Ex Parte Brown et al

Patent Trial and Appeal Board

Dec 19, 2014

11750568 (P.T.A.B. Dec. 19, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte MICHAEL S. BROWN,
NEIL ADAMS, STEVEN FYKE, and
HERBERT LITTLE
____________

Appeal 2012-008492
Application 11/750,568
Technology Center 2600
____________

Before LEE E. BARRETT, JEAN R. HOMERE, and
DANIEL N. FISHMAN, Administrative Patent Judges.

BARRETT, Administrative Patent Judge.

DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s final
rejection of claims 1–3, 9–16, and 21–25. Claims 4–8 and 17–20 have been
canceled. We have jurisdiction under 35 U.S.C. § 6(b).
We affirm-in-part.

THE INVENTION
The invention relates to protecting data in a mobile communications
device which may be lost or stolen. The Specification describes that a
mobile device memory may be wiped in response to a “kill packet” or a
policy message to protect the security of stored data. However, it is possible
that a device wipe that should otherwise have occurred will not occur due to
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the mobile device turning off due to a discharged battery. Spec. ¶ 44. The
claims relate to determining if a battery level in a mobile communications
device falls below a predetermined threshold below and performing a
security action of encrypting at least some of the data on a storage element if
the battery power falls below the predetermined threshold. Id.
Claim 1 is reproduced below.

1. A mobile communications device, comprising:
a processor;
a communications subsystem connected to the processor
operable to exchange signals with a wireless network and with
the processor;
a battery connected to the processor;
a persistent storage element connected to the processor
and having a plurality of application modules and data stored
thereon, the data comprising at least user application data
associated with the application modules and service data
including data for establishing communications with the
wireless network; and
a security module operable to determine if a battery level
of the battery falls below a predetermined threshold and
perform a security action comprising encrypting at least some
of the data on the storage element if the battery power falls
below the predetermined threshold.

THE PRIOR ART
Knapczyk US 5,131,040 July 14, 1992
Wright et al. (Wright) US 2004/0123153 A1 June 24, 2004
Dunstan US 2005/0044433 A1 Feb. 24, 2005
Kim US 2005/0070339 A1 Mar. 31, 2005
Dietl et al. (Dietl) US 2005/0136979 A1 June 23, 2005
Levi et al. (Levi) US 2007/0100978 A1 May 3, 2007
(filed Nov. 3, 2005)
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THE REJECTIONS
Claims 1, 3, 12, 13, 15, 24, and 25 are rejected under 35 U.S.C.
§ 103(a) as being unpatentable over Wright in view of Knapczyk, further in
view of Dunstan.
Claims 2, 14, and 16 are rejected under 35 U.S.C. § 103(a) as being
unpatentable over Wright, Knapczyk, and Dunstan, further in view of Kim.
Claims 9, 10, 21, and 22 are rejected under 35 U.S.C. § 103(a) as
being unpatentable over Wright, Knapczyk, and Dunstan, further in view of
Dietl.
Claims 11 and 23 are rejected under 35 U.S.C. § 103(a) as being
unpatentable over Wright, Knapczyk, and Dunstan, further in view of Levi.

ANALYSIS
Claims 1, 3, 12, 13, 15, 24, and 25 – Wright, Knapczyk, Dunstan
Independent claim 1
Wright teaches a mobile communications device. Wright, ¶ 46.
Knapczyk discloses actively erasing encryption keys stored in static
memory if the battery level of a back-up battery falls below a threshold
while a successful erase can still be guaranteed. Knapczyk states that
“[e]ncryption keys are normally stored in memory devices that require a
constant power source in order to preserve memory integrity,” Knapczyk,
1:36–38, e.g., a static memory. Knapczyk discloses that an AC power
source can be used with fixed equipment installations to maintain the
memory, but “some kind of backup power supply is required in order to
preserve encryption keys should partial or total failure of A.C. power come
to pass.” Knapczyk, 1:45–48. Knapczyk states that it is important to keep
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encryption keys out of the hands of an adversary and if main voltage fails, a
battery backup may “decay to the point where it is no longer possible to
successfully erase an associated key store.” Knapczyk, 1:54–56, 3:21–24.
Knapczyk describes that when a back-up battery falls below a predetermined
threshold, the microprocessor is powered up and executes a code segment
that writes logic zeros or any other predetermined values into the associated
memory. Knapczyk, 3:17–40. Simultaneously, a memory shutoff pulse is
applied to the memory regulator:
The memory shutoff pulse causes power to be removed from
the memory (104) for a short interval. As is well-known, the
removal of power form a static memory device tends to result in
stored information being lost. This additional attempt at key
erasure affords added security.

