It is not a new discussion of the question of whether the development of quantum computers could be the end of cryptocurrencies and the blockchain. Normally, from time to time, coinciding with the presentation of a new and spectacular quantum computing machine, it is put back on the table.

In this case, a quantum processor has been IBM, the one that Eagle has just presented, which exceeds the barrier of 100 qubits, to go up to 127. Quantum computing in less than a decade, can end cryptocurrencies.

“Quantum computing is a new paradigm in computer science, which takes advantage of quantum phenomena such as superposition, entanglement and interference to obtain a significant improvement in the speed of solving certain complex problems compared to classical algorithms.”

Now, with quantum computing much less advanced than it is today, in November 2017, Divesh Aggarwal, a researcher at the National University of Singapore, conducted research in which he claimed that the development of this type of computer posed a “real” danger. and imminent” for Bitcoin.

Some of the conclusions of the study were published in the MIT Technology Review, in a text focused on the largest cryptocurrency by market capitalization, but extrapolated (with minor variations) to the rest of digital currencies.

They argue that an essential feature of Bitcoin is its security, which prevents digital currencies from being stolen or copied, thanks to cryptographic protocols that are really difficult to crack.

They exploit mathematical functions like factorization, they say, “that are easy in one direction, but difficult in the other, at least for a traditional computer.” Not for a quantum one.

They deal with the process of cryptocurrency mining, whereby computers (miners) solve complicated mathematical problems and get bitcoins as rewards.

But, they point out at MIT, this process has an important shortcoming: that it can suffer what is known as the ‘51% Attack’. In other words, if a group of miners controls more than 50% of the computational power, it is, de facto, as if it unilaterally controlled the entire chain of blocks.

This group could have malicious intentions, for example, deleting transactions and spending bitcoins 2 times. A quantum computer, they maintain, would be able to easily exceed that 50%.

Aggarwal pointed out that this would not be an immediate thing, but that it would take about 10 years for quantum computers to surpass the speed of ASIC circuits, which are the majority used in bitcoin mining.

**More threats to cryptocurrencies**

The above is not the only way in which quantum computers threaten the future of cryptocurrencies.

Ergo, the owner generates 2 numbers: a public key and a private and secret key. The public one, he stresses, is easy to create from the private one, but not the other way around. The researcher also referred to the fact that Bitcoin ensures that only the owner of the token can spend it, and does so based on mathematics that is also used for public key encryption schemes.

You can only fool the system in one way: by finding the private key from the public one. Again, an extremely complicated operation for a normal computer, but relatively simple for a quantum computer.

Aggarwal bluntly stated, “The elliptic curve signature scheme used by Bitcoin is at much greater risk, and could be completely broken by a quantum computer by 2027.”

The researcher from the University of Singapore does not seem to be at all misguided. Four years later, Jian-Wei Pan, a scientist who created a 66-qubit quantum computer, says that there are still 4 or 5 years left for this technology to be ready.

It’s called Eagle, and it’s a 127-qubit processor. It is not known whether he took into account IBM’s newly unveiled quantum computer in making that claim. They ensure that, with this computer, “users will exploit uncharted computational territory and experience a key milestone on the path to practical quantum computing.”

They predict that by 2023 they will prepare Osprey (with 433 qubits) and, above all, Condor, with 1,121 qubits. The threat grows for cryptocurrencies.

With these figures, the announcement, in October 2019, in which they congratulated themselves for having created Sycamore, a 54-qubit quantum computer, capable of performing a calculation in 200 seconds for which the most powerful traditional computer in the world is far away. time would need 10,000 years. Posted by **Cryptobtcbrowser**, news and information agency.