US 12,461,554 B2Granted

System including a secure application configured to perform a clock update procedure

AssigneeNXP USA, Inc.

InventorsRay Charles Marshall, Mohit Satsangi, Andreas Bening

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Abstract

A system comprising a real time clock, RTC, and a processor configured to execute a secure application to provide a secure clock and configured to operate in a first low-power-mode and a first normal-mode, and a non-secure application configured to perform a clock modification procedure and configured to operate in a second low-power-mode and a second normal-mode, the system configured to perform a secure clock initialisation procedure comprising obtaining a record of a current time from the RTC based on a transition from the first low-power-mode to the first normal-mode, wherein the secure application is configured to perform a clock update procedure including updating the RTC with a secure record of the current time and wherein the system is further configured to prevent performing the clock modification procedure after the clock update procedure has been performed.

Claims20

Dependent claims

A system comprising:

a real time clock, RTC, configured to keep a record of a current time,
at least one processor configured to execute at least a secure application and a non-secure application, wherein
the secure application is configured to operate in a first low-power-mode and a first normal-mode, wherein the secure application is configured to provide a secure clock for maintaining a secure record of the current time when operating in the first normal-mode, and wherein the secure clock is disabled during the first low-power-mode;
and wherein
the non-secure application is configured to operate in a second low-power-mode and a second normal-mode, wherein the non-secure application is configured to perform a clock modification procedure to update the RTC via a second communication link between the non-secure application and the RTC when the non-secure application is operating in the second normal-mode and not when the non-secure application is operating in the second low-power-mode;
and wherein
the system is configured to cause the secure application to perform a secure clock initialization procedure comprising obtaining the record of the current time from the RTC for initializing the secure clock based on a transition from the first low-power-mode to the first normal-mode, wherein
the secure application is configured to perform a clock update procedure as part of a transition from the first normal-mode to the first low-power-mode, the clock update procedure comprising, via a first communication link between the secure application and the RTC, providing for updating of the RTC with the secure record of the current time, and wherein
the system is further configured to prevent the non-secure application from performing the clock modification procedure after the clock update procedure has been performed, whilst the secure application is in the first low-power-mode and prior to the secure clock initialization procedure.

6 more elements

A method of operating a system, the system comprising:

a real time clock, RTC, configured to keep a record of a current time,
at least one processor configured to execute at least a secure application and a non-secure application, wherein the secure application is configured to operate in a first low-power-mode and a first normal-mode, wherein the secure application is configured to provide a secure clock for maintaining a secure record of the current time when operating in the first normal-mode, and wherein the secure clock is disabled during the first low-power-mode;
and wherein the non-secure application is configured to operate in a second low-power-mode and a second normal-mode, wherein the non-secure application is configured to perform a clock modification procedure to update the RTC via a second communication link between the non-secure application and the RTC when the non-secure application is operating in the second normal-mode and not when the non-secure application is operating in the second low-power-mode;
and wherein the method comprises:
performing, by the secure application, a secure clock initialization procedure comprising obtaining the record of the current time from the RTC for initializing the secure clock based on a transition from the first low-power-mode to the first normal-mode;
performing, by the secure application, a clock update procedure as part of a transition from the first normal-mode to the first low-power-mode, the clock update procedure comprising, via a first communication link between the secure application and the RTC, providing for updating of the RTC with the secure record of the current time;
and
preventing the non-secure application from performing the clock modification procedure after the clock update procedure has been performed, whilst the secure application is in the first low-power-mode and prior to a subsequent secure clock initialization procedure.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/458,748Filed 30 Aug 2023
Priority: EP 2220836918 Nov 2022
Published: US 2024/0168537 A123 May 2024
Granted: 4 Nov 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G06F 1/14
Generating or distributing clock signals or signals derived directly therefrom: time supervision arrangements, e.g. real time clock
G06F 1/08
Generating or distributing clock signals or signals derived directly therefrom: clock generators with changeable or programmable clock frequency
G06F 1/3237
Power saving characterised by the action undertaken: by disabling clock generation or distribution
G06F 21/57
Monitoring users, programs or devices to maintain the integrity of platforms, e.g. of processors, firmware or operating systems: certifying or…