Ex Parte Wuidart

Board of Patent Appeals and Interferences

Jun 25, 2012

10388324 (B.P.A.I. Jun. 25, 2012)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte SYLVIE WUIDART
____________

Appeal 2009-012590
Application 10/388,324
Technology Center 2400
____________

Before MAHSHID D. SAADAT, MARC S. HOFF, and
CARL W. WHITEHEAD, JR., Administrative Patent Judges.

HOFF, Administrative Patent Judge.

DECISION ON APPEAL
Appellant appeals under 35 U.S.C. § 134(a) from a final rejection of
claims 1-23. We have jurisdiction under 35 U.S.C. § 6(b).
We reverse.

Appeal 2009-012590
Application 10/388,324

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STATEMENT OF THE CASE
Appellant’s invention concerns a method and circuit for scrambling
current consumption of an integrated circuit during execution of a
confidential operation. A charge pump is activated for causing current
leakage for generating current consumption fluctuations on a power supply
line of an integrated circuit. These fluctuations are of sufficient intensity to
mask the variations in current consumption associated with the execution of
the confidential operation. (Spec. 4).
Independent claim 1, reproduced below, is representative of the
subject matter on appeal.
1. A method for scrambling current consumption of an
integrated circuit comprising a booster circuit comprising a charge
pump, at least during execution of a confidential operation, the
method comprising:

reading confidential data stored in the integrated i circuit during
execution of the confidential operation; and

activating the charge pump for providing a high voltage from a
power supply voltage for causing a current leakage constrained within
the booster circuit during execution of the confidential operation for
generating current consumption fluctuations on a power supply line of
the integrated circuit, the current consumption fluctuations having an
intensity large enough to mask current consumption variations
assoclated with the execution of the confidential operation.

REFERENCES
Kocher US 6,327,661 B1 Dec. 4, 2001
Odinak US 6,419,159 B1 July 16, 2002
Feyt US 6,698,662 B1 Mar. 2, 2004
Appellant’s Admitted Prior Art (hereinafter “AAPA”).
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REJECTIONS
Claims 1, 2, 4-7, 9-12, 17-19, and 21-23 stand rejected under 35
U.S.C. § 102(b) as being anticipated by Feyt.
Claims 1-3, 5-8, 10-12, 14, 16-20, 22, and 23 stand rejected under 35
U.S.C. § 102(b) as being anticipated by Odinak.
Claims 3, 8, 14, and 20 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Feyt in view of Odinak.
Claims 13 stands rejected under 35 U.S.C. § 103(a) as being
unpatentable over Feyt in view of Kocher.
Claims 4, 9, 15, and21 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Odinak in view of AAPA.
Claims 13 stands rejected under 35 U.S.C. § 103(a) as being
unpatentable over Odinak in view of Kocher.

ISSUES
Appellant argues that Feyt fails to teach a charge pump in its first and
second embodiments (App. Br. 6, 7). Appellant further argues that the
charge pump in Feyt’s third embodiment is not used for causing a current
leakage (id. at 9).
With respect to the rejection over Odinak, Appellant argues that
Odinak’s use of multiple current sinks and a random current generator does
not equate to the use of a charge pump for causing a current leakage (App.
Br. 12-13).
Appellant’s arguments present us with the following issues:
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Application 10/388,324

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1. Does Feyt teach activating a charge pump for providing a high
voltage from a power supply voltage for causing a current leakage for
generating current consumption fluctuations on a power supply line?
2. Does Odinak teach activating a charge pump for providing a high
voltage from a power supply voltage for causing a current leakage for
generating current consumption fluctuations on a power supply line?

FINDINGS OF FACT (FF)
Feyt
1. Feyt teaches, in one embodiment, an output current modifying
device 20 “produced by means of resistors 30, in fact transistors, which are
powered or not according to the random signals supplied by a generator 28.
The currents flowing in the powered resistors increase, modifying the total
current value and hiding the current due to the cryptographic calculations”
(col. 2, ll. 57-62).
2. Feyt further teaches an EEPROM programming circuit that includes
a charge pump (col. 3, ll. 16-27).
Odinak
3. Odinak teaches “the power analysis protection circuitry 40 [having]
multiple current sinks 42(1), . . ., 42(N) coupled to the power contacts Vcc
and Gnd. The power analysis protection circuitry 40 also has a random state
generator 44 to randomly turn on and off any combination of individual ones
of the current sinks to vary the power fluctuations measurable on the power
lines Vcc and Gnd” (col. 3, ll. 41-48).

