NAME

grille - Create and manipulate a grille cipher

SYNOPSIS

set cipherProc [cipher create grille]

cipherProc configure ?options?
cipherProc cget option
cipherProc substitute row col
cipherProc restore key
cipherProc undo
cipherProc solve

DESCRIPTION

cipherProc configure ?options?
Configure the settings for the grille cipher. Valid options are:

cipherProc configure -ciphertext string
cipherProc configure -ct string
Set the ciphertext for this cipher instance to string. Invalid letters or numbers in the ciphertext are silently discarded.

cipherProc configure -period n
Since the period of a grille cipher is based on the ciphertext length, this option has no effect.

cipherProc configure -stepinterval n
Set the display interval while solving to n. The stepcommand procedure will be called for every nth iteration while solving. This is used to provide user feedback while solving is taking place.

cipherProc configure -stepcommand proc
Set the display command while solving to proc. This command will be called for every nth iteration while solving. The arguments for this procedure are:

stepcommand iter key pt

iter is the current iteration number. key is the current value of the key that is being used. pt is the plaintext that is produced with this key.

cipherProc configure -bestfitcommand proc
Set the best fit display command while solving to proc. This command will be called every time a better solution is found while autosolving. The arguments for this procedure are:

bestfitcommand iter key value pt

iter is the current iteration number. key is the current value of the key that is being used. value is the value of the metric used to judge how good this solution is. The value is often a digram or trigram frequency count. pt is the plaintext that is produced with this key.

cipherProc configure -language language
This option is currently ignored for all cipher types. Set the current cipher language to language. If the cipher has a solve method then digram frequencies for this language are used to determine the best fit. If the language is not specified or not known then english is used.

cipherProc cget option
Look up the value for a given option. Valid options are:

cipherProc cget -type
Returns the type of this cipher. In this case, grille

cipherProc cget -ciphertext
cipherProc cget -ct
Return the ciphertext for this cipher.

cipherProc cget -plaintext
cipherProc cget -pt
Return the plaintext for this cipher based on the current key setting.

cipherProc cget -ptblock
undocumented feature

cipherProc cget -key
Returns the current key setting for this cipher. The result can be passed back to this cipher instance or another cipher with the cipherProc restore subcommand.

cipherProc cget -length
Returns the length of the ciphertext for this cipher. 0 is returned if the ciphertext has not been set.

cipherProc cget -period
Return the period for this cipher.

cipherProc cget -stepinterval
Returns the current value of the stepinterval.

cipherProc cget -stepcommand
Returns the name of the procedure currently set for the stepcommand. An empty string is returned if no stepcommand is set.

cipherProc cget -bestfitcommand
Returns the name of the procedure currently set for the bestfitcommand. An empty string is returned if no bestfitcommand is set.

cipherProc cget -language
Returns the name of the language used for this cipher.

cipherProc restore key
The restore command restores the cipher's key to a previously stored state. The output from cipherProc cget -key can be passed back into the restore command to implement a crude save feature. Example:

set key [$firstCipher cget -key]
$secondCipher restore $key

cipherProc substitute row col
undocumented feature

cipherProc undo
Clears all changes that have been made to the ciphertext.

cipherProc solve
Iterate through all combinations of possible keys. The key that produces plaintext with the highest digram frequency count is used as the solution.

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wart@kobold.org
Created on Wed Mar 31 08:18:24 PST 2004
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