Browse Prior Art Database

IMAGE ENCRYPTION USING PSEUDO RANDOM NUMBER GENERATOR

IP.com Disclosure Number: IPCOM000026448D
Original Publication Date: 1992-Feb-29
Included in the Prior Art Database: 2004-Apr-05
Document File: 2 page(s) / 99K

Publishing Venue

Xerox Disclosure Journal

Abstract

The present invention is directed towards a method of encrypting an image using a pseudo random number generator. The applications for such encrypted image files are not described herein, however, it is apparent that efficient methods of encoding and decoding are desirable. Given that it would take approximately 200 times longer to encrypt a 300 spot per inch (spi) image which fills a standard size page, versus the same page filled with text, the need for a faster encryption method is apparent. Furthermore, because each byte of image data has less information content, the encryption method may not need to be as secure.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 57% of the total text.

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XEROX DISCLOSURE JOURNAL

Image

IMAGE ENCRYPTION USING Proposed Classification PSEUDO RANDOM NUMBER U.S. C1.3581259 GENERATOR Int. C1. H04N 1/06 Leon C. Williams

Vi *

y 12a

Encrypted Image, Ei

n

12b \ 16

XEROX DISCLOSURE JOURNAL - Vol. 17, No. 1 January/February 1992 27

[This page contains 1 picture or other non-text object]

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IMAGE ENCRYPTION USING PSEUDO RANDOM NUM.BER GENERATOR(C0nt'd)

The present invention is directed towards a method of encrypting an image using a pseudo random number generator. The applications for such encrypted image files are not described herein, however, it is apparent that efficient methods of encoding and decoding are desirable. Given that it would take approximately 200 times longer to encrypt a 300 spot per inch (spi) image which fills a standard size page, versus the same page filled with text, the need for a faster encryption method is apparent. Furthermore, because each byte of image data has less information content, the encryption method may not need to be as secure.

Accordingly, the present invention uses a random number generator seeded with an encryption key. As illustrated in the figure, which shows a block diagram of the present invention, random number generator 12a is seeded with an encryption key. For each byte, or word, of image data (Vi), encryption function 14 uses the next random number (Ni) to generate an encrypted image byte Ei, where Ei is determined as follows:

The encrypted image may then be sent thro...