Quantum Computing Threatens Bitcoin Encryption, Researchers Warn

Quantum computers capable of breaking bitcoin encryption may become feasible in the future, according to researchers who estimated the size of a quantum computer needed to achieve this task. By examining this benchmark, the study sheds light on the potential capabilities of future quantum computers and the potential implications for secure communication protocols like Bitcoin's elliptic curve digital signature algorithm, which could become susceptible to attacks as quantum computing advances.

Quantum Computing Poses Threat to Bitcoin Encryption, Researchers Warn

In a groundbreaking study published in AVS Quantum Science, researchers have projected that future advancements in quantum computing technology will render the encryption currently safeguarding the Bitcoin network vulnerable to attack.

The study, led by Mark Webber of the University of Sussex, focused on estimating the necessary size of a quantum computer capable of breaking the Bitcoin network's encryption. This benchmark serves as a gauge for the future scale of quantum computing required to accomplish more complex tasks.

"Previous research in this area has predominantly concentrated on a specific hardware platform, namely superconducting devices," said Webber. "However, different hardware platforms exhibit significant variations in crucial hardware specifications, such as operational speed and qubit control quality."

Quantum computers leverage quantum bits (qubits) instead of the conventional '1's' and '0's' used in digital information encoding. Qubits possess the unique ability to exist in a superposition state, simultaneously representing both a '1' and a '0.' This property enables an exponential increase in computational power with each additional qubit introduced, unlike the linear growth observed in traditional computing.

The full realization of quantum computing's potential hinges on the development of error-corrected quantum computers. These machines compensate for inherent errors within the system, allowing for the execution of longer algorithms, albeit at the expense of requiring more physical qubits.

"To accelerate the execution of quantum algorithms, we can increase the number of operations performed concurrently by adding more physical qubits," explained Webber. "We incorporate additional qubits as necessary to achieve the desired runtime, which is critically dependent on the operational speed at the physical hardware level."

However, most contemporary quantum computers face limitations due to the restricted interaction between qubits, typically confined to neighboring qubits. Certain designs circumvent this constraint by enabling physical relocation of qubits, facilitating interactions with a broader range of their counterparts.

Quantum computers excel at breaking encryption compared to their conventional counterparts. Secure communication protocols often rely on RSA encryption, introduced in 1977. The security of RSA stems from the computational complexity of factoring two large prime numbers, which form the basis of the public key. Deciphering a message encrypted with such a key requires knowledge of these prime numbers.

While Bitcoin employs a distinct encryption scheme, the elliptic curve digital signature algorithm, researchers believe both methods will succumb to future quantum attacks.

"Current state-of-the-art quantum computers possess only 50-100 qubits," said Webber. "Our estimations indicate a requirement of 30 million to 300 million physical qubits, suggesting that Bitcoin remains relatively secure against quantum attacks for the time being. However, devices of this scale are generally deemed achievable, and future advancements may further reduce the necessary size."

Bitcoin may have the capability to implement a "hard-fork" to adopt a quantum-resistant encryption technique, but such a transition could introduce network scaling challenges due to increased memory demands.

The study, titled "The Impact of Hardware Specifications on Reaching Quantum Advantage in the Fault Tolerant Regime," provides valuable insights into the imminent challenges and opportunities presented by quantum computing's inexorable march forward.