Determination of time of execution of predetermined data processing routing in relation to occurrence of prior externally observable event
US5249294A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 1993 |
| Grant date | Sep 28, 1993 |
| Priority date | — |
| Expiry date | Feb 3, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2221/2123
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
Compromise of a predetermined secure data processing routine by a procedure known as a "clock attack" is prevented by a method that inhibits synchronization with externally generated instructions by preventing determination of the time of execution predetermined data processing routine in relation to occurrence of an externally observable event that precedes the execution of the predetermined routine. The method includes the step of (a) randomly varying the duration between the occurrence of the externally observable event and the execution of the predetermined routine. Step (a) includes the steps of (b) executing one or more interim data processing routines between the occurrence of the externally observable event and the execution of the predetermined routine; and (c) randomly varying the duration of said interim routines. Steps (b) and (c) may include the step of (d) randomly assembling m said interim routines for said execution from a group of n stored routines having different durations, wherein m and n are integers, with n being greater than m. Step (d) may include either the step of (e) randomly accessing said m interim routines from a secure memory; or the steps of (f) rand…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.