Root of trust (RoT) provides a means of assuring that each entity in the boot process is reviewed for integrity in a chain of trust. Each BIOS module contains a hash of the next module in the chain.
The key modules in BIOS are:
- Initial boot block (IBB)
- Security (SEC)
- Pre-EFI initialization (PEI)
- Memory reference code (MRC)
- Driver execution environment (DXE)
- Boot device selection (BDS)
In PowerEdge servers, the RoT is provided through the Integrated Dell Remote Access Controller (iDRAC). The iDRAC boot process uses its own independent silicon-based root of trust that verifies the iDRAC firmware image. The iDRAC root of trust also provides a critical trust anchor for authenticating the signatures of Dell Technologies firmware update packages (DUPs).
![Chain of trust authentication](/static/media/9198938f-8c47-5a0e-82d9-6db6a62cd3f7/DAM-b09bb69a-e771-4560-8b30-a28ab48636be/out/6=GUID-8F9F7ADE-91FA-46E2-8957-1864E72C698C=1=en-us=Low.png)