Quantum Computing: What Businesses Should Know and How to Prepare

Quantum computing has a reputation problem. Depending on who you ask, it is either about to transform every industry or a perpetual science project that is always ten years away. The truth sits somewhere in between, and for most businesses the most urgent quantum question is not “how do we use a quantum computer?” It is “how do we protect our data from one?”

That is because a sufficiently powerful quantum computer would be able to break much of the public-key cryptography that secures the internet today. Nobody can say exactly when such a machine will exist, but the work required to upgrade cryptography across an organization takes years, and some data being stolen today could still be sensitive when that day arrives.

In this guide, we explain what quantum computers are, where they might genuinely help, why they threaten current encryption, what the new post-quantum cryptography standards are, and a step-by-step readiness plan you can start now.

Quantum Computing in Plain Language

Classical computers process information in bits, which are either 0 or 1. Quantum computers use qubits, which can exist in a superposition of 0 and 1 at the same time. Qubits can also be entangled, meaning their states are linked in ways that have no classical equivalent. Quantum algorithms use interference to amplify the probability of correct answers and cancel out wrong ones.

The result is not a faster general-purpose computer. A quantum computer will not run your spreadsheet or website faster. Instead, it offers potentially dramatic speedups for specific kinds of problems where these quantum effects can be exploited.

Why it is so hard

Qubits are extremely fragile. Heat, vibration, and electromagnetic noise cause them to lose their quantum state, a process called decoherence, which introduces errors. Many hardware approaches require extreme cooling or isolation. Today’s machines are often described as noisy intermediate-scale quantum (NISQ) devices: useful for research, but too error-prone for many of the applications people get excited about.

The path forward is quantum error correction, which combines many physical qubits into more reliable logical qubits. Researchers and companies have reported meaningful progress on error correction in recent years, but building large numbers of high-quality logical qubits remains a major engineering challenge.

Competing hardware approaches

Several technologies are in the race, each with different strengths:

• Superconducting qubits, used by several large technology companies.
• Trapped ions, which offer high-fidelity operations.
• Neutral atoms, held in place by lasers.
• Photonic qubits, which use particles of light.
• Spin qubits in silicon, which may leverage existing chip manufacturing.
• Topological qubits, an approach that aims for inherently more stable qubits and is still at an early stage.

It is not yet clear which approach, or combination, will dominate.

Where Quantum Computing Could Help Business

It is worth being careful here, because this area attracts a lot of hype. The applications researchers consider most promising include:

• Chemistry and materials science. Simulating molecules and materials is naturally suited to quantum computers and could aid drug discovery, battery chemistry, and catalyst design.
• Optimization. Some logistics, scheduling, and portfolio problems may benefit, though it remains an open research question how large any practical advantage will be over the best classical methods.
• Machine learning. Quantum approaches to machine learning are an active research area, but practical advantages are not yet established.
• Cryptanalysis. Breaking certain encryption schemes, which is the reason security teams are paying close attention.

For most businesses today, the practical way to explore quantum computing is through cloud-based access offered by major providers and quantum hardware companies, which lets teams experiment without buying hardware. If you work in pharmaceuticals, chemicals, materials, finance, or logistics, it may be worth having a small team track developments and run experiments. For everyone else, the priority is cryptography.

Why Quantum Threatens Today’s Encryption

Most secure communication on the internet relies on public-key cryptography, such as RSA and elliptic curve cryptography. These systems are secure because certain math problems, factoring large numbers and computing discrete logarithms, are practically impossible for classical computers to solve at the key sizes we use.

In 1994, mathematician Peter Shor described a quantum algorithm, now known as Shor’s algorithm, that could solve these problems efficiently on a large enough quantum computer. That would break RSA, elliptic curve Diffie-Hellman, and the digital signature schemes widely used to secure websites, software updates, VPNs, email, and much more.

Symmetric encryption, such as AES, is much less affected. Another quantum algorithm, Grover’s algorithm, offers a quadratic speedup for brute-force searches, which effectively halves the security level of a key. The common guidance is that using larger keys, such as AES-256, keeps symmetric encryption comfortably secure.

Harvest now, decrypt later

The most pressing reason to act now is a strategy known as harvest now, decrypt later. An adversary can capture encrypted data today and store it, waiting until a capable quantum computer exists to decrypt it. If your data needs to remain confidential for many years, such as health records, intellectual property, government information, financial data, or long-lived secrets, it may already be at risk from future decryption.

Key takeaway: You do not need to know exactly when a cryptographically relevant quantum computer will arrive. If your data must stay secret for years, and migrating your cryptography will itself take years, the time to start preparing is now.

The New Post-Quantum Cryptography Standards

Post-quantum cryptography (PQC) refers to new cryptographic algorithms that run on today’s classical computers but are designed to resist attacks from both classical and quantum computers. They are based on mathematical problems, such as those involving lattices and hash functions, that are believed to be hard even for quantum machines.

