STMicroelectronics (Rousset) SAS

Patent Trials and Appeals BoardJul 24, 2020

2019005149 (P.T.A.B. Jul. 24, 2020)

UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 14/668,676 03/25/2015 Yannick Teglia 14-RO-0391US01 859463.435 5218 38106 7590 07/24/2020 Seed IP Law Group LLP/ST (EP ORIGINATING) 701 FIFTH AVENUE, SUITE 5400 SEATTLE, WA 98104-7092 EXAMINER ZHANG, HAIDONG ART UNIT PAPER NUMBER 2858 NOTIFICATION DATE DELIVERY MODE 07/24/2020 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): USPTOeAction@SeedIP.com pairlinkdktg@seedip.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD Ex parte YANNICK TEGLIA Appeal 2019-005149 Application 14/668,676 Technology Center 2800 Before JEFFREY T. SMITH, JEFFREY B. ROBERTSON, and WHITNEY N. WILSON, Administrative Patent Judges. ROBERTSON, Administrative Patent Judge. DECISION ON APPEAL1 STATEMENT OF THE CASE Pursuant to 35 U.S.C. § 134(a), Appellant2 appeals from the Examiner’s decision to reject claims 1–20. See Appeal Br. 34. We have jurisdiction under 35 U.S.C. § 6(b). We affirm. 1 This Decision includes citations to the following documents: Specification filed March 25, 2015 (“Spec.”); Final Office Action mailed September 7, 2018 (“Final Act.”); Appeal Brief filed January 7, 2019 (“Appeal Br.”); Examiner’s Answer mailed April 22, 2019 (“Ans.”); and Reply Brief filed June 21, 2019 (“Reply Br.”). 2 We use the word Appellant to refer to “applicant” as defined in 37 C.F.R. § 1.42(a). Appellant identifies the real party in interest as STMicroelectronic (Rousset) SAS. Appeal Br. 2. Appeal 2019-005149 Application 14/668,676 2 CLAIMED SUBJECT MATTER Appellant states the invention relates to electronic circuits containing elements storing data in non-volatile fashion. Spec. 1, ll. 4–6. Claim 1, reproduced below, is illustrative of the claimed subject matter (Appeal Br., Claims Appendix 44): 1. A method, comprising: sampling, using a sampling circuit, a series of bits output by a logic circuit of an integrated circuit; generating, using the sampling circuit, an indication of a proportion of the series of bits in a first state; generating, using the sampling circuit, an indication of detection of a cold-boot attack based on the generated indication of the proportion of the series of bits in the first state; and restricting access to the integrated circuit in response to the indication of detection of a cold-boot attack indicating a cold-boot attack. REFERENCES The prior art relied upon by the Examiner is: Name Reference Date Keigo US 2009/0096495 A1 April 16, 2009 Adams et al. hereinafter “Adams” US 2012/0079593 A1 March 29, 2012 Appeal 2019-005149 Application 14/668,676 3 REJECTION3 The Examiner rejected claims 1–20 under 35 U.S.C. § 103 as unpatentable over Adams and Keigo. Final Act. 10–14. OPINION Appellant presents separate arguments with respect to claims 1, 3, 4, 8, 10, 11, and 17. See Appeal Br. 35, 41. We select claims 1, 3, and 4 as representative for disposition of this appeal, with the patentability of the other claims standing or falling with claims 1, 3, and 4. 37 C.F.R. § 41.37(c)(1)(iv). Claim 1 The Examiner’s Rejection In rejecting claim 1 as obvious over the combination of Adams and Keigo, the Examiner found Adams discloses a method to generate an indication of a cold-boot attack,4 but Adams is silent as to generating an indication of a portions of bits in a sampled output in a first state as recited in claim 1. Final Act. 10–11, citing Adams ¶ 9. The Examiner found Keigo, which discloses a ring oscillator for a temperature sensor, also discloses generating an indication of a proportion of bits in a sampled output in a first state, where the output of synchronizing circuit 6 is a sampled output in a 3 The Examiner withdrew rejections of claims 1–20 under 35 U.S.C. § 101. Ans. 3. 