Dustin Moody
Post Quantum Cryptography TeamNational Institute of Standards and Technology (NIST)

When will a quantum computer be built that breaks current crypto?
◦ 15 years, $1 billion USD, nuclear power plant (to break RSA-2048)(PQCrypto 2014, Matteo Mariantoni)Impact:◦ Public key crypto: FIPS 186-4, SP 800-56A/56B
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RSA
Elliptic Curve Cryptography (ECDSA)
Finite Field Cryptography (DSA)
Diffie-Hellman key exchange◦ Symmetric key crypto: FIPS 197, SP 800-57
 AES
 Triple DES◦ Hash functions: FIPS 180-4, FIPS 202 SHA-1, SHA-2 and SHA-3

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When will a quantum computer be built?

◦ 15 years, $1 billion USD, nuclear power plant(PQCrypto 2014, Matteo Mariantoni) Impact:◦ Public key crypto:
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RSA
Elliptic Curve Cryptography (ECDSA)
Finite Field Cryptography (DSA)
Diffie-Hellman key exchange◦ Symmetric key crypto:
 AES
 Triple DES◦ Hash functions:

Need larger keys
Need larger keys

 SHA-1, SHA-2 and SHA-3

Use longer outputHow long does encryption need to be secure (x years)
How long to re-tool existing infrastructure with quantum safe
solution (y years)
How long until large-scale quantum computer is built (z years)
Theorem (Mosca): If x + y > z, then worry
What do we do here??

yxz

secret keys revealedtime

NSA is transitioning in the “not too distant” future <https://www.iad.gov/iad/programs/iad-initiatives/cnsa-suite.cfm>
European PQCrypto projectETSI work
IETF – hash-based signature RFC’s
NIST report - <http://csrc.nist.gov/publications/drafts/nistir-8105/nistir_8105_draft.pdf>

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NIST is calling for quantum-resistant cryptographic
algorithms for new public-key crypto standards◦ Digital signatures◦ Encryption/key-establishment

We see our role as managing a process of achieving
community consensus in a transparent and timely manner

We do not expect to “pick a winner”

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We may pick one (or more) for standardization◦ Ideally, several algorithms will emerge as ‘good choices’◦ Only algorithms publicly submitted considered Fall 2016 – formal Call For Proposals
 Nov 2017 – Deadline for submissions
 3-5 years – Analysis phase◦ NIST will report its findings
 2 years later - Draft standards ready Workshops◦ Early 2018 – submitter’s presentations◦ One or two during the analysis phase

Post-quantum cryptography is more complicatedthan AES or SHA-3◦ No silver bullet - each candidate has some disadvantage◦ Not enough research on quantum algorithms to ensure
confidence for some schemes

We do not expect to “pick a winner”

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We may narrow our focus at some point

Requirements/timeline could potentially change
based on developments in the field◦ Ideally, several algorithms will emerge as ‘good choices’◦ This does not mean algorithms are “out”

 The formal Call will have detailed submission

requirements◦

A complete written specification of the algorithms shall be included, consisting of all necessary mathematicaloperations, equations, tables, diagrams, and parameters that are needed to implement the algorithms. The
document shall include design rationale and an explanation for all the important design decisions that are made.

 Minimal acceptability requirements◦ Publicly disclosed and available with no IPR◦ Implementable in wide range of platforms◦ Provides at least one of: signature, encryption, or keyexchange◦ Theoretical and empirical evidence providing justification
for security claims Implementation◦ Reference version◦ Optimized version

 Cryptographic API will be provided◦ Can call approved hash functions, block ciphers,
modes, etc…

 Known Answer and Monte Carlo tests
 Optional – constant time implementation Signed statements◦ Submitted algorithm◦ Implementations

 Disclose known patent information

 Available worldwide without royalties or any

intellectual property restrictions during theanalysis phase◦ Submitters can reclaim rights by withdrawing
submission from consideration

 To be detailed in the formal Call

◦ Security◦ Cost (computational and memory)◦ Algorithm and implementation characteristics

 Draft criteria will be open for public comment
 We strongly encourage public evaluation andpublication of results concerning submissions

 NIST will summarize the evaluation results andreport publicly

Target security levels

Correct security definitions?

Quantum/classical algorithm complexity◦ 128 bits classical security◦ 64/80/96/128 bits quantum security?

◦ IND-CCA2 for encryption◦ EUF-CMA for signatures◦ CK best for key exchange?

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Stability of best known attack complexity
Precise security claim against quantum computation
Parallelism?
Attacks on multiple keys?
How many chosen ciphertext queries allowed?

Security proofs

Quality and quantity of prior cryptanalysis

 Computational efficiency◦ Hardware and software Key generation
 Encryption/Decryption
 Signing/Verification
 Key exchange Memory requirements◦ Concrete parameter sets and key sizes for target
security levels◦ Ciphertext/signature size Ease of implementation◦ Tunable parameters◦ Implementable on wide variety of platforms andapplications◦ Parallelizable◦ Resistance to side-channel attacks

 Ease of use◦ How does it fit in existing protocols (such as TLS or IKE)
◦ Misuse resistance Simplicity

How is the timeline? Too fast? Too slow?

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How to determine if a candidate is mature enough for standardization?

Should we just focus on encryption and signatures, or should we also
consider other functionalities?

How many "bits of security" do we need against quantum attacks?

How can we encourage more work on quantum cryptanalysis? Maybe weneed "challenge problems"?

How can we encourage people to study practical impacts on the existing
protocols?

◦ Do we need an ongoing process, or is one time enough?
◦ hash-based signatures for code signing◦ For example, key sizes may be too big

 NIST is calling for quantum-resistant algorithms◦ We see our role as managing a process of achieving
community consensus in a transparent and timelymanner◦ Different from (but similar to) AES/SHA-3 competitions

 We don’t have all the answers

 Wanted: Postdocs, guest researchers at NIST We would like public feedback◦ Email: pqc-comments@nist.gov◦ PQC forum: pqc-forum@nist.gov