Every time someone logs in to online banking, sends a private message, or shops from a phone, silent bodyguards protect that data. Those bodyguards are math formulas called encryption.
Now, a new type of machine is on the rise: Quantum Computers. Experts warn that this tech could smash many of the locks that keep the internet safe. Some call this the coming quantum threat.
Right now, no one has broken real-world RSA or ECC encryption with a quantum device. But researchers, governments, and attackers all know the race has started. The key questions are simple: what is the quantum threat, how does it work, how close is it, and what can people do to prepare?
What Are Quantum Computers and Why Do They Matter for Encryption?
Quantum Computers use the rules of quantum physics to process information in a different way from normal machines. Instead of bits that are only 0 or 1, they use qubits that can be 0, 1, or something like both at the same time.
This strange behavior lets a quantum machine test many possible answers in parallel. For some problems, it can make it much faster than any normal computer could ever be.
Companies like IBM, Google, and IonQ are building bigger systems every year. IBM already shows chips with over 1,000 physical qubits, and Google’s Willow chip has more than 100. These machines are still noisy and limited, but the direction is clear.
Why should anyone outside a lab care? Because many forms of encryption rely on math problems that are hard to solve. A machine that can blast through those problems fast turns from a science project into a security threat.
For readers who want a deeper background on risks and preparation, this guide to understanding quantum computing security risks gives a broader view of how the topic affects data safety.
From bits to qubits: how Quantum Computers think differently
A normal computer bit is like a light switch. It is either off (0) or on (1). A qubit is more like a dimmer switch that can be off, on, or anywhere in between until it is checked. This in-between state is called superposition.
Now picture two dimmer switches that always move together. If one is turned up, the other is turned down, no matter how far apart they are. That link is called entanglement.
By putting many qubits into superposition and tying them together with entanglement, a quantum computer can work on many possible answers at once. It is like trying all the keys on a huge keyring at nearly the same time, instead of one by one.
Why a faster kind of math is bad news for current encryption
Most modern encryption depends on math puzzles that are easy to set up but very hard to undo. Multiplying two big numbers is simple. Splitting that big number back into the two starting numbers is extremely hard for a normal computer.
Quantum Computers change the balance. For some math problems, a quantum machine can test many options in parallel. That turns a puzzle that would take longer than the age of the universe for a normal computer into a task that a future quantum device could solve in hours or days.
Online banking, secure email, and private chats all lean on this “hard one way, easy the other way” idea. Once that idea stops holding, the locks on those systems start to look weak.
How Quantum Computers Can Break Modern Encryption Like RSA and ECC
Most secure websites, VPNs, and software updates rely on public key cryptography. The best known versions of this are RSA and elliptic-curve cryptography (ECC).
In each case, the system uses a pair of keys. One key can be shared with the world. The other must stay secret. The security comes from a math trick that works like a one-way street.
A special quantum algorithm, called Shor’s algorithm, bends that one-way street into a two-way road for a powerful quantum machine. That is the heart of the quantum threat to today’s online security.
How RSA and ECC protect most of the internet today
Public key systems work a bit like a mailbox. The public key is the slot anyone can put letters into. The private key is the only key that opens the back of the box.
With RSA, the public key is built from two very large prime numbers multiplied together. The private key is tied to those original primes. Normal computers can multiply those primes quickly, but they struggle to factor the result back into the two pieces. That one-way property keeps RSA safe.
ECC uses math on special curves. It relies on a hard problem called the discrete logarithm. Again, going forward is easy; going backward is hard for normal computers.
Browsers use RSA or ECC keys during the HTTPS handshake. Software vendors use them to sign updates. VPNs use them to set up secure tunnels. In short, most of the internet depends on these locks.
Shor’s algorithm: the quantum shortcut that breaks the rules
Shor’s algorithm is a clever set of steps that runs on a quantum computer. It gives a fast way to factor large numbers and solve discrete log problems. That means it attacks the very core of RSA and ECC.
In lab tests so far, Shor’s algorithm has only worked on tiny numbers, like factoring 15 into 3 and 5. That sounds silly, but it proves the math idea works.
The reason it has not cracked real keys yet is simple. Current quantum machines do not have enough stable, error-corrected qubits. They are too small and too noisy to run the huge version of Shor’s algorithm needed for a 2048-bit RSA key.
Still, security experts treat Shor’s algorithm as a real warning. Once the hardware catches up, the shortcut is ready.
