How to implement field-level AES-256-GCM encryption in Spring Boot (and why we packaged it into one annotation) (opens in new tab)

If you've ever had to encrypt a nationalId, a creditCardNumber, or a medicalRecord field in a Spring Boot entity, you already know the drill. You write an AttributeConverter, you wire up a Cipher instance, you generate an IV, you figure out where the key lives, you get the GCM tag handling wrong once, you fix it, and three weeks later you finally trust it enough to ship. We've done this enough times — across healthcare and fintech projects — that we stopped doing it manually. This post walks ...