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snowdrop
Langue: en
Version: 250642 (debian - 07/07/09)
Section: 1 (Commandes utilisateur)
NAME
sd-eng, sd-engf, sd-c - text watermarking and watermark recoverySYNOPSIS
sd-eng [-6] -i origfile newfile Recipient [Comment]sd-eng [-6] -e origfile newfile
sd-eng [-6] -l
DESCRIPTION
snowdrop is a stenographic text watermarking and watermark recovery system. It is composed of three programs:- sd-eng
- Watermark normal English text.
- sd-engf
- Watermark fine quality English text, yeilding higher quality output but encoding less information.
- sd-c
- Watermark C code.
The three programs operate similarly, with the same parameters and usage. The watermark is encoded in using a number of techniques, such as whitespace reformatting, typo insertation, word substitutions, punctuation changes, and for C code, logic reordering, variable name mangling, etc.
The watermark is a md5sum, which is retreivable from as little as 5 or 10 lines of the watermarked document. Even large changes to a medium sized document should not obscure the watermark, as it is stored redundently in multiple independant channels.
The three usage modes are adding a watermark, checking for the presense of a watermark, and listing the contents of your database of watermarks. Note that to later check a watermark, you must retain a copy of the original, un-watermarked file.
OPTIONS
- -i
- Inject a watermark into a file. You must pass it the original file, the filename to output the watwrmarked version to, information about who you intend the watermarked file for, and an optional comment.
- -e
- Extract a watermark from a file. Needs the original file and the new file that you suspect bears the watermark.
- -l
- Lists the contents of the watermark database. Each of the three programs will have a different list.
- -6
- Enable 64 bit waterarking. The default is a weak 32 bit watermark.
ENVIRONMENT
- SD_SYNONYMS
- This variable can be used to point snowdrop at a customized synonyms file.
FILES
- ~/.snowdrop/database
- Database of watermarked files.
SEE ALSO
- /usr/share/snowdrop/README
- Explain snowdrop in more depth, its limitations, and how to write additional watermarking modules for other tpyes of files.
AUTHOR
Michal Zalewski <lcamtuf@coredump.cx>Contenus ©2006-2024 Benjamin Poulain
Design ©2006-2024 Maxime Vantorre