David W Farber

US Patent:

20030078037, Apr 24, 2003

Filed:

Jul 25, 2002

Appl. No.:

10/205167

Inventors:

David Auckland - Silver Spring MD, US
Stewart Skomra - Poway CA, US
Lee Stein - Del Mar CA, US
David Farber - Landenberg PA, US

International Classification:

H04Q007/20

US Classification:

455/422000, 455/450000

Abstract:

Subscriber units and base stations of telecommunication systems are equipped with RF to IF (EXA) circuit boards which provide complete flexibility for radio communication. The boards may communicate on any air interface standard (CDMA, TDMA, Bluetooth, 3G cellular, etc.) at any frequency or band of frequencies. Separate, independent forward and reverse channels may be assignment, each having its own air interface and frequency band. When a call is initiated, a set of optimum forward and reverse channels are assigned, taking into account relevant factors such as traffic, subscriber requirements for high speed data, etc., so that the channel assignment is tailored to the current communication needs. Channel assignment is updated as needs change, as other channels become available and at handoff. In a business model, air time on multiple telecommunication systems is sold to subscribers who can use this technology to roam widely. Revenue is also generated from licensing of the EXA circuit boards in subscriber units and in base stations.

US Patent:

61856789, Feb 6, 2001

Filed:

Oct 2, 1998

Appl. No.:

9/165316

Inventors:

William A. Arbaugh - Ellicott City MD
David J. Farber - Landenberg PA
Angelos D. Keromytis - Philadelphia PA
Jonathan M. Smith - Princeton NJ

Assignee:

Trustees of the University of Pennsylvania - Philadelphia PA

International Classification:

G06F 900
G06F 1130

US Classification:

713 2

Abstract:

Integrity is rarely a valid presupposition in many systems architectures, yet it is necessary to make any security guarantees. To address this problem, the present invention discloses a secure bootstrap process, which presumes a minimal amount of integrity. The basic principle is sequencing the bootstrap process as a chain of progressively higher levels of abstraction, and requiring each layer to check a digital signature of the next layer before control is passed to it. A major design decision is the consequence of a failed integrity check. A simplistic strategy is to simply halt the bootstrap process. However, the bootstrap process of the present invention can be augmented with automated recovery procedures which preserve the security properties of the bootstrap process of the present invention under the additional assumption of the availability of a trusted repository. A variety of means by which such a repository can be implemented are disclosed with attention focused on a network-accessible repository. The recovery process is easily generalized to applications other than the bootstrap process of the present invention, such as standardized desktop management and secure automated recovery of network elements such as routers or "Active Network" elements.