A new study from Craig Gidney, a researcher at Google Quantum AI, suggests that cracking the widely-used RSA encryption could require significantly fewer quantum computing resources than previously anticipated – possibly up to 20 times fewer.
While the research didn’t focus on Bitcoin or other digital currencies specifically, it challenges the encryption methods that provide the security framework for crypto wallets and, in some cases, online transactions.
RSA, or Rivest–Shamir–Adleman, utilizes public-key cryptography, involving linked yet distinct public and private keys for data encryption and decryption.
While Bitcoin itself relies on Elliptic Curve Cryptography (ECC), not RSA, ECC is also susceptible to quantum attacks via Shor’s algorithm, a tool designed to break public key cryptography by factoring large numbers and resolving complex logarithmic challenges.
ECC secures data with mathematical curves – essentially one-way calculations – offering a “smaller key” solution with comparable strength to RSA’s larger keys.
While 256-bit ECC keys currently offer superior security to 2048-bit RSA keys, the threat from quantum computing increases rapidly and disproportionately. Research, such as Gidney’s, accelerates the timeline for potential attacks.
Gidney estimates a quantum computer with less than one million “noisy qubits” could break a 2048-bit RSA integer in under a week. This contrasts sharply with his previous estimate from 2019, which projected a need for 20 million qubits and eight hours of processing time.
Currently, these powerful quantum computers remain theoretical. IBM’s most advanced processor, Condor, has just over 1,100 qubits, while Google’s Sycamore has 53.
Quantum computing harnesses the principles of quantum mechanics, employing quantum bits (qubits) in place of standard binary bits.
Qubits can exist in multiple states simultaneously (superposition) and are linked via entanglement, allowing quantum computers to conduct many calculations at once. This gives them the potential to solve complex problems currently beyond the reach of traditional computers.
“This is a 20-fold reduction in the required qubits compared to our prior assessment,” Gidney stated. This efficiency boost in quantum resource estimation for RSA could portend similar advancements impacting ECC. RSA currently has vital applications in TLS, email encryption, and certificate authorities, which are fundamental to the infrastructure that crypto depends on.
Researchers, including the Project 11 quantum research group, are actively investigating whether even weakened versions of Bitcoin’s encryption can be breached by existing quantum hardware.
This year, Project 11 offered a public reward of 1 BTC (approximately $85,000) to the first person who can successfully break small ECC key sizes – between 1 and 25 bits – using a quantum computer.
The aim isn’t to immediately compromise Bitcoin, but to gauge the vulnerability of existing systems to near-term quantum computing capabilities.