems impossible is becoming a task that can be solved in less than 10 minutes.

Quantum computing

The problem of quantum computing is not new to cryptography , and many experts believe that we still have about ten years to develop quantum-resistant cryptography. However, some cryptographers say that recent (and unexpectedly fast) progress in quantum computing is leading to a sharp reduction in this safe period, and by 2027, bitcoin could be hacked.

“Over the past two years, we have moved further than the past 15 or 20 years ,” said Stuart Allen, director of IonQ, which claims to produce some of the most powerful quantum computers in the world, in a comment to Decrypt .

On Thursday, August 22, the best cryptographers will meet in Santa Barbara at the University of California in the semifinal of the National Institute of Standards and Technology (NIST) post-quantum cryptography contest.

Finalists of the NIST contest will be announced in a few months and it may take years before a winner is determined. Cryptographers argue that standards developed at the competition can provide blockchains with better protection against the rapidly growing power of quantum computers.

“If someone breaks your key, they can do whatever they want ,” said Decrypt Rob Campbell of Med Cybersecurity, a cybersecurity company. He says that anyone who stores sensitive information on the blockchain is at risk.

“Quantum hackers” can fake your name and take away your money, and if medical data is stored on the blockchain, then maliciously “triple your dose of medicine”.

What is a quantum world?

Transistors in conventional computers collect data in units of 1 and 0. Is the sky blue today? If yes, 1. If not, 0. Calculations are, in fact, combinations of zeros and ones: having a sufficient number of transistors, you can calculate almost everything.

With quantum computers, the same input, called a qubit, can simultaneously represent both 0 and 1 — this is a state known as “quantum superposition”. It makes quantum computers significantly more powerful than conventional computers. Using modified versions of Shore’s quantum algorithm , hackers can reverse the process that makes private keys so hard to crack.

But at the moment, the best quantum computer is perhaps Google’s 72-qubit Bristlecone. Miruna Roska, a post-graduate student of post-quantum cryptography, suggests that about 4,000 qubits are needed to crack modern cryptographic algorithms.

So how much time do we have?

IonQ Allan believes that post-quantum cryptography will take about ten years to become a real force. By then, he believes, someone is likely to be developing a quantum-resistant blockchain.

Danny Ryan, lead researcher at the Ethereum Foundation, thinks the same:

“This is not a very significant problem in the next 10 years, and probably not in 20-30 years. At the same time, we admit the worst-case scenario in such matters, so we must be prepared for this in advance. ”

But others say the problem needs to be addressed immediately, and that – in addition to the threat to bitcoin – quantum computing can pose a serious threat to cybersecurity in general. Rob Campbell of Med Cybersecurity says a government armed with quantum decryption software can "learn all the secrets of the world."

Campbell, who has been specially trained by the US Navy Liaison Officer in the R&D department, knows like no one else that government secret technologies are often ahead of relatively affordable commercial developments.

“We were decades ahead ,” he says. “We did not want potential adversaries to know about our capabilities.”

Even if Campbell’s claims seem exaggerated, he correctly indicates that the development of quantum-resistant cryptographic algorithms should become a national security issue today, since the arms race for quantum superiority is in full swing: China has already spent $ 10 billion on a quantum computer research center; The United States is also investing hundreds of millions of dollars in this area.

Quantum resistance

Quantum computing can be just as effective for cryptographers as it is for hackers. Unobservable superpositional particles exist in several states, but upon detection they “collapse” to one point in space-time. Quantum cryptography has the same properties, since the protons that make up the encrypted transaction are shifted during observation; a successful attacker must break the laws of physics in order to intercept it.

This makes the information encrypted at the quantum level resistant, among other things, to the so-called “man in the middle” attacks, when attackers intercept the data transmission itself without the need to decrypt the key.

Several blockchain projects claim to use quantum-resistant methods to provide encryption of signatures and hashes – these are QRL, IOTA, HyperCash and Starkware. But with quantum computing that is still in its infancy, it's hard to determine the validity of these claims.

Until quantum-proof algorithms are tested and accepted by the wide academic community, there is no certainty that any of these blockchains will be sufficiently resistant to quantum computers. Campbell and other scientists will be waiting for the results of the NIST contest, however, as mentioned above, the final winners can be announced in a few years. NIST itself expects project evaluations to be completed by 2022.

“Winners are likely to become standard cryptography and will be used by most of the planet ,” Campbell says.

However, adopting the developed algorithm can be a difficult task for large blockchains such as Bitcoin or Ethereum. While owners of centralized protocols can update the system at their discretion, blockchains, democratic in nature, require broad agreement to implement the update.

In the case of an update, all cryptocurrency wallets that are not quantum resistant become vulnerable to attacks. On such potentially vulnerable wallets today, for example, there are about 1 million bitcoins mined by the creator of bitcoin Satoshi Nakamoto – if they are not transferred to a new quantum-resistant wallet, they can become the prey of the first person with a fairly powerful quantum computer.

“If powerful quantum computers appear tomorrow,” says Ryan of the Ethereum Foundation, “we will have much more problems than just blockchain security.”

A 2019 report from the US National Academy of Sciences concludes that even if the real application of quantum computing is expected to take about ten years, the necessary research must already be done today to minimize the “potential disaster in security and privacy.”

Publication date 08/20/2019
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