Format-Preserving Encryption for PII in Polars: FF3-1 vs FF1

MaskOps introduces format-preserving encryption (FPE) for digit-based PII like Chilean RUTs, CPF, and DNI in Polars. The tool uses AES-256 and a client-held key to encrypt data while preserving length and check digits, enabling reversible pseudonymization. It supports FF3-1 and FF1 algorithms but only for digit strings, not alphanumeric IDs.