Court Opinion

ID: 210397
Source: CourtListenerOpinion
Date Created: 2011-03-13 08:06:59+00
Date Added: 2024-06-11T17:28:01.160233
License: Public Domain

NOTE: This disposition is nonprecedential.

 United States Court of Appeals for the Federal Circuit

                                        2006-1603

                         DATA ENCRYPTION CORPORATION,

                                                 Plaintiff/Counterclaim Defendant-
                                                 Appellant,

                                            v.

                             MICROSOFT CORPORATION,

                                                 Defendant/Counterclaimant-Appellee,

                                           and

                          DELL COMPUTER CORPORATION,

                                                 Defendant-Appellee.

       Roderick G. Dorman, Hennigan, Bennett & Dormann LLP, of Los Angeles,
California, argued for plaintiff/counterclaimant defendant-appellant. With him on the
brief were Lawrence M. Hadley, Bless S. Young, and Hazim H. Ansari.

       Kelly C. Hunsaker, Fish & Richardson P.C., of Redwood City, California, argued
for defendant/counterclaimant-appellee. With him on the brief for Microsoft Corporation
were Juanita R. Brooks and William Chad Shear, of San Diego, California. Of counsel
was Robert B. Lytle, Microsoft Corporation, of Redmond, Washington.

      Daniel T. Conrad, Jones Day, of Dallas Texas, argued for defendant-appellee.
With him on the brief for Dell Computer Corporation was Mark N. Reiter. Of counsel
was Amy E. Blackwelder.

Appealed from: United States District Court for the Central District of California

Judge Manuel L. Real
                      NOTE: This disposition is nonprecedential.

 United States Court of Appeals for the Federal Circuit

                                      2006-1603

                        DATA ENCRYPTION CORPORATION,

                                                      Plaintiff/Counterclaim Defendant-
                                                      Appellant,

                                           v.

                            MICROSOFT CORPORATION,

                                                      Defendant/Counterclaimant-
                                                      Appellee,

                                          and

                         DELL COMPUTER CORPORATION,

                                                      Defendant-Appellee.

                           __________________________

                           DECIDED: September 6, 2007
                           __________________________

Before RADER, BRYSON, and PROST, Circuit Judges.

PROST, Circuit Judge.

      Plaintiff-Appellant, Data Encryption Corporation (“Data”) appeals the decision of

the United States District Court for the Central District of California granting summary

judgment of noninfringement of U.S. Patent No. 5,584,023 (the “’023 patent”) in favor of

Defendants-Appellees,    Microsoft   Corporation   (“Microsoft”)   and   Dell   Computer
Corporation (“Dell”). Data Encryption Corp. v. Microsoft Computer Corp., No. 05-CV-

05531 (C.D. Cal. Aug. 14, 2006). We affirm.

                                   I. BACKGROUND

      Data is the owner of the ’023 patent, entitled “Computer System Including a

Transparent and Secure File Transform Mechanism.”        Generally speaking, the ’023

patent is directed to computer systems that encrypt and decrypt files. On July 29, 2005,

Data sued Microsoft and Dell, alleging that Microsoft’s Windows operating systems and

Dell computers using Windows operating systems infringed claims 5-12 of the ’023

patent.

      The parties filed cross motions for summary judgment. On August 14, 2006, the

district court (1) granted Microsoft’s motion for summary judgment of noninfringement,

(2) granted Dell’s motion for summary judgment of noninfringement, and (3) denied

Data’s motion for partial summary judgment of infringement of claims 5, 6, and 7 by

Microsoft and Dell.

      Data appeals. We have jurisdiction under 28 U.S.C. § 1295(a)(1).

                                   II. DISCUSSION

                                           A

      On appeal, Data argues that the district court misconstrued the asserted claims

and that, therefore, the district court’s infringement analysis was incorrect. We review

the district court’s claim construction de novo. Cybor Corp. v. FAS Techs., Inc., 138

F.3d 1448, 1456 (Fed. Cir. 1998) (en banc). We also review de novo the district court’s

grant of summary judgment of noninfringement. O2 Micro Int’l Ltd. v. Monolithic Power

Sys., Inc., 467 F.3d 1355, 1369 (Fed. Cir. 2006).

2006-1603                                  2
      Of the asserted claims, claims 5 and 8 are independent. Claim 5 recites: 1

      5. A computer system including a file encryption mechanism, said system
      comprising:
             a) a file store providing for the storage of a file including one or
                more blocks of data;
             b) a memory store providing for the storage of blocks of data in first
                and second logical data areas; and
             c) a processor coupled to said memory store and said file store for
                executing instructions implementing a computer operating
                system as stored in said first logical data area and an application
                program as stored in said second logical data area, said
                processor providing for the controlled transfer of a predetermined
                block of data between said file store and said data store means,
                said processor including:
                     i) an encryption routine, defined by the execution of
                         instructions of said computer operating system, for
                         encrypting and decrypting said predetermined block of
                         data in said first logical data area separately from another
                         block of data;
                     ii) a request routine, defined by the execution of instructions
                         of said application program, for selecting said
                         predetermined block of data to be operated on by the
                         execution of instructions of said application program in
                         said second logical data area; and
                     iii) a system interface routine, defined by the execution of
                         instructions of said computer operating system and
                         responsive to said request routine, that controls the
                         transfer of said predetermined block of data between said
                         file store and said data store and between said first and
                         second logical data areas of said data store, said system
                         interface routine determining whether said predetermined
                         block of data is encrypted as stored by said file store, said
                         system interface routine selectively directing the transfer
                         of said predetermined block of data between said first and
                         second logical data areas through said encryption routine.

