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Data Loss Prevention (DLP)


To protect the University from the financial penalties and loss of reputation that result from High Risk Data being inappropriately released, Data Loss Prevention (DLP) appliances have been incorporated into Stanford's email infrastructure. Currently, these look only for Protected Health Information (PHI) that matches hospital records from Stanford Health Care or Stanford Children's Health. When a match is found in an email that was not sent via Secure Email the message is blocked from delivery and the sender is notified via email. Only data that matches hospital patient records should cause a message to be blocked. This technology has been successfully deployed in the two hospitals since 2013.

Email messages that are blocked by the DLP appliances are retained for a period of time to allow staff from Stanford's Privacy Office or the Stanford IT organizations to improve the accuracy of the protection rules in place.

User notification

When an email is blocked, the sender receives an automated email informing them of the block. A sample message is below:

Subject: Email Message Blocked

An email you sent has been blocked from delivery because it was not sent via Stanford Secure Email and appears to contain sensitive patient information from either Stanford Health Care or Stanford Children's Health. Additional information about the blocked email appears at the end of this email.

Stanford University has implemented Data Loss Prevention (DLP) technology to prevent the unencrypted transmission of Protected Health Information (PHI) from Stanford email accounts in accordance with Admin Guide 1.6.2 []. This DLP technology blocks any email message that it identifies as possibly containing PHI, and has not been sent using Stanford’s Secure Email service.

When PHI or any type of High Risk Data is sent either in the body of email, or as an email attachment, please remember to insert "Secure:" in the subject line of the email to make sure the message is sent via the Secure Email service.

If you would like to resend the blocked email, please first type “Secure:” anywhere in the subject line and then resend it. Read more information about the Secure Email service and DLP.

It is possible that your email has been mistakenly identified as containing PHI. If you believe that your message has been mistakenly blocked, or if you have any questions about DLP, please submit a Help ticket:​

Please note that a copy of the blocked email will be retained and may be reviewed by staff from the University Privacy Office, Office of General Counsel or the Information Security Office (ISO) for authorized investigations, or by University IT in response to user inquiries or to improve accuracy of the DLP protection rules in place.

Users can re-send the message, putting Secure: in the subject line  in order to have it delivered.


If you have any questions about DLP technology or need any information about why a specific message you sent was blocked please submit a Help ticket.

Last modified February 16, 2017