US 5898784

Patent Overview: US5898784A — "Transferring encrypted packets over a public network"

Bibliographic data (as supplied): Application US08/963,512; filed 1997-11-03; granted/publication date 1999-04-27; priority date 1996-01-16; original assignee Raptor Systems Inc.; inventors Alan J. Kirby, Jeffrey A. Kraemer, and Ashok P. Nadkarni. Legal status listed as "Expired – Lifetime," with anticipated expiration 2016-01-16. Classifications include H04L63/02 (firewalls), H04L63/0272 (virtual private networks), H04L63/0807 (authentication using tickets, e.g., Kerberos), H04L9/40 (network security protocols), and H04L2212/00 (encapsulation of packets).

Purpose: The patent relates to transferring encrypted packets over a public network. While data travels on a network, transmitted data—including source and destination addresses—is accessible to others monitoring the network, so data is often encrypted before being sent. Firewall computers with direct network access may prevent unauthorized access to internal/private networks. Encrypting/decrypting had been done by complex security software within applications or within the network protocol stack; this invention addresses handling such packets differently.

Plain-language scope (per the excerpted description): Encrypted network packets are received from the network at a network interface computer (which may be a firewall computer, with the network being a public network) and passed to a computer on an internal network. Determining the destination may include checking whether the source computer is authorized to send encrypted packets to the destination, and examining a header field that may correspond to a virtual network tunnel. Packets may be decrypted at the network interface computer, or passed through encrypted to the internal computer. A field in each packet may be examined to determine which of several encryption algorithms was used, and packets are decrypted accordingly. Packets may also be routed to a destination based on the determined virtual tunnel. The described approach supports "virtual private networking" (VPN), hiding internal addresses and topology.

What the excerpt does not establish: The supplied text does not include the full claims, the detailed description, drawings, or prior-art references. It does not establish claim scope, validity, infringement, ownership transfers, or litigation; such matters were excluded from this overview.

Source: https://patents.google.com/patent/[US5898784](/patent/US5898784)/en