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.