Tristrata, Inc. v. Microsoft Corporation

N OTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
TRISTRATA, INC.,
Plaintiff-Appellant,
v.
MICROSOFT CORPORATION,
Defendant-Appellee,
AND
ADOBE SYSTEMS INCORPORATED,
Defendant-Appellee.
______________________
2014-1168
______________________
Appeal from the United States District Court for the
Northern District of California in No. 3:11-cv-03797-JST,
Judge Jon S. Tigar.
______________________
Decided: December 4, 2014
______________________
BRUCE J. WECKER , Hausfeld LLP, of San Francisco,
California, argued for plaintiff-appellant. On the brief
was ROBERT J. Y ORIO, Carr & Ferrell LLP, of Menlo Park,
California.

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TRISTRATA, INC. v. MICROSOFT CORPORATION 2
ERIC L. WESENBERG, Perkins Coie LLP, of Palo Alto,
California, argued for defendant-appellee Microsoft Cor-
poration. With him on the brief were K ENNETH J.
HALPERN; CHRISTINA J. MCCULLOUGH , of Seattle, Wash-
ington, and D AN L. BAGATELL , of Phoenix, Arizona. Of
counsel on the brief was STACY Q UAN, Microsoft Corpora-
tion, of Redmond, Washington.
MARC BELLOLI, Feinberg Day Alberti & Thompson,
LLP, of Menlo Park, California, argued for defendant-
appellee Adobe Systems Incorporated. With him on the
brief were I AN F EINBERG, CLAYTON T HOMPSON, and YAKOV
ZOLOTOREV. Of counsel on the brief was T HOMAS R.
BURNS , J R., Adduci, Mastriani, & Schaumberg, LLP, of
Washington, DC.
______________________
Before L OURIE, SCHALL , and D YK, Circuit Judges.
SCHALL , Circuit Judge.
D ECISION
TriStrata, Inc. (“TriStrata”) appeals the judgment of
non-infringement of the United States District Court for
the Northern District of California in favor of Microsoft
Corporation and Adobe Systems Incorporated (“Appel-
lees”) in TriStrata’s suit against them for infringement of
U.S. Patent Nos. 7,257,706 (“the ’706 patent”) and
7,743,249 (“the ’249 patent”). TriStrata, Inc. v. Microsoft
Corp., No. 11-cv-03797-JST (N.D. Cal. Nov. 22, 2013),
ECF No. 131. The district court entered judgment in
favor of Appellees after the parties stipulated to non-
infringement following the court’s construction of five
claim terms. We have jurisdiction pursuant to 28 U.S.C.
§ 1295(a)(1). For the reasons set forth below, we affirm.

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TRISTRATA, INC. v. MICROSOFT CORPORATION 3
D ISCUSSION
I.
The patents-in-suit, which share a common specifica-
tion, relate to encrypting electronic documents so that
they may be openly distributed over insecure networks,
such as the Internet, but at the same time may be acces-
sible by permitted recipients. This encryption system is
referred to as an “efficient multicast key management
system.” ’706 patent col. 2 ll. 17–18. It provides security
by transmitting a data structure called a “seal” along with
the encrypted document. Id. col. 2 ll. 26–30. The “seal,”
in turn, contains an encryption key or information to
generate an encryption key, which allows recipients to
unlock the encrypted documents. Id. col. 2 ll. 31–36.
Claim 1 of each patent is representative of the claims at
issue.
Claim 1 of the ’706 patent reads as follows:
1. A method of securing a document stored in a
computer system which is part of a network, com-
prising:
creating a seal associated with a document which
is to be stored or shared within the computer sys-
tem or network:
placing in the seal information identifying the
person requesting that the document be secured
(hereinafter the “requestor”); and
placing in the seal information identifying who
can access the document;
thereby allowing one or more designated persons
to have access to the document in accordance with
the information in the seal.
Id. col. 10 ll. 37–49.
Claim 1 of the ’249 patent reads as follows:

