Ex Parte Franke et al

Patent Trial and Appeal Board

Nov 20, 2012

10528312 (P.T.A.B. Nov. 20, 2012)

UNITED STATES PATENT AND TRADEMARKOFFICE
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.
10/528,312 03/17/2005 Markus Franke 2002P15289WOUS 2692
7590 11/20/2012
Siemens Corporation
Intellectual Property Department
170 Wood Avenue South
Iselin, NJ 08830
EXAMINER
HAILU, TESHOME
ART UNIT PAPER NUMBER
2434
MAIL DATE DELIVERY MODE
11/20/2012 PAPER
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.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________________

Ex parte MARKUS FRANKE, ANDREAS FURCH, MARKUS HEINTEL
and OLIVER PFAFF
____________________

Appeal 2010-006852
Application 10/528,312
Technology Center 2400
____________________

Before DEBRA K. STEPHENS, KRISTEN L. DROESCH and HUNG H.
BUI, Administrative Patent Judges.

BUI, Administrative Patent Judge.

DECISION ON APPEAL
Appellants1 seek our review under 35 U.S.C. § 134(a) of the
Examiner’s Final Rejection of claims 6, 8, 10, 12, 14, 16, 18, 20, 22 and 23.2
We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.

1 Real Party in Interest is Siemens Aktiengesellschaft. Appeal Brief filed
September 2, 2009 (“App. Br.”).
2 Claims 1-5, 7, 9, 11, 13, 15, 17, 19 and 21 were canceled and thus, are not
on appeal.
Appeal 2010-006852
Application 10/528,312

2

I. STATEMENT OF THE CASE
Appellants’ Invention
Appellants’ claims are generally directed to a method for generating
and/or validating an electronic signature in which a certification of a public
validation key does not take place until after a calculation of an electronic
signature. This way the private signature key needs not be protected against
unauthorized access and can be destroyed following the calculation of the
electronic key. See generally Spec. pg. 4, ll. 4-19.
Claims on Appeal
Independent claims 6 and 18 are representative and are reproduced
below with disputed limitations emphasized:

6. A method for generating and/or validating
electronic signatures, the method comprising:

generating an asymmetrical key pair which includes a
private signature key and a public validation key;

calculating an electronic signature for an electronic
document by means of the private signature key and by
applying a predeterminable signature function; and

performing a certification of the public validation key
wherein, when validating, only those signatures generated at a
time prior to the certification of the public validation key are
recognized as valid.

18. A method for generating and/or validating
electronic signatures, the method comprising:

Appeal 2010-006852
Application 10/528,312

3

generating an asymmetrical key pair which includes a
private signature key and a public validation key;

calculating at least one electronic signature for at least
one electronic document by means of the private signature key
and by applying a predeterminable signature function; and

following calculation of the electronic signature, of
which there is at least one, carrying out a certification of the
public validation key wherein only those signatures generated
at a time prior to the certification of the public validation key
are recognized as valid.

Evidence Considered
The prior art relied upon by the Examiner in rejecting the claims on
appeal is:
Oka U.S. 2002/0108042 A1 Aug. 8, 2002

Examiner’s Rejections
Claims 6, 8, 10, 12, 14, 16, 18, 20, 22 and 23 stand rejected under 35
U.S.C. § 102(b) as being anticipated by Oka (Ans. 3-8).

II. ISSUES
Under § 102(b), the dispositive issue on appeal is whether the
Examiner has erred in rejecting claims 6, 8, 10, 12, 14, 16, 18, 20, 22 and 23
as being anticipated by Oka. In particular, the issue turns on whether:
(1) Oka discloses the features “calculating an electronic signature
for an electronic document” and “performing” or alternatively, “carrying out
a certification of the public validation key wherein only those signatures
Appeal 2010-006852
Application 10/528,312

4

generated at a time prior to the certification of the public validation key are
recognized as valid,” as recited in independent claims 6 and 18;
(2) Oka discloses the feature “when certifying the public validation
key, a reference to the electronic document is included in addition to a user
identifier and the public validation key,” as recited in claims 8 and 20;
(3) Oka discloses the feature “an implementation of the reference is
performed by a calculation of a hash value for the electronic document,” as
recited in claims 10 and 22; and
(4) Oka discloses the feature “following calculation of the
signature and prior to its transfer to a recipient, a validation is performed
by an author of the electronic document, in order to verify an action of intent
which is expressed by the electronic document,” as recited in claims 12, 14,
16 and 23.

