Ex parte Sprunk

Board of Patent Appeals and Interferences

Jan 31, 2002

08972835 (B.P.A.I. Jan. 31, 2002)

The opinion in support of the decision being entered today was not
written for publication and is not binding precedent of the Board.
Paper No. 39
UNITED STATES PATENT AND TRADEMARK OFFICE
____________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________
Ex parte ERIC SPRUNK
____________
Appeal No. 2000-1330
Application No. 08/972,835
____________
HEARD: December 13, 2001
____________
Before FLEMING, LALL, and BLANKENSHIP, Administrative Patent
Judges.
FLEMING, Administrative Patent Judge.
DECISION ON APPEAL
This is a decision on appeal under 35 U.S.C. § 134 from
the final rejection of claims 1 through 6, 8 through 20 and 23
through 31, all of the claims pending in the present
application. Claims 7, 21 and 22 have been canceled.
The invention is directed to a method and apparatus for
generating cryptographic keys with a concealed work factor.
The system provides a high apparent work factor to maintain a
Appeal No. 2000-1330
Application No. 08/972,835
2
high level of security against attackers. At the same time,
with knowledge of a secret distribution key, a government
agency is presented with a lower work factor.
Independent claim 1 is reproduced as follows:
1. A method for providing a cryptographic key for
cryptographically processing information, said method
comprising the steps of:
(a) generating a first key according to a key generator
scheme;
(b) reducing a key space of said first key in accordance
with a key space reduction function; and
(c) distributing said reduced key space over a larger key
space in accordance with a one-way key space distribution
function to provide said cryptographic key; wherein:
said cryptographic key has an associated first work
factor S for a person without knowledge of said key space
distribution function; and
said cryptographic key has an associated second work
factor W < S for a person with knowledge of said key space
distribution function.
The Examiner relies on the following references:
Elander et al. (Elander) 5,323,464 June 21,
1994
Applied Cryptography, Bruce Schneier, CIP of 1993 and
copyright of 1994.
Claims 1 through 6, 8 through 20 and 23 through 31 stand
rejected under 35 U.S.C. § 103 as unpatentable over Elander.
Appeal No. 2000-1330
Application No. 08/972,835
Appellant filed an Appeal Brief on June 11, 1999. Appellant 1
filed a Reply Brief on October 26, 1999. The Examiner mailed
an Office communication on December 30, 1999 stating that the
Reply Brief has been entered and considered.
3
Claims 26 through 31 stand rejected under 35 U.S.C. § 103
as being unpatentable over Elander in view of Schneier.
Rather than repeat the arguments of Appellant or
Examiner, we make reference to the Briefs and Answer for the
details thereon.1
OPINION
We will not sustain the rejection of claims 1 through 6,
8 through 20 and 23 through 31 under 35 U.S.C. § 103.
In rejecting claims under 35 U.S.C. § 103, the Examiner
bears the initial burden of establishing a prima facie case of
obviousness. In re Oetiker, 977 F.2d 1443, 1445, 24 USPQ
1443, 1444 (Fed. Cir. 1992). See also In re Piasecki, 745
F.2d 1468, 1472, 223 USPQ 785, 788 (Fed. Cir. 1984). The
Examiner can satisfy this burden by showing that some
objective teaching in the prior art or knowledge generally
available to one of ordinary skill in the art suggests the
claimed subject matter. In re Fine, 837 F.2d 1071, 1074, 5
Appeal No. 2000-1330
Application No. 08/972,835
4
USPQ2d 1596, 1598 (Fed. Cir. 1988). Only if this initial
burden is met does the burden of coming forward with evidence
or argument shift to the Appellants. Oetiker, 977 F.2d at
1445, 24 USPQ at 1444. See also Piasecki, 745 F.2d at 1472,
223 USPQ at 788 ("After a prima facie case of obviousness has
been established, the burden of going forward shifts to the
applicant.").
Appellant points out in the Brief and the Reply Brief
that Appellant's independent claims 1 and 14 both require
"distributing said reduced key space over a larger key space
in accordance with a one-way key space distribution function."
Appellant argues that this is not disclosed or suggested by
the prior art. Appellant further argues that there is no
motivation to modify Elander's teaching by replacing or
augmenting the use of DEA encryption with a one way function
to provide the encrypted weakened key (KWEAK) because KWEAK is
not communicated over a weak channel. See page 3 of
Appellant's Reply Brief.
We note that Appellant's claim 1 recites:
distributing said reduced key space over a larger
key space in accordance with a one-way key space
Appeal No. 2000-1330
Application No. 08/972,835
5
distribution function to provide said cryptographic
key; wherein: said cryptographic key has an
associated first work factor S for a person without
knowledge of said key space distribution function;
and said cryptographic key has an associated second
work factor W < S for a person with knowledge of
said key space distribution function.

