RosettaCodeData/Task/Chaocipher/Arc/chaocipher-1.arc

36 lines
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(= lshift '((0 1) (2 14) (1 2) (14 26)))
(= rshift '((1 3) (4 15) (3 4) (15 26) (0 1)))
(= rot (fn (alpha shift)
(let shift (mod shift 26)
(string (cut alpha shift) (cut alpha 0 shift)))))
(= scramble-wheel (fn (alpha moves)
(= oput '())
(up i 0 (- (len moves) 1)
(push (cut alpha ((moves i) 0) ((moves i) 1)) oput))
(= oput (string (rev oput)))))
(= chaocipher (fn (left right msg (o crypted) (o dec?))
(unless crypted
(prn "Encoding " msg " with chaocipher")
(prn left " " right))
(when dec? (swap left right))
(= offset ((positions (msg 0) right) 0))
(= left (rot left offset))
(= right (rot right offset))
(push (cut left 0 1) crypted)
(when dec? (swap left right))
(prn (scramble-wheel left lshift)
" " (scramble-wheel right rshift))
(if (> (len msg) 1)
(chaocipher (scramble-wheel left lshift)
(scramble-wheel right rshift)
(cut msg 1) crypted dec?)
(string (rev crypted)))))
(chaocipher "HXUCZVAMDSLKPEFJRIGTWOBNYQ" "PTLNBQDEOYSFAVZKGJRIHWXUMC"
"WELLDONEISBETTERTHANWELLSAID")
(chaocipher "HXUCZVAMDSLKPEFJRIGTWOBNYQ" "PTLNBQDEOYSFAVZKGJRIHWXUMC"
"OAHQHCNYNXTSZJRRHJBYHQKSOUJY" nil 1)