Knapczyk, 3:53–58. Knapczyk discloses that “the removal of power from a
static memory device tends to result in stored information being lost,” and
therefore recognizes that there is some amount of persistence in a static
memory (known in the art as “data remanence”) or it would not be necessary
to take the step of overwriting the encryption keys in memory; the step of
removing power is an additional step at erasure. However, the static
memory in Knapczyk is not a “persistent storage element.” Knapczyk
corresponds to Appellants’ embodiment of overwriting data stored on
permanent and transient storage with meaningless bits (e.g., all zeros or all
ones), paragraph 41, and the security sub-process of Figure 4, paragraph 44.
Knapczyk discloses “a security module operable to determine if a
battery level of the battery falls below a predetermined threshold and
perform a security action comprising [overwriting with logic zeros or any
other predetermined values] at least some of the data on the storage element
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if the battery power falls below the predetermined threshold,” as recited in
claim 1. The differences are that Knapczyk discloses that the security action
is “overwriting with logic zeros or any other predetermined values,” not
“encrypting,” and discloses a static memory, not a “persistent storage
element,” Ans. 14.
Dunstan describes that a “system, such as a Personal Computer (PC),
may enter a low-power state during a period of relative inactivity,” Dunstan,
¶ 1. “In some cases, context information may be saved when the system
enters the low-power state (e.g., by saving an operating system and memory
image to a non-volatile storage device). The context information may then
be retrieved when the system returns to a higher-power state.” Dunstan, ¶ 2.
Dunstan recognizes that by saving context information to a non-volatile
storage device, such as a hard disk drive 220 or another type of non-volatile
storage device, confidential information may be exposed. Dunstan, ¶¶ 18,
40. Dunstan describes determining when a system is to enter a low-power
state based on current system workload, power failure, or user action.
Dunstan, ¶ 20. Power failure is the relevant teaching here. In response to
determining that the system is to enter a low-power state, “the system
context information is encrypted before being saved directly to non-volatile
memory.” Dunstan, ¶ 21. Dunstan further states:
[I]n some cases the system context information might be saved
to non-volatile memory because of a system power failure
(e.g., the power failure might have triggered a transition to a
low-power state). As a result, the maximum amount of
information that can be saved might be limited by the amount
of power available from a back-up power source. To reduce the
amount of information that needs to be saved, FIG. 5 is a flow
chart of a method that includes compression according to some
embodiments.
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Dunstan, ¶ 26. Thus, Dunstan teaches taking a security action of encrypting
and saving system context information to a non-volatile memory (“persistent
storage element”) when it is determined that the system has lost power (i.e.,
the power has fallen below a predetermined threshold) and while sufficient
power is available from a back-up power source.
Accordingly, both Knapczyk and Dunstan teach taking a security
action on data in memory in response to loss of power. Further, both
Knapczyk and Dunstan teach taking the security action while sufficient
battery (back-up) power remains to perform the security action. Knapczyk
teaches taking a security action of overwriting data in memory when it is
determined that the battery power falls below a predetermined threshold.
Knapczyk’s teaching of writing “any predetermined values into the
associated memory, not just logic zeros” (Knapczyk, 3:39–40) suggests
using other methods to destroy the data. While we think that one of ordinary
skill in the art would appreciate that Knapczyk’s teaching of overwriting
(wiping or erasing) data in a memory in response to the level of a battery
falling below a predetermined level is not limited to erasing encryption keys
(the specific type of data) or the type of memory, volatile or non-volatile,
Dunstan teaches encrypting data in a persistent memory in response to
determining a loss of power and while sufficient back-up power remains. It
would have been obvious in view of Dunstan to encrypt data in a non-
volatile memory instead of overwriting the data in static memory as taught
by Knapczyk. Encrypting data instead of overwriting is simply an alternate
way of making the data in memory unusable. Dunstan encrypts the data
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because it later decrypts and uses it, but there is no such recovery of data
claimed here; encryption merely is another way of erasing the data.
Appellants argue that because Knapczyk discloses erasing encryption
keys in static memory, “Knapczyk is in a different field from mobile
communication devices and in particular persistent storage elements on
those devices.” Appeal Br. 13. Knapczyk discloses that “the removal of
power from a static memory device tends to result in stored information
being lost,” and therefore that some amount of data may remain in a static
memory or it would not be necessary to take the additional step of
overwriting the encryption keys in memory. The fact that Knapczyk
describes keys in static memory does not make it nonanalogous art as
Appellants argue. In fact, Appellants’ Specification describes erasing data