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TRISTRATA, INC. v. MICROSOFT CORPORATION 4
1. A system for securing a document stored in a
computer system which is part of a network, com-
prising:
a storage device storing a seal for association with
a document which is to be stored or shared within
the computer system or network, said seal com-
prising;
a) information identifying a requestor requesting
that the document be secured; and
b) information identifying one or more parties
qualified to access the document.
’249 patent col. 10 ll. 29–37.
On appeal, TriStrata challenges the district court’s
construction of only one term in the ’706 and ’249 patents:
“seal.” It appears in every asserted claim. The district
court rejected a general-use dictionary definition of “seal”
and construed it as “[a] data structure generated by a
security server and containing a key or information to
generate a key, wherein part or all of the data structure is
encrypted and decrypted only by the security server that
created it.” TriStrata, Inc. v. Microsoft Corp., No. 11-cv-
03797-JST, 2013 WL 5645984, at *7–8 (N.D. Cal. Oct. 15,
2013) (“Claim Construction Order”). TriStrata argues
that, in construing “seal,” the district court erred because
it deviated from the plain and ordinary meaning of the
term and imported three features from the specification
as claim limitations.
Before the district court, TriStrata proposed that
“seal” be construed as “[i]nformation in the form of com-
puter bits used by a computer system to secure documents
through encryption . . . [which] contains information
relating to an encryption/decryption key, such as infor-
mation from which the key can be derived or the key
itself.” TriStrata now urges that “seal” should have been
construed in accordance with its general-purpose diction-

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TRISTRATA, INC. v. MICROSOFT CORPORATION 5
ary definition as “something that secures (as a wax seal
on a document).”
II.
The only issue on appeal is claim construction. Claim
construction is a question of law that we review de novo.
Cybor Corp. v. FAS Techs., Inc., 138 F.3d 1448, 1454 (Fed.
Cir. 1998) (en banc).* The words of a claim are generally
given their ordinary and customary meaning. Phillips v.
AWH Corp., 415 F.3d 1303, 1312 (Fed. Cir. 2005) (en
banc). In determining that meaning, we look to how one
of skill in the relevant art would understand the term at
the time of the invention, based upon the language of the
claim and the pertinent intrinsic evidence, and where
appropriate, extrinsic evidence. Id. at 1312–14, 1317; see
also Medrad, Inc. v. MRI Devices Corp., 401 F.3d 1313,
1319 (Fed. Cir. 2005) (“We cannot look at the ordinary
meaning of the term . . . in a vacuum. Rather, we must
look at the ordinary meaning in the context of the written
description and the prosecution history.”).
A.
TriStrata argues that the ordinary and customary
meaning of “seal” according to a general-purpose diction-
ary is controlling. In support of its position, TriStrata
interprets our decision in Thorner v. Sony Computer
Entertainment America, Inc., 669 F.3d 1362 (Fed. Cir.
2012), as requiring an ordinary dictionary definition
absent clear lexicography or manifest disavowal of claim
* In Teva Pharmaceuticals USA v. Sandoz Inc., No.
13-854, the Supreme Court is considering the level of
deference given to a district court’s claim construction.
The outcome of that appeal would not affect the outcome
here. Deference to the district court’s claim construction
or factual findings would serve only to underscore the
appropriateness of affirmance in this case.

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TRISTRATA, INC. v. MICROSOFT CORPORATION 6
scope. In Thorner, we stated that there are only two
exceptions to the general rule that claim terms are given
their ordinary and customary meanings: “1) when a
patentee sets out a definition and acts as his own lexicog-
rapher, or 2) when the patentee disavows the full scope of
a claim term either in the specification or during prosecu-
tion.” 669 F.3d at 1365. TriStrata contends that neither
of these exceptions is present here and that, thus, the
dictionary definition of “seal” as “something that secures”
is both the customary and guiding meaning of the term.
We do not agree. As explained in Phillips, because
the meaning of a claim term, as viewed by a skilled arti-
san, is not always immediately apparent, and because
patentees may use claim terms idiosyncratically, the
specification is highly relevant to the claim construction
analysis. 415 F.3d at 1314. Indeed, it is often “the single
best guide to the meaning of a disputed term.” Id. at 1315
(quoting Vitronics Corp. v. Conceptronic, Inc., 90 F.3d
1576, 1582 (Fed. Cir. 1996)). Examining the written
description before relying on extrinsic evidence, such as
dictionaries, mitigates the risk of “transforming the
meaning of the claim term to the artisan into the meaning
of the term in the abstract, out of its particular context.”
Id. at 1321.
In the two patents at issue, the term “seal” is used in
a manner particular to the invention and unique to the
cryptographic arts. The specification states that the
“system allows the transmission of what are called ‘per-
mits’ and ‘seals,’” that “the encoded key is called a ‘seal,’”
and that the “security sever generates what is called a
‘seal.’” ’706 patent col. 2 ll. 26–38 (emphases added).
Indeed, the Detailed Description states that “[s]eals and
permits are described in detail below,” id. col. 4 ll. 33–36,
which would be unnecessary if “seal,” as used in the
patents, had a broad, accepted meaning in the crypto-
graphic arts. Intentionally off-setting the term “seal” and
providing additional, term-specific explanations are

