eRoT Measurements

The measurements returned by each eRoT represent both the eRoT itself and the component it protects. It is important to note that updating either the eRoT firmware or the component firmware will result in changes to the measurement values reported by the eRoT.

A total of 64 measurements are returned by the eRoT. Some of these measurements are reserved, deprecated, device-specific (such as a serial number), or informational/metadata (such as the firmware build date). The reference measurements published by NVIDIA only include meaningful measurements that are not tied to a specific device instance. Measurement indexes not included in the reference should be ignored by the attestation verifier.

The "Part of Reference?" column indicates whether the CoMID contains a reference value for each measurement.

Whenever a hash value is reported in the table, the hash algorithm used is SHA-384.

Measurement indices may change over the product's lifetime with eRoT firmware updates. Any such changes are always reflected in the reference measurements provided with the release. Verifiers should not assume the structure of the measurement blocks, the number of measurements, or their internal formats. The reference measurements provided as part of the release collateral serve as the authoritative source for the measurement structure of that release. The following two sections outline the measurements mapped to Oberon release milestones and eRoT versions.

The tables below show the measurements returned by the Switch Tray with an eRoT firmware version greater than or equal to 01.04.0009.0000.

In the table above, "Active Slot" refers to the currently booted image, while "Inactive Slot" represents the second copy of the firmware. Both the eRoT firmware and the component firmware have two slots. During an update, the Inactive Slot is overwritten as part of the update and authentication process. After a successful update and boot, the previously Inactive Slot becomes the Active Slot, and a background copy process transfers the new Active Slot firmware into the now-unused Inactive Slot. This process may take a few minutes. If measurements are collected before the background copy completes, the two slots may have different values. The reference measurements assume a stable state, where both slots are identical, once the background copy process is finished.