STMicroelectronics (Rousset) SAS

Patent Trials and Appeals Board

Jul 24, 2020

14668676 - (D) (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

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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
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Application 14/668,676

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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.
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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
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Application 14/668,676

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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.
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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.
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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
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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
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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