Custom policy is a type of DLP policy template that must be used to create a policy that meets this requirement. Custom policy allows the administrator to define their own criteria for detecting sensitive or confidential data in messages, such as keywords, regular expressions, file types, etc.
To create a custom DLP policy on Cisco ESA, the administrator can follow these steps:
Select Mail Policies > DLP Policy Manager and click Add Policy.
Enter a name and description for the DLP policy, such as Patent Protection.
Under Policy Template, select Custom Policy.
Click Submit.
Under Content Matching Criteria, click Add Criteria.
Choose a matching type, such as Keyword or Regular Expression, and enter a value that matches the proprietary patent documents, such as “patent number” or “\d{4}/\d{6}”.
Click Submit.
The other options are not valid types of DLP policy templates to create a policy that meets this requirement, because they are predefined templates that do not match the proprietary patent documents.
References: [User Guide for AsyncOS 15.0 for Cisco Secure Email Gateway], page 9-3 and page 9-5.