Browse Prior Art Database

Method of Providing Encryption/Decryption for Integrated Services Digital Network Telecommunications

IP.com Disclosure Number: IPCOM000120861D
Original Publication Date: 1991-Jun-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 8 page(s) / 320K

Publishing Venue

IBM

Related People

Parker, TE: AUTHOR

Abstract

A technique is described whereby encrypted and decrypted information can be transmitted over integrated services digital network (ISDN) telecommunications channels enabling network terminating equipment to transmit information in encoded format.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 30% of the total text.

Method of Providing Encryption/Decryption for Integrated Services
Digital Network Telecommunications

      A technique is described whereby encrypted and decrypted
information can be transmitted over integrated services digital
network (ISDN) telecommunications channels enabling network
terminating equipment to transmit information in encoded format.

      Typically, many different ISDN data communication products
require encrypt/decrypt data streams to be transmitted/received over
ISDN bearer channels.  The concept described herein enables network
terminating (NT1 or NT2) equipment to act as general-purpose ISDN
bearer channel hardware encryption or decryption devices.  The
concept effectively eliminates the need for having each ISDN product
require encryption on each specific product.  Also described is the
proprietary usage of the embedded operations channel (EOC) for ISDN
Basic Rate access so as to transmit the encrypt/decrypt key to the
NT1 from the terminal equipment (TE), or NT2, and to activate or
deactivate encryption or decryption on one or both bearer channels.

      The concept essentially uses NT1 to perform hardware encryption
and decryption of circuit switched bearer channels.  Use is made of
the embedded operations channels ("Q" and "S") for the Basic Rate and
the "M" channel for the North American Primary Rate.  Potentially,
the Sa, or the Sn, bits will be used for the European Primary Rate
from TE to the NT1, or NT2, to activate and deactivate encryption or
decryption on each bearer channel.  Also, embedded operations are
used to send messages in such a way so as to not interfere with the
usage of the channels currently defined for network maintenance
functions.

      Fig. 1 illustrates the use of TE to send messages on the Q
channel directly to NT1 so as to pass encryption keys for each
channel and to activate or deactivate encryption on either, or both,
B channels.  NT1 acknowledges the receipt of the message with
responses on the S channel, using subchannel S1.

      Fig. 2 illustrates the use of the private branch exchange
(PBX), or NT2, to send messages on the Q channel directly to NT1 so
as to pass encryption keys for each channel and to activate or
deactivate encryption on either, or both, B channels.  NT1
acknowledges the receipt of the message with responses on the S
channel, using subchannel S1, to the PBX.  The PBX must have been
programmed with the capability to handle the messaging on the Q and S
channels as required so as to make the use of the NT1 encryption
feature on behalf of the TE attached to it.

      Alternately, the TE can send messages on the Q channel to the
NT1 to pass encryption keys for each channel and to activate or
deactivate encryption on either, or both, B channels.  NT1
acknowledges the receipt of the messages with responses on the S
channel, using subchannel S1, to the PBX which must pass the messages
on to the TE.

      Fig. 3 illustrates the us...