Browse Prior Art Database

Integrated QIC Data Compression and Encryption Device

IP.com Disclosure Number: IPCOM000113241D
Original Publication Date: 1994-Jul-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Medan, Y: AUTHOR

Abstract

This article describes a technique for integrating an encryption function within the framework of a QIC coded data stream.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 67% of the total text.

Integrated QIC Data Compression and Encryption Device

      This article describes a technique for integrating an
encryption function within the framework of a QIC coded data stream.

      QIC-122 is an industry standard for decoding compressed data
for 1/4- inch cartridge tape drives.  The standard defines, in a very
concise and fixed way, the format of the encoded compressed data.  It
does not however imply how compression may be achieved as long as the
encoded stream follows the standard.  There exist a number of fast
hardware implementations of QIC-122.

      The QIC-122 standard assumes that a byte-oriented input stream
is to be encoded using a mixture of direct coding, stating the actual
value of the byte ('raw_byte'), and indirect coding using an offset
and a runlength value to point to a previous instance of a given
string ('compressed-byte').  The direct encoded symbol and the offset
field have a fixed-length code word while the runlength value is
encoded using a variable-size bit-string.  The encoding format is
fixed and therefore no provisions are made in the standard to adopt
its parameters according to the context, nature and statistical
properties of the data to be encoded.  Moreover, no encryption
facilities are enabled within the QIC framework to secure the data
from unauthorized access.

      The technique of this disclosure provides means to decode an
encrypted data stream as an integral part of the QIC-122 decoded
process, without...