Why post-quantum, and why now
You will be able to explain which part of a normal chain a quantum computer breaks, and what "harvest now, decrypt later" means for money.
The exposed part
It is the signature, not the hashing.
Bitcoin and Ethereum prove ownership with elliptic-curve signatures. Shor's algorithm, on a large enough quantum computer, recovers the private key from the public key those schemes publish. Hashing is far more resilient: Grover's algorithm only halves the effective strength of a hash, which a 256-bit hash absorbs. So the danger is concentrated in exactly one place — the thing that authorises a payment.
Illustration to come
Real photograph: a handwritten signature on paper under a magnifying lens, sharp on the signature. Human, tactile, slightly imperfect — it must not look like a stock "cyber security" image.
The timing argument
A key you publish today is a key an adversary can keep.
"Harvest now, decrypt later" is the reason this cannot wait for the machine to exist. Every public key and every signature ever broadcast is already recorded by anyone who cared to record it. The day a cryptographically relevant quantum computer arrives, that archive becomes a list of keys to recover — retroactively, over coins that were spent years earlier from addresses whose public keys are now known.
Illustration to come
Real photograph of an archival tape library or long-term storage racks. Cold, industrial, unglamorous. It illustrates the "harvest" half: somebody is keeping all of this already.
The standards
Not a homemade scheme — the ones NIST finalised.
In 2024 NIST published FIPS 203, 204 and 205: ML-KEM for key exchange, ML-DSA for signatures, SLH-DSA as a hash-based alternative. VigiChain signs with ML-DSA-65 (FIPS 204). This matters more than any clever design would: a monetary network that invented its own post-quantum mathematics would be asking users to trust a scheme nobody has spent a decade attacking.
Illustration to come
Real photograph: printed, tabbed standards documents (FIPS-style covers, no fabricated logos) stacked on a desk with a pen. Suggests published, reviewed, boring-in-a-good-way rigour.
The honest boundary
This protects what VigiChain signs. It does not protect other chains.
A wallet can hold bitcoin, ether and solana beside VIGI, and those assets are signed with their own chains' classical curves. No wallet can change that; only those networks can. What is post-quantum here is what VigiChain itself carries — its signatures, its consensus and its identities — and any lesson, page or product that blurs this line is selling you something.
Illustration to come
Real photograph: an umbrella sheltering part of a table while the rest is wet. The metaphor must be legible without a caption — protection with a visible edge to it.
In short
- Quantum computers threaten the signature scheme, not the hash function.
- Recorded public keys make the threat retroactive, which is why the change had to happen before the machine exists.
- VigiChain signs with ML-DSA-65 from FIPS 204 — a finalised standard, not a private invention.
- Assets from other chains held in the same wallet remain as post-quantum as those chains are: not at all.
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