Encrypted Custom Fields allows the merchant to store encrypted personal information for Data Vault clients.
To enable this feature the "Encrypt" checkbox should be checked for the specific Custom field under the Administration tab > Setup Custom Fields page.
Merchant will be able to view encrypted data on Data Vault > Clients > Edit Data Vault Client page > Custom Fields tab.
Merchant with corresponding role permissions will be able to decrypt data.
Also merchant has an ability to decrypt data via API using token of the data vault client and name of the custom field.