It may require to have support from the motherboard.
EFI firmware has a var (/sys/firmware/efi/efivars/) named MemoryOverwriteRequestControl that if set is supposed to instruct the firmware to overwrite memory on next boot. If you set it and if you can somehow trigger a reboot memory should not be recoverable.
You can also set init_on_free=1 in linux cmdline, the kernel will overwrite freed memory. If a reboot is physically interrupted or if the EFI firmware does not honor the var mentioned above, encryption keys and any other private data may have been freed.
It may require to have support from the motherboard.
EFI firmware has a var (/sys/firmware/efi/efivars/) named MemoryOverwriteRequestControl that if set is supposed to instruct the firmware to overwrite memory on next boot. If you set it and if you can somehow trigger a reboot memory should not be recoverable.
You can also set init_on_free=1 in linux cmdline, the kernel will overwrite freed memory. If a reboot is physically interrupted or if the EFI firmware does not honor the var mentioned above, encryption keys and any other private data may have been freed.