Following the December 9 announcement in which Google announced the launch of Willow, its new quantum chip, developers and bitcoiners expressed their opinions regarding the alleged ability of this chip to compromise the Bitcoin (BTC) encryption.
In theoretical terms, quantum computing could compromise the cryptography used by Bitcoin. Using the Shor algorithm it would be possible to derive private keys from public keys, affecting the ECDSA scheme (Elliptic Curve Digital Signature Algorithm) who signs the transactions.
Also, Grover’s algorithm could reduce the time needed to solve problems of hash in SHA-256. This, hypothetically, would put the mining process at risk and, with it, the security of the network.
What do developers and analysts think about Willow, Google’s chip?
Analysts at Bernstein Research, an investment research arm of AllianceBernstein, were optimistic about the potential implications of quantum computing on Bitcoin.
Should Bitcoin contributors start preparing for the quantum future? Yes, but any practical threat to Bitcoin appears to be decades away.
Bernstein Research analysts.
Furthermore, they made it clear that “Bitcoin contributors have also been debating a transition to quantum-resistant encryption.”
In line with this opinion, a developer who calls himself Investor Arch on X shared a study from the University of Sussex.
In this document, it was estimated that a power of 13 million qubits is necessary (qubits) to compromise BTC encryption in one day, while Willow’s quality is 105 qubits. Qubits represent the basic unit of information in a quantum computer, just like bits in a classical computer.
In response to Investor Arch’s post, other users also contributed their opinions. Such is the case of a quantum cryptography researcher who explained that the immediate risk to Bitcoin cryptography remains low due to current technical limitations.
This user detailed that “the best estimate I know for breaking the ECDSA algorithm’s discrete logarithm problem on a 256-bit elliptic curve is around 2500 logical qubits.”
As mentioned above, Willow has 105 physical qubits in its architecture. With current technologies, between 100 and 1,000 physical qubits are needed to build a single logical qubit.
Conversion from physical qubits to logical qubits requires millions of physical qubits due to errors and instability, which remains a significant technical challenge.
Therefore, following the quantum cryptography researcher’s estimates, Willow’s capabilities would still be far from being able to compromise Bitcoin’s encryption systems.
However, the researcher closed his comment with some pessimism:
I’m not saying quantum computers are anywhere close to meeting the actual requirements, but don’t be surprised if future techniques reduce them by two orders of magnitude.
Publication by a researcher in X.
Blockstreams Co-Founder Suggests Willow Is Not a Threat
Adam Back, co-founder and CEO of Blockstreams, a technology company linked to Bitcoin, responded to Investor Arch’s message stating that the BTC network and its encryption would require 13 million qubits to be corrupted.
Adam argued that ECDSA and Bitcoin are not based on encryption, but on digital signatures. The quantum threat to Bitcoin comes from the possibility of deriving private keys from public keys, not from breaking an encryption scheme.
In this sense, Willow would be far from being a threat, according to the CEO of Blockstreams. With only 105 physical qubits, Willow is limited to experimental tasks and poses no practical threat to existing cryptography.
To compromise the ECDSA, a quantum system 300 million physical qubits and an efficiency in correcting errors that currently does not exist, according to Adam Back.
Finally, Gustavo Flores Echaiz, a developer linked to the community bitcoineragreed that quantum computing does not yet pose a threat to Bitcoin security.
Although Google’s Willow quantum chip may be a relevant advance, with 105 physical qubits, it is a far cry from the millions needed to compromise the ECDSA algorithm that protects Bitcoin transactions. This level of quantum capacity is not expected in the short term.
In a future scenario with more advanced quantum computers, only a fraction of BTC would be at risk, as detailed by Flores Echaiz.
This includes coins in P2PK (Pay-to-Public-Key) addresses, used before 2011, and those in reused addresses, where the public key is exposed when signing transactions. Coins in addresses that do not reuse public keys or remain unspent have greater protection.
The Pay-to-Taproot (P2TR) standard, a method of transferring BTC built in 2021, offers some additional resilience by hiding public keys until the funds are spent.
Thus, given the opinions of some specialists, for now, the impact of quantum computing on Bitcoin remains a risk. theoretical and controllable for now.