Cryptography Fundamentals
The foundations post-quantum cryptography builds upon.
PQCRadar is not only a directory of PQC algorithms. Understanding what cryptography is, how it achieves security, and what assumptions it relies on comes first — only then does it make sense to ask what quantum computing changes, and why a migration is needed at all.
Individual topic pages are still being written. This page maps out what's planned — every topic below links to the same honest placeholder until its dedicated page exists.
Core Concepts
What cryptography is for and the security goals it targets — the conceptual entry point before any formalism.
Cryptographic Preliminaries
The mathematical, computational, and randomness-related prerequisites the rest of cryptography is built on top of.
Mathematical Foundations
Computational Foundations
Primitives
The fundamental functionalities cryptography provides — not yet concrete algorithms, but the capabilities concrete schemes are built to deliver.
Oblivious & Verifiable Primitives
Schemes
Concrete constructions that instantiate a primitive — RSA and ElGamal instantiate encryption, Schnorr and ECDSA instantiate signatures.
Security Notions
Formal definitions of what “secure” means for a given primitive or scheme, precise enough to prove or break.
Signature Security
Key-Exchange Security
Protocols & Techniques
Interactive protocols between parties, and the transformations — like Fiat–Shamir — used to convert them into non-interactive constructions.
Proof System Properties
Zero-Knowledge Proofs
Secret Sharing
Provable Security
How a security notion is actually established for a scheme: security games, adversaries, and reductions to an underlying hard problem.
Hardness Assumptions
The unproven computational problems — factoring, discrete log, and their elliptic-curve and lattice-based successors — that cryptographic security ultimately rests on.