Shield Platform Encryption is a Salesforce feature that allows you to encrypt sensitive data at rest while preserving critical platform functionality. It uses a combination of tenant secrets, encryption keys, and masking policies to protect your data. A field encryption policy is a set of rules that defines which fields are encrypted and how they are masked when displayed. A field encryption policy can be used to encrypt and mask the identification number field, except for the last two digits. Reference: https://help.salesforce.com/s/articleView?id=sf.security_pe_overview.htm&type=5 https://help.salesforce.com/s/articleView?id=sf.security_pe_field_encryption_policies.htm&type=5