Post-Quantum Cryptography Landscape

Protecting against the quantum computing revolution

By Sky Sharma

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QUANTUM THREAT
Quantum computers will break RSA, ECC, and other classical cryptography systems

Five Cryptographic Approaches

Lattice-Based

High-dimensional grid structures

✓ NIST STANDARDIZED
Standards:
• ML-KEM (Kyber)
• ML-DSA (Dilithium)
• FN-DSA (FALCON)
Key Strengths:
✓ Encryption + Signatures
✓ Fast performance
✓ Compact keys (~1-2 KB)
⭐ PRIMARY CHOICE

Hash-Based

Cryptographic hash functions

✓ NIST STANDARDIZED
Standards:
• SLH-DSA (SPHINCS+)
Key Strengths:
✓ Most conservative
✓ Long history (1970s)
Limitations:
✗ Signatures only
✗ Large signature sizes
BACKUP OPTION

Code-Based

Error-correcting codes

MATURE APPROACH
Examples:
• McEliece (encryption)
• Classic McEliece
Key Strengths:
✓ Very mature (40+ years)
✓ Well-studied security
Limitations:
✗ Very large keys (MB)
SPECIALIZED USE

Multivariate

Polynomial equations

RESEARCH ACTIVE
Examples:
• Rainbow (broken 2022)
• UOV, HFE variants
Key Strengths:
✓ Fast verification
✓ Small signatures
Challenges:
✗ Recent breaks
UNDER REVIEW

Isogeny-Based

Elliptic curve isogenies

EMERGING FIELD
Examples:
• SIKE (broken 2022)
• CSIDH
Key Strengths:
✓ Smallest key sizes
✓ Interesting math
Status:
⚠ Recent vulnerability
RESEARCH PHASE

Primary Use Cases

🔒 ENCRYPTION

Best Solution: Lattice-Based ML-KEM
Why Lattice-Based Wins:
• Only practical PQC encryption option
• Key sizes ~1-2 KB (vs MB for code-based)
• Deployed in: TLS, VPNs, secure messaging

✍️ DIGITAL SIGNATURES

Multiple Strong Options Available
NIST Standardized Options:
• ML-DSA (Dilithium) - Fast performance
• FN-DSA (FALCON) - Compact signatures
• SLH-DSA (SPHINCS+) - Conservative choice

🔄 HYBRID APPROACH

Recommended for Migration Period
Defense-in-Depth Strategy:
• Combine classical (RSA/ECC) + PQC algorithms
• Protected even if one cryptosystem fails
• Smooth migration with backward compatibility

Deployment Timeline

2024
NIST Standards Released
→
2025-2026
Early Adoption
→
2027-2030
Mass Migration
→
2030+
Widespread Deployment
⚠️ "Harvest now, decrypt later" threat is active NOW
The transition to post-quantum cryptography represents one of the largest security upgrades in computing history