Configure the Master Key

1. Backup the configuration.
2. (HA only) Disable Config Sync.

   This step is required before deploying a new master key to any firewall HA pair

   Before you deploy a new master key to any firewall HA pair, you must disable Config Sync. For Panorama-managed firewalls, if you do not disable Config Sync before deploying a new master key, Panorama loses connectivity to the primary firewall.

   1. Select DeviceHigh AvailabilityGeneral and edit the Setup.
   2. Disable (clear) Enable Config Sync and then click OK.
   3. Commit your configuration changes.
3. Select DeviceMaster Key and Diagnostics and edit the Master Key section.
4. Enter the Current Master Key if one exists.
5. Define a new New Master Key and then Confirm New Master Key. The key must contain exactly 16 characters.
6. To specify the master key Lifetime, enter the number of Days and/or Hours after which the key will expire.

   You must configure a new master key before the current key expires. If the master key expires, the firewall or Panorama automatically reboots in Maintenance mode. You must then Reset the Firewall to Factory Default Settings.

   Set the Lifetime to two years or less, depending on how many encryptions the device performs. The more encryptions a device performs, the shorter the Lifetime you should set. The critical consideration is to not run out of unique encryptions before you change the master key. Each master key can provide up to 2³² unique encryptions based on the master key value and the Initialization Vector (IV) value. After 2³² unique encryptions, encryptions repeat (are no longer unique), which is a security risk.

   Set a Time for Reminder value (see next step) for the master key and when the reminder notification occurs, change the master key.
7. Enter a Time for Reminder that specifies the number of Days and Hours before the master key expires when the firewall generates an expiration alarm. The firewall automatically opens the System Alarms dialog to display the alarm.

   Set the reminder so that it gives you plenty of time to configure a new master key before it expires in a scheduled maintenance window. When the Time for Reminder expires and the firewall or Panorama sends a notification log, change the master key, don’t wait for the Lifetime to expire. For grouped devices, track every device (e.g., firewalls that Panorama manages and firewall HA pairs) and when the reminder value expires for the any device in the group, change the master key.

   To ensure the expiration alarm displays, select DeviceLog Settings, edit the Alarm Settings, and Enable Alarms.
8. Enable Auto Renew Master Key to configure the firewall to automatically renew the master key. To configure Auto Renew With Same Master Key, specify the number of Days and/or Hours to renew the same master key. The key extension allows the firewall to remain operational and continue securing your network; it is not a replacement for configuring a new key if the existing master key lifetime expires soon.

   Automatically renewing the master key has benefits and risks. The benefit is that extending the master key Lifetime protects against failure to change the master key before its lifetime expires. The risk is that encryptions will repeat and cause a security risk if the number of encryptions the device performs with the master key exceeds the number of unique encryptions the master key can generate (2³² unique encryptions).

   If the Master Key expires (you do not automatically renew it and you do not replace it in a timely manner), the device goes into maintenance mode.

   If you enable Auto Renew Master Key, set it so that the total time (lifetime plus the auto renew time) does not cause the device to run out of unique encryptions. For example, if you believe the device will consume the master key’s number of unique encryptions in two and a half years, you could set the Lifetime for two years, set the Time for Reminder to 60 days, and set the Auto Renew Master Key for 60-90 days to provide the extra time to configure a new master key before the Lifetime expires. However, the best practice is still to change the master key before the lifetime expires to ensure that no device repeats encryptions.

   Consider the number of days until your next available maintenance window when configuring the master key to automatically renew after the lifetime of the key expires.
9. (Optional) For added security, select whether to use an HSM to encrypt the master key. For details, see Encrypt a Master Key Using an HSM.
10. Click OK and Commit.
11. (HA only) Re-enable Config Sync.

    1. Select DeviceHigh AvailabilityGeneral and edit the Setup.
    2. Enable (check) Enable Config Sync and then click OK.
    3. Commit your configuration changes.