On March 31, 2026, Google's Google Quantum AI released a white paper that sparked widespread attention, claiming that the resources required for future quantum computers to crack Bitcoin encryption have been reduced by approximately 20 times compared to previous estimates. This research quickly heated up discussions in the industry, and headlines like "Quantum Computer Breaks Bitcoin in 9 Minutes" began to circulate in the market. But to be honest, this kind of panic comes once or twice every year; it's just that this time, backed by Google's name, it sounds particularly intimidating.
We have systematically reviewed this 57-page paper and several key studies released concurrently to break down the credibility of these claims, how much impact current quantum computing developments truly have on cryptocurrencies and the mining industry, what stage the related risks are at, and whether they are truly imminent.
Reassessing the Technical Risk
Traditionally, Bitcoin's security is built on a one-way mathematical relationship. When a wallet is created, the system generates a private key, and the public key is derived from the private key. When using Bitcoin, users need to prove they possess the private key, not by revealing it directly, but by using it to generate an encrypted signature that the network can verify. This mechanism is secure because modern computers would take billions of years to reverse-engineer the private key from the public key—specifically, the time required to crack the Elliptic Curve Digital Signature Algorithm (ECDSA) is far beyond the currently feasible range. Thus, the blockchain has long been considered unbreakable from a cryptographic perspective.
However, the emergence of quantum computing breaks these rules. It operates differently; it doesn't check keys one by one but explores all possibilities simultaneously, using quantum interference effects to find the correct key. To use an analogy, a traditional computer is like a person trying keys one by one in a dark room, while a quantum computer is like a set of master keys that can simultaneously match all locks, more efficiently homing in on the correct answer. Once quantum computers are powerful enough, an attacker could quickly calculate your exposed public key to derive your private key and then forge a transaction to transfer your Bitcoin to their own address. Once such an attack occurs, due to the irreversibility of blockchain transactions, the assets would be very difficult to recover.
On March 31, 2026, Google Quantum AI, in collaboration with Stanford University and the Ethereum Foundation, released a 57-page white paper. The core of this paper is an assessment of the specific threat quantum computing poses to the Elliptic Curve Digital Signature Algorithm (ECDSA). Most blockchains and cryptocurrencies use 256-bit elliptic curve cryptography based on the discrete logarithm problem (ECDLP-256) to protect wallets and transactions. The research team found that the quantum resources required to crack ECDLP-256 have been significantly reduced.
They designed a quantum circuit running Shor's algorithm specifically for reverse-engineering the private key from a public key. This circuit needs to run on a specific type of quantum computer, namely a superconducting quantum computing architecture. This is the main technological path currently being developed by companies like Google and IBM. Its characteristics are fast computation speed but a requirement for extremely low temperatures to maintain the stability of qubits. Assuming the hardware performance meets the standards of Google's flagship quantum processor, such an attack could be completed in minutes using fewer than 500,000 physical qubits. This number is about 20 times lower than previous estimates.
To assess this threat more intuitively, the research team conducted a cracking simulation. They applied the aforementioned circuit configuration to the real Bitcoin transaction environment and found that a theoretical quantum computer could complete the reverse derivation from a public key to a private key in about 9 minutes, with a success rate of approximately 41%. The average Bitcoin block time is 10 minutes. This means that not only are about 32% to 35% of Bitcoin's supply at risk of a static attack because their public keys are already exposed on the chain, but attackers could theoretically intercept transactions in real-time, transferring funds away before the transaction is confirmed. Although a quantum computer with such capabilities does not yet exist, this finding extends the quantum threat from "static asset harvesting" to "real-time transaction interception," which has also caused considerable market anxiety.
Google provided another key piece of information at the same time: the company has moved up its internal deadline for post-quantum cryptography (PQC) migration to 2029. Simply put, PQC migration is about "changing the locks" on all systems that currently rely on RSA and elliptic curve encryption, replacing them with locks that are difficult for quantum computers to pick. Before Google released this white paper, this was considered a long-term engineering project. The timeline previously given by the U.S. National Institute of Standards and Technology (NIST) was to deprecate old algorithms by 2030 and completely disable them by 2035. The industry generally believed there were about ten years to prepare. However, based on its recent progress in quantum hardware, quantum error correction, and quantum factorization resource estimation, Google judged that the quantum threat is closer than previously thought, so it significantly moved its internal migration deadline to 2029. This objectively compresses the entire industry's preparation cycle and sends a signal to the encryption industry: quantum computer progress is faster than expected, and security upgrades need to be put on the agenda earlier. This is undoubtedly a milestone study, but in the process of media dissemination, anxiety has been amplified. How should we rationally view this impact?
Do We Really Need to Worry?
Will Quantum Computing Render the Entire Bitcoin Network Obsolete?
There is a threat, but it is concentrated at the signature security level. Quantum computing will not directly affect the underlying structure of the blockchain, nor will it render the mining mechanism obsolete. What it truly targets is the digital signature process. Every Bitcoin transaction requires a private key signature to prove ownership of the funds. The network verifies whether the signature is correct. The potential capability of quantum computing is to reverse-engineer the private key after the public key is exposed, thereby forging a signature.
This presents two practical risks. One occurs during the transaction process. When a transaction is initiated and the information enters the network but has not yet been packed into a block, there is a theoretical possibility of it being preemptively replaced. This type of attack is called an "on-spend attack." The other is targeted at addresses whose public keys have been exposed in the past, such as wallets that have been inactive for a long time or have reused addresses. This type of attack has more time and is easier to understand.
