diff options
Diffstat (limited to 'security/outguess/files/outguess.1')
| -rw-r--r-- | security/outguess/files/outguess.1 | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/security/outguess/files/outguess.1 b/security/outguess/files/outguess.1 new file mode 100644 index 000000000000..88ac5b6315af --- /dev/null +++ b/security/outguess/files/outguess.1 @@ -0,0 +1,182 @@ +.\" outguess manpage, converted from README +.\" dugsong@monkey.org +.TH OUTGUESS 1 "6 August 1999" +.SH NAME +outguess - universal steganographic tool +.SH SYNOPSIS +.B outguess +[ +.B \-emt +] [ +.B \-r +] [ +.B \-k +.I key +] [ +.B \-d +.I datafile +] [ +.B \-s +.I seed +] [ +.B \-i +.I limit +] [ +.B \-x +.I maxkeys +] [ +.B \-p +.I param +] [ +.I inputfile +[ +.I outputfile +]] +.LP +.SH DESCRIPTION +.LP +.I Outguess +is a universal steganographic tool that allows the insertion +of hidden information into the redundant bits of data sources. The +nature of the data source is irrelevant to the core of +.IR outguess . +The program relies on data specific handlers that will extract +redundant bits and write them back after modification. Currently only +the PPM, PNM, and JPEG image formats are supported, although +.I outguess +could use any kind of data, as long as a handler were provided. +.PP +.I Outguess +uses a generic iterator object to select which bits in the data should +be modified. A seed can be used to modify the behavior of the +iterator. It is embedded in the data along with the rest of the +message. By altering the seed, +.I outguess +tries to find a sequence of bits that minimizes the number of changes +in the data that have to be made. +.PP +A bias is introduced that favors the modification of bits that were +extracted from a high value, and tries to avoid the modification of +bits that were extracted from a low value. +.PP +Additionally, +.I Outguess +allows for the hiding of two distinct messages in the data, thus +providing plausible deniablity. It keeps track of the bits that have +been modified previously and locks them. A (23,12,7) Golay code is +used for error correction to tolerate collisions on locked bits. +Artifical errors are introduced to avoid modifying bits that have a +high bias. +.SH OPTIONS +.LP +The following command line options, when specified as capital letters, +indicate options for the second message. +.TP +.B \-kK \fIkey\fR +Specify the secret key used to encrypt and hide the message in the +provided data. +.TP +.B \-dD \fIdatafile\fR +Specify the filename containing a message to be hidden in the data. +.TP +.B \-sS \fIseed\fR +Specify the initial seed the iterator object uses for selecting bits +in the redundant data. If no upper limit is specified, the iterator +will use this seed without searching for a more optimal embedding. +.TP +.B \-iI \fIlimit\fR +Specify the upper limit for finding an optimal iterator seed. The +maximum value for the limit is 65536. +.TP +.B \-eE +Use error correction for data encoding and decoding. +.PP +Other options that apply to the general execution of +.IR outguess : +.TP +.B \-r +Retrieve a message from a data object. If this option is not +specified, +.I outguess +will embed messages. +.TP +.B \-x \fImaxkeys\fR +If the second key does not create an iterator object +that is successful in embedding the data, the program +will derive up to specified number of new keys. +.TP +.B \-p \fIparam\fR +Passes a string as parameter to the destination data handler. For the +JPEG image format, this is the compression quality, it can take values +between 75 and 100. The higher the quality the more bits to hide a +message in the data are available. +.TP +.B \-m +Mark pixels that have been modified. +.TP +.B \-t +Collect statistics about redundant bit usage. Repeated use increases +output level. +.PP +For embedding messages, you need to specify a source and a destination +filename. +.I Outguess +determines the data format by the filename extension. If no filenames +are specified +.I outguess +operates as a filter and assumes the PPM data format. +.SH EXAMPLES +.LP +To embed the message +.I hidden.txt +into the +.I monkey.jpg +image: +.IP +.B outguess \-k +"my secret pass phrase" +.B \-d +.I hidden.txt monkey.jpg out.jpg +.PP +And in the other direction: +.IP +.B outguess \-k +"my secret pass phrase" +.B \-r +.I out.jpg message.txt +.PP +will retrieve the hidden message from the image. +.PP +If you want to embed a second message, use: +.IP +.B outguess \-k +"secret1" +.B \-d +.I hide1.txt +.B \-E \-K +"secret2" +.B \-D +.I hide2.txt monkey.jpg out.jpg +.PP +.I Outguess +will first embed +.I hide1.txt +and then +.I hide2.txt +on top of it, using error correcting codes. The second message +.I hide2.txt +can be retrieved with +.IP +.B outguess \-k +"secret2" +.B \-e \-r +.I out.jpg message.txt +.LP +.SH "SEE ALSO" +cjpeg(1), djpeg(1), pnm(5), stirmark(1) +.SH AUTHOR +Niels Provos <provos@citi.umich.edu> +.SH BUGS +.LP +Not all the redundant data available in the JPEG encoding is used, +this is due to a problem when reconstructing the Huffman coefficients. |