on permanent and transient storage. Spec. ¶ 41. Knapczyk is clearly related
to the problem faced by Appellants of making sure that data stored in
memory cannot be recovered.
Appellants argue that because Knapczyk teaches overwriting
encryption keys, combining Knapczyk with any reference would not result
in the combination recited in claim 1 that recites the encryption of data
stored on a persistent storage element. Appeal Br. 13. However, Dunstan
teaches encrypting data on a persistent storage element. Appellants’ attack
of the references individually is not persuasive because the Examiner’s
rejection is based on obviousness and the collective teachings of the
references.
Appellants argue that “Dunstan does not contemplate a security action
based on battery level falling below a threshold.” Appeal Br. 13. Knapczyk
teaches a security action based on a battery level falling below a threshold.
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Appellants’ attack of the references individually is unavailing because the
Examiner’s rejection is based on obviousness, and on the combination of the
references. In addition, however, Dunstan discloses determining when the
system is to enter a low power state and taking a security action on data in
non-volatile memory (Fig. 3) and discloses that the encryption must take
place while sufficient back-up power remains, which indicates that Dunstan
must be aware of the battery level.
Appellants argue here and with respect to other claims that “[n]either
[Knapczyk nor Dunstan] discloses encrypting data stored on a persistent
memory of a mobile communications device in response to the battery level
of the device falling below a threshold.” Appeal Br. 15. This fails to
address the combination: Knapczyk discloses a security action to destroy
data in memory in response to the battery level of the device falling below a
threshold, Dunstan discloses encrypting data on a persistent memory in
response to a loss of power but where sufficient backup power remains, and
Wright discloses a mobile communications device in which the security
techniques of Knapczyk and Dunstan would be useful.
Appellants argue that there is no motivation to combine Knapczyk and
Dunstan because “encrypting data would require encryption keys, which
Knapczyk teaches to overwrite.” Appeal Br. 13. Again, Appellants do not
address the obviousness combination. Dunstan discloses a security action of
encrypting data which takes the place of overwriting in Knapczyk.
Appellants argue that the Examiner erred in stating that the “persistent
storage element” in claims 1, 13, and 25 includes RAM because one skilled
in the art would understand RAM to be volatile and not persistent. Appeal
Br. 14. The Examiner states that substituting a persistent memory for RAM
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would yield predictable results. Ans. 16. Dunstan discloses encrypting data
in a persistent memory so arguments about Knapcyzk’s RAM are, once
again, irrelevant in view of the Examiner’s rejection based on the combined
teachings.
Appellants argue that “a person skilled in the art would not have been
motivated to look to Dunstan because encrypting data stored on RAM in the
context of the present claims would not be useful, as any data stored on
RAM would be lost once the battery of the mobile device loses power.”
Appeal Br. 14. This sounds like a nonanalogous art argument. However,
Dunstan discloses that a security danger occurs when data is stored on non-
volatile storage device, Dunstan, ¶ 18, and that “the system context
information might be saved to non-volatile memory because of a system
power failure” and encrypting data before storing it on non-volatile memory.
Dunstan, ¶ 26; Fig. 5. Thus, Dunstan discloses encrypting data stored in
non-volatile (persistent) memory. Dunstan is clearly related to the same
problem facing the Appellants of making data in memory unusable.
Appellants argue that an advantage of the security module recited in
claim 1 is “that data stored on the device is encrypted before the battery
loses power so that the data is stored in a secure manner should the mobile
device subsequently become lost or stolen and unable to receive a security
command via wireless communications.” Appeal Br. 14. It is argued that
this is not a concern for data stored on RAM because the data will be lost
once the battery loses power. Dunstan discloses encrypting and storing data
into non-volatile memory after a system power failure and while the back-up
power supply has sufficient power. Dunstan, ¶ 26. This is in addition to the
teachings of taking a security action before the battery loses too much power
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in Knapczyk. The claims do not recite anything about the mobile device
being unable to receive a security command via wireless communication.
Appellants argue there is no motivation to combine Knapczyk with
any reference that teaches encrypting the data based on battery level because
the data in Knapczyk would be lost in any event. Reply Br. 3. Knapczyk
indicates that the data may not be completely lost or there would be no
reason for overwriting data. One of ordinary skill in the art would have been
motivated to use Knapczyk’s teaching of overwriting data in memory based
on the battery threshold whenever it is necessary to protect data.
Appellants argue that it makes no sense to replace the RAM in
Dunstan with persistent memory because Dunstan already includes
non-volatile memory. Reply Br. 3. It is sufficient for the rejection that
Dunstan discloses encrypting data in non-volatile memory.
For the reasons stated above, we affirm the rejection of claim 1.

