Account records that are related to interactions sometimes contain sensitive or personally identifiable data. Now you can encrypt data at rest in the Comment field on the new Interaction Related Account object with the probabilistic encryption scheme.
Where: This change applies to Lightning Experience and Salesforce Classic in Enterprise, Performance, Unlimited, and Developer editions.
Who: This change applies to editions that have both Shield Platform Encryption and Financial Services Cloud add-on subscriptions.
How: From Setup, on the Encryption Policy page, click Encrypt Fields. Then click Edit, and select the fields that you want to encrypt.
Encrypt More Financial Services Interaction Data (salesforce.com)