The Quantum Era for Blockchains: Not Hype, but Engineering Preparation for the Inevitable
The development of quantum computing is not the plot of a science fiction novel, but a very real technological challenge that threatens the very foundation of modern blockchain security—digital signature algorithms. The industry is aware of this and is already actively implementing post-quantum cryptography (PQC). Today, we'll explore where real preparation is happening and where it's just a trendy label.
Briefly about the main point: why PQC, not quantum physics
Developers are preparing networks for a new era by changing cryptography. Powerful quantum computers capable of breaking Bitcoin do not yet exist. However, the "harvest now, decrypt later" (HNDL) threat is already real: attackers archive intercepted traffic while waiting for the necessary computing power. Shor's algorithm on a sufficiently powerful machine can solve the problems that underpin all modern public-key cryptography—ECDSA, EdDSA, Schnorr signatures. Symmetric algorithms and hash functions remain resistant for now, but elliptic curve schemes are vulnerable.
PQC is mathematics, not physics. It involves replacing signature algorithms with new ones that work on conventional hardware today. The foundation is three standards approved by NIST in August 2024:
- ML-KEM (key exchange, formerly CRYSTALS-Kyber);
- ML-DSA (digital signatures, formerly CRYSTALS-Dilithium);
- SLH-DSA (hash-based signatures, formerly SPHINCS+).
A fourth standard, FN-DSA based on FALCON, is in the final stage.
Who is preparing seriously, and who is just slapping on labels
Some projects are inherently quantum-resistant from the start. QRL has been built on hash-based signatures since its launch. Algorand uses the Falcon lattice-based signature in its State Proofs for cross-chain verification. This is engineering work, not marketing.
With the flagships, it's more complicated. Discussions are ongoing in the Bitcoin and Ethereum communities. For the first cryptocurrency, two proposals are being considered: BIP-360 (a new P2MR output type that eliminates the vulnerable public key) and BIP-361 (a phased migration away from ECDSA and Schnorr signatures over five years). In Ethereum, account abstraction is seen as a key tool, allowing wallets to transition to PQC without a hard fork.
Who else is in the game?
- Blueshift launched the Winternitz Vault solution on Solana with one-time quantum-resistant signatures.
- Ripple revealed a multi-phase plan for the XRP Ledger.
- Circle is promoting Arc as a natively quantum-resistant blockchain.
- Zcash includes a mechanism for recovery after quantum compromise.
My expert opinion
Quantum resistance is not a race for hype, but tedious yet critically important engineering work. Check project claims: do they use standardized NIST algorithms, is there open source code and audits, is a migration plan for existing addresses described? The term "quantum-resistant" has become a trendy label, but real protection lies in dates, standards, and code, not loud announcements. The industry is moving in the right direction, but the pace of migration must accelerate: the HNDL threat is already here, and waiting for "quantum day" X without preparation means playing with fire.