Prior art

Prior Art Analysis for US 5,987,610

As of May 11, 2026, the following analysis details the most relevant prior art cited against US patent 5,987,610. The filing date for the '610 patent is February 12, 1998, establishing the critical date for prior art.

Patents Incorporated by Reference

The '610 patent's specification explicitly incorporates two prior U.S. patents by reference. These are highly relevant as they form a basis for the technology described.

1. U.S. Patent 5,319,776: "Apparatus and method for detecting computer viruses"

• Full Citation: US 5,319,776, Hile, et al.
• Publication/Filing Date: Issued June 7, 1994 / Filed August 26, 1992. This predates the '610 patent.
• Brief Description: This patent describes a method for detecting viruses by creating a "decoy" or "model" environment. An executable file is run in this simulated environment, which includes decoy files and system areas. The system monitors for changes to these decoy components, such as modifications to file contents or system interrupts. If suspicious changes are detected, the system flags the executable file as potentially infected.
• Potential Anticipation of Claims:
  • Claim 43: This reference appears to directly anticipate the core inventive concept of claim 43. Claim 43 requires "providing a first computer having a model of a second computer," "modifying the model by executing the executable program," and "screening the model for at least one virus." The '776 patent teaches the creation of a decoy/model environment to test executable programs and monitoring that environment for virus-like activity, which constitutes a form of screening. The execution of the program within the decoy environment directly corresponds to "modifying the model."

2. U.S. Patent 5,623,600: "Virus detection and removal apparatus for computer networks"

• Full Citation: US 5,623,600, Ji, et al.
• Publication/Filing Date: Issued April 29, 1997 / Filed August 10, 1995. This predates the '610 patent.
• Brief Description: This patent discloses a system for detecting and removing viruses from files transferred over a computer network. It describes using a "proxy server" on a network gateway that intercepts file transfers. Before a file is transmitted to the recipient node on the network, it is first sent to the proxy server, which performs virus detection. If a virus is found, a preset action is taken; if not, the file is forwarded to the recipient.
• Potential Anticipation of Claims:
  • Claims 1, 12, and 23: This patent is highly relevant to the network-level screening claims of the '610 patent. While the '600 patent describes a computer network gateway (like a LAN/WAN gateway) and not explicitly a "telephone network," the underlying concept is very similar.
    • Claim 23 calls for "receiving a first signal representative of computer data... and screening the computer data within the... network." The '600 patent's proxy server at a network gateway performs exactly this function.
    • Claim 1 specifies routing a call "between a calling party and a called party of a telephone network" and screening the data "within the telephone network." The '600 patent does not mention a "telephone network" or "call," but teaches the interception and screening of data at a central network point (the gateway/proxy). An argument could be made that applying this known network security technique to a telephone network would be an obvious extension.
    • Claim 12 describes the system for this method, including a "telephone switching node" and an associated "processor." The '600 patent's gateway and proxy server are analogous system components performing the same functions.

Other Cited Prior Art

The following references were also cited by the patent examiner during the prosecution of the '610 patent.

3. U.S. Patent 5,572,643: "Distributed configurable computer virus screening system"

• Full Citation: US 5,572,643, Judson.
• Publication/Filing Date: Issued November 5, 1996 / Filed June 7, 1995. This predates the '610 patent.
• Brief Description: This patent describes a virus screening system for a computer network where a central "virus screening server" provides virus scanning services to client computers. The server can distribute virus signature files and software updates to the clients. It also discloses a method where files can be sent to the server for scanning, centralizing the virus detection process rather than relying solely on each client.
• Potential Anticipation of Claims:
  • Claims 1, 12, and 23: Similar to the '600 patent, this reference teaches network-based virus scanning. It describes a client-server architecture for centralized screening. While not explicitly set in a "telephone network," it discloses the fundamental concept of offloading the scanning process from the end-user computer to a centralized network resource. This challenges the novelty of performing virus scanning "within the network" as taught in claims 1, 12, and 23.

4. U.S. Patent 5,613,002: "Method for detecting viruses in a data file"

• Full Citation: US 5,613,002, Kephart, et al.
• Publication/Filing Date: Issued March 18, 1997 / Filed November 29, 1994. This predates the '610 patent.
• Brief Description: This patent focuses on methods for detecting computer viruses, including both known and unknown viruses. It describes techniques for analyzing the code of a file to identify virus-like characteristics and behaviors, such as self-modification or attempts to write to system files. A key aspect is the use of an emulator to safely execute and observe the behavior of suspect code.
• Potential Anticipation of Claims:
  • Claim 43: This reference strongly anticipates the method described in claim 43. The '002 patent's use of an "emulator" to run and observe code is functionally identical to the '610 patent's concept of executing a program on a "model of a second computer." The purpose in both patents is to screen for viruses in a safe, simulated environment before allowing the program to run on the actual user's machine.

5. U.S. Patent 5,826,013: "System for virus-checking network data during download to a client device"

• Full Citation: US 5,826,013, Tso, et al.
• Publication/Filing Date: Issued October 20, 1998 / Filed December 30, 1997. Note: The issue date is after the '610 filing, but the filing date is prior, making it relevant prior art under pre-AIA rules.
• Brief Description: This patent describes a system where a network device scans a data object for viruses while it is being downloaded to a client device. If a virus is detected, the download is aborted. This system is designed to be implemented in network devices like routers or servers.
• Potential Anticipation of Claims:
  • Claims 1, 12, and 23: This reference further supports the position that network-based virus scanning was a known concept. It explicitly teaches scanning data objects for viruses on a network device before the download to the client is complete. This directly reads on the limitation of "screening the computer data within the telephone network" (Claim 23) and "detecting, within the telephone network, a virus in the computer data" (Claim 1).

6. U.S. Patent 5,842,002: "Method and system for providing secured access to a server connected to a private computer network"

• Full Citation: US 5,842,002, Schnurer, et al.
• Publication/Filing Date: Issued November 24, 1998 / Filed September 5, 1996. Note: The issue date is after the '610 filing, but the filing date is prior, making it relevant prior art.
• Brief Description: This patent discloses a "security agent" or firewall system that controls access between a private network and an external network like the Internet. The system inspects data packets and can be configured to perform various security checks, including virus scanning, on data transfers that pass through it.
• Potential Anticipation of Claims:
  • Claims 1, 12, and 23: This patent describes a firewall performing security checks, including virus scanning, on data at the boundary of a network. This is another example of a network-based security function that anticipates the general concept of screening data "within the network" rather than on the end-user's computer, challenging the novelty of the '610 patent's network-centric claims.