The suspicion of risks that quantum computing could represent for the security of Bitcoin (BTC) and other cryptographic systems that support traditional banks is once again the focus of analysis.
On this occasion, Google Quantum AI software engineer and researcher Craig Gidney and BlackRock, the world’s largest financial asset manager, issued two warnings that would revive the debate. Cryptographic vulnerabilities Before quantum technology development.
Craig Gidney: Advances in quantum attacks
Google Quantum AI engineer Craig Gidney deepened this risk in a study published last May 21st. Resources needed to break encryption systems.
In 2019, Craig Gidney, along with researcher Martin Ekerå, calculated that it would break 2048-bit RSA encryption (a encryption system that protects sensitive data similar to mathematicians’ padlocks). You need a quantum computer with 20 million qubits Working for 8 hours is noisy. Cubits are the basic units of quantum computers, such as the bits of traditional computers, but thanks to the laws of quantum physics, they have the ability to perform much more complex calculations. However, “noisy” Qubits should use a lot to fix many errors, such as the instruments provided.
With his new research in 2025, Gidney has achieved amazing advances. “We estimate that the entire 2048-bit RSA could be a factor with less than a million loud Qubits within a week,” he said. This means an encrypted padlock that protects systems such as Bitcoin. It was able to open on a much more powerful machine than was thought.
This jump comes from a technical innovation that optimizes the process, as if Gidney had found a shortcut in a mathematical maze. Similar to rounded numbers, to simplify complex calculations, approximate waste arithmetic is used, a technique that simplifies complex calculations to solve faster problems. It also uses optimized surface code. This is like an error correction system that stabilizes Qubits, comparable to a safety network that prevents the balancer from falling.
Additionally, we will introduce “magical state” cultivation. This is a way to prepare special qubits that accelerate certain operations, such as cultivating selected seeds to obtain a more efficient harvest.
Gidney maintains the technical assumption for 2019, but as its approach, its approach is that of a grid of qubits connected only to the closest neighbor and one microsecond cycle time, i.e. the time it takes for a machine to perform the basic operations. It significantly reduces the number of qubits you need.
This makes a quantum attack that can decrypt the private key of Bitcoin. It’s more feasible in the not too distant future, but we’re still years away from that reality.
BlackRock points out quantum risk
In early May 2025, BlackRock updated its outlook for iShares Bitcoin Trust (IBIT), a fund that manages approximately 655,000 BTC, according to Bitbo data. Among them, in the section detailing the risks associated with Bitcoin, particularly the company added: Quantum computing can “harm the viability” of cryptographic systems Protects Bitcoin, such as the SHA-256 algorithm used for mining, and ECDSA (digital signature algorithm for elliptic curves) that guarantees private keys.
According to the document, sufficient advancements in this technology could undermine “all global technological infrastructure” as well as digital assets.
However, Bloomberg analyst James Seifert contextualized the warning: «These are Standard risk spread. BlackRock lists the underlying products and what you can experience with active issues. It’s completely normal and makes sense». Although the declaration is a protocol, it is true that its inclusion reflects growing concern over the future impact of quantum computing.
Other risks BlackRock presents include Trump’s orders such as branching, FTX, collection, volatility, and more, the fact that Bitcoin mining hardware is primarily manufactured in China, and the high power consumption of Bitcoin mining.