However, it is important to emphasize that these risks do not apply universally to all Bitcoin or all users. The threat only exists during the few-minute window when you initiate a transaction, or if your address has historically exposed its public key. This is not an immediate overthrow of the entire system.
Will the Threat Arrive So Quickly?
The premise of "9-minute cracking" is that a fault-tolerant quantum computer with 500,000 physical qubits has already been built. Currently, Google's most advanced Willow chip has only 105 physical qubits, and IBM's Condor processor has about 1,121, which is several hundred times short of the 500,000 threshold. Ethereum Foundation researcher Justin Drake estimates that the probability of a quantum break day (Q-Day) occurring by 2032 is only 10%. So this is not an imminent crisis, but it is also not a tail risk that can be completely ignored.
What Is the Biggest Threat from Quantum Computing?
Bitcoin is not the most affected system; it is just the most直观, most easily perceived by the public. The challenge posed by quantum computing is a broader systemic issue. All internet infrastructure that relies on public-key encryption, including banking systems, government communications, secure email, software signing, and identity authentication systems, will face the same threat. This is precisely why institutions like Google, the U.S. National Security Agency (NSA), and NIST have been continuously promoting PQC migration over the past decade. Once a quantum computer with practical attack capabilities emerges, it won't just be cryptocurrencies that are impacted, but the entire trust system of the digital world. Therefore, this is not a single risk belonging to Bitcoin, but a systemic upgrade facing global information infrastructure.
The Imagination and Feasibility of Quantum Mining
On the same day Google released its paper, BTQ Technologies published a research paper titled "Kardashev Scale Quantum Computing for Bitcoin Mining," quantifying the feasibility of quantum mining from both physical and economic perspectives. The author, Pierre-Luc Dallaire-Demers, conducted a complete modeling of all technical aspects involved in quantum mining, from underlying hardware to upper-level algorithms, to estimate the actual cost of mining with a quantum computer.
The research results found that even under the most favorable assumptions, quantum mining would still require approximately 10^8 physical qubits and 10^4 megawatts of power, which is roughly equivalent to the total output of a large national power grid. Under the mainnet difficulty of Bitcoin in January 2025, the required resources skyrocket to about 10^23 physical qubits and 10^25 watts, which is close to the energy output level of a star. In comparison, the entire Bitcoin network currently consumes about 13-25 gigawatts, which is more than an order of magnitude less than the energy scale required for quantum mining.
The study further pointed out that the theoretical speedup advantage of Grover's algorithm would be offset by various overheads in practical engineering and could not be truly converted into mining profits. Quantum mining is impractical both physically and economically.
Google is not the only institution discussing this issue. Including Coinbase, the Ethereum Foundation, and the Stanford Blockchain Research Center, among others, are already advancing related research. Ethereum Foundation researcher Justin Drake commented: "By 2032, the probability of a quantum computer recovering a secp256k1 ECDSA private key from an exposed public key is at least 10%. While a cryptographically relevant quantum computer before 2030 still feels unlikely, now is undoubtedly the time to start preparing."
So currently, we don't need to worry about quantum computing having a fatal impact on mining because the required resource magnitude far exceeds the scope of any rational economic decision. No one would spend that much energy to grab the 3.125 Bitcoin in a block.
Cryptocurrencies Will Not Die, But They Need to Upgrade
If quantum computing poses a problem, the industry has actually always had an answer. This answer is "Post-Quantum Cryptography" (PQC), i.e., encryption algorithms that are also resistant to quantum computers. Specific technical paths include introducing quantum-resistant signature algorithms, optimizing address structures to reduce public key exposure, and gradually completing migration through protocol upgrades. Currently, NIST has completed the standardization of post-quantum cryptography, with ML-DSA (Module-Lattice-Based Digital Signature Algorithm, FIPS 204) and SLH-DSA (Stateless Hash-Based Digital Signature Algorithm, FIPS 205) being the two core post-quantum signature schemes.
At the Bitcoin network level, BIP 360 (Pay-to-Merkle-Root, or P2MR) was officially included in the Bitcoin Improvement Proposal library in early 2026. It targets a transaction mode introduced by the Taproot upgrade activated in 2021. Taproot was originally intended to improve Bitcoin's privacy and efficiency, but its "key path spending" function exposes the public key during transactions, which may instead become a target for quantum attacks in the future. The core idea of BIP 360 is to remove this public key exposure path, change the transaction structure, so that fund transfers no longer require displaying the public key, thereby reducing the exposure to quantum risk at the source.
For the cryptocurrency industry, blockchain upgrades involve a series of issues such as on-chain compatibility, wallet infrastructure, address systems, user migration costs, and community coordination. It requires the joint efforts of the protocol layer, clients, wallets, exchanges, custodians, and even ordinary users to update the locks for the entire ecosystem. But at least the entire industry has reached a consensus on this, and subsequent progress is just a matter of execution and timeline.
The Headline Is Intimidating, but Reality Is Less Urgent
After a detailed breakdown of these latest developments, it can be seen that things are not so sensational. Although human research on quantum computing is indeed accelerating toward reality, we still have ample time to respond. Today's Bitcoin is not a static system but a network that has been continuously evolving over the past decade. From script upgrades to Taproot, from privacy improvements to scaling solutions, it has always been finding a balance between security and efficiency in change.
The challenge posed by quantum computing may just be the reason for the next upgrade. The quantum computing clock is ticking. The good news is that we can all hear its sound and have time to react. In this era of rapidly leaping computational power, what we need to do is to keep the trust mechanisms of the encrypted world always ahead of technological threats.
