What Is Format-Preserving Encryption (FPE)?
Your database stores a credit card number: 4532 1234 5678 9010. You encrypt it for security. Now it looks like this: %Xk92@!mQz#Lp&7. Problem. Your payment system can’t process that. It expects a 16-digit number. Your billing software breaks. Your downstream analytics fail. Your whole pipeline comes to a halt. This is the exact problem that format-preserving encryption was built to solve.