Invalidity dossier
US 6032259
Secure network authentication server via dedicated serial communication path
Current assignee: Trend Micro Inc
Added 9/23/2026, 6:18:06 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview: US 6032259
Title: Secure network authentication server via dedicated serial communication path
Patent number: US 6,032,259 B1
Inventor: Kazuo Nemoto
Original assignee: International Business Machines Corp. (IBM); the record also lists a later assignment to Trend Micro Incorporated.
Dates: Priority date 1997-05-16; filed 1998-01-27; granted/published 2000-02-29; anticipated expiration 2018-01-27. Legal status: expired – lifetime.
Purpose: To provide a network security system with a higher security level that avoids defects in an essential portion of a conventional firewall. The patent describes prior dual-firewall arrangements (bastion hosts, screening router, DMZ) and notes that bugs, hardware faults, or setup misses can produce a "stuck-at" fault that passes data through, potentially allowing header information such as a destination IP address or service type to be faked.
Plain-language scope: A first computer ("outside host") exchanges header-bearing packets with an external network and is linked to a second computer ("inside host") by a dedicated communication path. The first computer strips the header before forwarding the packet over that dedicated path, and appends a header to packets received back before sending them to the external network. The path may use a start-stop transmission scheme. Per the description, the dedicated path is occupied by first and second connection programs rather than multiplexed, and dedicated serial port device drivers make the connection inaccessible from the outside. The second computer may validate the headerless packet's format, forward its data to a connected server (e.g., an authentication server issuing decryption keys), or process the data and return a result. A protected host on a secured internal network may also serve as the inside host.
Source: https://patents.google.com/patent/US6032259/en
What the excerpt does not establish: It does not provide the full claim text, complete figures, or omitted description portions. It does not establish litigation, the validity or enforceability of any claim, the accuracy of listed assignees or legal status, or prior-art conclusions.
Generated 10/1/2026, 9:42:52 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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