Patent ID: 11921858
Assignee: DELL PRODUCTS L.P.
Field: Computer technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 12:
13. A system for protecting against alterations in chain sequencing, the system comprising:
a BIOS memory medium storing a set of BIOS instructions for transitioning between entities in a sequence; and
a root of trust memory medium separate from the BIOS memory medium, the root of trust memory medium storing a chain of trust database comprising a plurality of authorized chains of trust and a set of root of trust instructions executable to:
in response to the information handling system receiving an instruction to start a boot process:
select a chain of trust from the plurality authorized chains of trust;
measure a first entity in the selected chain of trust;
store a root of trust identifier as a previous entity identifier; and
set a sequence count to zero;
the set of BIOS instructions are executable to send a first entity identifier as a next entity identifier to the root of trust;
wherein the set of root of trust instructions are executable to:
receive the next entity identifier;
increment the sequence count;
retrieve, based on a chain of trust in the chain of trust database, a correct transition link between the previous entity identifier and the next entity identifier;
compare the next entity identifier with a stored previous entity identifier based on the sequence count; and
notify the BIOS if the next entity identifier matches the stored entity identity;
wherein the BIOS comprises instructions executable to:
determine if the sequence count for the chain of trust is valid; and
transition control to the next entity in the chain of trust.