Disk encryption headers, hardware keystore keys and secure element data are each securely erased. Each of those mechanisms prevents deriving the key encryption keys which prevents ever recovering the data. Secure element data isn't stored on the SSD and prevents recovering data via an earlier image of the SSD. We implemented doing all 3 of those before reboot to recovery for device admin wipe and we used the same code for duress PIN/password wipe. We filed an Android security bug for device admin wipe and convinced them to add the hardware keystore wipe before reboot to recovery, but we still add the other 2 forms of wiping there ourselves.