For decades, classical computing has been the backbone of our digital society. However, a new technological revolution is quietly brewing in labs around the world: quantum computing. This breakthrough not only promises to transform entire industries, but also poses a real threat to cryptocurrencies like Bitcoin. And most importantly: we’re not talking about the distant future. Quantum computing is already here, and its impact could be felt in just a few years.
What is Quantum Computing?
Quantum computing is a branch of computer science based on the laws of quantum physics, the same laws that govern the behavior of subatomic particles. Unlike traditional computing, which uses bits representing 0 or 1, quantum computers use qubits, which can be 0, 1 or both at the same time thanks to a phenomenon called superposition.
In addition, qubits can intertwine with each other (quantum entanglement), allowing simultaneous operations to be performed at an exponentially higher speed. This means that quantum computers can solve certain problems thousands or millions of times faster than today’s most powerful supercomputers.
Why Is It the Future (and the Near Future)?
Companies such as Google, IBM, Microsoft and specialized startups such as Rigetti or IonQ are investing billions in this technology. In 2019, Google announced having reached “quantum supremacy”, achieving its quantum processor to solve in seconds a problem that a classical supercomputer would take thousands of years to process.
Although we are still in an experimental phase, advances in qubit stability, error correction and scalability suggest that we could have functional and affordable quantum computers within the next decade or even sooner.
And this is where the alarm bells for Bitcoin come in….
The Quantum Threat to Bitcoin
Bitcoin, like many other cryptocurrencies, bases its security on classical cryptographic principles, namely algorithms such as SHA-256 (for mining) and ECDSA (for public and private keys). These systems are designed to resist attacks with classical computers. However, a sufficiently powerful quantum computer could break them in a matter of minutes or even seconds.
Let’s see how:
1. Risk to Private Keys
Currently, Bitcoin public addresses are derived from private keys using elliptic cryptography. With a quantum computer, one could calculate the private key from the public key using Shor’s algorithm, a quantum algorithm designed to factor large numbers and break asymmetric cryptography.
This means that, if someone sees your public address (which happens every time you make a transaction), an attacker with a quantum computer could discover your private key and steal your funds.
2. Risk to the Mining Algorithm
The SHA-256 algorithm that secures the mining process could also be weakened by quantum computing using Grover’s algorithm, which allows faster searches in key spaces. While it would not break SHA-256 completely, it would drastically reduce the difficulty of mining, altering the entire Bitcoin security and reward ecosystem.
When could it happen?
According to quantum security experts, with a quantum computer of around 2,500 error-corrected logical qubits, it would be possible to break Bitcoin’s current protections. Although we are still far from that number, the growth in quantum development is exponential, not linear.
Some optimistic forecasts estimate that this could happen before 2030. If no action is taken, Bitcoin could completely lose its value, as it cannot guarantee the security of its funds.
Is there a Solution?
Yes, and work is underway. There are post-quantum cryptography initiatives that seek to develop new algorithms resistant to quantum attacks. Some cryptocurrencies are already exploring this path, but Bitcoin has not yet implemented any concrete solutions.
Upgrading the entire Bitcoin system is not trivial: it requires community consensus, network changes and global adaptation. And that, as we know, can take years.
Conclusion: Time is running out
Quantum computing is no longer science fiction. It is a rapidly developing reality that, while promising incredible benefits in medicine, logistics, artificial intelligence and more, also poses a direct threat to cryptocurrencies as we know them.
If the crypto ecosystem does not adapt in time, the arrival of a functional quantum computer could be the beginning of the end for Bitcoin.
The future is no longer distant. It is just around the corner.
