US 12,406,065 B2
Method for securely starting device software, in particular an operating system, of an electronic device
Christian Peter Feist, Munich (DE); and Fabrizio De Santis, Munich (DE)
Assigned to Siemens Aktiengesellschaft, Munich (DE)
Appl. No. 17/774,269
Filed by Siemens Aktiengesellschaft, Munich (DE)
PCT Filed Oct. 30, 2020, PCT No. PCT/EP2020/080516
§ 371(c)(1), (2) Date May 4, 2022,
PCT Pub. No. WO2021/094105, PCT Pub. Date May 20, 2021.
Claims priority of application No. 19209148 (EP), filed on Nov. 14, 2019.
Prior Publication US 2022/0391514 A1, Dec. 8, 2022
Int. Cl. G06F 21/57 (2013.01); G06F 9/4401 (2018.01)
CPC G06F 21/575 (2013.01) [G06F 9/4406 (2013.01); G06F 2221/033 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method for securely starting device software, of an electronic device, in which a plurality of successive software modules containing software code are executed by the device, comprising:
a) executing a first software module of the plurality of successive software modules, wherein the first software module comprises trusted software code and forms a root of trust;
b) loading a second software module of the plurality of successive software modules;
c) checking software code of the second software module and identifying security features of the second software module on the basis of a first identification scheme by the first software module;
d) assessing the identified security features of the second software module on the basis of a first security guideline by the first software module;
e) executing the second software module when the assessment reveals a second software module trustworthiness value which is above a first predefined threshold value;
f) loading a third software module of the plurality of successive software modules;
g) checking software code of the third software module and identifying security features of the third software module on the basis of a second identification scheme by the second software module;
h) assessing the identified security features of the third software module on the basis of a second security guideline by the second software module; and
i) executing the third software module when the assessment reveals a third software module trustworthiness value which is above a second predefined threshold value;
wherein security features are functions which are performed by the software code and are undesirable within the software module.