4 A cold-boot attack is performed by switching an integrated circuit down and back up, often involving cooling of the circuit in an attempt to slow down the reset process and gain access to data stored in the circuit. Spec. 6, ll. 3–10. Appeal 2019-005149 Application 14/668,676 4 first state and the count value generated by counter 7 is an indication of a proportion of bits in the output of synchronizing circuit 6, wherein the proportion of bits may be bits with rising edges. Id. at 11, Keigo, ¶¶ 3, 29, 30, 57, 80, 82; Fig. 10. As further explained by the Examiner in the Answer, Adams, which discloses sensing temperatures in order to determine whether a cold boot attack may be occurring, failed to disclose the type of temperature sensor used to detect the temperature. Ans. 7; Adams ¶ 9. The Examiner then pointed to Keigo for an example of a temperature sensor that may be employed to sense temperatures in order to provide an indication of a cold boot attack as disclosed in Adams. Id. at 8. The Examiner found the teachings of Adams and Keigo to be combinable because both references disclose temperature sensors to detect temperature of a memory electric circuitry that stores data. Id. at 8, citing Adams ¶ 9, Keigo, ¶ 8. The Examiner then explained that modifying Adams by apply the teaching of the temperature circuits in Keigo would have been obvious to improve on accurately measuring temperature. Id.; Final Act. 12. Appellant’s contentions Appellant argues neither Adams nor Keigo discloses a proportion of bits in a sampled output which are in a first state and which would serve as an indication of an occurrence of a cold boot attack. Appeal Br. 36. Appellant argues also that it would not have been obvious to have modified Adams to use the temperature sensor of Keigo, because Keigo detects temperature over a lengthy period of time and thus would be too slow to detect the cold boot attacks disclosed in Adams. Id. citing ¶ 83. Appellant Appeal 2019-005149 Application 14/668,676 5 argues Keigo counts rising edges over a period of several thousand cycles to determine frequency, not bits, where rising edges do not correspond to a number of bits. Id. at 37. Appellant argues Keigo discloses frequency of an oscillator as an indication of temperature, not a proportion of bits in a particular state. Id. Issue Has Appellant demonstrated reversible error in the Examiner’s position that the combination of Adams and Keigo renders obvious generating, using a sampling circuit, an indication of a proportion of the series of bits in a first state as recited in claim 1? Discussion We are not persuaded by Appellant’s arguments. Although Appellant argues that Keigo does not disclose determining a proportion of bits in a first state, because Keigo counts the number riding edges of the output of a ring oscillator over a period of several thousand cycles to determine the oscillating frequency of the ring oscillator, Appellant does not dispute that Keigo may determine the output frequency by counting bits. Reply Br. 8. Indeed, as found by the Examiner, “the ‘first state’ as claimed is so broad that [it] may reasonabl[y] [be] interpreted as any instant in time such as when the counter 7 [in Keigo] generates a count by counting [a] corresponding number of bits in its rising edge state.” Ans. 7. The Examiner’s position appears to be consistent with the Specification, which states “the generating the indication of the proportion comprises counting a number of bits in the first state.” Spec. 3, ll. 6–7. Appeal 2019-005149 Application 14/668,676 6 Appellant’s main issue with Keigo appears to be that Keigo discloses measuring or counting bits over a period of time, which would be too long to detect a cold boot attack as disclosed in Adams. Appeal Br. 36–37. However, as explained above, the Examiner’s position is that because Adams fails to disclose the type of temperature sensor used to detect the temperature to determine whether a cold boot attack may be occurring, one of ordinary skill in the art would have turned to Keigo for temperature sensors to employ. Ans. 7–8. Appellant’s arguments focus on the particular cycle periods of Keigo, rather than taking into account how one of ordinary skill in the art would have applied the teachings of Keigo in order to sense temperatures that may be associated with a cold boot attack as disclosed in Adams. Yet, in KSR, the Supreme Court explained, “[w]hen a work is available in one field of endeavor, design incentives and other market forces can prompt variations of it, either in the same field or a different one. If a person of ordinary skill can implement a predictable variation, §103 likely bars its patentability.” KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 417 (2007). “A person of ordinary skill is also a person of ordinary creativity, not an automaton.” Id. at 421. In addition, “the test for combining references is not what the individual references themselves