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TRISTRATA, INC. v. MICROSOFT CORPORATION 7
signals that “seal” is used in a context-specific manner,
thereby undercutting TriStrata’s argument for a general-
use dictionary definition. The use of “seal” here also
stands in contrast to what was the case in Thorner.
There, a customary meaning in the mechanical arts for
the term “attached” was readily and immediately appar-
ent. 669 F.3d at 1367–68 (“The plain meaning of the term
‘attached’ encompasses either an external or internal
attachment” in the context of mechanical “tactile feedback
controllers.”). We find no error in the district court’s
refusal to apply a dictionary definition of “seal” in view of
the specification and the field of invention.
B.
The district court explained why the specification pro-
vided the appropriate definition of “seal.” Claim Con-
struction Order, 2013 WL 5645984, at *6–9. Relying on
Irdeto Access, Inc. v. Echostar Satellite Corp., 383 F.3d
1295 (Fed. Cir. 2004), the district court found that TriS-
trata had limited the ordinary meaning of “seal” by impli-
cation. Claim Construction Order, 2013 WL 5645984, at
*7–8; Irdeto, 383 F.3d at 1300 (absent an “accepted mean-
ing, we construe a claim term only as broadly as provided
for by the patent itself”). The district court held that a
person of skill in the cryptographic arts, after reading the
claims and written description, would understand “seal”
to include the following limitations: “[a] data structure
generated by a security server . . . , wherein part or all of
the data structure is encrypted and decrypted only by the
security server that created it.” Claim Construction
Order, 2013 WL 5645984, at *8. TriStrata argues against
the “generated by a security server” and “encrypted and
decrypted only by the security server” limitations. We
find no error in the district court’s reasoning and reject
TriStrata’s argument that the district court erred by
importing these limitations into the claims from the
specification.

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TRISTRATA, INC. v. MICROSOFT CORPORATION 8
First, a server-generated “seal” is consistently and ex-
clusively taught throughout the patents. The Summary of
the Invention states that, “[i]n accordance with this
invention, the security server generates seals and per-
mits.” ’706 patent col. 2 ll. 50–51; see also, e.g., id. col. 2
ll. 31–32 (“[T]he security server generates what is called a
‘seal.’”). The use of “in accordance with this invention,” in
conjunction with its place in the Summary of the Inven-
tion, suggests that the phrase “the security server gener-
ates seals” applies to the entire invention, and not merely
one embodiment. While the location of a passage in the
specification is not determinative, “the location [in the
Summary of the Invention] can signal the likelihood that
the statement will support a limiting definition.” C.R.
Bard, Inc. v. United States Surgical Corp., 388 F.3d 858,
864 (Fed. Cir. 2004). We have also held that the use of
phrases such as “in accordance with the present inven-
tion” is a strong indication that a statement is not limited
to a single, preferred embodiment. E.g., Honeywell Int’l,
Inc. v. ITT Indus., Inc., 452 F.3d 1312, 1318 (Fed. Cir.
2006).
Second, the specification is also clear that a “seal” is a
data structure encrypted and decrypted by the same
security sever. The Summary of the Invention states that
“[t]he encoded key is called a ‘seal’ which is generated by
the security server.” ’706 patent col. 2 ll. 36–38. It con-
tinues by unequivocally stating: “All the information
contained in a seal is encrypted by the security server and
can only be ‘opened,’ i.e., decrypted, by the security server
which encrypted the seal.” Id. col. 2 ll. 46–49. The De-
tailed Description reiterates, in a paragraph starting with
the words “in general,” that “[t]he seal can only be
‘opened’ by security server 303, and cannot be interpreted
unless security server 303 opens it.” Id. col. 6 ll. 50–58.
It is precisely this server architecture that “solves the
broadcast key distribution problem” by allowing a party to
“broadcast[] the same encrypted data stream to all the

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TRISTRATA, INC. v. MICROSOFT CORPORATION 9
recipients regardless of the identity or the number of
recipients” because “[u]nauthorized recipients are not
allowed to open the seal at the security server [that
created it].” Id. col. 7 ll. 57–65. And, as the district court
correctly explained, “[i]f the seal were not encrypted, the
security scheme would not function, and the security
server would serve no purpose, as it would be transmitted
in plaintext.” Claim Construction Order, 2013 WL
5645984, at *8. The use of a security server to encrypt
and decrypt the “seal” is fundamental to the invention,
and nothing TriStrata has pointed to convincingly demon-
strates that the seal could be generated, encrypted, and
decrypted in any other way.
III.
For the foregoing reasons, we hold that the district
court properly construed “seal” as it is disclosed in the
claims and the written description of the invention. We
therefore affirm the judgment of non-infringement.
AFFIRMED

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