As part of the Open Compute Project (OCP), Project Cerberus defines a hierarchical Root of Trust (RoT) architecture. All active components are required to support both hardware and firmware combined identifing through the Device Identifier Composition Engine (DICE).

Figure 4-3 thru 4-6 describe the power on sequence, boot flow, recovery flow, and firmware update flow.

Figure 4-3: Cerberus power on sequence (source: “Project Cerberus Hardware Security”)

Figure 4-4: Cerberus boot flow (source: “Project Cerberus Hardware Security”)

Figure 4-5: Cerberus recovery flow (source: “Project Cerberus Hardware Security”)

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Figure 4-6: Cerberus firmware update (source: “Project Cerberus Hardware Security”)

The concept of Cerberus is similar to Intel® Boot Guard., but there are several key differences:

1. Intel® Boot Guard uses Microcode as RoT, while Cerberus uses a dedicated RoT device.

2. Intel® Boot Guard can mitigate hardware bus attacks.

3. Intel® Boot Guard only verifies the host system firmware, while Cerberus verifies all boot firmware (platform firmware, BMC, etc.)

4. Cerberus defines a detailed flow for update and recovery.

Table 4-3: Cerberus Boot

Table 4-4: Cerberus Recovery

Table 4-5: Cerberus Firmware Update