suggest but rather what the combination of disclosures taken as a whole would suggest to one of ordinary skill in the art.” In re McLaughlin, 443 F.2d 1392, 1395 (CCPA 1971). In this case, we are not persuaded by Appellant’s argument because it does not take into account the modifications that would have been made by one of ordinary skill in the art in applying the teachings of Keigo to Adams. Appeal 2019-005149 Application 14/668,676 7 That is, although Keigo discloses in an embodiment that the cycle times are “several thousand times as long as” on cycle of a ring oscillator, Keigo also discloses that the one cycle of the output of the frequency-dividing circuit “is made sufficiently longer than” one cycle of the ring oscillator. Keigo ¶ 83. Appellant has not provided sufficient evidence that one of ordinary skill in the art could not have modified Keigo in order to provide the temperature sensing capability required in order to detect cold boot attacks as disclosed in Adams. Accordingly, we affirm the Examiner’s rejection of claim 1. Claim 3 Claim 3 depends indirectly from claim 1, and recites: “wherein the generating the indication of the proportion comprises counting a number of bits in the first state and the generating the indication of detection of the cold-boot attack comprises determining whether the number of bits in the first state is within a range of values.” In rejecting claim 3, the Examiner determined the combination of Adams and Keigo discloses determining whether a number of bits in the first state is within a range of values. Final Act. 12, citing Keigo, Figs. 7, 10. Appellant contends that in Keigo, there does not appear to be any discussion or suggestion of generating an indication detection of a cold-boot attack based on whether the count is within a range of values as recited, and the Examiner provides no reasoned basis for the required further modifications. Appeal Br. 41, citing Keigo ¶¶ 55–62. We are not persuaded by Appellant’s argument, because it appears not to consider the rejection as a whole. That is, as explained above, the Appeal 2019-005149 Application 14/668,676 8 Examiner relied on Adams for disclosing temperature sensors to determine whether the temperature falls below a threshold as an indication of a cold- boot attack. Adams, ¶ 9. Keigo discloses also both upper and lower threshold values for temperatures. Keigo, ¶ 59. Thus, both Adams and Keigo disclose the idea of comparing information corresponding to sensed temperatures values with measured values in order to assess whether the information corresponding to the sensed temperature falls within a range of values. Accordingly, as discussed above with respect to claim 1, we are not persuaded that when the disclosures of Adams and Keigo are considered together, the determining step recited in claim 3 would not have been obvious. As a result, we affirm the Examiner’s rejection of claim 3. Claim 4 Claim 4 depends from claim 3 and recites “wherein said range of values is determined by statistical analysis in a training phase during which the integrated circuit is operated in a normal temperature range.” In rejecting claim 4, the Examiner cited to Keigo for the training phase recitation in claim 4. Final Act. 12, citing Keigo ¶¶ 59, 62; Fig. 7. Appellant contends the portions of Keigo cited by the Examiner do not discuss a training phase or statistical analysis, nor does the Examiner provide sufficient reasoned analysis. Appeal Br. 41–42. We are not persuaded by Appellant’s argument for similar reasons as discussed above for claim 3. Keigo expressly discloses counted values corresponding to different temperatures are stored in the semiconductor Appeal 2019-005149 Application 14/668,676 9 device, which corresponds to a training phase as recited in claim 4. Keigo, ¶ 59. Thus, when the prior art is considered as a whole, we are not persuaded that the limitations of claim 4 would not have been obvious to one of ordinary skill in the art. As a result, we affirm the Examiner’s rejection of claim 4. In sum, we affirm the Examiner’s rejection of claims 1–20 as obvious over Adams and Keigo for the reasons discussed above. DECISION SUMMARY In summary: Claims Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 1–20 103 Adams, Keigo 1–20 TIME PERIOD FOR RESPONSE No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R. § 1.136(a)(1)(iv). AFFIRMED