What a quantum attack on real-world encryption would look like
Picture a future where someone has a powerful quantum computer with enough reliable qubits. A simple attack could look like this:
- The attacker records the public key from a bank’s website.
- The attacker feeds that public key into Shor’s algorithm on the quantum machine.
- The machine spits out the private key that should have stayed secret.
- With that private key, the attacker can pretend to be the bank, forge digital signatures, or decrypt captured traffic.
That could lead to fake banking sites that look perfectly valid, forged software updates that install malware, or broken VPNs that leak internal company traffic.
Resources like the Palo Alto Networks overview of quantum computing’s threat to cybersecurity describe similar attack paths and why they worry defenders.
How Close Are Quantum Computers to Breaking Encryption in Real Life?
Headlines sometimes make it sound like Quantum Computers will break the internet next week. The truth is more subtle.
As of late 2025, IBM, Google, IonQ, Quantinuum, and others have made big advances. IBM has chips like Condor at 1,121 qubits and high-fidelity Heron devices. Google’s Willow chip has 107 qubits with better error rates. Quantinuum and Microsoft have shown progress on logical qubits, which are more reliable combinations of many physical qubits.
Even with these gains, experts estimate that breaking a strong RSA key would need millions of high-quality, error-corrected qubits, not just thousands of noisy ones.
Today’s Quantum Computers: powerful in theory, limited in practice
Current machines fall into a category called NISQ, or noisy intermediate-scale quantum. They have dozens or hundreds of qubits, but each qubit is fragile. Tiny amounts of heat or stray signals can flip bits and ruin a calculation.
To fix this, engineers use error correction. They tie many physical qubits together to act as one logical qubit that is more stable. Today, it can take hundreds or even thousands of physical qubits to make a single logical qubit.
Estimates for breaking 2048-bit RSA run from a few hundred thousand to tens of millions of physical qubits. Compared with current systems in the low thousands, that shows how far the hardware still has to climb.
For readers tracking progress as it happens, this overview of quantum computing news and future impact gives a broader picture of recent advances.
Has any Quantum Computer broken RSA or ECC yet?
The short answer is no.
Researchers have factored small numbers and solved toy versions of RSA using combinations of quantum tricks and classical computers. These proofs of concept help science, but they do not break any real-world encryption.
Claims that someone secretly cracked big RSA keys with a quantum machine do not stand up when experts examine them. Articles such as Is Quantum Computing a Cybersecurity Threat? from American Scientist explain that current devices are far from breaking common encryption methods and that the danger is still future-focused. Readers can see a clear explanation in this discussion of quantum computing as a cybersecurity threat.
The race to a cryptographically relevant quantum computer
Researchers use the phrase cryptographically relevant quantum computer (CRQC) for a machine strong enough to break real keys in a useful time, such as hours or a day.
No one knows exactly when a CRQC will arrive. Many expert forecasts place it somewhere in the 5 to 15 year range, with some bets around the early 2030s. There is wide uncertainty, but also strong funding from governments and big tech.
Security planners cannot wait until the first CRQC appears. By then, years of sensitive data might already be sitting in storage, ready to be cracked.
Studies like Secureworks’ analysis on predicting Q-day and the impact of breaking RSA-2048 show how serious the fallout could be once such a machine exists.
The Real Quantum Threat Today: Harvest Now, Decrypt Later
The biggest quantum danger right now has a simple name: harvest now, decrypt later.
Attackers can copy encrypted data today, store it, and wait. Once a CRQC is built, it can return to that stored data and use quantum tools to unlock it.
This is a problem for secrets that must stay private for many years. A health record, legal case file, or state secret can still matter a decade or two from now.
Why stolen encrypted data can still hurt years from now
Think about a few examples:
- A foreign intelligence group records encrypted government emails today. In 15 years, a CRQC could let them read everything, including messages that shaped policy or exposed informants.
- A criminal group records traffic from a major hospital’s VPN. Years later, they decrypt it and gain medical histories, insurance data, and personal details.
- Blockchain transactions that look anonymous today might be traced back to real people once related keys or side data are cracked.
The harm is delayed, but no less real. The clock on quantum risk starts when data is captured, not when it is finally decrypted.
Who should worry most about the quantum threat right now?
Some groups face higher quantum risk than others:
- Governments and defense organizations
- Critical infrastructure operators, such as power and water
- Banks and large financial firms
- Healthcare providers and insurers
- Tech and telecom companies with long-term customer data
Everyday users are also part of the picture. Even if one person is not a direct target, their records live inside large data sets. Once an attacker breaks into those sets in the future, one person’s messages, purchases, or location history can be used in scams, identity theft, or targeted ads.
