Cryptography terms
The mathematics keeping secrets in an adversarial world
Cryptography is the foundation of secure communication, authentication, and data integrity across the internet. This category covers symmetric and asymmetric encryption, hashing, digital signatures, TLS, key exchange protocols, and the common mistakes developers make when implementing or misapplying cryptographic primitives. Use libraries — but understand what they are doing.
Block Cipher Modes PHP 7.1+
How a block cipher (AES) processes data larger than one block — ECB is insecure, CBC requires a MAC, GCM provides authenticated encryption and is the correct choice.
2mo ago
cryptography advanced
Certificate Transparency Logs
Public append-only logs of all issued TLS certificates — enabling detection of misissuance and rogue certificates within hours rather than months.
2mo ago
cryptography advanced
Post-Quantum Cryptography
CRYSTALS-Kyber (ML-KEM) and CRYSTALS-Dilithium (ML-DSA) standardised by NIST in 2024 — designed to resist attacks from quantum computers.
2mo ago
cryptography advanced
Secret Sharing — Shamir's Scheme
Splitting a secret into N shares where any K can reconstruct it — preventing single points of failure for root encryption keys and disaster recovery credentials.
2mo ago
cryptography advanced
Asymmetric Encryption PHP 5.0+ A cryptographic system with a public key (shared freely) and a private key (kept secret) — data encrypted with the public key can only be decrypted with the private key.
2mo ago
cryptography advanced
Digital Signatures PHP 5.0+ Cryptographic proof that data was created by the holder of a private key and has not been altered — providing authentication, integrity, and non-repudiation.
2mo ago
cryptography advanced
Encryption at Rest PHP 7.0+ Encrypting stored data so that physical access to storage media does not expose plaintext — protecting against data theft from stolen drives, decommissioned hardware, and storage breaches.
2mo ago
cryptography advanced
JWT Deep Dive PHP 7.0+
JSON Web Tokens carry signed (or encrypted) claims — three Base64url-encoded sections: header.payload.signature. Security depends entirely on algorithm choice and verification correctness.
2mo ago
cryptography advanced
Key Derivation Functions PHP 5.5+
KDFs (PBKDF2, bcrypt, scrypt, Argon2) derive a cryptographic key from a password by being intentionally slow — making brute-force attacks computationally infeasible.
2mo ago
cryptography advanced
Public Key Infrastructure (PKI)
The system of certificate authorities, certificates, and protocols that establishes trust in public keys — enabling HTTPS, code signing, and email encryption at internet scale.
2mo ago
cryptography advanced
Symmetric Encryption PHP 7.2+
Encryption where the same key encrypts and decrypts data — fast and suitable for bulk data, but key distribution is the primary challenge.
2mo ago
cryptography advanced