III. ANALYSIS
We have reviewed Appellants’ arguments in the Briefs, the
Examiner’s rejections and the Examiner’s responses to Appellants’
arguments. We are not persuaded by Appellants’ arguments and
conclusions. We adopt as our own (1) the findings and reasons set forth by
the Examiner in the final Office Action, and (2) the reasons set forth by the
Examiner in the Examiner’s Answer in response to Appellants’ Appeal
Brief. We further highlight and address specific findings and arguments for
emphasis as follows.

Appeal 2010-006852
Application 10/528,312

5

Independent Claims 6 and 18

With respect to independent claims 6 and 18, Appellants contend that
Oka does not disclose the features “calculating an electronic signature for
an electronic document” and “performing” or alternatively, “carrying out a
certification of the public validation key wherein only those signatures
generated at a time prior to the certification of the public validation key are
recognized as valid,” as recited in independent claims 6 and 18. In
particular, Appellants argue that: (1) Oka discloses in step 8 of FIG. 22 only
generation of a signature on a certificate, and not for an electronic document,
and (2) Oka does not limit “validation of signatures on documents to only
those generated on documents prior to the certification of the public
validation key.” App. Br. 6-7; Rep. Br. 2-4 (emphasis added).
However, we are not persuaded by Appellants’ arguments. The
claims measure the invention. See SRI Int’l v. Matsushita Elec. Corp., 775
F.2d 1107, 1121 (Fed. Cir. 1985) (en banc). During examination, claim
terms must be given their “broadest reasonable interpretation” consistent
with the specification. In re Hyatt, 211 F.3d 1367, 1372 (Fed. Cir. 2000).
First, as found by the Examiner, Oka discloses that an electronic
signature is attached to a document using the private key. Ans 6; see also
¶0009 of Oka. Moreover, an electronic signature is typically formed by
encrypting a hash code (hash function) of a text message (data) with a
sender’s private key, as described in Appellants’ Specification, pages 1-3, or
alternatively, as shown, for example, in FIG. 1 of Oka, ¶¶0011-0013.

Appeal 2010-006852
Application 10/528,312

6

FIG. 1 of Oka is reproduced below:

FIG. 1 is a schematic view of a typical public key certificate.

Once generated, such an electronic signature is attached on message
data constituting a public key certificate, as shown in FIG. 1 and described
in step 8, FIG. 22, claims 1-2 of Oka.
In view of the aforementioned disclosures in Oka and Appellants’
Specification, we agree with the Examiner’s reasonable interpretation that
Appellants’ claimed feature “calculating an electronic signature for an
electronic document” encompasses the “message data” constituting a public
key certificate as shown in FIG. 1 of Oka, or the subsequent electronic
document as discussed in ¶0009 of Oka. Ans. 6 (emphasis added).
Second, as correctly noted by the Examiner, an electronic signature is
generated in steps 5-6 and verified in step 8, FIG. 22 of Oka before a
certification of a public validation key. Ans. 5-6.
Appeal 2010-006852
Application 10/528,312

7

FIG. 22 of Oka is reproduced below:

FIG. 22 shows an electronic signature generation process performed
by signature modules in which an electronic signal is generated before
certification of a public validation key.

