Post-Quantum Cryptography
Post-quantum cryptography (PQC) refers to cryptographic algorithms designed to remain secure against attacks from both classical and quantum computers. It exists because a sufficiently large quantum computer could run Shor's algorithm to efficiently break the math — integer factoring and discrete logarithms — that today's widely used RSA and ECC (elliptic-curve) algorithms rely on. NIST ran a multi-year public competition to standardize PQC algorithms, publishing the first finalized standards, including the signature standard Certivu uses, in 2024.
Why classical cryptography is at risk
RSA and elliptic-curve cryptography (ECC/ECDSA) — the algorithms behind most of today's digital signatures and key exchange — derive their security from problems that are hard for classical computers but that Shor's algorithm, published by mathematician Peter Shor in 1994, can solve efficiently on a large enough quantum computer. No such machine exists yet at the scale needed to break real-world keys, but the risk isn't only about the future: data or signatures that must stay trustworthy for years can be undermined once capable quantum hardware arrives, even if it arrives after the content was created.
NIST's standardization effort
In 2016, NIST opened a public call for post-quantum algorithm submissions, running a multi-round evaluation with cryptographers worldwide before announcing its first selections in 2022. That process produced FIPS 203 (a key-encapsulation mechanism), FIPS 204 (the ML-DSA digital signature standard, derived from CRYSTALS-Dilithium), and FIPS 205 (a hash-based signature standard), all finalized and published in August 2024. These standards rest on different hard math problems — primarily structured lattices — with no known efficient quantum attack. See NIST FIPS 204 & CRYSTALS-Dilithium for a deeper look at the standardization process.
Why it matters for signed content
A digital signature is only as durable as the algorithm behind it. Content or records signed today may need to remain verifiable a decade or more from now, so choosing a post-quantum algorithm at the outset avoids a disruptive re-signing migration later. Certivu signs all content provenance exclusively with ML-DSA and does not use RSA or ECC anywhere in its signing stack.
Source: NIST Post-Quantum Cryptography Project
FAQ
Is post-quantum cryptography needed today if quantum computers can't break RSA yet?
Yes, for anything that needs to stay verifiable for a long time. Even though no current quantum computer can break real-world RSA or ECC keys, signatures and records created now may still need to be trusted years into the future — well within the window many researchers consider plausible for capable quantum hardware to exist.
What's the difference between post-quantum encryption and post-quantum signatures?
Both are part of PQC but solve different problems. Key-encapsulation/encryption standards like FIPS 203 protect data confidentiality; digital signature standards like FIPS 204/ML-DSA protect authenticity and integrity — proving who signed something and that it hasn't been altered. Certivu only needs the signature side, since it verifies provenance, not confidentiality.
Does post-quantum cryptography use the same public/private key model as RSA?
Conceptually yes — PQC algorithms still use a private key to sign and a public key to verify, the same digital signature verification model used everywhere in cryptography. What changes is the underlying math problem, replacing factoring or elliptic curves with structured lattice problems believed hard even for quantum computers.