systemd-tpm2-setup8
Set up the tpm2 storage root key (srk) at boot
Part of systemd-tpm2-setup.service(8).
Usage
systemd-tpm2-setup.service
Overview
systemd-tpm2-setup.service and systemd-tpm2-setup-early.service are services that generate the Storage Root Key (SRK) if it has not been generated yet, and stores it in the TPM.
The services will store the public key of the SRK key pair in a PEM file in /run/systemd/tpm2-srk-public-key.pem and /var/lib/systemd/tpm2-srk-public-key.pem. They will also store it in TPM2B_PUBLIC format in /run/systemd/tpm2-srk-public-key.tpm2_public and /var/lib/systemd/tpm2-srk-public-key.tpm2b_public.
systemd-tpm2-setup-early.service runs very early at boot (possibly in the initrd), and writes the SRK public key to /run/systemd/tpm2-srk-public-key.* (as /var/ is generally not accessible this early yet), while systemd-tpm2-setup.service runs during a later boot phase and saves the public key to /var/lib/systemd/tpm2-srk-public-key.*.
Files
/run/systemd/tpm2-srk-public-key.pem, /run/systemd/tpm2-srk-public-key.tpm2b_public
The SRK public key in PEM and TPM2B_PUBLIC format, written during early boot.
Added in version 255.
/var/lib/systemd/tpm2-srk-public-key.pem, /var/lib/systemd/tpm2-srk-public-key.tpm2_public
The SRK public key in PEM and TPM2B_PUBLIC format, written during later boot (once /var/ is available).
Added in version 255.