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Glossary

Post-Quantum Cryptography

Post-Quantum Cryptography (PQC) refers to cryptographic algorithms designed to be secure against an attack by a quantum computer, ensuring long-term security for encrypted data and digital signatures.
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CRYPTOGRAPHY

What is Post-Quantum Cryptography?

Post-Quantum Cryptography (PQC) refers to cryptographic algorithms designed to be secure against an attack by a quantum computer, ensuring long-term security for encrypted data and digital signatures.

Post-Quantum Cryptography (PQC) comprises cryptographic algorithms designed to be secure against cryptanalytic attacks launched by both classical and future quantum computers. It addresses the threat posed by Shor's algorithm, which can efficiently break widely used public-key systems like RSA and ECC. The goal is to create a cryptographic transition to new, quantum-resistant standards before large-scale quantum computers become operational, protecting sensitive data with long-term confidentiality requirements.

PQC algorithms are based on mathematical problems considered hard for quantum computers to solve, such as lattice-based cryptography, code-based cryptography, and hash-based signatures. For Edge AI security, PQC is critical for protecting model weights, inference data, and device authentication in distributed environments. It ensures that encrypted communications and stored data remain secure over decades, forming a foundational component of a preemptive algorithmic cybersecurity posture against future quantum adversaries.

CRYPTOGRAPHIC FOUNDATIONS

Key Mathematical Approaches in PQC

Post-Quantum Cryptography (PQC) is built on mathematical problems believed to be intractable for both classical and quantum computers. These approaches form the bedrock of algorithms selected for standardization by bodies like NIST.

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Multivariate Cryptography

This approach is based on the hardness of solving systems of multivariate quadratic polynomials over finite fields. The secret is a structured, easily invertible multivariate map, while the public key is its disguised, complex form.

  • Key Algorithms: CRYSTALS-Dilithium (uses structured lattices, but general multivariate schemes exist).
  • Typical Use: Primarily for digital signatures (e.g., Rainbow, though it was broken in later analysis).
  • Operation: Signing involves using the secret trapdoor to find a solution to the public system of equations. Verification checks that the solution satisfies the public polynomials.
  • Consideration: Many historical multivariate schemes have been broken, highlighting the need for careful parameter selection and design.
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Isogeny-Based Cryptography

A more recent approach that uses the mathematical theory of elliptic curves, but derives security from the difficulty of computing an isogeny (a special kind of map) between two supersingular elliptic curves, rather than from the discrete logarithm problem.

  • Key Algorithms: SIKE (Supersingular Isogeny Key Encapsulation), though it was later found to have a potential vulnerability.
  • Core Problem: The Supersingular Isogeny Diffie-Hellman (SIDH) problem.
  • Advantage: Offers very small key sizes compared to other post-quantum schemes.
  • Status: An active area of research; the cryptanalysis of SIKE demonstrated the relative youth and evolving understanding of this mathematical area for cryptography.
GLOSSARY

Why PQC is Critical for Edge AI Security

Post-Quantum Cryptography (PQC) is the development of cryptographic algorithms designed to be secure against cryptanalytic attacks by quantum computers, ensuring long-term data protection.

Post-Quantum Cryptography (PQC) comprises algorithms like lattice-based, code-based, and multivariate cryptography, designed to replace current public-key standards (RSA, ECC) that quantum computers could break. For Edge AI, this is foundational: models, inference data, and Over-The-Air (OTA) updates transmitted across untrusted networks require encryption that remains secure for decades, protecting intellectual property and sensitive operational data from future quantum-enabled adversaries.

Edge devices often lack the physical security of data centers, making cryptographic agility—the ability to update algorithms post-deployment—essential. Integrating PQC with hardware roots of trust like Trusted Platform Modules (TPMs) and using Authenticated Encryption for data-in-motion creates a defense-in-depth strategy. This preemptively secures the AI supply chain against harvest-now, decrypt-later attacks, where data is intercepted today for decryption by future quantum computers.

CRYPTOGRAPHIC PARADIGM COMPARISON

Classical vs. Post-Quantum Cryptography

A technical comparison of cryptographic algorithm families based on their underlying mathematical problems and resilience to quantum computing attacks.

Cryptographic Property / MetricClassical Cryptography (e.g., RSA, ECC, AES)Post-Quantum Cryptography (e.g., Lattice-based, Hash-based)

Underlying Mathematical Problem

Integer Factorization (RSA), Discrete Logarithm (ECC, DSA), Symmetric Block Ciphers (AES)

Lattice Shortest Vector Problem (LWE, NTRU), Multivariate Quadratic Equations, Hash Functions, Error-Correcting Codes

Security Against Classical Computers

Secure with sufficient key size (e.g., RSA-2048, AES-256)

Designed to be secure with sufficient parameter size

Security Against Quantum Computers (Shor's Algorithm)

Broken. Polynomial-time attacks exist for RSA, ECC, DSA.

Believed to be secure. No known polynomial-time quantum attacks.

Security Against Quantum Computers (Grover's Algorithm)

Symmetric key strength halved. AES-256 provides ~128-bit post-quantum security.

Hash-based and code-based schemes affected similarly; requires parameter adjustment.

Key & Signature Sizes

Relatively compact. RSA-2048 sig: ~256 bytes. ECDSA-256 sig: ~64 bytes.

Significantly larger. Dilithium-2 sig: ~2.5 KB. Falcon-512 sig: ~0.7-1.2 KB.

Computational Performance (General)

Highly optimized. Fast encryption/decryption and signing/verification.

Variable. Some schemes (e.g., lattice-based) are slower than ECC but often faster than RSA. Others (hash-based) can be very fast for verification.

Memory & Bandwidth Overhead

Low

High. Larger keys and ciphertexts increase memory and transmission costs.

Algorithm Maturity & Standardization

Decades of cryptanalysis (NIST, IETF standards). Considered mature.

Undergoing final standardization (NIST PQC Project). Newer, with less long-term cryptanalysis.

Primary Use Cases in Edge AI Security

Securing data-in-transit for legacy systems, internal authentication.

Future-proofing long-lived edge devices, securing models & updates for 10+ year lifespans, quantum-resilient digital signatures.

POST-QUANTUM CRYPTOGRAPHY

Frequently Asked Questions

Post-Quantum Cryptography (PQC) is the next generation of cryptographic algorithms designed to secure data against the future threat of quantum computers. These FAQs address its core mechanisms, relevance to Edge AI, and practical deployment considerations.

Post-Quantum Cryptography (PQC) is a class of cryptographic algorithms designed to be secure against cryptanalytic attacks launched by both classical and future quantum computers. It is critical for Edge AI because edge devices often handle sensitive inference data, model weights, and proprietary algorithms for years or decades. The long lifespan of deployed industrial and IoT hardware creates a cryptographic vulnerability window: data encrypted today with classical algorithms (like RSA or ECC) could be harvested, stored, and decrypted later by a sufficiently powerful quantum computer using Shor's algorithm. PQC ensures long-term confidentiality and authentication for edge deployments, protecting intellectual property and sensitive operational data throughout the device's lifecycle.

Prasad Kumkar

About the author

Prasad Kumkar

CEO & MD, Inference Systems

Prasad Kumkar is the CEO & MD of Inference Systems and writes about AI systems architecture, LLM infrastructure, model serving, evaluation, and production deployment. Over 5+ years, he has worked across computer vision models, L5 autonomous vehicle systems, and LLM research, with a focus on taking complex AI ideas into real-world engineering systems.

His work and writing cover AI systems, large language models, AI agents, multimodal systems, autonomous systems, inference optimization, RAG, evaluation, and production AI engineering.