Also, we note that the only other independent claim, claim 14,
is in the apparatus format which recites substantially the
same limitations.
Upon our review of Elander, we fail to find that Elander
teaches the above limitations. In column 9, line 39, through
column 10, line 45, Elander discloses that Figure 3 is a block
diagram illustration of two cryptographic systems, A and B,
that communicates CDM keys via a strong key distribution
channel 50 and communicate CDM-masked data via a weakened
privacy channel 60. From the careful reading of Elander, we
find that Elander's system provides a separate weak (CDM) and
a strong (DEA) keys and does not teach a single apparently
strong key that is weak for the government's use only.
Although the Elander's final CDM key is weak, the CDM key K
transmitted in Figure 3 is the strong key. We note that
Appellant is claiming protecting the weak key with a one-way
function, whereas Elander only protects the strong key with a
Appeal No. 2000-1330
Application No. 08/972,835
6
one-way function. Therefore, we fail to find that Elander
teaches or suggest Appellant's claimed method recited in
Appellant's claim 1 or a key distributor recited in
Appellant's claim 14, lines 8 through 17. Furthermore, upon
our review of Schneier, we fail to find that Schneier closes
the gap.
The Federal Circuit states that "[t]he mere fact that the
prior art may be modified in the manner suggested by the
Examiner does not make the modification obvious unless the
prior art suggested the desirability of the modification." In
re Fritch, 972 F.2d 1260, 1266 n.14, 23 USPQ2d 1780, 1783-84
n.14 (Fed. Cir. 1992), citing In re Gordon, 733 F.2d 900, 902,
221 USPQ 1125, 1127 (Fed. Cir. 1984). It is further
established that "[s]uch a suggestion may come from the nature
of the problem to be solved, leading inventors to look to
references relating to possible solutions to that problem."
Pro-Mold & Tool Co. v. Great Lakes Plastics, Inc., 75 F.3d
1568, 1573, 37 USPQ2d 1626, 1630 (Fed. Cir. 1996), citing In
re Rinehart, 531 F.2d 1048, 1054, 189 USPQ 143, 149 CCPA 1976)
(considering the problem to be solved in a determination of
Appeal No. 2000-1330
Application No. 08/972,835
7
obviousness). The Federal Circuit reasons in Para-Ordnance
Mfg. Inc. v. SGS Importers Int’l Inc., 73 F.3d 1085, 1088-89,
37 USPQ2d 1237, 1239-40 (Fed. Cir. 1995), that for the
determination of obviousness, the court must answer whether
one of ordinary skill in the art who sets out to solve the
problem and who had before him in his workshop the prior art,
would have been reasonably expected to use the solution that
is claimed by the Appellants. However, "[o]bviousness may not
be established using hindsight or in view of the teachings or
suggestions of the invention." Para-Ordinance Mfg. v. SGS
Importers Int’l, 73 F.3d at 1087, 37, USPQ2d at 1239, citing
W.L. Gore & Assocs., Inc. v. Garlock, Inc. 721 F.2d at 1551,
1553, 220 USPQ at 311, 312-13. In addition, our reviewing
court requires the PTO to make specific findings on a
suggestion to combine prior art references. In re Dembiczak,
175 F.3d 994, 1000-01,
50 USPQ2d 1614, 1617-19 (Fed. Cir. 1999).
In view of the foregoing, we have not sustained the
rejection of claim 1 through 6, 8 through 20 and 23 through 31
Appeal No. 2000-1330
Application No. 08/972,835
8
under 35 U.S.C. § 103. Accordingly, the Examiner's decision
is reversed.
REVERSED
MICHAEL R. FLEMING )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
PARSHOTAM S. LALL ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
HOWARD B. BLANKENSHIP )
Administrative Patent Judge )
MRF/LBG
Appeal No. 2000-1330
Application No. 08/972,835
9
BARRY R. LIPSITZ
BRADFORD GREEN
755 MAIN STREET
MONROE, CT 06468
Lesley
Appeal No. 2000-1330
Application No. 08/972,835
APJ FLEMING
APJ BLANKENSHIP
APJ LALL
DECISION: REVERSED

Prepared: August 21, 2002
Draft Final
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