(Emphases added). The parties agreed before the district court that the term “first

logical data area” as recited in the claim refers to the kernel memory area and that the

term “second logical data area” refers to the user memory area.

      1
             On appeal, Data presents no separate argument regarding independent
claim 8. We therefore discuss only independent claim 5.

2006-1603                                    3
        In granting summary judgment of noninfringement, the district court held that

certain statements in the specification amounted to a disavowal of coverage of systems

that maintain data subject to encryption in an unencrypted state in the kernel memory

buffer pool, or cache. Data Encryption Corp. v. Microsoft Computer Corp., No. 05-CV-

05531, slip op. at 2 (C.D. Cal. Aug. 14, 2006) (order granting Microsoft’s motion for

summary judgment). The court further held that the phrase “system interface routine

selectively directing the transfer of said predetermined block of data between said first

and second logical data areas through said encryption routine” requires that “the

encryption routine in kernel memory transforms (i.e., encrypts or decrypts) the data in

user memory when it is transferred between kernel memory and user memory, not

when it is transferred between memory and the disk.” Id. In light of its interpretation,

the court concluded that there was no genuine dispute as to any material fact that

Microsoft Windows products did not infringe any of the asserted claims and,

accordingly, granted summary judgment to Microsoft and Dell. Id., slip op. at 2-3; Data

Encryption Corp. v. Microsoft Computer Corp., No. 05-CV-05531, slip op. at 2 (C.D. Cal.

Aug. 14, 2006) (order granting Dell’s motion for summary judgment).

                                           B

        At issue is the proper construction of the phrase “system interface routine

selectively directing the transfer of said predetermined block of data between said first

and second logical data areas through said encryption routine.” Data argues that the

district court incorrectly concluded that the inventor disavowed coverage of systems that

maintain data subject to encryption in an unencrypted state in the kernel memory buffer

pool.

2006-1603                                  4
       We agree with the district court that the specification reveals a disavowal of claim

scope. See Phillips v. AWH Corp., 415 F.3d 1303, 1316 (Fed. Cir. 2005) (en banc)

([T]he specification may reveal an intentional disclaimer, or disavowal, of claim scope by

the inventor. In that instance . . ., the inventor has dictated the correct claim scope, and

the inventor’s intention, as expressed in the specification, is regarded as dispositive.”).

The ’023 patent specification explains that, in accordance with the invention,

       data pending either a read or write operation to disk 22 or other storage
       medium persists only in an encrypted state. All data subject to encryption
       by operation of the present invention is maintained in an encrypted state in
       the buffer pool. 2

’023 patent, col. 14, ll. 10-14 (emphasis added). This language is unambiguous. By

stating that “[a]ll data subject to encryption by operation of the present invention is

maintained in an encrypted state in the [kernel memory] buffer pool,” the inventor has

disavowed coverage of systems that maintain data subject to encryption in an

unencrypted state in the kernel memory buffer pool.

       Data nevertheless asserts that the above-quoted language should not inform the

construction of claim 5—and should therefore not amount to a disavowal of claim

scope—because claim 5 makes no mention of how data is “maintained” in the kernel

memory buffer pool. While it is true that claim 5 makes no mention of how data is

maintained in the kernel memory buffer pool, it is also true that claim 5 specifies that the

system decrypts data when it is transferred from the kernel memory to the user

memory. Specifically, claim 5 requires the system to “selectively direct[] the transfer of

said predetermined block of data between said first and second logical data areas[, i.e.,

       2
              The buffer pool is located within the kernel memory area. See ’023
patent, col. 5, ll. 63-64 (“Within the kernel space, a buffer pool, or buffer cache, is
maintained by the operating system.”).

2006-1603                                    5
between the kernel memory and the user memory,] through said encryption routine.”

Thus, the specification’s statement that “[a]ll data subject to encryption by operation of

the present invention is maintained in an encrypted state in the [kernel memory] buffer

pool” is clearly relevant to claim 5’s requirement that data be decrypted upon its transfer

from the kernel memory to the user memory.

       In light of the inventor’s disavowal of claim scope, we affirm the district court’s

grant of summary judgment of noninfringement. Data does not dispute that, in normal

operation, Windows operating systems maintain data subject to encryption in an

unencrypted state in the kernel memory buffer pool, or cache.

       Notwithstanding the disavowal, Data argues that there is a genuine issue of

material fact regarding infringement by operation of Windows operating systems in non-

default mode. We have carefully examined Data’s arguments in this regard and find

them to be unpersuasive. We similarly find unpersuasive Data’s contention that the

district court erroneously denied its motion for further discovery pursuant to Federal

Rule of Civil Procedure 56(f).

                                   III. CONCLUSION

       For the above reasons, we affirm the district court’s judgment of noninfringement.

2006-1603                                   6