Patents on Antivirus Software

Index of Selected Antivirus Software Patents

Symantec's Web Update Patents

Symantec - the publisher of Norton Antivirus software - holds two U.S. patents that cover the online updating of virus definitions. Symantec calls this process (which is used by the "Live Update" function of Norton Antivirus) "microdefinition." According to a Symantec press release about the patents (referenced below):

"Although the newly patented technology is currently being implemented by Symantec for its virus protection software, the technology may also be used to update general computer readable files, which may include data files, program files, database files, graphics files, or audio files. As the patent holder, Symantec is the only company authorized to incorporate this sophisticated technology into its best-of-breed products."

  • 6,052,531. This is Symantec's "Multi-tiered incremental software updating" patent, granted April 18, 2000. Here is the abstract:

    A software application (110) is updated to a newer version by means of incremental update patches (122). The incremental update patches (122) each contain that information necessary to transform one version of an application to another version. Any version of an application (110) may be upgraded to any other version of the application, through the use of a series of incremental update patches (122). The appropriate incremental update patches (122) are distributed in a multi-tiered manner, such that some update patches (122) update the application (110) by only one version, and others update the application (110) by several versions.

  • 6,167,407. This is Symantec's "Backtracked incremental updating" patent, awarded on December 26, 2000. Here is the abstract:

    A computer readable file of an original state is updated to a final state. The original state and the final state are both states within a sequence (100) of states, which sequence (100) includes at least one hub state and one non-hub state. A first hub version, which corresponds to a hub state which is at least as early in the sequence as the original state, is stored locally. A hub incremental update (110) is retrieved (314) and used to update (316) the hub version to a second hub version, which second hub version corresponds to a hub state which is at least as early in the sequence (100) as the final state. A final incremental update (112) is retrieved (320) and used with the file of the final hub version to produce (322) a file of the final state. The files corresponding to both the second hub state and the final state are retained (324).

    Litigation Involving Symantec's Web Update Patents

    Carey Nachenberg, a Symantec researcher and holder of the patents was quoted in a Feb. 9, 2001 Reuters article as saying "We have no desire to proactively pursue litigation in regards to these patents...If companies were already doing this before the patent application was filed, then it is probably unenforceable."

    Resources on Symantec's Web Update Patents:

    Trend Micro's Patents

    Litigation Involving Trend Micro's Patent

    On May 13, 1997, Trend Micro filed suit against Mc Afee Associates and the Symantec Corporation for patent infringement in the U.S. District Court for Northern California.

    Resources on Trend Micro's Patent

    Hilgraeve's Virus Detection Patent

  • 5,319,776. This is the Hilgraeve Corporation's virus detection patent, granted on June 7, 1994 and entitled "In transit detection of computer virus with safeguard." Here is the abstract:

    Data is tested in transit between a source medium and a destination medium, such as between two computer communicating over a telecommunications link or network. Each character of the incoming data stream is tested using a finite state machine which is capable of testing against multiple search strings representing the signatures of multiple known computer viruses. When a virus is detected the incoming data is prevented from remaining on the destination storage medium. Both hardware and software implementations are envisioned.

    Resources on the Hilgraeve Virus Detection Patent

    Questions, comments and suggestions to Vergil Bushnell

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