computer science

NIST Post-Quantum Cryptography Standardization

NIST Post-Quantum Cryptography Standardization is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand NIST Post-Quantum Cryptography Standardization rather than just read about it. In short: Post-Quantum Cryptography Standardization is a program and competition by NIST to update their standards to include post-quantum cryptography. It was announced at PQCrypto 2016.

Key takeaways

NIST Post-Quantum Cryptography Standardization belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect NIST Post-Quantum Cryptography Standardization to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of NIST Post-Quantum Cryptography Standardization from memory before moving on to harder problems.

Reference excerpt

Post-Quantum Cryptography Standardization is a program and competition by NIST to update their standards to include post-quantum cryptography. It was announced at PQCrypto 2016. Twenty-three signature schemes and fifty-nine encryption/KEM schemes were submitted by the initial submission deadline at the end of 2017 of which sixty-nine total were deemed complete and proper and participated in the first round. Seven of these, of which three are signature schemes, advanced to the third round, which was announced in July 2020. On August 13, 2024, NIST released final versions of the first three Post Quantum Crypto Standards: FIPS 203, FIPS 204, and FIPS 205. On March 11, 2025 NIST released Hamming Quasi-Cyclic (HQC) as the fifth algorithm for post-quantum asymmetric encryption as used for key encapsulation / exchange.

Background Academic research on the potential impact of quantum computing dates back to at least 2001. A NIST published report from April 2016 cites experts that acknowledge the possibility of quantum technology to render the commonly used RSA algorithm insecure by 2030. As a result, a need to standardize quantum-secure cryptographic primitives was pursued. Since most symmetric primitives are relatively easy to modify in a way that makes them quantum resistant, efforts have focused on public-key cryptography, namely digital signatures and key encapsulation mechanisms. In December 2016 NIST initiated a standardization process by announcing a call for proposals.

Round one Under consideration were: (strikethrough means it had been withdrawn)

Round one submissions published attacks Guess Again by Lorenz Panny RVB by Lorenz Panny RaCoSS by Daniel J. Bernstein, Andreas Hülsing, Tanja Lange and Lorenz Panny HK17 by Daniel J. Bernstein and Tanja Lange SRTPI by Bo-Yin Yang WalnutDSA by Ward Beullens and Simon R. Blackburn by Matvei Kotov, Anton Menshov and Alexander Ushakov DRS by Yang Yu and Léo Ducas DAGS by Elise Barelli and Alain Couvreur Edon-K by Matthieu Lequesne and Jean-Pierre Tillich RLCE by Alain Couvreur, Matthieu Lequesne, and Jean-Pierre Tillich Hila5 by Daniel J. Bernstein, Leon Groot Bruinderink, Tanja Lange and Lorenz Panny Giophantus by Ward Beullens, Wouter Castryck and Frederik Vercauteren RankSign by Thomas Debris-Alazard and Jean-Pierre Tillich McNie by Philippe Gaborit; Terry Shue Chien Lau and Chik How Tan

Round two Candidates moving on to the second round were announced on January 30, 2019. They are:

Round three On July 22, 2020, NIST announced seven finalists ("first track"), as well as eight alternate algorithms ("second track"). The first track contains the algorithms which appear to have the most promise, and will be considered for standardization at the end of the third round. Algorithms in the second track could still become part of the standard, after the third round ends. NIST expects some of the alternate candidates to be considered in a fourth round. NIST also suggests it may re-open the signature category for new schemes proposals in the future. On June 7–9, 2021, NIST conducted the third PQC standardization conference, virtually. The conference included candidates' updates and discussions on implementations, on performances, and on security issues of the candidates. A small amount of focus was spent on intellectual property concerns.

Finalists

Alternate candidates

Intellectual property concerns After NIST's announcement regarding the finalists and the alternate candidates, various intellectual property concerns were voiced, notably surrounding lattice-based schemes such as Kyber and NewHope. NIST holds signed statements from submitting groups clearing any legal claims, but there is still a concern that third parties could raise claims. NIST claims that they will take such considerations into account while picking the winning algorithms.

Round three submissions published attacks Rainbow: by Ward Beullens on a classical computer

Adaptations During this round, some candidates have shown to be vulnerable to some attack vectors. It forces these candidates to adapt accordingly:

CRYSTAL-Kyber and SABER may change the nested hashes used in their proposals in order for their security claims to hold. FALCON side channel attack using electromagnetic measurements to extract the secret signing keys. A masking may be added in order to resist the attack. This adaptation affects performance and should be considered whilst standardizing.

Selected Algorithms 2022 On July 5, 2022, NIST announced the first group of winners from its six-year competition.

Round four On July 5, 2022, NIST announced four candidates for PQC Standardization Round 4.

Round four submissions published attacks SIKE: by Wouter Castryck and Thomas Decru on a classical computer

Selected Algorithm 2025 On March 11, 2025, NIST announced the selection of a backup algorithm for KEM.

First release On August 13, 2024, NIST released final versions of its first three Post Quantum Crypto Standards. According to the release announcement:

While there have been no substantive changes made to the standards since the draft versions, NIST has changed the algorithms’ names to specify the versions that appear in the three finalized standards, which are:

Federal Information Processing Standard (FIPS) 203, intended as the primary standard for general encryption. Among its advantages are comparatively small encryption keys that two parties can exchange easily, as well as its speed of operation. The standard is based on the CRYSTALS-Kyber algorithm, which has been renamed ML-KEM, short for Module-Lattice-Based Key-Encapsulation Mechanism. FIPS 204, intended as the primary standard for protecting digital signatures. The standard uses the CRYSTALS-Dilithium algorithm, which has been renamed ML-DSA, short for Module-Lattice-Based Digital Signature Algorithm. FIPS 205, also designed for digital signatures. The standard employs the SPHINCS+ algorithm, which has been renamed SLH-DSA, short for Stateless Hash-Based Digital Signature Algorithm. The standard is based on a different math approach than ML-DSA, and it is intended as a backup method in case ML-DSA proves vulnerable. Similarly, when the draft FIPS 206 standard built around FALCON is released, the algorithm will be dubbed FN-DSA, short for FFT (fast-Fourier transform) over NTRU-Lattice-Based Digital Signature Algorithm.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with NIST Post-Quantum Cryptography Standardization

Start with the simplest possible case. Write down what NIST Post-Quantum Cryptography Standardization claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to NIST Post-Quantum Cryptography Standardization before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about NIST Post-Quantum Cryptography Standardization ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of NIST Post-Quantum Cryptography Standardization

In research: NIST Post-Quantum Cryptography Standardization appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses NIST Post-Quantum Cryptography Standardization in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: NIST Post-Quantum Cryptography Standardization is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cryptography contests, Cryptography standards, Post-quantum cryptography, so understanding it makes those chapters shorter.
In everyday life: Look for NIST Post-Quantum Cryptography Standardization outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study NIST Post-Quantum Cryptography Standardization in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what NIST Post-Quantum Cryptography Standardization means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain NIST Post-Quantum Cryptography Standardization out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is NIST Post-Quantum Cryptography Standardization in simple terms?

Post-Quantum Cryptography Standardization is a program and competition by NIST to update their standards to include post-quantum cryptography. It was announced at PQCrypto 2016.

Why does NIST Post-Quantum Cryptography Standardization matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study NIST Post-Quantum Cryptography Standardization?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on NIST Post-Quantum Cryptography Standardization.