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Browse Prior Art Database

Link-State Updating Method

IP.com Disclosure Number: IPCOM000117557D
Original Publication Date: 1996-Mar-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Tsudik, G: AUTHOR

Abstract

Disclosed is a method to aid in fast and secure construction, dissemination and processing of Link-State Updates (LSUs) in routing protocols employing the Link-State technique. It achieves the same level of security (in terms of non-repudiation, origin authentication and data integrity) as current state-of-the-art methods such as [*] while incurring significantly lower costs.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Link-State Updating Method

      Disclosed is a method to aid in fast and secure construction,
dissemination and processing of Link-State Updates (LSUs) in routing
protocols employing the Link-State technique.  It achieves the same
level of security (in terms of non-repudiation, origin authentication
and data integrity) as current state-of-the-art methods such as [*]
while incurring significantly lower costs.

      It has been observed that a large percentage (50%, by some
estimates) of LSUs are simply re-statements of previous LSUs.  In
other words, an LSU often carries no novel information other than
it's timing since links and nodes rarely go up and down.

      It is assumed that, whenever a link state changes, an
originating node will generate a fresh LSU.  Such LSUs are called
C-LSUs.  Each C-LSU must be digitally signed by it's originator, thus
allowing each receiving node to establish unambiguously the origin
and the data integrity of the C-LSU.  Furthermore, in addition to the
digital signature and all the usual information carried by an LSU, a
C-LSU will carry an "anchor" value called H ^n(R) where H ^n denotes
n successive (recursive) application of a strong one-way hash
function to a unique, randomly-chosen quantity R.  For example,
H^10(R) denotes 10 hash function applications to R.

      The anchor value is stored (along with the rest of C-LSU) by
each receiving node after the signature has been successfully
verified.  Thereafter, if the originating node needs to send out a
new update (e.g., because the old one expired or because it is
programmed to do so regularly) it releases H^(n-1)(R) as the new
update referred to as V-LSU_1.  Every receiver can easily verify a
V-LSU_1 by checking that
  H(H^(n-1)(R))=H^n(R).

      As long as no link incident to the originator changes state, a
subsequent V-LSU_i can be...