According to a recent article, Chinese researchers claim to have discovered a novel method to break the 2048-bit Rivest-Shamir-Adleman (RSA-2048) signature algorithm found in blockchains and other security protocols. RSA is a cryptographic technique that uses a public key to encrypt information and a private key to decrypt it.
Cracking the RSA-2048 algorithm requires, similar to other algorithms in the RSA family of numbers, finding the prime factors of a number with 617 decimal digits and 2048 binary digits. Experts estimate that it would take normal computers 300 trillion years to crack an RSA-2048 encryption key.. However, the Chinese researchers state in their article that the encryption could be reversed with a quantum computer with 372 qubits, or the basic unit of information that acts as a substitute for computing power.
Compared, the latest IBM Osprey quantum computer has a processing capacity of 433 qubits. Previously, experts calculated that factoring RSA-2048 with quantum computers using Shor’s algorithm (a quantum factoring method) would require 13,436 qubits.
Unlike classical computers, which operate on a binary basis of 0 or 1, quantum computers use quantum bits that can assume infinite states at temperatures of -273 °C (-459.4 °F), which is achieved using refrigerants of liquid gas. Thus, the quantum computer is capable of drawing up all possible solutions to a cryptographic problem and trying them all at once, increasing efficiency on an astronomical scale.
As told by American cryptographer Bruce Schneier, Chinese researchers appear to have combined “classical latency reduction factorization techniques with a fuzzy quantum optimization algorithm” that successfully factored 48-bit numbers using a 10-qubit quantum computer. “And while there are always potential problems when multiplying something like this by a factor of 50, there are no obvious barriers,” Schneier said.
Security expert Roger Grimes also added:
“Apparently, what happened is another guy who had previously announced that he could break traditional asymmetric encryption using classical computers…but the reviewers found a flaw in his algorithm and that guy had to retract his paper. But this Chinese team got realized that the step that killed the whole thing could be solved with little quantum computers. So they tried it and it worked.”
Schneier also cautioned that the algorithm is based on a recent article on factorization by Peter Schnorr, in which his algorithm works well for small bits but breaks down for larger bits, without any tangible explanation. “So if it’s true that the Chinese paper depends on this Schnorr technique that doesn’t scale, the techniques in this Chinese paper won’t scale either,” Schneier wrote.
“In general, the smart bet is that the new techniques don’t work. But one day, that bet will be wrong.”
Quantum computers are also limited by operational factors such as heat loss and the need for complex cooling infrastructure to -273 °C (-459.4 °F). So that, the number of nominal qubits required to invert cryptographic algorithms is likely to be much higher than theoretical estimates.
Although the researchers have not yet done so, the methodology could theoretically be replicable to other RSA-2048 protocols used in computing technology, such as HTTPS, email, web browsing, two-factor authentication, etc. Ethereum (ETH) co-founder Vitalik Buterin previously stated that his long-term goals include making the blockchain quantum-resistant. In theory, this involves forking the network to use a higher-order encryption algorithm that would require more qubits to break.
Jeffrey Albus, Staff Writer at Cointelegraph, contributed to this article.
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