Chaocipher: Difference between revisions
Added AppleScript.
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The recovered plaintext is : WELLDONEISBETTERTHANWELLSAID
</pre>
=={{header|AppleScript}}==
<lang applescript>-- Chaocipher algorithm by J.F.Byrne 1918.
on chaocipher(input, |key|, mode)
-- input: text to be enciphered or deciphered.
-- |key|: script object or record with leftAlpha and rightAlpha properties, each of whose values is a shuffled alphabet text.
-- mode: the text "encipher" or "decipher".
script o
property inputChars : input's characters
property leftAlpha : |key|'s leftAlpha's characters
property rightAlpha : |key|'s rightAlpha's characters
property inAlpha : leftAlpha
property outAlpha : rightAlpha
property output : {}
end script
set alphaLen to (count o's leftAlpha)
if ((count o's rightAlpha) ≠ alphaLen) then error
if (mode is "encipher") then
set {o's inAlpha, o's outAlpha} to {o's rightAlpha, o's leftAlpha}
else if (mode is not "decipher") then
error
end if
set zenith to 1
set nadir to alphaLen div 2 + 1
repeat with char in o's inputChars
set char to char's contents
set found to false
repeat with i from 1 to alphaLen
if (o's inAlpha's item i = char) then
set end of o's output to o's outAlpha's item i
set found to true
exit repeat
end if
end repeat
if (found) then
rotate(o's leftAlpha, zenith, alphaLen, -(i - zenith))
rotate(o's leftAlpha, zenith + 1, nadir, -1)
rotate(o's rightAlpha, zenith, alphaLen, -i)
rotate(o's rightAlpha, zenith + 2, nadir, -1)
end if
end repeat
return join(o's output, "")
end chaocipher
on rotate(theList, l, r, amount)
set listLength to (count theList)
if (listLength < 2) then return
if (l < 0) then set l to listLength + l + 1
if (r < 0) then set r to listLength + r + 1
if (l > r) then set {l, r} to {r, l}
script o
property lst : theList
property storage : missing value
end script
set rangeLength to r - l + 1
set amount to (rangeLength + rangeLength - amount) mod rangeLength
if (amount is 0) then return
set o's storage to o's lst's items l thru (l + amount - 1)
repeat with i from (l + amount) to r
set o's lst's item (i - amount) to o's lst's item i
end repeat
set j to r - amount
repeat with i from 1 to amount
set o's lst's item (j + i) to o's storage's item i
end repeat
end rotate
on join(lst, delim)
set astid to AppleScript's text item delimiters
set AppleScript's text item delimiters to delim
set txt to lst as text
set AppleScript's text item delimiters to astid
return txt
end join
-- Return a script object containing a couple of randomised alphabets to use as a choacipher key.
on makeKey()
set lAlpha to "ABCDEFGHIJKLMNOPQRSTUVWXYZ"'s characters
copy lAlpha to rAlpha
script |key|
property leftAlpha : join(shuffle(lAlpha, 1, -1), "")
property rightAlpha : join(shuffle(rAlpha, 1, -1), "")
end script
return |key|
end makeKey
-- Fisher-Yates (aka Durstenfeld, aka Knuth) shuffle.
on shuffle(theList, l, r)
set listLength to (count theList)
if (listLength < 2) then return array
if (l < 0) then set l to listLength + l + 1
if (r < 0) then set r to listLength + r + 1
if (l > r) then set {l, r} to {r, l}
script o
property lst : theList
end script
repeat with i from l to (r - 1)
set j to (random number from i to r)
set v to o's lst's item i
set o's lst's item i to o's lst's item j
set o's lst's item j to v
end repeat
return theList
end shuffle
-- Demo using the two-alphabet key from the Rubin paper and another generated at random.
-- Decription must be with the key that was used for the encription.
on demo(originalText)
set key1 to {leftAlpha:"HXUCZVAMDSLKPEFJRIGTWOBNYQ", rightAlpha:"PTLNBQDEOYSFAVZKGJRIHWXUMC"}
set key2 to makeKey()
set enciphered to chaocipher(originalText, key1, "encipher")
set doubleEnciphered to chaocipher(enciphered, key2, "encipher")
set deDoubleEnciphered to chaocipher(doubleEnciphered, key2, "decipher")
set deciphered to chaocipher(deDoubleEnciphered, key1, "decipher")
return join({"Original text = " & originalText, ¬
"Enciphered = " & enciphered, "Double enciphered = " & doubleEnciphered, ¬
"De-double enciphered = " & deDoubleEnciphered, "Deciphered = " & deciphered}, linefeed)
end demo
demo("WELLDONEISBETTERTHANWELLSAID")</lang>
{{output}}
<lang applescript>"Original text = WELLDONEISBETTERTHANWELLSAID
Enciphered = OAHQHCNYNXTSZJRRHJBYHQKSOUJY
Double enciphered = ZJVDGIXNNDNRHAXQUUJZGAFTANHW
De-double enciphered = OAHQHCNYNXTSZJRRHJBYHQKSOUJY
Deciphered = WELLDONEISBETTERTHANWELLSAID"</lang>
=={{header|Arc}}==
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