Geometric lattice with one node highlighted, illustrating post-quantum cryptography

Post-Quantum Cryptography for People Who Aren’t Cryptographers

By Resolute Security

Field notes from a senior-led security practice

Every few months I get a forwarded email from a client. The subject line is some flavor of “quantum threat” and the body is a vendor warning that quantum computers will break their encryption and they should buy a quantum-safe something for $20,000. The first time you see one of these, it’s alarming. The fifth time, you start wondering how much of it is real.

The short answer: there’s a real story underneath all the marketing, but it doesn’t require panic, and it doesn’t require buying anything urgent. Here’s the version without the jargon.

What quantum computers actually do

Modern encryption, the stuff that protects your bank logins, your email, your customer data, mostly relies on a single mathematical idea: it’s easy to multiply two large prime numbers together, and very hard to do the reverse. Modern computers can’t reverse it in any reasonable amount of time. So your data stays encrypted.

Quantum computers, hypothetically, can. There’s an algorithm called Shor’s algorithm, invented in 1994, that can factor those numbers efficiently if you run it on a sufficiently large quantum computer. Sufficiently large is the key phrase. The biggest quantum computer in 2026 has about a thousand qubits. To break the RSA encryption protecting your email, you’d need somewhere between several million and several billion of them. That’s not a small engineering problem.

Estimates of when this becomes practical range from “ten years” to “never.” Most cryptographers I trust land somewhere around fifteen to twenty-five years. There is genuine debate.

Why people are talking about it anyway: harvest now, decrypt later

Here’s the part of the story that’s actually concerning. Nation-state intelligence services have, for years, been quietly collecting encrypted internet traffic, VPN connections, encrypted file transfers, anything they can grab. They can’t decrypt it today. But if they store it, and quantum computers eventually arrive, they’ll be able to decrypt it then.

This means data being sent today that needs to stay secret for twenty-plus years, trade secrets, classified material, certain medical records, attorney-client communications, has a meaningful quantum risk right now. Not because someone can read it today. Because someone is saving it for later.

For most SMBs, this isn’t a serious concern. The vast majority of your data has a useful life of a few years at most. By the time quantum computers can break today’s encryption, the data they’d decrypt about your business will be commercially irrelevant.

What NIST has actually done

While the vendors have been writing scare emails, the National Institute of Standards and Technology has been doing the unglamorous work of solving the problem. In 2024, NIST finalized the first standardized post-quantum cryptography algorithms, primarily ML-KEM (a key-exchange method, formerly called Kyber) and ML-DSA (a digital signature method, formerly called Dilithium). Real mathematicians worked on these for years. They’ve been scrutinized by other real mathematicians. They’re good.

These algorithms are being rolled into TLS, SSH, VPN protocols, and operating systems over the next few years. When you renew your laptop’s OS in 2027 or 2028, you’ll quietly get post-quantum cryptography. It will happen the same way you got HTTPS everywhere, through your existing software vendors, not through a separate purchase.

What you should actually do

For 95% of SMBs, my advice is: do nothing right now. Don’t buy quantum-safe products. Don’t replace any infrastructure. The vendors will do the work for you.

Three things you should plan for over the next two to three years:

  1. Inventory your cryptography. Where do you use TLS? Where do you use VPNs? Where are you doing internal encryption? You don’t need to act on this list yet, but you’ll want it ready when the migrations start.
  2. Check that your vendors have a post-quantum plan. Especially anyone storing your data long-term, backup vendors, archival services, document management. If they shrug, that’s a signal.
  3. For high-stakes long-lived data, trade secrets, M&A material, CUI, start asking specific questions now. If you’re a defense contractor, your CMMC assessor will start asking about post-quantum readiness soon enough.

That’s it. That’s the whole strategy. If a vendor is selling you something urgent, the urgency is probably about hitting their quarterly number.

The math behind post-quantum cryptography is intimidating, but the business decisions aren’t. Patient, boring planning beats panic every time.

Further reading