Encryption in Salesforce discusses symmetric encryption, which uses the same key for encryption and decryption, and asymmetric encryption, which uses different public and private keys. It describes Salesforce Classic Encryption, which masks custom fields, and Salesforce Shield Platform Protection, which provides stronger 256-bit encryption of standard and custom fields but requires controlling visibility with field level security since it does not mask data. Shield Platform Protection has an additional cost but offers broader functionality while Classic Encryption can only encrypt custom fields up to 16 characters and requires profile configuration.