After a multi-year public competition and evaluation process, the US National Institute of Standards and Technology (NIST) published its first three finalized post-quantum standards in August 2024:

• FIPS 203 (ML-KEM): a key encapsulation mechanism, derived from CRYSTALS-Kyber, used to establish shared secret keys. It is the primary replacement for key exchange.
• FIPS 204 (ML-DSA): a digital signature algorithm, derived from CRYSTALS-Dilithium, intended as the main general-purpose signature standard.
• FIPS 205 (SLH-DSA): a stateless hash-based digital signature algorithm, derived from SPHINCS+, providing a backup signature method based on different mathematics.

NIST has continued its work, including selecting an additional key encapsulation algorithm, HQC, as a backup to ML-KEM, and developing a further signature standard based on the FALCON algorithm. NIST has also published draft guidance on transitioning away from quantum-vulnerable algorithms, proposing that they be deprecated by 2030 and disallowed by 2035 for US federal systems. Other governments and standards bodies are issuing their own guidance, so check the requirements relevant to your sector and region.

Hybrid approaches

During the transition, many systems use hybrid key exchange, combining a traditional algorithm with a post-quantum one, so a connection remains secure as long as either algorithm holds up. Major web browsers and content delivery networks have already begun deploying hybrid post-quantum key exchange for TLS connections, which means some of your web traffic may already be protected without you doing anything.

Your Post-Quantum Readiness Plan

Migrating cryptography is less like flipping a switch and more like a large infrastructure modernization project. Here is a practical roadmap.

Step 1: Assign ownership and build awareness

Make someone accountable for post-quantum readiness, typically within the security team, with sponsorship from leadership. Brief executives on the risk in business terms: data confidentiality, regulatory expectations, and long-term trust.

Step 2: Build a cryptographic inventory

You cannot migrate what you cannot find. Identify where and how your organization uses cryptography:

• TLS on websites, APIs, and internal services.
• VPNs and remote access.
• Code signing and software update mechanisms.
• Public key infrastructure and certificates.
• Data encryption in databases, backups, and storage.
• Hardware security modules and key management systems.
• Embedded devices, IoT, and operational technology.
• Third-party software and SaaS providers.

Some organizations formalize this as a cryptographic bill of materials (CBOM), similar to a software bill of materials.

Step 3: Prioritize by data lifetime and exposure

Rank systems by how long the data they protect must stay confidential, how exposed they are to interception, and how hard they will be to upgrade. Long-lived sensitive data and hard-to-update systems, such as devices in the field for many years, deserve early attention.

Step 4: Talk to your vendors

Much of your cryptography lives inside products you buy. Ask vendors about their post-quantum roadmaps, when they will support the NIST standards, and whether they offer hybrid modes. Add post-quantum requirements to procurement criteria for new purchases.

Step 5: Build crypto-agility

Crypto-agility is the ability to swap cryptographic algorithms without redesigning systems. Avoid hard-coding algorithms, centralize cryptographic functions in well-maintained libraries, and make sure you can rotate keys and certificates efficiently. This pays off for post-quantum migration and for any future algorithm changes.

Step 6: Pilot and test

Test post-quantum and hybrid algorithms in non-production environments. Post-quantum keys and signatures are often larger than their classical counterparts, which can affect performance, bandwidth, and compatibility with older devices or network equipment. Find these issues early.

Step 7: Migrate in phases

Start with high-priority systems, typically key exchange for data in transit, since that is what harvest-now-decrypt-later attacks target. Signatures, PKI, and embedded systems often follow, as they can require more coordination.

A Quantum Readiness Checklist

• An executive sponsor and an owner for post-quantum readiness are named.
• Leadership understands the harvest-now-decrypt-later risk.
• We have started a cryptographic inventory, including third-party products.
• Systems are prioritized by data sensitivity, lifetime, and upgrade difficulty.
• Key vendors have shared their post-quantum roadmaps.
• New procurement includes post-quantum and crypto-agility requirements.
• Symmetric encryption uses strong key sizes such as AES-256 where appropriate.
• We have tested hybrid or post-quantum algorithms in a lab environment.
• A phased migration plan exists, aligned with relevant regulatory timelines.

Conclusion: Prepare Calmly, Start Early

Quantum computing is real, it is progressing, and its long-term impact on science and industry could be significant. But for most businesses, the most important action is not buying quantum computing time; it is getting cryptography ready for a post-quantum world.

The standards are here, the tools are maturing, and parts of the internet have already begun the switch. Start with ownership and an inventory, prioritize by data lifetime, press your vendors for roadmaps, and build crypto-agility into everything new. Doing this steadily now is far less painful, and far less risky, than scrambling later.