Hybrid computer security clock

• US 7,539,890 B2
• Filed: 04/25/2006
• Issued: 05/26/2009
• Est. Priority Date: 04/25/2006
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Thibadeau, Robert H.
• Primary Examiner(s): CONNOLLY, MARK A
• Application Number:
  US11/410,447
• Publication Number:
  US 20070250734A1
• Time in Patent Office: 1,127 Days
• Field of Search: 713/500, 713/502, 726/2, 368/9, 368/107, 368/111, 368/184, 368/187
• US Class Current: 713/502
• CPC Class Codes: G06F 1/14 Time supervision arrangements, e.g. real time clock

Abstract

A clock object is provides, which includes a clock time and a monotonic time that are readable by the electronic device. The monotonic time is incremented every read of the monotonic time from the clock object. The clock object can also include an indication of a level of trust of the clock time.

Claims

1. A clock object comprising:

a clock time that is readable by an electronic device; and

a monotonic time that is readable by the electronic device and is incremented for every read of the monotonic time from the clock object.

2. The clock object of claim 1 wherein in response to a clock read request from the electronic device, the clock object is adapted to return the clock time and the monotonic time in a single message to the electronic device.

3. The clock object of claim 1 wherein the monotonic time is independent of the clock time.

4. The clock object of claim 1 wherein the clock time and the monotonic time together form a hybrid time, and wherein the monotonic time increments in response to each read of the hybrid time from the clock object.

5. The clock object of claim 4 and further comprising:

a volatile clock database, which is maintained within a volatile memory and stores the monotonic time as a volatile monotonic time; and

a non-volatile clock database, which is maintained in a non-volatile memory, wherein the clock object is adapted to periodically store the volatile monotonic time to the non-volatile database as a non-volatile monotonic time.

6. The clock object of claim 5 and further comprising a reserve value and wherein:

the clock object stores the volatile monotonic time to the non-volatile database every reserve value number of changes of the volatile monotonic time; and

upon a reset of the clock object, the clock object is adapted to set the volatile monotonic time to at least a sum of the non-volatile monotonic time and the reserve value.

7. The clock object of claim 1 and further comprising:

a clock database, which comprises;

a static set time representative of a source time received from a clock source; and

a timer, which increments a timer value, wherein the clock time is a function of the set time and the timer value.

8. The clock object of claim 1 and further comprising:

a clock database, which comprises;

a static set time representative of a source time read from a clock source, wherein the clock time is based on the source time; and

a lag time representative of a delay in successfully recording the set time in the clock database.

9. The clock object of claim 8 wherein in response to a clock read request from the electronic device, the clock object is adapted to return the clock time and the lag time to the electronic device.

10. The clock object of claim 1 and further comprising an indication of a trust level of the clock time.

11. The clock object of claim 1 wherein:

the clock time comprises at least one kind selected from the group comprising a high trust clock time, a low trust clock time and a timer value, wherein the high trust clock time is more authoritative than the low trust clock time; and

in response to a clock read request from the electronic device, the clock object is adapted to return at least one of the high trust clock time, the low trust clock time and the timer value to the electronic device with an indication of the kind of clock time being returned.

12. The clock object of claim 11 and further comprising a clock database, which stores the high trust clock time and the low trust clock time, if available, and an indication of whether the database contains the high trust clock time and whether the database contains the low trust clock time.

13. A clock object comprising:

a hybrid time that is readable by an electronic device, which comprises a clock time and monotonic time, wherein the monotonic time is incremented for every read of the hybrid time from the clock object; and

a trust indicator indicative of a trust level of the clock time, wherein the clock object is adapted to return the clock time and the trust indicator to the electronic device in response to a clock read request from the electronic device.

14. The clock object of claim 13 wherein:

the clock time comprises at least one kind of a high trust clock time and a low trust clock time, wherein the high trust clock time is more authoritative than the low trust clock time; and

in response to the clock read request, the clock object is adapted to return at least one of the high trust clock time and the low trust clock time and the trust indicator to the electronic device.

15. The clock object of claim 14 wherein the trust indicator indicates the kind of clock time being returned.

16. The clock object of claim 14 and further comprising a clock database, which stores the high trust clock time and the low trust clock time, if available, and an indication of whether the database contains the high trust clock time and whether the database contains the low trust clock time.

17. The clock object of claim 13 and further comprising:

a reserve value;

a volatile clock database, which is maintained within a volatile memory and stores the monotonic time as a volatile monotonic time;

a non-volatile clock database, which is maintained in a non-volatile memory, wherein the clock object is adapted store the volatile monotonic time to the non-volatile database as a non-volatile monotonic time, every reserve value number of changes of the volatile monotonic time; and

upon a reset of the clock object, the clock object is adapted to set the volatile monotonic time to at least a sum of the non-volatile monotonic time and the reserve value.

18. The clock object of claim 13 and further comprising:

a clock database, which comprises;

a static set time representative of a source time received from a clock source; and

a timer, which increments a timer value, wherein the clock time is a function of the set time and the timer value.

19. The clock object of claim 13 and further comprising:

a clock database, which comprises;

a static set time representative of a source time read from a clock source; and

a lag time representative of a delay in successfully recording the set time in the clock database.