Quantum Computing and the Future of Web Security
Most of today’s web security quietly assumes attackers are stuck with classical hardware. Quantum computers break that assumption. This piece is a gentle primer on what that means for TLS and your database, and what "post‑quantum" actually looks like from a web developer’s point of view.
Quantum computing isn't just a cool demo from research labs anymore. We still don't have machines that can casually shred 4096‑bit RSA in a few seconds, but we've crossed the point where that future feels inevitable. The uncomfortable truth is that most of the public‑key crypto we rely on today, RSA and ECC in particular, has a giant "quantum break me" sign on it.
The Quantum Threat
The short version: quantum computers can use tricks like superposition and entanglement to chew through some maths problems dramatically faster than classical machines. Shor's algorithm is the headline act here; on a big enough quantum computer it turns factoring large numbers, the thing RSA relies on, from "effectively impossible" into "annoyingly feasible".
“We need to start preparing for post-quantum cryptography today, even if quantum computers are years away. The data we encrypt now may still be valuable when quantum computers arrive.”
Post-Quantum Cryptography
Post‑quantum cryptography (PQC) is our plan B: new algorithms that stay safe even in a world where Shor’s algorithm is practical. NIST has been slowly working through a long list of candidates and is in the process of standardising a handful of them, which means browser vendors and TLS libraries can start wiring them in without guessing.
- CRYSTALS-Kyber: Key encapsulation mechanism
- CRYSTALS-Dilithium: Digital signature algorithm
- SPHINCS+: Hash-based signatures
- FALCON: Compact digital signatures
Preparing Your Web Applications
The good news is that you don't need a physics degree to prepare. Start by mapping where you rely on RSA or ECC today, certificates, database encryption, internal services, and then keep an eye on PQC support in your tooling. Over the next few years "hybrid" setups that combine classical and post‑quantum algorithms will become the norm, giving us a long, fairly boring migration window instead of a cliff edge.
// Example: Hybrid key exchange
// Use both classical and post-quantum algorithms
const classicalKey = await generateECDHKey();
const pqKey = await generateKyberKey();
// Combine both keys
const hybridKey = combineKeys(classicalKey, pqKey);
// This provides security against both classical and quantum attacks
// during the transition periodThe Timeline
Most estimates put "cryptographically relevant" quantum computers at least a decade away, which sounds comforting until you remember how long it takes big organisations to change their crypto. The point isn’t to panic; it’s to quietly start the work now so that when the hardware catches up, your users’ data isn’t an easy time capsule for attackers.