Platform Encryption: Support for Flows, Formulas, Leads, and More

You can bring your own encryption key to protect your search index, and take more detailed control of your HSM-protected certificates. You can use flows and processes with encrypted data (beta). You can encrypt standard Lead fields (beta) and more elements in your Chatter feed (pilot).
Available as add-on subscription in: Enterprise, Performance, and Unlimited Editions. Requires purchasing Salesforce Shield. Available in Developer Edition at no charge for organizations created in Summer ’15 and later.
Available in both Salesforce Classic and Lightning Experience.