The immense computational power that quantum computing offers raises significant concerns, particularly around its potential to compromise private keys that secure digital interactions. Among the most pressing fears is its ability to break the private keys safeguarding cryptocurrency wallets.
While this threat is genuine, it is unlikely to materialize overnight. It is, however, crucial to examine the current state of quantum computing in terms of commercial capabilities and assess its potential to pose a real danger to cryptocurrency security.
Before delving into the risks, it’s essential to understand the basics of quantum computing. Unlike classical computers, which process information using bits (either 0 or 1), quantum computers rely on quantum bits, or qubits. Qubits leverage the principles of quantum mechanics to exist in multiple states simultaneously (0, 1, or both 0 and 1, thanks to the phenomenon of superposition).
Quantum Computing Risks: Shor’s Algorithm
One of the primary risks posed by quantum computing stems from Shor’s algorithm, which allows quantum computers to factor large integers exponentially faster than classical algorithms. The security of several cryptographic systems, including RSA, relies on the difficulty of factoring large composite numbers. For instance, RSA-2048, a widely used cryptographic key size, underpins the private keys used to sign and authorize cryptocurrency transactions.
Breaking RSA-2048 with today’s classical computers, even using massive clusters of processors, would take billions of years. To illustrate, a successful attempt to crack RSA-768 (a 768-bit number) in 2009 required years of effort and hundreds of clustered machines. The computational difficulty grows exponentially with key size, making RSA-2048 virtually unbreakable within any human timescale—at least for now.
Commercial quantum computing offerings, such as IBM Q System One, Google Sycamore, Rigetti Aspen-9, and AWS Braket, are available today for those with the resources to use them. However, the number of qubits these systems offer remains limited — typically only a few dozen. This is far from sufficient to break even moderately sized cryptographic keys within any realistic timeframe. Breaking RSA-2048 would require millions of years with current quantum systems.
Beyond insufficient qubit capacity, today’s quantum computers face challenges in qubit stability, error correction, and scalability. Additionally, their operation depends on extreme conditions. Qubits are highly sensitive to electromagnetic disturbances, necessitating cryogenic temperatures and advanced magnetic shielding for stability.
Future Projections and the Quantum Threat
Unlike classical computing, quantum computing lacks a clear equivalent of Moore’s Law to predict how quickly its power will grow. Google’s Hartmut Neven proposed a “Neven’s Law” suggesting double-exponential growth in quantum computing power, but this model has yet to consistently hold up in practice beyond research and development milestones.
Hypothetically, achieving double-exponential growth to reach the approximately 20 million physical qubits needed to crack RSA-2048 could take another four years. However, this projection assumes breakthroughs in addressing error correction, qubit stability, and scalability—all formidable challenges in their own right.
While quantum computing poses a theoretical threat to cryptocurrency and other cryptographic systems, significant technical hurdles must be overcome before it becomes a tangible risk. Current commercial offerings remain far from capable of cracking RSA-2048 or similar key sizes. However, as research progresses, it is crucial for industries reliant on cryptographic security to explore quantum-resistant algorithms to stay ahead of potential threats.
