charemap
Charemap is a little program to play with substitution ciphers. It's able to remap text, perform characters and word analysis and to automatically decrypt ciphertext.
Download:
- charemap-0.5.tar.gz (20/01/2010) (md5sum: 4ebf48a2ffc2a30441241a803df23abe)
Requirements
Glib, GNU make and a C compiler.
Installation
In order to compile charemap, simply type `make'. No installation required.
Running charemap
See ./charemap -h
Usage: charemap [options]...
Options:
-h This help.
-v Print version.
-d Decrypt the file.
Warning, this algorithm works ONLY on alphabetic lowercase characters.
Remap ciphertext with charemap before using this option.
-s Show only character occurrences and mapping.
-c Case sensitive.
-a Remap alpha characters only (preserves dots, blanks and so on...).
-p Print substituted text.
-b Show bigrams.
-t Show trigrams.
-w Show words.
-m <file> Use a sample file to generate digram statistics (default samples/moby.txt).
-i <file> Input file to parse.
-o <file> Output file with remapped characters.
-l <file> Remap using the typical character frequency of selected language (default: languages/en.txt).
Example
Here is an example of automatic decryption with a ciphertext shipped with charemap.
ciphertext:
SG PW, GH VGS SG PW: SKLS YI SKW AOWISYGV:
CKWSKWH 'SYI VGPZWH YV SKW MYVR SG IOFFWH
SKW IZYVNI LVR LHHGCI GF GOSHLNWGOI FGHSOVW,
GH SG SLXW L LHMI LNLYVIS L IWL GF SHGOPZWI,
LVR PU GBBGIYVN WVR SKWM. SG RYW: SG IZWWB;
VG MGHW; LVR PU L IZWWB SG ILU CW WVR
SKW KWLHSLJKW, LVR SKW SKGOILVR VLSOHLZ IKGJXI
SKLS FZWIK YI KWYH SG.
Decryption:
./charemap -i ciphers/tobeornot.txt -d -m samples/dorian.txt
Decripting using bigram and trigram detection...
done!
The mapping found is:
<- etaoihnsrdlumwyfcgpbvkxqjz
||||||||||||||||||||||||||
-> jzfusrgtkxapyeilwomdnhbqcv
Decryption result:
to me, or not to me: that is the fuestion:
whether 'tis nomver in the yink to suller
the svings ank arrows ol outrageous lortune,
or to tabe a arys against a sea ol troumves,
ank mp oddosing enk they. to kie: to sveed;
no yore; ank mp a sveed to sap we enk
the heartache, ank the thousank naturav shocbs
that lvesh is heir to.
Affining result with dictionary-based decryption...
done!
The mapping found is:
<- etaoihnsrdlumwyfcgpbvkxqjz
||||||||||||||||||||||||||
-> jzqusrgtdxaymeifwobpnhkvcl
Decryption result:
to be, or not to be: that is the question:
whether 'tis nobler in the mind to suffer
the slings and arrows of outrageous fortune,
or to take a arms against a sea of troubles,
and by opposing end them. to die: to sleep;
no more; and by a sleep to say we end
the heartache, and the thousand natural shocks
that flesh is heir to.