資源簡介
Jsteg是一種基于JPEG的常用信息隱藏算法步驟如下:
首先,把掩體圖像分為不重疊的8*8的子塊,對每一子塊進行DCT并對變換得到的DCT系數(shù)進行量化;其次,將待隱藏的信息進行加密,將加密結(jié)果嵌入到量化后值不為0,1或-1的DCT系數(shù)的最
低有效位(LSB)中,其嵌入順序是按zigzag掃描順序進行的。最后,用JPEG的嫡編碼(包括哈夫曼編碼,游程編碼及DPCM)對嵌入秘密信息后的每一子塊進行編碼,從而得到一個含有秘密信息的JPEG stego文件。

代碼片段和文件信息
/*?Copyright?(C)?1989?1991?Aladdin?Enterprises.??All?rights?reserved.
???Distributed?by?Free?Software?Foundation?Inc.
This?file?is?part?of?Ghostscript.
Ghostscript?is?distributed?in?the?hope?that?it?will?be?useful?but
WITHOUT?ANY?WARRANTY.??No?author?or?distributor?accepts?responsibility
to?anyone?for?the?consequences?of?using?it?or?for?whether?it?serves?any
particular?purpose?or?works?at?all?unless?he?says?so?in?writing.??Refer
to?the?Ghostscript?General?Public?License?for?full?details.
Everyone?is?granted?permission?to?copy?modify?and?redistribute
Ghostscript?but?only?under?the?conditions?described?in?the?Ghostscript
General?Public?License.??A?copy?of?this?license?is?supposed?to?have?been
given?to?you?along?with?Ghostscript?so?you?can?know?your?rights?and
responsibilities.??It?should?be?in?a?file?named?COPYING.??Among?other
things?the?copyright?notice?and?this?notice?must?be?preserved?on?all
copies.??*/
/*
----------?Here?is?the?Ghostscript?file?COPYING?referred?to?above?----------
-----?These?terms?do?NOT?apply?to?the?JPEG?software?itself;?see?README?------
????GHOSTscript?GENERAL?PUBLIC?LICENSE
????(Clarified?11?Feb?1988)
?Copyright?(C)?1988?Richard?M.?Stallman
?Everyone?is?permitted?to?copy?and?distribute?verbatim?copies?of?this
?license?but?changing?it?is?not?allowed.??You?can?also?use?this?wording
?to?make?the?terms?for?other?programs.
??The?license?agreements?of?most?software?companies?keep?you?at?the
mercy?of?those?companies.??By?contrast?our?general?public?license?is
intended?to?give?everyone?the?right?to?share?Ghostscript.??To?make?sure
that?you?get?the?rights?we?want?you?to?have?we?need?to?make
restrictions?that?forbid?anyone?to?deny?you?these?rights?or?to?ask?you
to?surrender?the?rights.??Hence?this?license?agreement.
??Specifically?we?want?to?make?sure?that?you?have?the?right?to?give
away?copies?of?Ghostscript?that?you?receive?source?code?or?else?can?get
it?if?you?want?it?that?you?can?change?Ghostscript?or?use?pieces?of?it
in?new?free?programs?and?that?you?know?you?can?do?these?things.
??To?make?sure?that?everyone?has?such?rights?we?have?to?forbid?you?to
deprive?anyone?else?of?these?rights.??For?example?if?you?distribute
copies?of?Ghostscript?you?must?give?the?recipients?all?the?rights?that
you?have.??You?must?make?sure?that?they?too?receive?or?can?get?the
source?code.??And?you?must?tell?them?their?rights.
??Also?for?our?own?protection?we?must?make?certain?that?everyone?finds
out?that?there?is?no?warranty?for?Ghostscript.??If?Ghostscript?is
modified?by?someone?else?and?passed?on?we?want?its?recipients?to?know
that?what?they?have?is?not?what?we?distributed?so?that?any?problems
introduced?by?others?will?not?reflect?on?our?reputation.
??Therefore?we?(Richard?M.?Stallman?and?the?Free?Software?Foundation
Inc.)?make?the?following?terms?which?say?what?you?must?do?to?be?allowed
to?distribute?or?change?Ghostscript.
COPYING?POLICIES
??1
?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????文件???????16705??1992-11-04?11:59??ansi2knr.c
?????文件???????67745??1992-12-01?19:54??architecture
?????文件????????2740??1997-06-01?20:44??bitsink.c
?????文件?????????101??1997-06-01?20:44??bitsink.h
?????文件????????4109??1997-06-01?23:55??bitsourc.c
?????文件?????????131??1997-06-01?20:44??bitsourc.h
?????文件????????8320??1997-06-01?20:44??cjpeg.1
?????文件???????13425??1992-07-24?18:30??ckconfig.c
?????文件????????4047??1991-09-27?22:06??codingrules
?????文件????????4841??1997-06-01?20:44??djpeg.1
?????文件???????27510??1992-11-14?17:07??example.c
?????文件????????3377??1992-11-01?13:32??jbsmooth.c
?????文件????????1206??1992-11-10?21:43??jcarith.c
?????文件???????11597??1992-08-07?19:02??jccolor.c
?????文件???????15051??1992-11-04?20:40??jcdeflts.c
?????文件????????2023??1992-11-01?13:33??jcexpand.c
?????文件???????20716??1992-07-23?22:05??jchuff.c
?????文件???????22069??1997-06-01?23:54??jcmain.c
?????文件????????4339??1992-11-10?21:44??jcmaster.c
?????文件????????6212??1997-06-01?20:44??jcmcu.c
?????文件???????12380??1992-11-11?20:44??jconfig.h
?????文件???????27641??1992-11-10?21:45??jcpipe.c
?????文件???????16932??1992-11-05?10:54??jcsample.c
?????文件????????1189??1992-11-10?21:46??jdarith.c
?????文件????????9384??1992-08-23?15:59??jdcolor.c
?????文件????????6692??1992-07-25?15:03??jddeflts.c
?????文件???????13143??1997-06-01?20:44??jdhuff.c
?????文件???????14600??1997-06-01?20:44??jdmain.c
?????文件????????5796??1992-11-10?21:47??jdmaster.c
?????文件????????6475??1992-11-01?13:48??jdmcu.c
?????文件???????39207??1992-11-10?21:47??jdpipe.c
............此處省略55個文件信息
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