Appeal 2009-012590
Application 10/388,324

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PRINCIPLES OF LAW
“A rejection for anticipation under section 102 requires that each and
every limitation of the claimed invention be disclosed in a single prior art
reference.” See In re Buszard, 504 F.3d 1364, 1366 (Fed. Cir. 2007)
(quoting In re Paulsen, 30 F.3d 1475, 1478-79 (Fed. Cir. 1994)).

ANALYSIS
§ 102 REJECTION OVER FEYT
The Examiner finds that Feyt anticipates claims 1, 2, 4-7, 9-12, 17-19,
and 21-23. The Examiner correctly states that Appellant’s Specification
discloses that “a charge pump is used to generate current consumption
fluctuations on the electric power supply line of the integrated circuit” (Ans.
12; Spec. 4). The Examiner is also correct that a reference need not
explicitly use the term “charge pump” in order to anticipate the invention. It
is nevertheless true that a “charge pump” is a type of circuit known in the
art. One definition of a charge pump is “a] power supply which uses
capacitors to store and transfer energy to the output, often stepping the
voltage up or down. Charge is transferred from one capacitor to another
under control of regulator and switching circuitry.”1 Appellant discloses a
conventional embodiment example of a charge pump consistent with this
definition (Spec. 12; Fig. 5).
The Examiner is not correct to consider any circuit that generates
current consumption fluctuations on the electric power supply line of an
integrated circuit to correspond to a charge pump. Feyt’s first embodiment,

1 http://www.maxim-ic.com/glossary/definitions.mvp/term/Charge-
Pump/gpk/55, last visited on June 21, 2012.
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in which “transistors, which are powered or not according to the random
signals supplied by a generator 28,” causing “currents flowing in the
powered resistors [to] increase, modifying the total current value and hiding
the current due to the cryptographic calculations” (FF 1), does not include a
charge pump as the term is understood by those skilled in the art. We
further agree with Appellant that Feyt’s third embodiment does mention a
charge pump (FF 2), but provides no teaching that the charge pump causes
current leakage constrained within the booster circuit, as the claims recite
(App. Br. 9).
We find that Feyt does not teach a charge pump for providing a high
voltage from a power supply voltage for causing a current leakage
constrained within the booster circuit during execution of the confidential
operation for generating current consumption fluctuations on a power supply
line of the integrated circuit. As a result, we find that the Examiner erred in
rejecting claims 1, 2, 4-7, 9-12, 17-19, and 21-23 under § 102 as being
anticipated by Feyt, and we will not sustain the rejection.
§ 102 REJECTION OVER ODINAK
As we stated with respect to the rejection over Feyt, supra, the term
“charge pump” has a recognized meaning in the art. The Examiner is not
correct to consider any circuit that generates current consumption
fluctuations on the electric power supply line of an integrated circuit to
correspond to a charge pump. Odinak’s power analysis protection circuitry
40 contains a plurality of current sinks 42(1)-42(N), and a random state
generator 44 (FF 3), but it does not include a charge pump as the term is
known to be understood by those skilled in the art.
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We find that Odinak does not teach a charge pump for providing a
high voltage from a power supply voltage for causing a current leakage
constrained within the booster circuit during execution of the confidential
operation for generating current consumption fluctuations on a power supply
line of the integrated circuit. As a result, we find that the Examiner erred in
rejecting claims 1-3, 5-8, 10-12, 14, 16-20, 22, and 23 under § 102 as being
anticipated by Odinak, and we will not sustain the rejection.
§ 103 REJECTION
We will not sustain the § 103 rejection over Feyt in view of Odinak,
for the same reasons given supra with respect to the § 102 rejections over
Feyt or Odinak individually.

CONCLUSIONS
1. Feyt does not teach activating a charge pump for providing a high
voltage from a power supply voltage for causing a current leakage for
generating current consumption fluctuations on a power supply line.
2. Odinak does not teach activating a charge pump for providing a
high voltage from a power supply voltage for causing a current leakage for
generating current consumption fluctuations on a power supply line.

DECISION
The Examiner’s decision rejecting claims 1-23 is reversed.

REVERSED

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