Securing the code you ship: XSS, SQL injection, SSRF, auth flaws, and the bugs attackers actually use.
Signing is encryption with the keys swapped, and that symmetry is exactly what makes the naive implementation breakable. Here are two forgeries executed against textbook RSA signatures, and what PSS does that hashing alone cannot.
First, allow me to start off with that I am absolutely loving using Passkeys to login into CloudFlare, Stripe, and other important services that I use to run
Cipher.getInstance("AES") compiles, runs, encrypts, decrypts, and hands you the weakest mode in the box. Here is the OpenJDK source that makes that decision, and the line where ECB gets chosen for you.
Extend a bare PHP MVC skeleton into something real: dependency injection, PDO-backed models with prepared statements, route params, and view escaping.
Build a REST API in Node.js and Express the way production systems need: input validation, JWT auth, refresh token rotation, status codes, rate limiting, idempotency keys, and centralized error handling.