How the World Is Fighting Back With Quantum-Safe Encryption
The good news is that cryptographers have not been sitting still. A whole field called post-quantum cryptography (PQC) designs algorithms that are hard for both normal and quantum machines.
The idea is simple. Replace vulnerable public key systems like RSA and ECC with new schemes that do not break under Shor’s algorithm. Make that switch before a CRQC comes online.
The U.S. National Institute of Standards and Technology (NIST) has been running a long process to pick quantum-safe algorithms. In 2022 and 2023, it announced finalists, and in 202,4 it started publishing formal standards.
What is post-quantum cryptography, and how is it different?
Post-quantum cryptography uses math problems that, as far as experts know, are hard even for Quantum Computers. Two common families are:
- Lattice-based schemes, which use problems about points on high-dimensional grids.
- Hash-based schemes, which build on one-way functions already used in many systems.
The key point is that the internet will not need quantum hardware to defend against quantum attacks. Quantum-safe algorithms will run on the same laptops, phones, and servers that people use now. It is mostly a software and protocol upgrade, not a hardware revolution.
NIST’s own explainer on what post-quantum cryptography is gives a clear overview of these new tools and the reasons behind them.
NIST’s new quantum-safe standards and why they matter
NIST has chosen three main algorithms for standardization:
- CRYSTALS-Kyber for key establishment
- CRYSTALS-Dilithium for digital signatures
- SPHINCS+ as a backup hash-based signature scheme
These names sound abstract, but their role is concrete. Browser makers, VPN vendors, and secure messaging apps can adopt these as new building blocks. That way, different products can speak the same quantum-safe “language”.
Many large companies and governments have already started testing Kyber and Dilithium in pilot systems. Over the next few years, these names will likely sit under the hood of browsers, operating systems, and cloud platforms.
Steps organizations can take now to prepare for Quantum Computers
Preparing for the quantum era does not require deep math expertise. Organizations can start with practical steps:
- Create a crypto inventory: Map where RSA, ECC, and other public key tools are used, such as TLS, VPNs, email, and code signing.
- Classify data by lifetime: Mark which data must stay secret for 5, 10, or 20 years or more.
- Test post-quantum options: Run pilot projects with PQC libraries, especially for long-lived systems.
- Use hybrid encryption: Combine classical algorithms with post-quantum ones during the transition. If either part stays secure, the whole connection does too.
- Plan for upgrades: Design systems so that algorithms can be swapped without ripping out entire products.
These steps spread out the work instead of forcing a rushed scramble once a CRQC appears.
What Everyday Users Should Do About the Quantum Threat
Individual users cannot control when Quantum Computers reach ch CRQC scale. They can, however, choose habits and tools that keep their data safer both now and later.
The key idea is simple. Attackers usually pick the easiest path. If passwords are weak and devices are not updated, there is no need for quantum tricks.
Simple habits that keep data safer today and tomorrow
A few basic habits make a big difference:
- Use a password manager and create strong, unique passwords for every account.
- Turn on multi-factor authentication wherever possible.
- Keep phones, laptops, and browsers updated so they get the latest security patches.
- Prefer secure messaging apps that use strong end-to-end encryption.
- Watch for phishing emails and fake login pages.
These steps reduce the chance that an attacker ever needs to think about Quantum Computers in the first place.
How to spot services moving toward quantum-safe security
Over the next few years, more products will start to mention quantum-safe features. Users may see terms like post-quantum, quantum-resistant, or PQC in update notes and security pages.
Some changes will be invisible, such as a browser quietly adding support for Kyber-based key exchange. Others will show up in marketing, as banks or cloud providers point to quantum-safe upgrades as a trust signal.
When choosing tools, it makes sense to favor services that talk clearly about long-term security plans, including post-quantum cryptography and strong default settings.
Conclusion
Quantum Computers are not yet tearing through real-world encryption, but they are no longer science fiction either. The same physics that make them powerful for research also make them a serious future threat to RSA, ECC, and the locks that protect the internet today.
The bigger risk has already started with the harvest now, decrypt later attacks. Encrypted data stolen today can become clear text in a quantum future if nothing changes.
Post-quantum cryptography offers a path forward. With new algorithms, careful planning, and steady upgrades, governments, companies, and everyday users can keep online life secure even after the first cryptographically relevant quantum computer arrives.
The key is to start preparing while there is still time on the clock, not after the locks have already failed.