Independent claim 13
Appellants rely on the same arguments for the method of claim 13 as
for claim 1. Appeal Br. 15. The rejection of claim 13 is affirmed for the
reasons stated with respect to claim 1.

Independent claim 25
Appellants rely on the same arguments for the computer program
product of claim 25 as for claim 1. The rejection of claim 25 is affirmed for
the reasons stated with respect to claim 1. In addition, it is noted that
Dunstan describes that the method of determining a low-power state and
performing a security action including encrypting and storing data on non-
volatile storage is performed by a computer and, thus, a computer program.
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Dependent claims 3 and 15
Appellants rely on the same arguments as for claims 1 and 13. The
rejection of claims 3 and 15 is affirmed for the reasons stated with respect to
claims 1 and 13.

Dependent claims 12 and 24
Appellants argue that claims 12 and 24 are patentable because they
depend on claims 1 and 13. Appeal Br. 17. Because we sustain the rejection
of claims 1 and 13 this argument is not persuasive.
Appellants also argue that “neither [Knapczyk nor Dunstan] discloses
selectively erasing or encrypting data store in persistent memory. In both
Knapczyk and Dunstan, all of the encryption keys or information is treated
the same.” Appeal Br. 17. The Examiner states that Knapczyk teaches a
key erase sequence and Dunstan teaches encrypting stored data. Ans. 7.
Claim 12 and 24 recite that the security module or security action “is
configurable by the user to encrypt the data on the storage element, or
selectively encrypt portions of the data on the storage element.” That is, the
security module or action is configurable to encrypt all or some of the data.
Knapczyk discloses selectively erasing encryption keys. Dunstan discloses
that “a BIOS may arrange for some or all of the system context information
in volatile memory to be encrypted and/or compressed by a streaming engine
710 and saved to non-volatile memory.” Dunstan, ¶ 38. It would have been
obvious to encrypt all or selective portions of the data in view of Dunstan.
Furthermore, Dunstan discloses that “the maximum amount of information
that can be saved might be limited by the amount of power available from a
back-up power source” (Dunstan, ¶ 26) and one of ordinary skill in the art
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would have been motivated to decide to selectively encrypt only critical
portions of the data based on the limited amount of power available.
The rejection of claims 12 and 24 is affirmed.

Claims 2, 14, and 16 -- Wright, Knapczyk, Dunstan, Kim
Dependent claims 2 and 14
Appellants argue that claims 2 and 14 are patentable because they
depend on claims 1 and 13. Appeal Br. 17. Because we sustain the rejection
of claims 1 and 13 this argument is not persuasive.
Claims 2 and 14 depend on independent claims 1 and 13, respectively,
and recite that a threshold of battery power level at which the security action
taken is the battery power level at which the mobile communication device
disables the communication subsystem. The Examiner finds that Kim
discloses disabling the operability of the communications subsystem in a
power saving mode and concludes that it would have been obvious to take a
security action and disable the communication subsystem at the same battery
power level. Ans. 9. Appellants argue that “[w]hile Kim discloses power
saving modes, it does not disclose taking the security action recited, i.e.
encrypting data, at the same threshold.” Appeal Br. 18.
We agree with the Examiner that the limitation of claims 2 and 12
would have been obvious to one of ordinary skill in the art. Appellants
argue the lack of an express teaching in Kim rather than considering the
collective teachings of the references. Knapczyk teaches the processor
taking a security action at a predetermined battery level while sufficient
power remains available. Dunstan teaches the processor taking a security
action of encrypting and saving information to a non-volatile memory when
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it is determined that the system has lost power and while sufficient power
remains available from a back-up power source. Kim teaches that a number
of power saving mode items, including “Bar Incoming/Outgoing Calls,” may
be selected to occur at a specific battery level. Kim, Figs. 3B and 3C;
¶¶ 37–39. Thus, Kim teaches that a number of actions can be selected to
take place at the same battery level and it would have been obvious to
disable the communications subsystem and take the security action at the
same battery level as two of the actions. Further, it would have been
obvious to one skilled in the art to disable the communications subsystem at
the same battery level that triggers the security action is taken in order to
conserve power to let the processor carry out the security action.
The rejection of claims 2 and 14 is affirmed.