In view of FIG. 22 of Oka in which an electronic signature is
generated before certification of a public validation key, and Appellants’
own Specification,3 we agree with the Examiner’s finding that Oka also

3 See page 4 of Appellants’ Specification where Appellants describe “[a]n
essential aspect of the present invention is that a certification of a public
validation key does not take place until after a calculation of an electronic
signature”. As a result, when validating an electronic signature, only those
signatures which were generated at a time prior to the certification of the
public validation key are recognized as valid. [T]his ensures that it is no
longer possible to misuse the private signature key after the time of the
certification of the public validation key. See Spec. 7, ll. 9-19.
Appeal 2010-006852
Application 10/528,312

8

discloses that “only those signatures generated at a time prior to the
certification of the public validation key are recognized as valid” as recited
in independent claims 6 and 18. Ans. 5-6.
For the reasons set forth above, Appellants have not persuaded us of
error in the Examiner’s anticipation rejection of representative claims 6 and
18. Accordingly, we sustain the Examiner’s rejection of independent claims
6 and 18.

Claims 8 and 20
With respect to claims 8 and 20, Appellants contend that Oka does not
disclose the feature “when certifying the public validation key, a reference to
the electronic document is included in addition to a user identifier and the
public validation key.” App. Br. 10 and 13.
We disagree. As correctly found by the Examiner, FIG. 1 of Oka
shows a typical public validation key as including a certificate version
number; a serial number allocated to a certificate user by a certificate
authority (CA); algorithm and parameters used for signature by the RSA,
ECDSA, etc.; a certificate authority name; the period of certificate validity;
the certificate user's name (user 10); the user's public key; and a digital
signature. Ans. 6-7. We also agree with the Examiner’s interpretation that
Appellants’ claimed “reference to the electronic document” encompasses
any of these items, shown in FIG. 1 of Oka. Id. Moreover, the Examiner’s
interpretation is reasonable in view of Appellants’ own Specification. Ans.
6-7. Therefore, we do not find any error in the Examiner’s § 102 rejection
of claims 8 and 20 over Oka.

Appeal 2010-006852
Application 10/528,312

9

Claims 10 and 22
With respect to claims 10 and 22, Appellants contend that Oka does
not disclose the feature “an implementation of the reference is performed by
a calculation of a hash value for the electronic document.” App. Br. 10-11
and 13.
Again, we disagree. As correctly found by the Examiner regarding
Oka, a hash value is generated using hash function, the private key is applied
to the harsh value to generate the signature, and then the generated signature
is attached to the document. Ans. 7. Alternatively, a hash value can also be
generated using hash function as applied to an entire message, as shown in
Oka’s FIG. 1. In light of Oka’s disclosure, Appellants’ claimed “electronic
document” reads on Oka’s entire message, shown in Oka’s FIG. 1. In view
of these reasons, we agree with the Examiner’s finding that Oka discloses
the feature “an implementation of the reference is performed by a
calculation of a hash value for the electronic document,” as recited in claims
10 and 22. Ans. 7. Therefore, we do not find any error in the Examiner’s §
102 rejection of claims 10 and 22 over Oka.

Claims 12, 14, 16 and 23
With respect to claims 12, 14, 16 and 23, Appellants contend that Oka
does not disclose the feature “following calculation of the signature and
prior to its transfer to a recipient, a validation is performed by an author of
the electronic document, in order to verify an action of intent which is
expressed by the electronic document.” App. Br. 11-12 and 14.
However, we disagree. As properly noted by the Examiner, an author
of an electronic document or data message can be broadly and reasonably
Appeal 2010-006852
Application 10/528,312

10

construed to read on a certification authority (CA) 321, as shown in FIG. 22
of Oka, where validation is performed following the calculation of an
electronic signature and prior to its transfer to a recipient, i.e., an end entity
(EE) 300. Ans. 7-8. Therefore, we do not find any error in the Examiner’s §
102 rejection of claims 12, 14, 16 and 23 over Oka.

V. CONCLUSION
On the record before us, we conclude that the Examiner has not erred
in rejecting claims 6, 8, 10, 12, 14, 16, 18, 20, 22 and 23 under 35 U.S.C. §
102(b) as being anticipated by Oka.

VI. DECISION
As such, we affirm the Examiner’s final rejection of claims 6, 8, 10,
12, 14, 16, 18, 20, 22 and 23 under 35 U.S.C. § 102(b).
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) (2011).

AFFIRMED

tj