Sankar Das Sarma – a physicist from the University of Maryland – recently wrote at length about why the capabilities of quantum computing are overhyped at the moment. Specifically, he clarifies that quantum computing has evolved nowhere close to the stage required to break the public key cryptography used in popular technologies today – such as Bitcoin.
A long way to go for quantum computing
As written in an opinion piece for Technology Review, Sarma suggests that “quantum computing” has become the second most overhyped buzzword after “artificial intelligence”. Yet, despite substantial investments in quantum R&D from major institutions like Alphabet, Amazon and Microsoft, they are unlikely to be able to produce anything useful anytime soon.
“Established applications for quantum computers do exist,” states Sarma. For example, there’s a theoretical application of Quantum computing for finding the prime factors of large numbers exponentially faster than existing schemes. This, he explains, is at the heart of breaking RSA-based cryptography widely used for both email and cryptocurrency transactions.
As such, national governments around the world have devoted great attention and funding to quantum computing. However, what can be conceptualized in theory is not always easy to integrate into practice.
“The most advanced quantum computers today have dozens of decohering (or “noisy”) physical qubits,” said the professor. These qubits are used primarily for a process called “quantum error correction”, which compensates for the fact that quantum states are fast to disappear.
However, a computer capable of cracking RSA would require many millions, if not billions, of qubits. Only tens of thousands would be used for the actual calculation, while the rest would be used for error correction.
While Sarma calls qubit systems today a “scientific achievement” they cannot yet solve a problem “that anybody cares about.”
“It’s like trying to make today’s best smartphones using vacuum tubes from the early 1900s… What’s missing is the breakthrough in integrated circuits and processors leading to smartphones.”
Bitcoin’s Public Key Cryptography
Most cryptocurrencies today use public keys as “crypto addresses” to which any outside party can send their digital assets. However, to send a transaction from that address, one is required to know the private key from which that public key was derived.
While a private key can easily identify a public key with which it is compatible, it is currently impossible to decrypt a private key simply by knowing only someone’s public key.
Nevertheless, not everyone is careful to keep their private keys safe. A hacker managed to steal $600 million in funds from the Ronin network this week by securing the private keys belonging to 5 of 9 validator nodes on the network.
