Substitution Cipher Breaker
scb [flags] trigram-stat-file dictionary-file cipher-text-file
Tries to decrypt the substitution cipher encrypted cipher-text-file.
It works reliable for texts of 150 characters and more.
Lengthy cipher texts slow the program down, though.
The cipher-text-file must contain word separators.
The program outputs two suggestions of what the plain text might be
together with a "history" of how these results were derived.
- Print debugging information to stderr.
- -r rounds
- Specify the number of times ("rounds") we do hillclimbing.
- -p penalty
- Specify a penalty for illegal trigrams (default: -1000).
We recommend to use the negative frequency of the trigram: "the".
"penalty" is used by the trigram scorer.
- -l linelength
- Specify the approximate length of a plain text line on your display (default: 75).
- -m maxlength
- Specify the maximal length of words in the dictionary.
Longer ones will be truncated (default: 9).
"maxlength" is used by the dictionary scorer.
- -w weight
- Specify the weight for the dictionary scorer
The trigram-stat-file is an ascii file that has
been generated by the
statistic tool .
The dictionary-file is an ascii file that has one word
per line. Only lowercase letters are allowed.
The ciphertext-file is an ascii file. Only lowercase
letters, space, and newline may used. Newlines
are ignored, though. It is expected that words are separated
by a word separator character that might be different from space.
Last Update: 15.04.96 (Format: DD.MM.YY)