Dependent claim 16
Claim 16 depends on claim 13 and recites that the monitoring to
determine if a battery level falls below a predetermined threshold is enabled
and disabled by policy messages received on the mobile communications
device. The Examiner cites paragraph 38 of Kim as disclosing the controller
receiving a request to set the power saving mode ON. Appellants argue that
Kim does not disclose that monitoring a battery level and performing a
security action of encrypting data in response to monitoring a battery level is
enabled and disabled by way of a policy message. Appeal Br. 18.
We agree with Appellants. Enabling and disabling a power saving
mode in Kim is not the same as enabling and disabling monitoring a battery
threshold level and then performing a security action in response to the
battery level. The rejection of claim 16 is reversed.
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Claims 9, 10, 21, and 22 – Wright, Knapczyk, Dunstan, Dietl
Dependent claims 9 and 21
Claims 9 and 21 depend on independent claims 1 and 13, respectively,
and further recite that the “security action comprises encrypting substantially
all of the user application data from the storage element.” The Examiner
cites paragraph 25 of Dietl as disclosing a security action encrypting
application data. Appellants argue that the claims must be read in light of
the context of the independent claims, i.e., that the security action is in
response to a battery level falling below a threshold and that the data is on a
persistent storage element. Appeal Br. 19. Appellants argue that Dietl does
not discuss encrypting any type of data if a battery level falls below a
threshold and the encryption of data in Dietl is in the context of storing the
data on a removable storage medium. Appeal Br. 19–20.
The rejection is based on the combination of Wright, Knapczyk, and
Dunstan which meets all the limitations of the independent claims. Dietl is
not relied on for monitoring battery level or storing data on a persistent, non-
removable, storage medium. Dietl is only relied on to evidence that user
application data can be encrypted and Appellants do not contest this finding.
Dunstan also discloses encrypting “context information” and we see no
reason why this cannot include user application data. One of ordinary skill
in the art would recognize that the data that is encrypted for security reasons
could be anything. The rejection of claims 9 and 21 is affirmed.

Dependent claims 10 and 22
Claims 10 and 22 depend on independent claims 1 and 13,
respectively, and further recite that the “security action comprises encrypting
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substantially all of the service data from the storage element.” As with the
rejection of claims 9 and 21, the Examiner cites paragraph 25 of Dietl as
disclosing a security action encrypting application data. As with the
response to the rejection of claims 9 and 21, Appellants argue that the claims
must be read in light of the context of the independent claims, i.e., that the
security action is in response to a battery level falling below a threshold and
that the data is on a persistent storage element. Appeal Br. 20. Appellants
argue that Dietl does not discuss encrypting any type of data if a battery
level falls below a threshold and the encryption of data in Dietl is in the
context of storing the data on a removable storage medium. Appeal Br. 20.
The rejection is based on the combination of Wright, Knapczyk, and
Dunstan which meets all the limitations of the independent claims. Dietl is
not relied on for monitoring battery level or storing data on a persistent, non-
removable, storage medium. Dietl is only relied on to teach encrypting
service data and Appellants do not contest this finding. Also, Dunstan
discloses encrypting “context information” and we see no reason why this
cannot include service data. One of ordinary skill in the art would recognize
that the data that is encrypted for security reasons could be anything. The
rejection of claims 10 and 22 is affirmed.

Claims 11 and 23 – Wright, Knapczyk, Dunstan, Levi
Claims 11 and 23 depend on independent claims 1 and 13,
respectively, and further recite that “the service data further includes data
required to establish communications through a wireless gateway connected
to the wireless network.” Claim 11 adds a wireless gateway limitation.
There is no antecedent basis in claim 13 for the service data in claim 23.
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The Examiner cites paragraph 110 and Figure 2 of Levi as disclosing
a mobile device connected to a wireless gateway. Ans. 12. Appellants
argue that “[w]hat claims 11 and 23 recite is that the security action of
claims 1 or 13 comprises encrypting substantially all of the service data,
including data required to establish communications through a wireless
gateway connected to a wireless network, from the persistent storage
element.” Appeal Br. 21. However, claims 1 and 13 only recite encrypting
at least some of the data; claim 1 does not recite encrypting the service data
and claim 13 does not recite service data. The mobile devices in Wright and
Levi have service data required to establish communications through a
wireless gate connected to a wireless network which is all that is required.
Appellants argue that the “claims must be read in the context of their
respective independent claims, i.e. that the security action in response to a
battery level falling below a threshold and that the data is on a persistent
storage element on the device.” Appeal Br. 21. The rejection is based on
the combination of Wright, Knapczyk, and Dunstan for the independent
claims. Levi is not relied on for the limitations of the independent claims.
The rejection of claims 11 and 23 is affirmed.

CONCLUSION
The rejections of claims 1–3, 9–15, and 21–25 are affirmed.
The rejection of claim 16 is reversed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).

AFFIRMED-IN-PART
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