Encryption & Cipher Guides

Understand DES and 3DES encryption — how they work, why DES is broken, and why 3DES remains deeply embedded in payment infrastructure.

A complete guide to AES encryption — key sizes, ECB/CBC/CTR/GCM modes, padding, IV best practices, and common mistakes to avoid.

Everything you need to know about RSA — key sizes, OAEP vs PKCS#1 padding, hybrid encryption, and when to choose RSA vs ECC.

Learn how Elliptic Curve Cryptography works — ECDSA signatures, ECDH key agreement, curve selection, and why ECC beats RSA for modern systems.

Learn how Format-Preserving Encryption works — FF1 and FF3-1 algorithms, tokenization of credit cards, PCI DSS compliance, and when to use FPE vs traditional encryption.

Compare AES-GCM and AES-CBC security, authentication, IV requirements, performance, and compatibility to choose the right encryption mode.

Learn why IV and nonce reuse breaks AES-CBC, CTR, and GCM security, how to generate safe values, and how to design reliable nonce storage.

Understand PKCS#7 padding byte by byte, including full-block padding, validation, common errors, and safe unpadding for AES-CBC.

Implement AES-GCM with the Web Crypto API using secure key generation, unique nonces, authenticated data, and portable ciphertext packaging.

Reproduce NIST AES-128, AES-192, AES-256, ECB, and CBC known-answer vectors in CryptoJS, Web Crypto, and the HSM Kit browser tool.