Bifid cipher: Difference between revisions
Added AppleScript.
(Created Nim solution.) |
(Added AppleScript.) |
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THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY => RASOAQXCYRORXESXADETSWLTNIATEGISBRGBALY => THEINVASIONWILLSTARTONTHEFIRSTOFIANUARY
</pre>
=={{header|AppleScript}}==
<syntaxhighlight lang="applescript">(* The "square" here is only notional, the characters' coordinates being calculated
from their offsets in a linear text key. But a square key is accepted if the
signaller's careless enough to keep or transmit one in this form. *)
on bifidEncipher(message, square)
return transcipher(message, square, 1)
end bifidEncipher
on bifidDecipher(message, square)
return transcipher(message, square, 2)
end bifidDecipher
on transcipher(message, square, code) -- code: 1 = encipher, 2 = decipher.
-- Check and massage the input.
set message to join(message's words, "")
if (message contains ".") then set message to replaceText(".", "", message)
set square to join(join(square, "")'s words, "")
set squarea to (count square)
set sqrt to (squarea ^ 0.5) as integer
if (sqrt * sqrt ≠ squarea) then error "Invalid key."
ignoring case
if ((sqrt < 6) and (message contains "J")) then ¬
set message to replaceText("J", "I", message)
end ignoring
-- Calculate coordinates from the message characters' offsets in the "square" text
-- and either split and recombine them (when enciphering) or not (deciphering).
set list1 to {}
set list2 to {{}, list1}'s item code
set astid to AppleScript's text item delimiters
ignoring case and diacriticals
repeat with chr in message
set AppleScript's text item delimiters to chr
set |offset - 1| to (count square's first text item)
set list1's end to |offset - 1| div sqrt + 1
set list2's end to |offset - 1| mod sqrt + 1
end repeat
end ignoring
set AppleScript's text item delimiters to astid
set coords to {list1 & list2, list1}'s item code
-- Calculate new offsets from the appropriate numbers in the coords list
-- and get the characters offset by those amounts in the "square" text.
set chrs to {}
set nCoords to (count coords)
set indexDifference to {1, nCoords div 2}'s item code
repeat with i from 1 to (nCoords div code) by (3 - code)
set |offset| to ((coords's item i) - 1) * sqrt + (coords's item (i + indexDifference))
set chrs's end to square's character |offset|
end repeat
return join(chrs, "")
end transcipher
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
on replaceText(searchText, replacement, mainText)
set astid to AppleScript's text item delimiters
set AppleScript's text item delimiters to searchText
set textItems to mainText's text items
set AppleScript's text item delimiters to replacement
set mainText to textItems as text
set AppleScript's text item delimiters to astid
return mainText
end replaceText
on task()
set output to {}
repeat with this in {{"Given example:", "ATTACKATDAWN", "ABCDEFGHIKLMNOPQRSTUVWXYZ"}, ¬
{"Wikipedia example:", "FLEEATONCE", {"BGWKZ", "QPNDS", "IOAXE", "FCLUM", "THYVR"}}, ¬
{"A 6 x 6 square allows all 36 letters & digits to be encoded:", ¬
"The invasion will start on the 1st of January", ¬
"THEQUI
9CKBR0
1OWNF8
7XJMP2
3SVLA6
5ZYDG4"}}
set {heading, message, square} to this
set encrypted to bifidEncipher(message, square)
set decrypted to bifidDecipher(encrypted, square)
set output's end to heading
set output's end to message & " --> " & encrypted & " --> " & decrypted
end repeat
return join(output, linefeed)
end task
task()</syntaxhighlight>
{{output}}
<syntaxhighlight lang="applescript">"Given example:
ATTACKATDAWN --> DQBDAXDQPDQH --> ATTACKATDAWN
Wikipedia example:
FLEEATONCE --> UAEOLWRINS --> FLEEATONCE
A 6 x 6 square allows all 36 letters & digits to be encoded:
The invasion will start on the 1st of January --> TTFAEWUAU9WTE3WP1S5KDF0B8M9AH7KHHVLAV --> THEINVASIONWILLSTARTONTHE1STOFJANUARY"</syntaxhighlight>
=={{header|J}}==
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