Post-Quantum Cryptography: The Algorithms That Survive
The good news: quantum computers can’t break everything
The Problem—And the Solution
Quantum computers will break RSA and ECDSA, the cryptographic algorithms protecting most cryptocurrency today. That’s the nightmare scenario keeping security researchers awake at night.
But here’s what the panic headlines miss: quantum computers cannot break all cryptography. Some mathematical problems remain hard even for quantum machines. And cryptographers have spent decades designing algorithms specifically built to resist quantum attacks.
This is post-quantum cryptography (PQC)—encryption and signatures that work on your regular computer but can’t be cracked by quantum computers. The math is different. The assumptions are different. And for cryptocurrency investors, understanding which projects are adopting PQC is the difference between protecting your portfolio and watching it evaporate.
Why This Matters to Investors: Coins adopting NIST-standard PQC algorithms are following the proven, vetted path. Coins inventing their own “quantum-resistant” schemes are rolling the dice. Coins ignoring PQC entirely are gambling that quantum computers stay 10+ years away—and that when they arrive, governance will move fast enough to save the network.
The NIST Competition: Crypto’s Olympics
In 2016, the U.S. National Institute of Standards and Technology (NIST) launched a global competition to identify the best post-quantum algorithms. Over six years, cryptographers worldwide submitted candidates, which were then attacked, analyzed, and stress-tested by the research community.
The result? In 2022, NIST selected the winners. In 2024, the standards were finalized. These are the algorithms the world will use to defend against quantum computers:
- CRYSTALS-Kyber — Public-key encryption for secure communications
- CRYSTALS-Dilithium — Digital signatures for transactions and authentication
- SPHINCS+ — Hash-based backup signatures (ultra-conservative)
- FALCON — Compact signatures (smaller than Dilithium, harder to implement)
For cryptocurrency, Dilithium is the critical one—it replaces ECDSA for transaction signatures. If a blockchain project tells you they’re “quantum-ready” but isn’t using Dilithium (or a NIST-equivalent), ask why.
The Four Families of PQC
NIST’s winners come from different mathematical families, each with unique strengths and trade-offs:
1. Lattice-Based Cryptography
Examples: Kyber, Dilithium, FALCON
The idea: Security relies on finding the shortest path through a multi-dimensional lattice—a problem that’s hard for classical and quantum computers.
Why it wins: Good performance, reasonable signature sizes, extensive cryptanalysis. Most projects exploring PQC are choosing lattice-based schemes.
2. Hash-Based Signatures
Examples: SPHINCS+, XMSS
The idea: Security relies only on hash functions (like SHA-256). If SHA is secure, the signature is secure—even against quantum.
Why it’s special: Provably secure assumptions (not relying on unproven math). The catch: Massive signature sizes (7-49 KB versus 64 bytes for ECDSA).
3. Code-Based Cryptography
Examples: Classic McEliece
Why it’s rare: Huge public keys (hundreds of KB). Not practical for blockchain.
Go Deeper: Explore the Technical Details
NIST Algorithms Explained
Kyber, Dilithium, SPHINCS+—how they work, why they were chosen, and what they mean for blockchain performance.
Hybrid Cryptography
Why many projects are using both classical and post-quantum signatures during the transition—the belt-and-suspenders approach.
Lattice-Based Crypto
The math behind Dilithium and Kyber—why lattice problems are hard for quantum computers and what risks remain.
Hash-Based Signatures
SPHINCS+ and why hash-based schemes are the “nuclear bunker” of post-quantum security—provably secure but impractical for high-frequency use.
Which Cryptocurrencies Are Using PQC?
See our live rankings and case studies tracking which projects have adopted post-quantum algorithms—and which are still vulnerable.